Category Archives: News and Announcements

By/par Stéphanie Côté
(Cassiopeia – Autumn/Automne 2015)

La version française suit

New Batch of Accepted Large and Long Programs in 2015

The results of the Large and Long Programs 2015 selection are out, and there are 5 new Programs that were accepted this year. All of them have US PIs, with a total of 8 Canadian Co-Is who are participating in three of the projects. Zachary Draper (PhD student at University of Victoria), Samantha Lawler (University of Victoria), Brenda Matthews (NRC Herzberg), Sebastian Bruzzone (PhD student at University of Western Ontario), Stan Metchev (University of Western Ontario), and Max Millar-Blanchaer (PhD student at University of Toronto) will be working on “Characterizing Dusty Debris in Exoplanetary Systems” led by Christine Chen (STScI). Chris Willott (NRC Herzberg) will be working with Yue Shen (Carnegie) on “A GNIRS Near-IR Spectroscopic Survey of z>5.7 Quasars”, and Craig Heinke (University of Alberta) will be working with Robert Hynes (Louisiana State University) on “Dynamical Masses of Black Holes and Neutron Stars from the Galactic Bulge Survey” using GMOS-S.

The two other accepted Large Programs for 2015 are led by Ian Crossfield (U of Arizona) “Validating K2’s Habitable and Rocky Planets with AO Imaging” and Catherine Huitson (University of Colorado) “The First Survey Dedicated to the Detection and Characterization of Clouds in Exoplanet Atmospheres”.

First GRACES Science Data Publically Available

A small set of science targets were observed with GRACES during its commissioning ahead of the 2015B semester. The targets were selected by the STAC and include a QSO, nuclei of nearby galaxies, a planetary nebula, some alpha-element rich stars, and a solar twin star, as well as spectrophotometric standards. The data both raw and reduced (via the Opera pipeline) are available publically here. The data are superb and GRACES throughput is even better than anticipated. Figure 1 shows a comparison with the performance of other high-resolution spectrographs on 8-10 meters telescopes and GRACES clearly outperforms them in the red starting at about 600 nm. GRACES was developed at NRC Herzberg in collaboration with FiberTech Optica (from Kitchener, ON), and the help of Gemini and CFHT staff. Another great success story for Canadian innovative technology!

Figure 1 – This shows the measured S/N obtained after a 1 hour observation of the star Feige 66 with GRACES (2 fiber mode, in black), compared to HIRES/Keck (in green) and UVES/VLT (in blue). In the red starting at about 600nm GRACES clearly outperforms them.

Fast Turnaround Proposals: deadline every end of the month

This is a reminder that the Fast Turnaround Program is continuing on Gemini-North all through the year, and that there is a deadline for proposals at the end of every month. Accepted programs will be active a month later and for a total of 3 months. Already many Canadian programs have been accepted and observed. The next deadline is on September 30th (even though there is also a regular Call for Proposals for PI time). Note that GRACES is offered for this September FT call, as well as all other facility instruments in the North.

Users might be under the impression that the FT program should be used exclusively for observations that need to be carried out promptly. This is not at all the case. FT proposals can be aimed at following up unusual or unexpected astronomical events but also for pilot studies, or short self-contained projects, or speculative and risky short observations, or for the completion of a thesis when only a few short extra observations are needed or for the completion of an existing dataset to allow publication, or any other kind of short project.

The latest news is that the Board has just approved for FT proposals to be accepted for Gemini-South as well. The first call for proposals including Gemini South will probably be for the end of October deadline. The plan is that proposals for both telescopes will go into a single pool with time allocated according to merit rather than enforcing a strict 50:50 North:South division.

Please sign up to the Fast Turnaround mailing list by sending a message to gemini-FT-reminders+subscribe@gemini.edu (similarly, you can unsubscribe using gemini-FT-reminders+unsubscribe@gemini.edu). The mailing list will be used to send monthly deadline reminders and news about changes to the program that may affect or interest users.

Lots of Good Stuff in the Gemini Data Reductions User Forum

This Forum is a place for trading ideas, scripts and best practices, and taking part in discussions with other users of data reduction processes and strategies. If you have a general question about strategies or approaches to reduction of particular types of data, try the Forum to find help. And if you have written a script, procedure, or have tips for other users you are very welcome to share them on the Forum. Since its creation last year it is now getting populated with a lot of interesting information, for example you can find a GMOS IFU reduction cookbook and reduction scripts, a GMOS longslit reduction scripts including a Nod&Shuffle tutorial, a new NIFS Python data reduction pipeline, as well as scripts for GNIRS and Flamingos2 reductions. Check it out at DR Forum.

Note also that there is a short new tutorial on “Installing Ureka and PyRAF 101” written by Kathleen Labrie available here.

Recent Canadian Press Releases

• The discovery of a young Jupiter-like exoplanet named 51 Eri b was announced by the GPI Campaign team. This is the first exoplanet discovered as part of the GPI Exoplanet Survey (GPIES), a survey of over 600 nearby stars to be carried out over the next three years. This new planet is about twice the mass of Jupiter and orbits a young star just 20 million years old. In addition to being what is likely the lowest-mass planet ever imaged, it is also the first one for which large amounts of methane have been directly detected in the atmosphere. This makes it very similar to the gas giant planets in our own Solar System, which have heavy methane dominated atmospheres. Thus 51 Eridani b gives us a glimpse of how Jupiter was when our solar system was young. GPIES is led by B.MacIntosh (Standford) and includes many Canadians: C.Marois, B.Matthews, L.Saddlemeyer (NRC Herzberg), Z.Draper, B.Gerard, M.Johnson-Groh (U of Victoria), J.Rameau, E.Artigau, R.Doyon, D.Lafreniere (U de Montréal), S.Bruzzone, S.Metchev (U of Western Ontario), J.Chilcote, J.Maire (Dunlap Institute), and M.Millar-Blanchaer (U of Toronto). You can view the full press release here.
  
  

  Figure 2 – GPI image of 51 Eri b. The bright central star has been mostly removed by a hardware and software mask to enable the detection of the exoplanet one million times fainter. Credits: J. Rameau (UdeM) and C. Marois (NRC Herzberg)

• A joint press release between University of Toronto and Gemini was released on September 16th 2015, presenting an updated orbit for beta Pic b based on new astrometric measurements taken in GPI’s spectroscopic mode spanning 14 months. The series of images captured between November 2013 to April 2015 shows the exoplanet β Pic b as it moves through 1 ½ years of its 22-year orbital period. Not only these are the most accurate measurements of the planet’s position ever made, but the data also enable to study the dynamical interactions of the exoplanet β Pic b and the surrounding debris disk. The orbital fit also constrains the stellar mass of Beta Pic, to 1.60\pm0.05 solar masses. The study was led by M.Millar-Blanchaer (U of Toronto), with the help of D-S.Moon (U of Toronto), J.Chilcote, J.Maire (Dunlap Institute), Z.Draper (U of Victoria), J.Dunn, C.Marois, L.Saddlemeyer (NRC Herzberg). To see the full press release and animation click here.

Nouveaux Programmes Longs et Larges accceptés pour 2015

Les résultats de la sélection des Longs et Larges programmes de 2015 sont sortis, et il y a 5 nouveaux programmes qui ont été acceptés cette année. Ils ont tous un PI américain, avec un total de 8 Canadian qui collaborent à trois des projets. Zachary Draper (étudiant PhD à l’Université de Victoria), Samantha Lawler (Université de Victoria), Brenda Matthews (NRC Herzberg), Sebastian Bruzzone (étudiant PhD à l’Université de Western Ontario), Stan Metchev (Université Western Ontario), et Max Millar-Blanchaer (étudiant PhD à l’Université de Toronto) travailleront sur ” Characterizing Dusty Debris in Exoplanetary Systems ” dirigé par Christine Chen (STScI). Chris Willott (NRC Herzberg) quant à lui travaillera avec Yue Shen (Carnegie) sur “A GNIRS Near-IR Spectroscopic Survey of z>5.7 Quasars “, et Craig Heinke (Université de l’Alberta) travaillera avec Robert Hynes (Louisiana State University) sur les « Dynamical Masses of Black Holes and Neutron Stars from the Galactic Bulge Survey” à l`aide de GMOS-S.

Les deux autres grands programmes acceptés pour 2015 sont dirigés par Ian Crossfield (U de l’Arizona) “Validating K2’s Habitable and Rocky Planets with AO Imaging” et Catherine Huitson (Université du Colorado) « The First Survey Dedicated to the Detection and Characterization of Clouds in Exoplanet Atmospheres “.

Premières Données Scientifiques de GRACES Maintenant Disponibles Publiquement

Quelques cibles scientifiques ont pu être observées avec GRACES lors de sa mise en service pour le semestre 2015B. Les cibles avaient été choisies par le STAC et comprennent un QSO, des noyaux de galaxies proches, une nébuleuse planétaire, certaines étoiles riches en alpha-éléments, et une étoile similaire au Soleil, ainsi que des étoiles standardes de spectrophotométrie. Les données à la fois brutes et réduites (via le pipeline Opera) sont disponibles publiquement ici. Les données sont superbes et le throughput de GRACES est encore mieux que prévu. La figure 1 montre une comparaison avec les performances des autres spectrographes à haute résolution sur des télescopes de 8-10 mètres, et GRACES les surpasse largement dans le rouge à partir d’environ 600 nm. GRACES a été développé au CNRC Herzberg en collaboration avec FiberTech Optica (de Kitchener, ON), et avec l’aide du personnel Gemini et TCFH. Encore une grande réussite pour la technologie innovatrice canadienne!

Figure 1 – Signal-sur-bruit mesuré après 1 heure d`observation de l’étoile Feige 66 avec GRACES (en mode 2-fibres, en noir), par rapport à HIRES / Keck (en vert) et UVES / VLT (en bleu). Dans le rouge à partir d`environ 600 nm GRACES les surpasse largement.

Demandes `Fast Turnaround`: date limite toujours à la fin du mois

Ceci est un rappel que le programme `Fast Turnaround` se poursuit à Gemini-Nord tout au long de l’année, et que la date limite pour les demandes est à la fin de chaque mois. Les programmes acceptés seront actifs un mois plus tard et pour un total de 3 mois. Déjà de nombreux programmes canadiens ont été acceptés et observés. La prochaine date limite est le 30 Septembre (même s`il y a aussi un appel de demandes régulier). Notez que GRACES est offert pour cet appel Fast Turnaround de Septembre, ainsi que tous les autres instruments Gemini du Nord.

Les utilisateurs ont peut-être l’impression que le programme FT doit être utilisé exclusivement pour les observations qui doivent être effectuées rapidement. Cela n`est pas du tout le cas. Les demandes FT peuvent viser des événements astronomiques inhabituels ou inattendus, mais peuvent aussi être pour des études pilotes ou des projets autonomes courts, ou des observations courtes spéculatives et risquées, ou pour la finition d’une thèse où seules quelques observations supplémentaires courtes sont nécessaires, ou pour l`achèvement d’un ensemble de données existant pour en permettre la publication, ou pour tout autre type de projet court.

Aux dernières nouvelles le Conseil de direction vient d’approuver que le programme FT soit ouvert à Gemini-Sud aussi. Le premier appel de demandes qui comprendra Gemini-Sud sera probablement pour la fin d`Octobre. Le plan est que les demandes pour les deux télescopes iront dans un seul pool et le temps sera alloué selon le mérite plutôt que selon une application d’une stricte division 50:50 pour le Nord et le Sud.

S’il vous plaît veuillez vous inscrire à la liste de courriels pour le programme FT en envoyant un message à gemini-FT-reminders+subscribe@gemini.edu (de même, vous pouvez vous désinscrire en utilisant gemini-FT-reminders+unsubscribe@gemini.edu). Cette liste sera utilisée pour envoyer des rappels des dates limites mensuelles et des nouvelles sur des changements au programme qui pourraient intéresser les utilisateurs.

Beaucoup de Bonnes Choses dans le Forum de Réductions de Données Gemini

Ce forum est un lieu d’échanges d’idées, de scripts et des meilleures pratiques, et pour prendre part à des discussions avec d’autres utilisateurs sur les processus et stratégies de réduction de données. Si vous avez une question générale sur les stratégies pour la réduction de certains types de données, visitez le Forum pour trouver de l’aide. Et si vous avez écrit un script, une procédure ou avez des conseils pour les autres utilisateurs alors vous êtes les bienvenus pour les partager sur le Forum. Depuis sa création l’an dernier, il s`est maintenant peuplé de beaucoup d’informations intéressantes, par exemple vous pouvez trouver un cookbook de réductions pour GMOS-IFU et des scripts de réduction, des scripts de réduction pour GMOS en longue-fente qui comprend un tutoriel pour le mode Nod&Shuffle, un nouveau pipeline Python pour la réduction de données NIFS, ainsi que des scripts de réduction pour GNIRS et Flamingos2.
Visitez-le à: DR Forum.

Notez également qu’il y a un nouveau court tutoriel sur «Installation Ureka et PyRAF 101″ écrit par Kathleen Labrie ici.

Communiqués de Presse Canadiens Récents

• La découverte d’une jeune exoplanète semblable à Jupiter nommé 51 Eri b a été annoncé par l’équipe de la campagne GPI. Ceci est la première exoplanète découverte dans le cadre du Sondage d`Exoplanètes GPI (GPIES), une étude de plus de 600 étoiles proches qui s`effectuera au cours des trois prochaines années. Cette nouvelle planète a environ deux fois la masse de Jupiter et tourne autour d’une jeune étoile de seulement 20 millions d’années. En plus d’être probablement la planète de plus faible masse jamais imagée, elle est également la première pour laquelle de grandes quantités de méthane ont été détectées directement dans son atmosphère. Cela la rend très semblable aux planètes géantes gazeuses de notre système solaire, qui ont des atmosphères lourdement dominées par le méthane. Ainsi 51 Eridani b nous donne un aperçu de ce que Jupiter avait l`air quand notre système solaire était jeune. GPIES est dirigé par B.MacIntosh (Standford) et comprend de nombreux Canadiens: C.Marois, B.Matthews, L.Saddlemeyer (Herzberg), Z.Draper, B.Gerard, M.Johnson-Groh (U de Victoria), J.Rameau, E.Artigau, R.Doyon, D.Lafreniere (U de Montréal), S.Bruzzone, S.Metchev (U of Western Ontario), J.Chilcote, J.Maire (Dunlap Institut), et M. Millar-Blanchaer (U de Toronto). Vous pouvez consulter le communiqué de presse au complet ici.
  
  

  Figure 2 – Image de GPI de 51 Eri b. L’étoile centrale lumineuse a été principalement éliminé par le coronagraphe ainsi que d`autres masques dans les logiciels pour permettre la détection de l’exoplanète un million de fois plus faible. Crédits: J. Rameau (UdeM) et C. Marois (CNRC Herzberg).

• Un communiqué de presse conjoint de l’Université de Toronto et Gemini a été lançé le 16 Septembre 2015, présentant une mise à jour plus précise de l`orbite de l`exoplanète bêta Pic b basée sur de nouvelles mesures astrométriques prises dans le mode spectroscopique de GPI sur une échelle de temps de 14 mois. La série d’images captées entre Novembre 2013 et Avril 2015 montre l’exoplanète β Pic b se déplaçant sur 1 an et demi de sa période orbitale de 22 ans. Non seulement ce sont les mesures les plus précises jamais obtenues de la position de la planète, mais les données permettent également d’étudier les interactions dynamiques de l’exoplanète β Pic b et le disque de débris entourant l`étoile. Les nouvelles mesures de l`orbite permettent également de mieux contraindre la masse stellaire de Beta Pic, à 1,60 \ pm0.05 masses solaires. L’étude a été dirigée par M.Millar-Blanchaer (U de Toronto), avec l’aide de D-S.Moon (U de Toronto), J.Chilcote, J.Maire (Institut Dunlap), Z.Draper (U de Victoria), J.Dunn, C.Marois, L.Saddlemeyer (CNRC Herzberg). Pour voir le communiqué de presse et l’animation complète, cliquez ici.

By Jeremy Webb
Thesis defended on July 17, 2015
Department of Physics & Astronomy, McMaster University
Thesis advisors: Alison Sills & Bill Harris (McMaster)

Abstract

Globular clusters are found in the halos of all types of galaxies, and have been shown to play major roles in the formation of stars and galaxies. The purpose of this thesis is to advance our level of understanding of the dynamical evolution of globular clusters through N-body simulations of clusters with a range of circular, eccentric, and inclined orbits. Theoretical studies have historically assumed that globular clusters experience a static tidal field, however the orbits of globular clusters are all non-circular and the tidal field of most galaxies is not symmetric. Understanding how clusters evolve in realistic potentials allows for them to be used to constrain the formation, merger history, and evolution of a host galaxy and even map out the current size, shape, and strength of a galaxy’s gravitational field.

We find that dense and compact clusters evolve as if they are in isolation, despite being subject to a non-static tidal field. For larger clusters, tidal shocks and heating inject energy into the cluster and significantly alter its evolution compared to previous studies. We describe how a non-static field alters the mass loss rate and relaxation time of a cluster, and propose methods for calculating a cluster’s size and orbit.

We then apply our work to clusters in the giant galaxies M87, NGC 1399, and NGC 5128. We consider each cluster population to be a collection of metal poor and metal rich clusters and generate models with a range of orbital distributions. From our models we constrain the orbital anisotropy profile of each galaxy, place constraints on their formation and merger histories, and explore the effects of nearby galaxies on cluster evolution.

By advancing studies of globular cluster evolution to include the effects of a non-static tidal field, we have made an important step towards accurately modelling globular clusters from birth to dissolution. Our work opens the door for globular clusters to be used as tools to study galaxy formation, evolution, and structure. Future studies will explore how galaxy formation and growth via the hierarchical merger of smaller galaxies will affect cluster evolution.

By Rachel Ward
Thesis defended on July 29, 2015
Department of Physics & Astronomy, McMaster University
Thesis advisors: Alison Sills & James Wadsley (McMaster)

Abstract

Recent generations of stars form principally, and possibly exclusively, in giant molecular clouds – large conglomerations of gas and dust primarily composed of molecular hydrogen and concentrated in the arms of spiral galaxies. These clouds are assumed to be gravitationally bound; however, recent observations suggest the presence of a substantial population of unbound clouds in the Milky Way. Using synthetic observations from high-resolution simulations of bound and unbound molecular clouds, we explore whether clouds in this mixed population could match observations of local molecular clouds. We find from the clouds in our sample that a state of virial equilibrium is not required to form stars and match the dynamics and structure of observed clouds, as described by the Larson scaling relations and the probability distribution function (PDF) of the mass surface density. As these clouds evolve, the underlying lognormal shape of the column density PDFs is effectively concealed as the peaks of their distributions shift to surface densities below observational detection thresholds, supporting recent observations which also find little to no evidence for a lognormal distribution in column density PDFs of nearby clouds. We explore these results further in an extragalactic context by simulating molecular clouds formed in a galactic disc, in order to demonstrate the role their environment, particularly the galactic shear, plays on their structure and evolution and on the star formation within them. We find that a substantial population of unbound molecular clouds forms naturally in a galactic disc environment and demonstrate that their presence not only matches galactic and extragalactic observations but also impacts several long-standing issues in star formation.

By Kazimierz Sliwa
Thesis defended on July 27, 2015
Department of Physics & Astronomy, McMaster University
Thesis advisor: Christine Wilson (McMaster)

Abstract

In this thesis, I analyze the physical conditions such as temperature, volume density and column density of the molecular gas in four Luminous Infrared Galaxies (LIRGs): Arp 55, NGC 1614, VV 114 and NGC 2623. LIRGs are systems where two gas-rich galaxies are in the process of merging. The goal of my thesis is to look for trends in the molecular gas properties during the merger process. I use several observations of transitions of carbon monoxide (¹²CO) and its isotopologue ¹³CO from the Submillimeter Array, Combined Array for Research in Millimeter-wave Astronomy and Atacama Large Millimeter/submillimeter Array. The high-resolution observations allow me to analyze the molecular gas at several positions inside a single galaxy. The observations are fitted to models obtained from a radiative transfer code using a Bayesian likelihood method. I find that advanced mergers such as NGC 2623 and VV 114 have warmer (≥ 40 K), less dense (≤ 10³ cm⁻³) molecular gas than early/intermediate stage mergers such as Arp 55 and NGC 1614. I suggest that there are mechanisms such as stellar winds, supernovae and AGN activity that dissipate the molecular gas and thus lower the density and warm the gas as the merger progresses. The molecular gas pressure of the advanced mergers is found to be lower by nearly an order of magnitude when compared to the early/intermediate stage mergers. I also find that the [¹²CO]/[¹³CO] abundance ratio in NGC 1614, VV 114 and NGC 2623 is unusually high (> 100) when compared to the interstellar medium value near the center of the Milky Way (∼ 30). Interestingly, Arp 55 does not conform to this trend with a [¹²CO]/[¹³CO] value of ∼ 30, similar to the Milky Way center. I suggest that nucleosynthesis may play a big role in enhancing the abundance ratio and/or the molecular gas from the outer radii of Arp 55 has not reached the central inner regions to drive the abundance ratio up. Nevertheless, Arp 55 is in an interesting merger stage. Finally, I measured the CO luminosity to molecular gas mass conversion factor, α_CO, across the sample in search of the transition stage from a Galactic-like α_CO to the 4-5 times lower value found in LIRGs. The four sources all have measured α_CO values that are consistent with the LIRG value of 0.8 M⊙ (K km s⁻¹ pc²)⁻¹. I suggest that we look at an even earlier merger stage such as Arp 240 to find the point of transition. With the golden age of submillimeter astronomy upon us, this is just the beginning of furthering our knowledge of the merger process and what happens to the molecular gas, the fuel for all star formation.

Submitted by Daniel Devost
(Cassiopeia – Autumn/Automne 2015)

CFHT has been operating since 1979 and a lot of students have had the opportunity to use the data for their Masters or PhD work. Unfortunately, no official record of thesis work exist for CFHT so at the recommendation of the CFHT Board of Directors, a list was started using all available web resources including tools from various institutions, the Theses Canada portal and ADS.

The current list holds 82 theses that go back to 1993. The theses originate mainly from Canada and France but also from other countries in the world. If you have done Master or PhD thesis work that involves CFHT data and do not see your manuscript listed below, please get in touch with me, devost@cfht.hawaii.edu, so I can add your work to this list.

List of Master and PhD Theses using CFHT data

Malo Lison, 2015, Recherche et caractérisation des étoiles jeunes de faible masse dans le voisinage solaire, UdM, PhD.

Baptista, Brian, 2013, Photodiode radiation hardness, lyman-alpha emitting galaxies and photon detection in liquid argon neutrino detectors, Indiana University, PhD.

Benjamin, Jonathan Remby Embro, 2013, A new approach to photometric redshift contamination, providing critical insight for weak lensing cosmology, UBC. PhD

Chueh-Yi Chou, Richard, 2013, Observational Studies of Interacting Galaxies and the Development of the Wide Integral Field Infrared Spectrograph, 2013, UT, PhD.

de la Chevrotière, Antoine, 2013, Recherche de champs magnétiques chez les étoiles Wolf-Rayet par l’analyse d’observations spectropolarimétriques.

Gandhali, Joshi, 2013, Substructure and Gas Clumping in the Outskirts of Abell 133, University of Waterloo. MsC.

Kezwer, Jason, 2013, The Life Cycle of Stars: Supernovae in Starbursts, UVic, MSc.

Radigan, Jacqueline Marie, 2013, Weather on Substellar Worlds:AStudy of Clouds, Variability and Binarity at the L/T Transition, UT, PhD.

Urquhart, Sheona Anne, 2013, Galaxy evolution in a large sample of X-ray clusters, University of Victoria

Cockcroft, Robert, 2012, Astro-archaeology in the triangulum galaxy: Studying galaxy formation and evolution with the globular clusters and stellar halo in M33, McMaster University

Damjanov, Ivana, 2012, Structural Evolution of Quiescent Galaxies from the Peak of the Cosmic Star Formation Epoch, University of Toronto.

Dong, Xiaoyi, 2012, Detecting AGNs using multi-filter imaging data, York University

Harris, Kathryn, A., 2012, The Cluster and Large Scale Environments of Quasars at z<0.9, University of Central, Lancashire. Kristensen, Lars E., 2012, Observational analysis of the physical conditions in galactic and extragalactic active star forming regions, Observatoire de Paris, PhD. San Roman, Izaskun, 2012, The formation and evolution of M33 as revealed by its star clusters, University of Florida, PhD. Villa, Francesca, 2012, Calibration photométrique de l'imageur MegaCam. Analyse des données SnDICE, Université Pierre et Marie Curie - Paris VI. Arcila Osejo, Liz Maria, 2011, Star-Forming and Passive Galaxies at z N2 in the CFHT Legacy Survey, Saint Mary's University. Bayliss, Matthew B, 2011, Broadband photometry of 105 giant arcs: Redshift distribution constraints and implications for giant arc statistics, University of Chicago Department of Astronomy & Astrophysics. Croll, Bryce, 2011, Near-infrared Characterization of the Atmospheres of Alien Worlds, University of Toronto. Dayal, Pratika, 2011, Cosmic Lighthouses : Unveiling the nature of high-redshift galaxies, International School for Advanced Studies. González Gaitán, Santiago, 2011, Supernova rates, rise-times, and their relations to progenitors, UT, PhD. Gorecki, Alexia, 2011, Cosmologie observationnelle avec le Large Synoptic Survey Telescope, Université de Grenoble, PhD Messias, Hugo, 2011, A multiwavelength study of near- and mid-infrared selected galaxies at high redshift: ERGs, AGN-identification and the contribution from dust, Lisbon University Baumont, Sylvain, 2010, Analyse des spectres VLT pour l'expérience SNLS Qualification de transients cosmologiques, Université Paris-Diderot - Paris VII. Bignamini, Andrea 2010 The Swift-XRT Survey of Groups and Clusters of Galaxies, Università degli studi di Trieste, PhD. Burgress, Andrew S. M., 2010, Exploration de la fonction de faible masse initiale dans les amas jeunes et les régions de formation stellaire, Université de Grenoble. Guillard, Pierre, 2010, H2 MAGIE: H2 as a Major Agent to Galaxy Interaction and Evolution, Institut d’Astrophysique Spatiale, Université Paris-Sud 11, PhD. Huang, Zhiqi, 2010, Probing early and late inflations beyond tilted ΛCDM, UT, PhD. Pfrommer, Thomas, 2010, Mesospheric dynamics and ground-layer optical turbulence studies for the performance of ground-based telescopes, University of British Columbia. Thanjavur, Karunananth G, 2010, Cosmic applications of Gravitational Lens Assisted Spectroscopy (GLAS), University of Victoria. Agra-Amboage Vanessa, 2009, Observations des régions internes des vents autour des étoiles jeunes de type T Tauri, Université Joseph-Fourier - Grenoble I. Anderson, Rachel Elizabeth, 2009, Searching for galaxy groups in photometric data from the CFHT Legacy Survey, McMaster University, MSc. Breton, René Paul, 2009, Radio pulsars in binary systems, McGill University, Canada. Di Cecco, Alessandra, 2009,: Deep and extended Multi-band photometry of the galactic globular cluster M92, University of Rome Tor Vergata. Épinat, Benoit, 2009, From nearby to distant galaxies: kinematical and dynamical studies, Universite de Provence (FRANCE), LAM. Harrington, David, 2009, Stellar spectropolarimetry with HiVIS: Herbig Ae/Be stars, circumstellar environments and optical pumping, University of Hawai'i at Manoa. Jolin, Marc-André, 2009, Étude polarimétrique d’étoiles jeunes, UdM, MSc. Dicaire, Isabelle, 2008, Cinématique haute résolution des galaxies de l'échantillon SINGS et observations du Ha profond de la galaxie NGC 7793, UdM, MSc. Van Grootel, Valérie, 2008, Etude des étoiles de la branche horizontale extrême par l'astérosismologie, UdM, PhD. Albert, Loïc, 2006, La recherche de naines brunes autour d'etoiles du voisinage solaire et le spectrographe multi-objets SIMON, Université de Montréal. Alecian, Evelyne, 2006, Étude de l'évolution de la structure interne et du champ magnétique des étoiles pré-séquence principale de masse intermédiaire, Université Paris-Diderot - Paris VII. Chilingarian, Igor, 2006, Formation and Evolution of Dwarf Elliptical Galaxies, Moscow State University and Université Claude Bernard Lyon-1 Clem, James Lewis, 2006, Galactic star clusters in the u'g'r'i'z' photometric system, University of Victoria. Juramy Claire, 2006, Métrologie des supernovae de type Ia pour la cosmologie: instrumentation et analyse calorimétrique. Université Paris 6. Leyrat, Cédric, 2006, Propriétés physiques des anneaux de Saturne : de CAMIRAS à la mission CASSINI, Université Paris-Diderot - Paris VII Malacrino, Frederic, 2006, Untriggered search for optical counterparts of gamma-ray bursts in images of the Canada-France-Hawaii Telescope "Very Wide Survey", Université Paul Sâbatier - Toulouse III, PhD. Okón, Waldemar M. M., 2006, The metallicity distribution function of globular clusters systems through near-infrared photometry, McMaster University. Ruiter, Ashley J, 2005, Infrared imaging of the sub-millimetre protocluster near NGC 2068 in Orion B, Saint Mary's University. Vaduvescu, Ovidiu 2005 Infrared Properties of Star Forming Dwarf Galaxies, York University, PhD. VanDalfsen, Marcel L., 2005, The globular cluster system of the Sombrero galaxy, McMaster University. Vergnole, Sébastien, 2005, Nouveaux interféromètres large bande pour l'imagerie haute résolution : interféromètre fibré hectométrique ; utilisation des Fibres à Cristaux Photoniques, Université de Limoges. Brodwin, Mark, 2004, The Canada-France deep fields-photometric redshift survey: An investigation of galaxy evolution using photometric redshifts. University of Toronto. Devost, D., 2004, Chronométrie a haute résolution de populations stellaires extragalactiques, Universite Laval. Kalirai, Jasonjot Singh, 2004, Astrophysics with white dwarfs, University of British Columbia. Mercurio, A. 2004 Dynamical Evolution and Galaxy Populations in the Cluster ABCG 209 at z=0.2 AA, Università di Trieste, Napoli, PhD. Shkolnik, E. 2004 Chromospheric Activity Induced by Short-Period Planets: A Search for Modulation of Ca II H & K Emission AA, UBC, PhD. Edwards, Louise, 2003, Molecular hydrogen in the cooling flow cluster Abell 1795, Saint Mary's University. Raux, Julien, 2003, Photométrie différentielle de supernovae de type Ia lointaines, Université Paris Sud - Paris XI. Woillez, Julien, 2003, Les Noyaux Actifs de Galaxies en interférométrie optique à très longue base - Projet 'OHANA, Observatoire de Paris, Université Paris XI, PhD. Mirioni, Laurent, 2002, Sources X Ultra-Lumineuses : Contreparties Optiques, Université Louis Pasteur - Strasbourg I Hamilton, Devon, 2001, Observational signatures of convection in solar type stars, University of Toronto. Lépine, Sébastien, 2001, Structure inhomogène et dynamique des vents stellaires chauds par spectroscopie de raies d'émission, Université de Montréal, PhD. Mullis, Christopher Robinson 2001 The ROSAT north ecliptic pole survey AA, University of Hawaii, PhD. Perrett, Kathryn, 2001, The globular cluster system of M31, Queen's University, PhD. Steinbring, Eric, 2001, Techniques in high resolution observations from the ground and space, and imaging of the merging environments of radio galaxies at redshift 1 to 4, University of Victoria. Font, Andreea Simona, 2000, Shocked molecular gas in three supernova remnants: W28, W44, 3C391, Saint Mary's University. Grosdidier, Yves, 2000, Le phénomène Wolf-Rayet au sein des étoiles chaudes de populations I et II, Université de Montréal. Hebrard, Guillaume, 2000, L'abondance du deutérium, de l'ultraviolet au visible, Université Paris-Diderot - Paris VII, PhD. Mallen-Ornelas, Gabriela, 2000, Internal kinematics of CFRS galaxies at z 0.6, University of Toronto. Billières, Malvina, 1999, Observations et Astéroséismologie de sous-naines de type B: une nouvelle classe d'étoiles pulsantes. Université de Montréal. Chapman, Scott Christopher, 1999, The nature of active galaxies, The University of British Columbia. Holland, Stephen, 1998, The globular clusters an halo of M31, University of British Columbia. Kavelaars, J. J., 1998, Globular clusters as dynamical probes of the S0 galaxy NGC 3115, Queen's University. Kroeker, Teresa Lynn, 1998, Evolution of elliptical galaxies, University of Toronto. Simard, Luc, 1998, The internal kinematics of intermediate redshift galaxies, University of Victoria, PhD Blake, R. Melvin, 1997, Photometric decomposition of NGC 6166, Saint Mary's University, MSc. De Propris, Roberto, 1996, The faint end of the luminosity function in clusters of galaxies, University of Victoria. Cederbloom, Steven E., 1995, Stellar Populations in the Core of the Globular Star Cluster M15, Indiana University, PhD. Langill, Philip Patrick, 1994, The circumstellar dust shells of proto-planetary nebulae, University of Calgary. Freedman, Wendy Laurel, 1994, The Young Stellar Content of Nearby Resolved Galaxies, UT, PhD. Tessier, Eric, 1993, Application of infrared two-dimensional speckle interferometry to the study of the young stars, Laboratoire d'Astrophysique de l'Observatoire de Grenoble, Université Joseph Fourier / CNRS, Grenoble, France, and Département de Recherche Spatiale, Observatoire de Meudon, France, PhD.

Submitted by Mark Halpern and Mateus Fandino
(Cassiopeia – Autumn/Automne 2015)

Construction of the structure for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope was completed in August 2015 and the receiver electronics and custom correlator will be built and installed on site over the coming winter. At 8,000 m², CHIME is now the largest telescope in continental North America with 2% more collecting area than the Green Bank telescope.

CHIME is a new radio interferometer located at the Dominion Radio Astrophysical Observatory (DRAO). It will map the 21 cm emission of neutral Hydrogen from redshifts 0.8 to 2.5 culminating in the largest-volume survey of the distribution of matter in the Universe ever made. This redshift range encompasses the critical period when Dark Energy becomes comparable to the energy density of matter and drives the late accelerated expansion of the Universe. The survey will allow the team to measure the expansion rate of the Universe through this critical epoch, thus helping to constrain the Dark Energy equation of state.

CHIME Cosmology

To map the history of the expansion rate of the Universe, the experiment will measure the relic of Baryon Acoustic Oscillations (BAO), spherical shells of matter over-density in which galaxies and gas are more likely to be found today. The radius of these shells was established by conditions in the early Universe (up to ~400,000 years after the Big Bang), and remains constant in co-moving coordinates afterwards. What this means is that, for the past 13 billion years, this characteristic distance scale evolved solely due to the expansion of the Universe, and hence provides a standard ruler to measure the expansion rate.

The BAO scale has been measured before using galaxy surveys to map the distribution of matter. This is a long and difficult process that requires resolving each individual galaxy and has a limited redshift range. CHIME will map the distribution of matter using the 21 cm emission of intergalactic hydrogen at a resolution much lower than that of individual galaxies, but high enough to measure the BAO scale (~150 Mpc today). This technique, known as Hydrogen Intensity (HI) Mapping, is much faster and will allow for a much larger survey volume than has ever been observed. It avoids reliance on the non-linear physics of galaxy formation since galaxies are not resolved and counted, and is well suited to measuring structure on large physical scales.

Ancillary Science

In addition to measuring the expansion rate of the Universe, the design and operation of CHIME make it well suited to pursue a variety of very important ancillary science objectives. The instrument will produce an independent map of the intensity and polarization of the Milky Way visible from the northern hemisphere every half MHz across the CHIME band. CHIME can time the pulse arrival times for a very large number of known pulsars, which pass through the beam every day, and a program is under way to perform these measurements with the CHIME Pathfinder. The full CHIME telescope will be a powerful instrument to detect Fast Radio Bursts and a separate back-end processor to perform the high-cadence de-dispersion this requires has been funded by the CFI. CHIME will act as a scientific and technical pathfinder for the SKA, pioneering the measurement of very low-surface brightness phenomena and developing key correlator hardware.

The CHIME Instrument

CHIME is a radio interferometer composed of four parabolic cylinders, 100 m long and 20 m wide each, oriented in the North-South direction. The focal line will be populated by dual polarization feeds whose main beams resemble thin cigar-shaped stripes ~100° long by ~2° wide. It has no moving parts and scans half the sky every day as the Earth rotates. Frequency and spatial North-South resolution are achieved by Fourier-transforming and correlating the signals from all feeds. The instrument operates over the frequency band from 400 to 800 MHz, corresponding to a redshift of 2.5 to 0.8 for 21 cm radiation. The signals are brought to a custom FX correlator, which performs a Fourier transform in time/frequency with 500 kHz resolution and then at each frequency performs a spatial correlation.

Figure 1 – The telescope structure for CHIME. The telescope consists of four parabolic cylinders 20 m wide and 100 m long with a focal length of 5 m. 256 dual-polarization antennas will be placed along the focal line of each cylinder and the signals are brought to a custom 2048-input correlator. The instrument has no moving parts.

Figure 2 – The CHIME telescope structure under construction in July 2015. The fourth cylinder (on the left) was being assembled. The full structure is now completed and the receiver electronics and custom correlator will be built and installed on site over the coming winter.

The CHIME Pathfinder

The CHIME Pathfinder is a smaller-scale prototype of full CHIME that has informed its design, will shape the analysis strategy and will produce sensitive maps of neutral hydrogen and of the Galaxy. The Pathfinder is composed of two cylinders 37 m long by 20 m wide whose focal lines are populated with 64 dual-polarization feeds each, totalling 256 analog signal channels.

The analog signal chain is composed of low-noise amplifiers and anti-aliasing filters made affordable by the use of components developed for the cell phone industry. After digitization, the 256 channels are Fourier-transformed and correlated by a purpose-built hybrid FPGA/GPU FX correlator based on consumer-grade GPUs and custom optimized data handling and processing software. With 32,896 baselines and 400 MHz bandwidth, the Pathfinder correlator is amongst the largest in the World and is already fully operational. It has a larger signal throughput than all North American telephone conversations combined.

Status

Construction of the structure of the full instrument was completed in August and its many analog and digital components are being finalized. Meanwhile, the Pathfinder is now fully assembled and its first stable science run will happen during the winter, initiating a period of signal integration necessary to extract the 21 cm signal.

CHIME is a collaboration between the University of British Columbia, the University of Toronto, McGill University and the Dominion Radio Astrophysical Observatory.

To learn more please see:

• Half-Pipe telescope will probe dark energy in the Universe Nature news article, August 2015
• Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder K. Bandura et al., 2014
• Calibrating CHIME: a new radio interferometer to probe dark energy L. Newburgh et al., 2014
• Coaxing cosmic 21 cm fluctuations from the polarized sky using m-mode analysis R. J. Shaw et al., 2014
• A Radio-Frequency-over-Fiber link for large-array radio astronomy applications J. Mena et al., 2013
• GPU Kernels for High-Speed 4-Bit Astrophysical Data Processing P. Klages et al., 2015
• A GPU-based Correlator X-engine Implemented on the CHIME N. Denman et al., 2015
• An Efficient Real-time Data Pipeline for the CHIME Pathfinder Radio Telescope X-Engine A. Recnik et al., 2015
• A compression scheme for radio data in high performance computing K. Masui et al., 2015

Submitted by Bryan Gaensler, Canadian SKA Science Director
(Cassiopeia – Autumn/Automne 2015)

Updates on the Square Kilometre Array (SKA) will now appear regularly in Cassiopeia. For more frequent and more detailed info, please subscribe to the Canadian SKA email list, at SKA email list.

International SKA Activities

The rebaselining process for the SKA has now concluded. The outcome is that the first 10% of the SKA (“SKA1”) will now consist of two components: SKA1-Mid in South Africa (0.35-14 GHz), and SKA1-Low in Australia (50-350 MHz), each of which will have spectacular scientific capabilities in its own right. Construction on SKA1 is planned to commence in 2018, with science operations to begin in 2023.

Canada is one of 10 member countries of the SKA Organisation, and is represented on the SKA Board of Directors by Greg Fahlman (NRC) and Bryan Gaensler (U. Toronto). The Board most recently met in March 2015 (Jodrell Bank) and July 2015 (Cape Town), with the year’s final meeting scheduled for November 2015 (Jodrell Bank). The SKA member organisations held a separate meeting in April 2015, at which they voted to site the permanent headquarters of the SKA at Jodrell Bank.

For further information, see the latest SKA Newsletter at SKA Newsletter and the monthly SKA Organisation Bulletin at SKAO Bulletin.

“Canada and the SKA” Workshop, Toronto, Dec 10-11, 2015

Canada is an active participant in both SKA technology development and SKA science programs, as described in detail below. This meeting will be an opportunity for the Canadian community to assess its main interests and activities for the SKA and its pathfinders, and to identify areas for synergy and coordination. For more details and to register, visit SKA Workshop.

The Murchison Widefield Array (MWA) will be holding its annual project meeting in Toronto immediately preceding the SKA workshop, over Dec 7-9, 2015. Canada is in discussions with the MWA Board about joining the MWA project and participating in the MWA upgrade path. The Canadian astronomy community is invited to to learn about the MWA and its capabilities, and to identify future areas for participation and collaboration. See MWA Meeting for more information.

SKA Engineering Meeting, Penticton, Nov 9-13, 2015

For the last number of years the SKA Project has held a week long all-hands engineering meeting at one of the member countries: 2013 was in Manchester, 2014 was in Fremantle, and 2015 is in Penticton! See SKA Engineering Meeting for more information.

SKA Science

The SKA science case went through a complete update in 2014, and has now been published in two large volumes. The entire science case (around 2000 pages) or individual chapters can be downloaded from SKA Books.

SKA science activities are advanced through several science working groups, as listed at SKA Working Groups. Anyone interested in joining a SKA science working group should contact Bryan Gaensler (bgaensler@dunlap.utoronto.ca). New ideas and new faces are very welcome!

The first SKA Key Science Workshop was held in Stockholm over August 24-27, 2015. Seven members of the Canadian astronomy community attended, covering expertise in five science working groups. Summaries of the resulting activities are as follows:

• Tim Robishaw (NRC), Jeroen Stil (U. Calgary) and Bryan Gaensler (U. Toronto) participated in the “Magnetism” science working group, which seeks to reveal the evolution of magnetic fields over cosmic time via sensitive broadband polarisation surveys of the sky. Significant progress was made in two key areas during the Stockholm meeting. First, the magnetism group was able to distil a wide range of competing ideas into two core thrusts: “Origin and Evolution of Magnetic Fields in Large Scale Structures”, focused on studying the polaristion of the diffuse Universe including clusters, filaments and the intergalactic medium, and “Origin and Evolution of Magnetic fields in Galaxies”, targeting magnetism in compact individual sources such as galaxies and AGN. Second, the Stockholm meeting proved to be a superb opportunity to hold discussions with other working groups on commensality. Most groups have needs for large surveys, requiring in excess of 10,000 hours each. Since scheduling all this observing time is impractical, there is a crucial need to identify similar observing programs that can be conducted simultaneously. The magnetism group has a need for two separate wide-field surveys with SKA1-Mid, in both bands 1 and 2. We were able to identify numerous areas of commenality with the Continuum, HI, Our Galaxy and Cosmology working groups, suggesting that it may indeed be feasible to meet the ambitious science goals of all parties.
• Doug Johnstone (NRC) represented Canadian interests in both the “Cradle of Life” and “Our Galaxy” working groups. The Cradle of Life key science focuses on dust evolution in protostellar disks, an investigation into prebiotic materials around forming stars, and searches for extraterrestrial intelligence. The Our Galaxy group is newly estabished, and is so far focusing on key science interests around formaldehyde absorption (as a measure of dense molecular gas), radio stars, and the HI galaxy. Both groups spent much time discussing possible commensality with other teams. In particular, the Our Galaxy group began more detailed discussions with the Magnetism working group on the overlap science of Galactic Magnetism, an area of Canadian strength.
• During the workshop, two major projects were highlighted by the Our Galaxy science working group: a moderately deep Galactic midplane survey (largely aimed at spectral lines) and a shallower but much wider Galactic plane plus bulge survey (the latter championed by G. Sivakoff). Both of these would provide unmatched sensitivity at high spatial resolutions and be done at sufficiently high radio frequencies (5 GHz and above) that would detect both non-thermal and thermal sources. There also appeared to be a consensus across multiple working groups for a deep Galactic Centre project, also at the same radio frequencies. These projects have great synergy with Canadian interests and expertise, especially given past plane surveys led by our community.
• Gregory Sivakoff (U. Alberta) and Michael Rupen (NRC) participated in the “Transients” working group, of which Rupen is co-chair. The transients group is focused on the study of variable sources on time scales from milliseconds to decades, encompassing sources as varied as exoplanets, accreting binary stars, supernovae, and tidal disruption and gravitational wave events. The group currently is working to ensure that the basic design and policies of the SKA make variable astronomy as accessible and as productive as possible, in areas ranging from commensal observations to cadenced scheduling to data access. We are also discussing the most important large-scale science which should be done with the SKA in the first few years of operations, with current candidates including searches for fast radio bursts, a wide-ranging program on explosive accretion-powered events, and a survey of the variable radio sky.
• Kristine Spekkens (RMC) participated in the HI working group. The HI group had a productive set of meetings during the Key Science Workshop. The meeting participants began the process of developing key science projects that would attain the highest-priority SKA1 science objectives for this field: resolving the HI distributions in galaxies out to redshifts as high as z~0.8, high spatial resolution studies of the interstellar medium in the local universe, and multi-resolution mapping of the interstellar medium in our own Galaxy. While survey definition work has just begun, it seems clear that a tiered blind HI survey using Bands 1 and 2 on SKA1-Mid, as well as targeted deep surveys of ~30 nearby galaxies and a shallower wide-field survey using Band 2 of SKA1-mid, will be the key observational components for achieving those science goals. Initial discussions with participants from other SWGs suggests that there is a strong potential for commensality with these surveys, allowing multiple science goals to be reached with the same set of observations. Commensal observing with additional surveys outlined by various SWGs could also afford exciting ancillary HI science, such as a search for HI absorbers out to high redshift. SKA1 is therefore poised to deliver transformation HI science through a variety of surveys.

SKA Technology Development

The Central Signal Processing (CSP) Consortium has completed a complicated downselection process, the outcome of which is that CSIRO will lead the SKA1-Low correlator/beamformer, while NRC Herzberg will lead the SKA1-Mid correlator/beamformer. Both of these are based on FPGA platforms. NRC Herzberg remains the CSP Consortium lead. NRC Herzberg is moving forward strongly on the powerMX FPGA platform (code-named Talon) for the SKA1-Mid correlator/beamformer, with prototyping activities well underway.

Within the Dish Consortium, the recommendation proposed for the downselect on the dish structure was to use the NRC Herzberg rim-supported composite reflectors. However, this recommendation fell short of the 2/3 assent required by the Dish Board, and a new panelised metal reflector design from Germany and China will be allowed to compete against the NRC Herzberg design. A final downselect is mandated by the SKA Office for Nov 2015. NRC Herzberg is working with Canadian industry partners to prepare a strong submission. The Dish Verification Antenna, “DVA1”, is continuing testing at DRAO, led by Lewis Knee and Tim Robishaw. Outstanding results have already been achieved using a prototype MeerKAT L-band feed. These results will form part of the downselect submission in Nov 2015. NRC Herzberg continues to lead the Single Pixel Feed digitiser sub-element, passing preliminary design review and preparing to build prototypes in stage 2. The re-baselining addition of Mid band 5 (4.6-13.8 GHz) has added work requiring higher speed samplers to maintain direct conversion. NRC Herzberg is collaborating with the ALMA high-speed sampler group led by U. Bordeaux, who are developing suitable high speed samplers. We are continuing are work on cryogenic low-noise amplifiers for single pixel feeds bands 1 and 2, and have delivered samples to Onsala and EMSS SA, respectively. These same amplifiers have been chosen for MeerKAT, and we are in full production with our industry partner Nanowave Technologies to deliver MeerKAT bands 1 and 2. We made a conscious choice not to bid for the new band 5 LNAs because of the large number of interested international partners. Our work on phased array feeds (PAFs) is continuing, although the re-baselining decision deleted SKA-Survey and the PAFs from SKA1. We are in discussion with CSIRO and ASTRON to form a new advance instrumentation program (AIP) consortium to continue work on PAFs for SKA. Our L-band PAF was recently equipped with the first room temperature CMOS LNAs from U. Calgary and achieved a hot/cold test system temperature of 20 K. We are working on a full prototype to be tested on DVA1. We are continuing work on our cryogenic PAF and have moved our concept design to band 4 (2.8-5.2 GHz). We will produce a prototype, again for testing on DVA1.

Within the Telescope Manager (TM) Consortium NRC-Herzberg is playing a supporting role to NCRA India to develop standards for the local monitor & control (LMC) software architecture. A standard based on Tango has been developed, and is being ratified for use by all the other consortia.

The SKA’s Science Data Processor (SDP) team is designing the flow of data from the SKA correlator to individual astronomers. A group of Canadian universities and the CADC are working on the SDP design and implementation. The SDP underwent a design review at the beginning of 2015 and the requirements for the SDP are becoming concrete. However, it remains an open question as to whether regional data centres will be used for the SKA. If so, the Canadian team hopes to establish a North American centre in Canada.

ACURA Advisory Council on the SKA

The Association of Canadian Universities for Research in Astronomy (ACURA) coordinates activities and discussion on the SKA through the ACURA Advisory Council on the SKA (AACS). Amongst the goals of AACS are to promote and advance Canadian participation in the SKA project, coordinate participation among universities, NRC, and industry in SKA pre-construction work packages, and to define a role for Canadian scientific participation and leadership in the SKA.

The AACS meets approximately 4-5 times per year. Details and minutes of meetings will be posted on the Canadian SKA WWW site (see below). For further information or to propose AACS agenda items, please contact the AACS Chair, Bryan Gaensler (bgaensler@dunlap.utoronto.ca).

Canada SKA WWW Site

A new Canadian SKA WWW site is currently under development, with the aim to launch this site in time for the Canadian SKA workshop in December 2015 (see item above). The site will be fully bilingual, and will provide detailed information on Canadian SKA activities for the public, for government, for industry, and for the astronomy community.

Submitted by Gregg Wade
(Cassiopeia – Autumn/Automne 2015)

Introduction

BRITE-Constellation (http://www.brite-constellation.at/, where BRITE stands for BRIght Target Explorer) is a network of five nanosatellites operating in low Earth orbit, designed to explore the properties of the brightest stars in the night sky.

Figure 1 – The mission patch of the BRITE-Constellation mission.

The BRITE mission is supported by three countries — Canada, Austria and Poland — where Canadian funding comes mainly from the Canadian Space Agency (CSA) and the prime contractor is the University of Toronto Institute for Aerospace Studies – Spaceflight Laboratory (UTIAS-SFL). The mission was planned to have 6 BRITE nanosats, a pair from each partner country, but one of the Canadian nanosats did not detach from the third stage of its launch vehicle.

Each BRITE nanosat (mass = 7 kg; dimensions 20 × 20 × 20 cm) has a 3-cm optical telescope feeding a CCD detector. The Constellation was designed to monitor photometrically through blue and red filters the brightness and temperature variations of stars generally brighter than V ~ 4 with precision, cadence and time coverage not possible from the ground. Each BRITE instrument has an enormous field-of-view: 24° square, large enough to encompass the entire constellation of Orion (but at a resolution of only about half an arcminute per pixel). That means BRITE-Constellation can collect data on several dozens of stars simultaneously.

The sample of the apparently brightest stars in the night sky is a sample dominated by the most intrinsically luminous stars in the Galaxy: hot massive stars at all evolutionary stages, and evolved intermediate-mass stars at the very end of their nuclear-burning phases. The main goals of BRITE-Constellation are to (1) measure the frequencies of pulsations (both acoustic and gravity modes) to probe the interiors and ages of stars through asteroseismology; (2) measure the rotational modulation of stars due to star spots carried across their disks; (3) search for exoplanets through transits; and (4) obtain light curves of massive eclipsing binaries. While goal (2) is often associated with cool solar-type stars, spots in the photospheres of luminous stars could be the sources of co-rotating interaction regions in the winds, possibly arising from magnetic subsurface convection in hot, massive stars.

Figure 2 – Hertzsprung-Russell diagram of the stars of brightest apparent magnitude, V<4.5. These ∼ 600 stars are the primary BRITE targets.[/caption] To develop the optimum data processing and reduction strategies, a BRITE Photometry Tiger Team (PHOTT) was assembled. PHOTT explored and compared various pipelines and ways to minimise data artifacts. To extract the maximum scientific value from the reduced BRITE photometry, the BRITE Ground-Based Observation Team (GBOT) organizes ground-based observing campaigns, primarily high-resolution, high-S/N spectroscopy of BRITE targets. A detailed overview of the scientific motivation of the mission, and technical aspects of the system, are provided by Weiss et al. (2015, PASP 126, 573; http://arxiv.org/pdf/1406.3778v1.pdf).

Mission Status and Data Releases

Five of the planned six BRITE nanosats are currently operating in low-altitude (600-800 km) orbits. The first pair of BRITE nanosats (from Austria) were launched on 25 Feb 2013, and the Canadian BRITEs were launched in August 2014 aboard a Russian rocket. The sixth satellite currently remains unusable in a higher elliptical orbit due to a malfunction in the release mechanism of the Russian rocket third stage.

[caption id="attachment_6337" align="alignright" width="300"] Figure 3 – The two Canadian BRITE nanosatellites (named “BRITE-Montreal”, blue filter and “BRITE-Toronto”, red filter), at UTIAS-SFL prior to shipment in 2014.

Three data releases to BRITE Target PIs have occurred so far. The first was a set of science commissioning data, including about 5 months of quasi-continuous observation of 15 stars in Orion. The two subsequent releases were 6-month campaigns of fields in Centaurus and Lupus fields (30 stars), and fields in Vela and Puppis (20 stars).

The first BRITE science results have been submitted to refereed journals, including a paper by Weiss et al. on the pulsating magnetic star α Cir. Weiss et al. (A&A, submitted) report two-colour BRITE photometry of this roAp star, excluding quadrupolar modes for the main pulsation frequency, and reporting remarkable differences in the rotationally-moduluation flux in the blue and red bandpasses.

The first BRITE science conference, “Science with BRITE-Constellation: Initial Results” (https://www.camk.edu.pl/konferencje/brite_science/) took place during 14 – 18 September 2015 in Gdansk Sobieszewo, Poland. The results are not available at press time, but over 60 participants have registered, with a full slate of scientific presentations in the program.

Figure 4 – Light curves of the eclipsing binary V Pup, observed as part of the BRITE Vela/Puppis field. Shown here is a 5-day interval of the BRITE-Austria (blue) and BRITE-Toronto (red) observations.

Mission Management and Contact

Executive decisions about the mission are made by the BEST (BRITE Executive Science Team), consisting of representatives from all three partner nations. The Canadian BEST members are Tony Moffat (BEST Chair, Université de Montréal), Jaymie Matthews (BEST vice-Chair, UBC), Slavek Rucinski (University of Toronto), and Gregg Wade (Royal Military College), with Jason Rowe (Université de Montréal) and Stefan Mochnacki (University of Toronto) serving as non-voting BEST members.

Setting priorities on BRITE targets and science goals was overseen by BEST, with input from the BRITE International Science Advisory Team (BIAST), consisting of 130 astronomers around the globe. Interested in joining BIAST, to participate in data analysis, and receive monthly mission updates? Please contact BEST through Tony Moffat (moffat@astro.umontreal.ca).

Weiss, W.W.; Rucinski, S.M.; Moffat, A.F.J.; Schwarzenberg-Czerny, A.; Koudelka, O.F.; Grant, C.C.; Zee, R.E.; Kuschnig, R.; Mochnacki, St.; Matthews, J.M.; Orleanski, P.; Pamyatnykh, A.; Pigulski, A.; Alves, J.; Guedel, M.; Handler, G.; Wade, G.A.; Zwintz, K., 2014, “BRITE-Constellation: Nanosatellites for Precision Photometry of Bright Stars”, PASP 126, 573.

Weiss, W.W.; Frohlich, H.-E.; Pigulski, A.; Popowicz, A.; Huber, D.; Kuschnig, R.; Moffat, A.F.J.; Matthews, J.M.;, Saio, H.; Schwarzenberg-Czerny, A.; Grant, C; Koudelka, O.; Lueftinger, T.; Rucinski, S.; Wade, G.A.; Alves, J.; Guedel, M.; Handler, G.; Mochnacki, S.; Orleanski, P.;, Pablo, B.; Pamyatnykh, A.; Ramiaramanantsoa, T; Rowe, J.; Whittaker, G.; Zawistowski, T.; Zoconska, E.; Zwintz, K., 2015, “The roAp star α Cir seen by BRITE-Constellation”, A&A, submitted.

Submitted by Patrick Hall, MSE Advisory Group member, Pat Cote (NRC), MSE Advisory Group member, Michael Balogh (Waterloo), Canada Contact Scientist on the MSE Science Executive
(Cassiopeia – Autumn/Automne 2015)

Maunakea Spectroscopic Explorer: Update, Mailing List, and Canadian MSE Team

Want to receive E-mail updates on MSE? Sign up for the CDN-MSE mailing list at MSE Forum; you’ll need to confirm your sign-up when you receive a confirmation E-mail (usually within a day). If you experience problems, contact cdnmse@gmail.com.

In early 2014 the CFHT Board of Directors approved funding for an independent Maunakea Spectroscopic Explorer (MSE) Project Office to develop the concept for replacing the current 3.6-meter CFHT into a full construction proposal by late 2017. Since that time, the MSE project has made great progress in its Design Phase.

It has been established that MSE will be a dedicated spectroscopic 11.25-meter telescope (with a 10-meter effective aperture), making it the largest non-ELT telescope in existence. The current MSE design calls for:

• A 1.5 square degree field of view, for an etendue of 117 m² deg²
• 3468 fibers feeding low-resolution (R~3,000) spectrographs covering 0.37 to 1.26 microns at least (possibly out to 1.8 microns)
• A moderate-resolution (R~6000) mode with wavelength coverage still to be defined
• 1156 fibers feeding high-resolution (R~40,000) spectrographs.

The MSE design phase collaboration includes in-kind engineering contributions from Australia, Canada, China, France, Hawaii and India, and 84 scientists from 14 countries are participating in the MSE Science Team. The Detailed Science Case, Science Requirements Document and other foundational documents are being finalised and will be made available later in the Fall. Please see Documents for the latest documentation.

The first annual MSE Science Team meeting was held this past July on the Big Island of Hawaii. Meeting presentations are available for download at Science meeting including details on Science Reference Observations addressing a wide range of scientific topics:

• SRO-1: Exoplanets and stellar velocity variability
• SRO-2: Revealing the physics of rare stellar types
• SRO-3: The formation and chemical evolution of the Galaxy
• SRO-4: Unveiling cold dark matter substructure with precision stellar kinematics
• SRO-5: Chemo-dynamical deconstruction of Local Group galaxies
• SRO-6: The baryonic content and dark matter distribution of the nearest massive clusters
• SRO-7: Galaxies and their environments in the nearby Universe
• SRO-8: Multi-scale clustering and the halo occupation function
• SRO-9: The chemical evolution of galaxies and AGN
• SRO-10: Mapping the inner parsec of quasars through reverberation mapping
• SRO-11: Linking galaxy evolution with the IGM through tomographic mapping
• SRO-12: A peculiar velocity survey out to 1 Gpc and the nature of the CMB dipole

A Design Reference Mission is currently being assembled, composed of these SROs uniquely possible with MSE.

Of course, moving MSE from the design phase into the construction phase to make its science a reality will depend on fulfilling requirements under a new Master Lease which is currently under discussion for the University of Hawaii’s hosting of Maunakea observatories, and on identifying funding from partner countries.

Canadian astronomers who are interested in the science that will be enabled by MSE are invited to join a small group who will keep national and local communities updated on MSE’s progress, promote the project to the public, and lay the groundwork for eventual funding proposals. If you are interested in joining this Canadian MSE Team, please contact Patrick Hall at yorkphall@gmail.com.

MSE website: http://mse.cfht.hawaii.edu/

By/par Dennis Crabtree (NRC-Herzberg)
with contributions from/avec des contributions de David Bohlender, Greg Burley, Alan McConnachie, and Dmitry Monin
(Cassiopeia – Autumn/Automne 2015)

La version française suit

These reports will appear in each issue of E-Cass with the goal of informing the Canadian astronomical community on the activities at NRC Herzberg. Feedback is welcome from community members about how NRC Herzberg is doing in fulfilling our mandate to “operate and administer any astronomical observatories established or maintained by the Government of Canada” (NRC Act).

General News

A BC-registered non-profit organization, Friends of the Dominion Astrophysical Observatory Society, has been formed. The main purposes of this new organization are to “promote interest and awareness of the DAO” and to restart the public education and outreach activities provided by the Centre of the Universe which NRC Herzberg closed in 2013 due to budget limitations. The organization has a website (Friends of the DAO) and is also on Facebook (www.facebook.com/FriendsDAO).

DAO Telescopes

The venerable DAO 1.2-m and 1.8-m telescopes continue to operate on every clear night in Victoria and we encourage new users and especially students to consider applying for time. The telescopes are scheduled on a quarterly basis with proposal deadlines nominally one month prior to the start of each calendar quarter.

Robotic operations are proving to be very popular on the 1.2-m telescope with typically 60% of the nights scheduled for automatic operation. While this telescope has no imaging capabilities, its McKellar spectrograph offers a large number of grating and camera configurations to provide spectra with dispersions between 2.4 and 40.9 Å/mm. Wavelength coverage is limited by the SITe-4 CCD’s 60 mm length. In good conditions during robotic nights we regularly obtain spectra for objects as faint as V = 11, mainly for radial velocity measurements using a cross-correlation analysis. Re-aluminizing of the primary mirror will take place in September.

Now in its 97th year of operation the 1.8-m Plaskett telescope offers users imaging, spectroscopy and spectropolarimetric capabilities. Spectroscopic programs (with a choice of dispersions between 10 and 120 Å/mm) continue to be most popular with the telescope but for several years about 20% of the time has been allocated to programs that use the dimaPol polarimeter module. This provides circular polarization measurements of a 300 Å region entered on the H-beta line and is being used to search for new magnetic upper main sequence stars as a complement to large programs being executed at the CFHT and other observatories. Imaging at the modified Newtonian focus is also possible and the dedicated E2V-1 CCD provides a 23.9’ x 10.6’ field of view. Contract observing services are available to applicants if preferred; this can provide insurance against long stretches of bad weather, especially in the winter months, since you are billed only for useful observing hours.

Given the success of the 1.2-m telescope automation our most recent DAO development efforts are concentrating on upgrades of the Plaskett telescope, dome and control software to eventually enable similar robotic operation of the 1.8-m telescope and spectrograph or imager. A new telescope control system has been released, the dome shutter and wind curtains are now controlled through the network, a rain sensor is in operation, and an updated absolute encoder has been installed on the RA axis to greatly improve telescope tracking. We anticipate installing new limit and horizon switches in the coming months; unlike the 1.2-m we have the extra complication of having to avoid collisions of the 1.8-m telescope with the pier or dome! Once this critical protection is installed and a number of other pieces are in place we will begin testing automated (but supervised) observations during the next several semesters.

Please feel free to contact David Bohlender (david.bohlender@nrc-cnrc.gc.ca) or Dmitry Monin (dmitry.monin@nrc-cnrc.gc.ca) at NRC Herzberg for further information.

Gemini GHOST Spectrograph

The GHOST project is a partnership with AAO, ANU, NRC and Gemini to design and build a high-resolution, fiber-fed spectrograph for Gemini South. The project lead – the AAO – are developing the fiber feed and fiber injection optics, ANU are providing the software, and NRC are developing the bench spectrograph and thermal enclosure. GHOST has been under intensive development and is currently nearing the end of its design phase.

The instrument includes a dual fiber feed for resolutions of 75,000 (high-resolution mode) and 50,000 (low-resolution mode). The wavelength range is from 363nm to 950nm, with the blue/red crossover at 535nm. The entire optical spectrum is obtained in a single observation. The bench spectrograph is a based on a high-efficiency echelle grating with VPH cross-dispersers. It is a dual beam (Red + Blue) optical design, with two independently operated CCD detectors to ensure high throughput across the full wavelength range.

For best instrument stability, the bench spectrograph is located in the telescope pier lab, and is housed in a temperature stabilized thermal enclosure. Although not optimized for precision radial velocities, it is expected that a radial velocity precision of a few m/s will be possible with GHOST.

Figure 1 – CAD drawing of GHOST optical bench layout

In the design and development phase, NRC engineers have been creating the optical design and opto-mechanical layout, designing and prototyping the detector system, and working on the enclosure concept and design. Critical and final design reviews are scheduled for the end of 2015/first quarter of 2016, and first light is expected to be in early 2018.

Montreal-Ohio-Victoria Echelle Spectrograph (MOVIES)

The Montreal-Ohio-VIctoria Echelle Spectrograph (MOVIES) is a collaboration between NRC, Université de Montréal and Ohio State University, and was one of 4 feasibility studies chosen through a competitive selection process for a 6 month, CAD100K study, as part of the process initiated by Gemini to design a new “Generation 4” instrument. The Feasibility Study Report was submitted to Gemini on August 24, 2015.

MOVIES is a broad bandwidth, moderate resolution (R3 – 10K) dual arm optical and near infrared (NIR) échelle spectrograph that simultaneously covers 0.36 – 2.45μm. It is supported by a rapid acquisition camera operating simultaneously in two optical and one NIR bands. MOVIES is designed for obtaining spectra of the faint Universe with high throughput, high efficiency and high reliability.

An essential and defining characteristic of MOVIES is that it will capitalize on Gemini’s “target of opportunity” mode. MOVIES will acquire targets (including starting the acquisition exposure, reading out the images, identifying the target, centering and verifying the object in the slit, switching to guiding mode and starting the science exposure) within 90 seconds. The acquisition and guiding cameras have large fields of view (3 x 3 arcmins) to ensure good sky coverage, to facilitate precise astrometry, and to enable blind acquisition when necessary. Two optical and one near-infrared acquisition images are obtained simultaneously, to easily acquire targets with an unknown spectral distribution. Further, they are designed to be used as simultaneous multi-band imagers to obtain “one-shot color-color diagrams”, and they are an important science imaging capability in their own right.

High throughput is achieved by the dual-arm design, where optimized optics in each arm and VPH gratings minimize light loss. The design has been developed to allow for a minimum number of optical elements per arm. Detectors optimized for broad wavelength ranges in the optical and NIR are used with coatings that further enhance their efficiency. For the optical arm, an option is included of using a large format electron multiplying CCD as the primary science detector; when used in EM-mode (large gain), these detectors allow for a very significant increase in observing efficiency obtained relative to normal CCDs for faint targets.

Figure 2 – Schematic of the MOVIES spectrograph

Further, zero-read noise in these detectors gives the option of temporal and spectral binning post-processing at potentially extremely high (hertz) cadence, opening up a new domain of high cadence optical spectroscopy for energetic, variable and/or transient observations. MOVIES will be reviewed by Gemini at the end of September. For more information on any aspect of MOVIES, Canadian contacts include:

Lead (NRC): Alan McConnachie (alan.mcconnachie@nrc-cnrc.gc.ca), Lead (UdM): René Doyon (doyon@astro.umontreal.ca), Leslie Saddlemyer (Leslie.Saddlemyer@nrc-cnrc.gc.ca), Olivier Hernandez (olivier.hernandez@umontreal.ca), and Étienne Artigau (artigau@ASTRO.UMontreal.CA).

Les rubriques qui suivent reviendront dans chaque numéro du bulletin et ont pour but de tenir les astronomes canadiens au courant des activités de CNRC Herzberg. Les commentaires des astronomes sur la manière dont CNRC Herzberg accomplit sa mission, c’est-à-dire « assurer le fonctionnement et la gestion des observatoires astronomiques mis sur pied ou exploités par l’État canadien » (Loi sur le CNRC), sont les bienvenus.

Généralités

Un organisme sans but lucratif enregistré en C.-B. a vu le jour sous l’appellation Friends of the Dominion Astrophysical Observatory Society. Cet organisme a pour buts principaux de faire connaître l’Observatoire fédéral d’astrophysique (OFA) et de rehausser l’intérêt qu’on lui porte. Il relancera les activités de vulgarisation publiques au Centre de l’univers dont le CNRC avait dû fermer les portes en 2013 faute de fonds. La société possède un site Web (Friends of the DAO) et une page Facebook (www.facebook.com/FriendsDAO).

Les télescopes de l’OFA

Les vénérables télescopes de 1,2 m et de 1,8 m de l’OFA continuent d’explorer le firmament chaque nuit quand le ciel est dégagé, à Victoria, et nous encourageons les nouveaux utilisateurs, les étudiants surtout, à solliciter du temps d’observation. Le calendrier des télescopes est établi trimestriellement, les astronomes ayant jusqu’à un mois avant le début du trimestre pour soumettre leurs demandes.

La robotique est en vogue au télescope de 1,2 m, où 60 % des nuits sont typiquement consacrées aux observations automatiques. Bien que l’instrument ne soit pas doté d’un imageur, son spectrographe autorise de nombreuses configurations de réseau et d’appareil photo de manière à restituer un spectre dont la dispersion varie de 2,4 à 40,9 Å/mm. La longueur du DCC de SITe-4 (60 mm) limite toutefois les longueurs d’onde couvertes. Quand les conditions sont bonnes, les observations automatisées restituent régulièrement le spectre d’objets d’une luminosité aussi faible que V = 11, ce qui permet essentiellement de calculer la vitesse radiale par corrélation croisée. Le miroir principal du télescope recevra un nouveau revêtement d’aluminium en septembre.

Exploité depuis 97 ans, le télescope Plaskett de 1,8 m propose des services d’imagerie, de spectroscopie et de spectropolarimétrie. Les programmes spectroscopiques (dispersion de 10 à 120 Å/mm) demeurent les plus populaires, mais depuis plusieurs années, on alloue 20% du temps d’observation environ aux programmes qui recourent au polarimètre dimaPol. Ce module permet d’établir la polarisation circulaire d’une zone de 300 Å centrée sur la raie H-bêta; on s’en sert pour chercher le champ magnétique de nouvelles étoiles dans le haut de la séquence principale en complément aux grands programmes poursuivis au CFHT et dans d’autres observatoires. Le télescope autorise aussi la prise d’images au foyer de type newtonien modifié, tandis que le DCC dédié de l’E2V-1 offre un champ de vision de 23,9 pi x 10,6 pi. Les astronomes qui le préfèrent peuvent conclure une entente afin de réserver du temps d’observation. Pareille entente sert en quelque sorte d’assurance contre les périodes prolongées d’intempéries, ce qui est particulièrement commode en hiver, puisque seules les heures d’observation utiles sont facturées.

Compte tenu du succès remporté par l’automatisation du télescope de 1,2 m, les plus récents travaux de perfectionnement réalisés à l’OFA se concentrent sur le télescope Plaskett, la coupole et le logiciel de commande, l’idée étant de robotiser de la même manière le télescope de 1,8 m ainsi que son spectrographe ou son imageur. Un nouveau système de contrôle du télescope a été mis en place, l’obturateur de la coupole et les volets coupe-vent sont désormais commandés par réseau, un détecteur de pluie est en service et l’on a installé un codeur absolu plus moderne sur l’axe AR, ce qui améliore considérablement les capacités de poursuite de l’instrument. Durant les mois qui viennent, nous devrions installer de nouveaux commutateurs pour l’horizon et la limite (contrairement au télescope de 1,2 m, celui de 1,8 m pourrait heurter la coupole ou le pilier, ce qui nous complique la tâche!). Dès que ces systèmes de protection cruciaux seront fonctionnels et que quelques autres composants seront en place, nous entamerons les observations automatiques (sous surveillance) pour quelques semestres.

N’hésitez pas à communiquer avec David Bohlender (david.bohlender@nrc-cnrc.gc.ca) ou Dmitry Monin (dmitry.monin@nrc-cnrc.gc.ca) à CNRC Herzberg pour en savoir plus.

Le spectrographe GHOST de Gemini

Le projet GHOST, auquel collaborent l’AAO, l’ANU, le CNRC et les observatoires Gemini, a pour but de concevoir et de bâtir un spectrographe à haute résolution alimenté par fibre optique pour le télescope Gemini Sud. L’AAO, qui pilote le projet, met au point le système d’alimentation par fibre optique et les éléments d’optique qui injecteront la lumière dans les fibres. L’ANU procurera le logiciel et le CNRC développera le banc de spectrographie de même que l’enceinte thermique. Les travaux de développement se poursuivent rondement et l’étape conceptuelle du projet tire à sa fin.

L’instrument sera alimenté par un double système de fibres optiques autorisant une résolution de 75 000 (haute) ou de 50 000 (faible). Il couvrira les longueurs d’onde de 363 nm à 950 nm, avec décalage bleu/rouge à 535 nm. La totalité du spectre sera obtenue en une seule observation. Le spectrographe repose sur un réseau échelle à haut rendement pourvu de dispositifs VPH à dispersion croisée. Les deux faisceaux optiques (rouge et bleu) sont reliés à autant de détecteurs DCC commandés séparément, ce qui garantit un débit élevé pour toute la plage de longueurs d’onde.

Pour conférer la plus grande stabilité à l’appareil, le spectrographe a été installé au laboratoire dans le pilier du télescope, à l’intérieur d’une enceinte thermique dont on stabilise la température. Bien que le GHOST ne soit pas optimisé pour établir la vitesse radiale avec précision, on s’attend à pouvoir la mesurer à quelques m/s près.

Figure 1 – Diagramme CAO du banc optique du GHOST

Durant la phase de conception et de développement, les ingénieurs du CNRC ont tracé les plans des systèmes optiques et optomécaniques, ont conçu le système de détection et créé un prototype, et ont travaillé à la conception de l’enceinte. Les examens du concept des étapes critique et finale devraient avoir lieu à la fin de 2015 et au premier trimestre de 2016, avec mise en service prévue au début de 2018.

Le spectrographe MOVIES (Montreal-Ohio-Victoria Echelle Spectrograph)

Le projet MOVIES est une collaboration entre le CNRC, l’Université de Montréal et l’Université d’État de l’Ohio. Il fait partie des quatre études de faisabilité retenues au terme d’un processus de sélection par concours concernant un projet de six mois de 100 000 CAD lancé par les observatoires Gemini en vue de créer un nouvel appareil de quatrième génération. Le rapport de l’étude de faisabilité a été remis aux responsables des observatoires Gemini le 24 août 2015.

MOVIES est spectrographe échelle à grande largeur de bande et à résolution moyenne (R3 – 10K) doté d’un bras pour la lumière visible et d’un second pour le proche infrarouge couvrant simultanément les longueurs d’onde de 0,36 à 2,45 μm. S’y ajoute un appareil photo à saisie rapide fonctionnant simultanément dans deux bandes optiques et une bande du proche infrarouge. L’appareil est conçu pour capter le spectre de l’univers peu lumineux à un débit élevé, avec un fort rendement et une grande fiabilité.

Un aspect capital et caractéristique du spectrographe MOVIES est qu’il exploitera au maximum le mode « cible occasionnelle » de Gemini. Quatre-vingt-dix secondes lui suffiront pour saisir la cible (démarrer l’exposition d’acquisition, lire les images, identifier la cible, centrer l’objet dans la fente et le vérifier, passer en mode guidage et démarrer l’exposition scientifique). Les appareils photo d’acquisition et de guidage embrassent un champ de vision assez grand (3 x 3 minutes d’arc) pour que l’on couvre une bonne partie du ciel, ce qui facilitera une astrométrie précise tout en permettant une saisie aveugle au besoin. L’instrument capte simultanément deux images dans le spectre visible et une dans le proche infrarouge, si bien qu’il est facile d’acquérir des cibles dont la distribution spectrale est inconnue. Ces dispositifs sont aussi conçus pour servir d’imageurs simultanés dans de nombreuses bandes et restitueront des diagrammes couleur-couleur instantanés. En soi, leurs capacités d’imagerie revêtent une grande importance pour la science.

Le concept du double bras, dont l’optique est optimisée et où un réseau VPH minimise l’affaiblissement du signal lumineux, garantit un débit élevé, car il mise sur le principe de la minimisation des éléments d’optique dans chaque ramification. Des détecteurs optimisés pour capter une grande fourchette de longueurs d’onde dans le spectre visible et le proche infrarouge ont été rendus plus efficaces encore grâce à un revêtement spécial. Le bras du spectrographe opérant dans la lumière visible permet, si on le désire, l’usage d’un DCC multiplicateur d’électrons de grand format comme détecteur principal, à des fins scientifiques. En mode multiplication d’électrons (gain important), ces détecteurs augmentent considérablement la valeur des observations comparativement à celles qu’autorisent les DCC normaux avec les objets peu lumineux.

Figure 2 – Diagramme du spectrographe MOVIES

Par ailleurs, l’absence de parasites en lecture dans ces détecteurs permet un compartimentage temporel et spectral après traitement à un rythme (hertz) extrêmement rapide, ce qui ouvre la porte à un tout nouveau domaine : celui de la spectroscopie optique à rythme élevé pour l’observation des objets variables ou passagers très énergétiques. Le personnel de Gemini examinera le spectrographe MOVIES à la fin de septembre. Pour en savoir plus sur l’un de ses aspects, les personnes à contacter au Canada sont:

Chef (CNRC): Alan McConnachie (alan.mcconnachie@nrc-cnrc.gc.ca), chef (UdM): René Doyon (doyon@astro.umontreal.ca), Leslie Saddlemyer (Leslie.Saddlemyer@nrc-cnrc.gc.ca), Olivier Hernandez (olivier.hernandez@umontreal.ca), et Étienne Artigau (artigau@ASTRO.UMontreal.CA).