Cassiopeia Newsletter – 2015 Autumnal Equinox

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In this issue:

President’s Report
NRC Herzberg News / Nouvelles du CNRC Herzberg
Gemini News / Nouvelles de Gemini
ALMA Matters
ACURA News
BRITE-Constellation News
MSE Update
SKA Update
CHIME Progress Report
CFHT Thesis List
Dissertation: The Structure and Evolution of Unbound Star-Forming Molecular Clouds
Dissertation: The Evolution of Star Clusters in Tidal Fields
Dissertation: Molecular Gas Properties in Local Luminous Infrared Galaxies


Editors: Magdalen Normandeau & Joanne Rosvick

Cassiopeia is CASCA’s quarterly Newsletter, published on or near the solstices and equinoxes (March 21, June 21, September 21 and December 21). To submit a contribution please email cassiopeia.editors@gmail.com. All submissions must be received at least one week in advance to be published in the next edition. We accept plain text and Word documents. Note that the formatting of your document will not be preserved. Please include any images as attachments in your email, not embedded in the text. Please include URLs in parentheses next to the word or phrase that you wish to act as link anchors.

Cassiopeia est le bulletin d’information de la CASCA, publié quatre fois par année, aux solstices et aux équinoxes (21 mars, 21 juin, 21 septembre et 21 décembre). Pour soumettre un article, écrivez à cassiopeia.editors@gmail.com. Les soumissions doivent être reçues au moins une semaine avant la parution. Nous acceptons les fichiers en format texte (ascii) et Word. Veuillez noter que la mise-en-page de votre document ne sera pas conservée. Veuillez faire parvenir vos images en pièces jointes à votre courriel plutôt que de les insérer dans votre article. Pour les liens à des sites internets, veuillez inclure l’adresse entre parenthèses à côté du mot ou de la phrase devant servir d’ancre.


Gemini News/Nouvelles de Gemini

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.

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)

    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.

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).

    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.

Dissertation: The Evolution of Star Clusters in Tidal Fields

Jeremy_headshot

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.

Dissertation: The Structure and Evolution of Unbound Star-Forming Molecular Clouds

RLWphoto

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.

Dissertation: Molecular Gas Properties in Local Luminous Infrared Galaxies

kazimierzsliwa

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, αCO, across the sample in search of the transition stage from a Galactic-like αCO to the 4-5 times lower value found in LIRGs. The four sources all have measured αCO 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.

Tenure-Track Position in Observational Astrophysics at York University

Department of Physics and Astronomy, Faculty of Science

The Department of Physics and Astronomy at York University in Toronto, Canada, invites applications for a tenure-track appointment at the Assistant Professor level in the field of observational astrophysics, to commence July 1, 2016 or as soon as possible thereafter. Candidates with a proven research record of planning, obtaining and analyzing observations to investigate profound questions about our Universe (enabled by facilities to which Canada is contributing, including the TMT, the JWST, and the SKA, and many wide-field survey facilities at all electromagnetic wavelengths) are invited to apply. The successful candidate will be positioned to participate in the scientific design and use of next-generation instrumentation and the planning of proposed future astronomical facilities, as well as to play a significant role in large national and international research projects and collaborations.

The successful candidate will develop a strong, externally funded research program, show excellence or promise of excellence in teaching at both undergraduate and graduate levels, and play an active role in York’s highly successful astronomy outreach initiatives. Applicants must have a PhD in Physics or Astronomy along with relevant postdoctoral experience and be eligible for prompt appointment to the Faculty of Graduate Studies.

Observational astronomers in the Department of Physics and Astronomy focus on active galactic nuclei, supernovae, exoplanets, and the evolution of galaxies and their constituents. Theoreticians focus on dark matter, early Universe cosmology, general relativity, and the analysis of measurements of the cosmic microwave background and large scale structure. The development of synergies between theory and observation is highly valued in the Department. Further information about the Department and the University can be found at http://www.physics.yorku.ca.

All York University positions are subject to budgetary approval. To guarantee full consideration, applications should be received before Dec. 1, 2015. Applicants should submit a CV, a three-page summary of key research contributions and outline of research plans, and a one-page statement of teaching philosophy, and should arrange for three signed letters of recommendation to be sent on their behalf. All materials should be submitted electronically throughhttps://academicjobsonline.org/.

York University is an Affirmative Action (AA) employer and strongly values diversity, including gender and sexual diversity, within its community. The AA Program, which applies to Aboriginal people, visible minorities, people with disabilities, and women, can be found at www.yorku.ca/acadjobs or by calling the AA office at 416-736-5713. All qualified candidates are encouraged to apply; however, Canadian citizens and permanent residents will be given priority.

Questions about the application process can be directed to Marlene Caplan (marlene@yorku.ca).

CFHT Thesis List

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.

CHIME Progress Report

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 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.

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:

SKA Update

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.

BRITE-Constellation News

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.

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.

Figure 2 – Hertzsprung-Russell diagram of the stars of brightest apparent magnitude, V<4.5. These ∼ 600 stars are the primary BRITE targets.

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.

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.

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.

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.