Canadian Gemini Office News / Nouvelles de l’Office Gemini Canadien

By / par Stéphanie Côté (CGO, NRC Herzberg / OGC, CNRC Herzberg)
(Cassiopeia – Autumn / l’automne 2018)

La version française suit

Korea Becomes a Full Gemini Partner!

On Tuesday, July 24th during the “Gemini Science and Evolution of Gemini” meeting in San Francisco, participants had the chance to witness the signing of the agreement between the Korea Astronomy and Space Science Institute (KASI) and the other partners of the Gemini Observatory, that establishes the Republic of Korea as a full Participant in the Gemini Observatory.

KASI has been a limited-time partner of Gemini since 2015, during which time over 100 Korean programs have been observed on Gemini and already 10 Korean papers based on Gemini data have been published. KASI was also a major partner in the team that developed IGRINS (in collaboration with University of Texas). This high-resolution near-infrared echelle spectrograph was offered as a Visitor instrument at Gemini-South in 2018A and turned out to be the most requested instrument in the South for that semester from all the Gemini community. Users will be happy to know that Korea will be building a similar instrument specifically for Gemini as part of their initial contribution to the Observatory.

Figure 1: The Republic of Korea flag was raised at Gemini Base Facility in Hilo, Hawai’i, during the signing event (Credit: Gemini Observatory/AURA)

The New Director of the Gemini Observatory is Announced: Dr Jennifer Lotz

Gemini Observatory and AURA have announced the appointment of the next Gemini Director: Dr. Jennifer Lotz. Dr. Lotz received her PhD in astrophysics from Johns Hopkins University in 2003, working on dwarf elliptical galaxies with Harry Ferguson. After holding a Leo Goldberg Fellowship at NOAO, and then a postdoctoral position at UC Santa Cruz, she has been a tenured astronomer at STScI with a joint appointment at Johns Hopkins University. She has been working on galaxy evolution and morphology, the high-redshift Universe and gravitational lensing. She is a leading expert in the field of galaxy mergers. She was the Principal Investigator of the highly successful and influential Hubble Frontier Fields program. She comes to Gemini with a solid record of scientific and technical leadership.

Dr. Lotz will succeed Dr. Laura Ferrarese on October 1, to start her 5 year appointment. Big kudos to Laura for her admirable leadership in the last year as Interim Director which has helped strengthen Gemini’s partnership.

New Large and Long Programs 2018

The new Large and Long Programs approved this year by the international LLP TAC were announced: two new programs were accepted, one of which is Canadian-led. The program “Chemistry of new metal-poor stars found in the Pristine Survey” is led by Kim Venn (University of Victoria), with Canadian co-Is Collin Kielty, Spencer Bialek and Julio Navarro (University of Victoria), Pat Côté and Alan McConnachie (NRC Herzberg) and Ray Carlberg (U of Toronto). This program will devote 150 hours over five semesters for GRACES high-resolution spectroscopic observations of ~80 extremely metal-poor stars found in the Pristine survey. High-resolution (R=40,000), high signal-to-noise (SNR>100) spectroscopy will be obtained to determine accurate chemical abundances for important elements that explore the variety of nucleosynthetic pathways in metal-poor stars, core-collapse supernovae, and the first stars.

The other new LLP is from PI Ian Crossfield (MIT) on “Validating TESS Exoplanet Candidates”. In addition to these two new programs, the Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) Survey led by Michael Balogh (U of Waterloo) was granted an extension.

GMOS-S Air Bubbles fixed

GMOS-S is back to work on-sky after its major surgery. It had to be taken off the telescope to fix the problem of air bubbles that had developed in the oil interfaces between its optical lenses. Although these units are sealed, there is still some oil loss over time due to slow leakage. The air bubbles unfortunately produced orientation-dependent scattering effects that affected the flatfields and throughput that were difficult to correct. To refill the oil, the GMOS intervention team had to extract the collimator from GMOS-S, which had never been done since its commissioning 17 years ago! At the same time, they upgraded the fill system to ensure that in the future oil refills can be done without opening the whole optical train. GMOS-S was put back on the telescope and flatfields show a dramatic improvement. It is now busy delivering great science data again.

GMOS IFU Tutorial and F2 Data Reduction Cookbook

A new tutorial on reducing GMOS IFU-1 data was held at the Science and Evolution of Gemini meeting in July by Kathleen Labrie (Gemini). The tutorial shows how to obtain the data and calibrations and go from raw data to a stacked cube, all the while addressing various possible data issues. An online version of this step-by-step tutorial is now available to everyone here.

Note that there is also a new Flamingos-2 data reduction cookbook that was released earlier this year and is available here.

Figure 2: Composite color image from two deep GMOS-N images in filters g’ and i’ of the ultra-diffuse galaxy NGC1052-DF2. (Image credit: Gemini Observatory/NSF/AURA/Keck/Jen Miller)

Recent Canadian Gemini Press Releases

Pieter Van Dokkum (Yale) and his team including Bob Abraham, Deborah Lokhorst, and Jielai Zhang (U of Toronto) reported in the March 29th issue of the journal Nature the discovery of a galaxy that appears to have almost no dark matter. NGC1052-DF2 is an ultra-diffuse galaxy that was first spotted with the Dragonfly Telephoto Array, a custom-built telescope in New Mexico that they designed to find these low-surface-brightness galaxies. They obtained the radial velocities of ten luminous globular-cluster-like objects in this galaxy, which has a stellar mass of approximately 2 × 108 solar masses. Using these they estimated its velocity dispersion to be less than 10.5 kilometres per second, which is very low and implies a total mass less than 3.4 × 108 solar masses. This implies that the mass ratio Mhalo/Mstars is of order unity (and consistent with zero), a factor of at least 400 lower than expected for a galaxy of this mass. The Nature paper is available here.

Join the thousands and thousands of Gemini Observatory followers on Facebook: @GeminiObservatory and Twitter: @GeminiObs



La République de Corée devient un pays partenaire de Gemini!

Le mardi 24 juillet, lors de la conférence “Science et Evolution” de Gemini à San Francisco, les participants ont pu assister à la signature de l’accord entre l’Institut Coréen d’astronomie et de sciences spatiales (KASI) et les autres partenaires de l’Observatoire Gemini, qui établit la République de Corée en tant que partenaire à part entière de l’Observatoire Gemini.

KASI est partenaire limité de Gemini depuis 2015, et depuis plus de 100 programmes coréens ont été observés sur Gemini et 10 articles coréens basés sur les données Gemini ont déjà été publiés. KASI était également un partenaire majeur dans l’équipe qui a développé IGRINS (en collaboration avec l’Université du Texas). Ce spectrographe échelle haute résolution en proche infrarouge a été offert en tant qu’instrument Visiteur à Gemini-Sud en 2018A et s’est avéré être l’instrument le plus demandé dans le Sud pour ce semestre par toute la communauté Gemini. Les utilisateurs seront heureux de savoir que la Corée construira un instrument similaire spécifiquement pour Gemini dans le cadre de sa contribution initiale à l’Observatoire.

Figure 1: Le drapeau de la République de Corée a été levé devant le quartier général de Gemini à Hilo, Hawaii, lors de la cérémonie de signature (Crédit: Observatoire Gemini / AURA)

La nouvelle directrice de l’Observatoire Gemini est annoncée: Dr Jennifer Lotz

L’Observatoire Gemini et AURA ont annoncé la nomination de la prochaine directrice de Gemini: Dr. Jennifer Lotz. Dr. Lotz a reçu son doctorat en astrophysique de l’Université Johns Hopkins en 2003, en travaillant sur les galaxies elliptiques naines avec Harry Ferguson. Après avoir obtenu une bourse Leo Goldberg à NOAO, puis un poste postdoctoral à l’Université de Californie à Santa Cruz, elle est astronome à STScI avec un poste conjoint à l’Université Johns Hopkins. Elle étudie l’évolution et la morphologie des galaxies, l’Univers à grand redshift et les lentilles gravitationnelles. Elle est une experte de premier plan dans le domaine des fusions de galaxies. Elle était l’investigatrice principale du programme Hubble Frontier Fields, très influent et très réussi. Elle vient à Gemini avec un solide dossier de leadership scientifique et technique.

Dr Lotz succédera à Dr Laura Ferrarese le 1 er octobre pour commencer son mandat de cinq ans. Un grand bravo à Laura pour son leadership remarquable au cours de l’année écoulée en tant que directrice par intérim, qui a contribué à renforcer le partenariat de Gemini.

Nouveaux programmes Longs et Larges cuvée 2018

Les nouveaux programmes longs et larges approuvés cette année par le TAC LLP international ont été annoncés: deux nouveaux programmes ont été acceptés, dont l’un est Canadien. Kim Venn (Université de Victoria) dirige le projet «Chemistry of new metal-poor stars found in the Pristine Survey», avec Collin Kielty, Spencer Bialek et Julio Navarro (Université de Victoria), Pat Côté et Alan McConnachie (CNRC Herzberg) et Ray Carlberg (U de Toronto). Ce projet consacrera 150 heures sur cinq semestres à des observations spectroscopiques à haute résolution avec GRACES d’environ 80 étoiles extrêmement pauvres en métaux trouvées lors du sondage Pristine. Ils obtiendront des données spectroscopiques de haute résolution (R = 40 000) avec rapport signal sur bruit (SNR> 100) pour déterminer les abondances chimiques précises des éléments importants qui exploreront la diversité des voies de nucléosynthèse des étoiles pauvres en métaux, les supernovae à affaissement central, et les premières étoiles.

L’autre nouveau programme LLP est mené par le PI Ian Crossfield (MIT) sur «Validating TESS Exoplanet Candidates». En plus de ces deux nouveaux programmes, le sondage GOGREEN (Observations of Galaxies in Rich Early Early Environment) mené par Michael Balogh (U de Waterloo) a été prolongé.

Suppression des bulles d’air dans GMOS-S

GMOS-S est de retour au télescope après sa chirurgie majeure. Il a fallu le démonter du télescope pour résoudre le problème des bulles d’air qui s’étaient développées dans les interfaces d’huile entre ses lentilles optiques. Bien que ces unités soient scellées, il y a toujours une certaine perte d’huile au fil du temps en raison d’une fuite lente. Les bulles d’air ont malheureusement produit des effets de diffusion dépendant de l’orientation qui ont affecté les flatfields et le throughput et sont difficiles à corriger. Pour remplir l’huile, l’équipe d’intervention de GMOS-S a dû extraire le collimateur de GMOS-S, ce qui n’avait jamais été fait depuis sa mise en service il y a 17 ans! De plus, ils ont installé un nouveau système de remplissage pour s’assurer qu’à l’avenir, les recharges d’huile pourront être effectuées sans ouvrir tout le train optique. GMOS-S a été remis sur le télescope et les flatfields sont nettement améliorés. GMOS-S est de retour au travail pour fournir de splendides données scientifiques.

Tutoriel GMOS IFU et manuel de réduction de données F2

Un nouveau tutoriel sur la réduction des données GMU IFU-1 a été organisé lors de la conférence “Science et Evolution de Gemini” en juillet par Kathleen Labrie (Gemini). Le tutoriel montre comment obtenir les données et les calibrations et passer des données brutes à un cube superposé, tout en abordant divers problèmes de données possibles. Une version en ligne de ce tutoriel étape par étape est maintenant disponible pour tous ici.

Notez qu’il existe également un nouveau manuel de recettes de réduction des données Flamingos-2 qui a été publié plus tôt cette année et qui est disponible ici.

Figure 2: Image couleur composée à partir de deux images profondes de GMOS-N dans les filtres g ’et i’ de la galaxie ultra-diffuse NGC1052-DF2. (Crédit d`image: Observatoire Gemini /NSF/AURA/Keck /Jen Miller)

Communiqués de presse canadiens récents

Pieter Van Dokkum (Yale) et son équipe incluant Bob Abraham, Deborah Lokhorst et Jielai Zhang (U de Toronto) ont rapporté dans le numéro du 29 mars de la revue Nature la découverte d’une galaxie qui ne semble pas avoir de matière noire. NGC1052-DF2 est une galaxie ultra-diffuse qui a été repérée pour la première fois avec le système de téléobjectifs Dragonfly, un télescope au Nouveau-Mexique conçu sur mesure pour détecter ces galaxies de faible brillance de surface. Ils ont obtenu les vitesses radiales de dix objets semblables à des amas globulaires lumineux dans cette galaxie, qui a une masse stellaire d’environ 2 × 108 masses solaires. En utilisant ces valeurs, ils ont estimé que la dispersion de la vitesse était inférieure à 10,5 kilomètres par seconde, ce qui est très faible et implique une masse totale inférieure à 3,4 × 108 masses solaires. Cela implique que le rapport de masse Mhalo/Mstars est près de 1 (et cohérent avec zéro), un facteur au moins 400 fois inférieur à celui attendu pour une galaxie de cette masse. L`article Nature est disponible ici.

Rejoignez les milliers et milliers de suiveurs de l’Observatoire Gemini sur Facebook: @GeminiObservatory et Twitter: @GeminiObs.

A CASCA-Westar visit to Ashcroft and Cache Creek

By / par Jon Willis (University of Victoria)
(Cassiopeia – Autumn / l’automne 2018)

The CASCA-Westar outreach program links educators and community groups across Canada to professional astronomers. The program offers isolated communities – whether geographically or economically – the opportunity to hear about the best that astronomy has to offer. Over twenty Canadian astronomers and CASCA members have made themselves available as CASCA-Westar lecturers to travel to remote communities and offer classroom activities for school kids, curriculum workshops for teachers and popular public talks.

I became a CASCA-Wester lecturer last year. Like many professional astronomers, I regularly engage with local schools and have developed a number of themed presentations for audiences ranging from elementary schools to seniors groups. I was therefore pleased to receive an invitation from CASCA-Westar in the early summer of 2018 to visit Ashcroft and Cache Creek in the interior of BC. My visit was hosted by Jenn Casorso, a youth coordinator with the Bonaparte Indian Band.

Ashcroft and nearby Cache Creek are both about an hour’s drive west of Kamloops – a leisurely day’s travel by ferry and car from my usual haunts on Vancouver Island. Ashcroft is a village of some 1,600 residents located on the banks of the Thompson River just south of a major confluence with the Bonaparte river. Nearby Cache Creek adds another 1,000 people to the local population. Both settlements were founded in the 1860s during the Cariboo gold rush on land traditionally inhabited by the Secwepemc people.


My busy day began at the Desert Sands Community School in Ashcroft with a presentation on “Everything you ever wanted to know about the Big Bang but were afraid to ask”. This is a prop-driven cosmology talk that features pupils expanding with the Universe, weighty chunks of meteorite, exploding balloons and the Period Tablecloth. It is a very interactive presentation and immense fun to deliver – it certainly warms the kids up to ask a barrage of questions.

After lunch we headed over to Cache Creek Elementary School for a “Little Guide to the Night Sky”. This presentation uses 10 spectacular images of planets, moons, stars, nebulae and galaxies to take the pupils on a journey from Earth to our nearest massive galaxy, Andromeda. The Discovery Channel and the internet had prepped my audience with a lot of topics on which they expected answers and I was very much saved by the bell at the end of the school day!

My enjoyable and rewarding day concluded with a public talk at Ashcroft Community Centre on the “Search for Life in the Universe” and welcomed residents of all ages to learn about the prospects for discovering life beyond Earth.

I hope that my audiences learned as much as I did through the day and I also hope that my CASCA-Westar visit lays the foundation for a lasting relationship with these communities and the opportunity to work with them again in the future.

END NOTE: Jon Willis is an associate professor in the Department of Physics and Astronomy at the University of Victoria. He combines research into cosmology and the large-scale structure of the universe with teaching and writing about astrobiology. He is the author of “All These Worlds Are Yours: The Scientific Search for Alien Life” (Yale 2016).

Maunakea Spectroscopic Explorer (MSE) Update

By / par Sarah Gallagher (MSE Science Advisory Group Member)
(Cassiopeia – Autumn / l’automne 2018)

Status of Science Team Membership

The MSE Science Team has grown substantially, and now has more than 300 members, including 33 Canadians. Science Working Groups have begun work for the Design Reference Survey work that will begin within the next couple of months. If you signed up for the Science Team but have not been receiving e-mails, please contact MSE Project Scientist Alan McConnachie.

MSE Design Challenges Featured on Social Media

The engineering software company SolidWorks chose to feature MSE and CFHT for their software launch event with an interview with Greg Green (Instrument Designer and Machinist, CFHT). The relevant video segment is within the first few minutes, with MSE design models showcased in minutes 6–9.

Wide Field Astronomy in Canada

MSE science interests will be represented at the Wide Field Astronomy in Canada workshop at the Perimeter Institute (October 10–11, 2018; Waterloo). MSE MG Chair Pat Hall will give an invited presentation on the interrelationship of MSE and LSST, and an MSE splinter meeting will be held on Friday, October 12. We hope to see you there!

MSE Project Book

The MSE Project Book will be released next month. The Project Book is a summary of the technical status of MSE for engineers and technical managers as the project advances from the Conceptual Design Phase into the Preliminary Design Phase. The Book also provides information on the science motivations for the MSE capabilities and requirements, as well as project management information on how the Project is organized and on our plan to progress through and beyond the Preliminary Design Phase for readers who are scientists and decision makers.

SPIE Papers

Fifteen MSE presentations made at the Society of Photo-Optical Instrumentation Engineers (SPIE) Astronomical Telescope and Instrumentation meeting (Jun 10–15, 2018; Austin, Texas, USA) this summer were posted on the arXiv. They are all available at this link. The breadth of topics is a testament to the hard work to date of the participants and the Project Office on the technical design and planning work key to the success of MSE.

IAU 2018

McConnachie presented at the International Astronomical Union (IAU) Focus Meeting 13, Global Coordination of International Astrophysics and Heliospheric Activities from Space and Ground (Aug 20 – 23, 2018; Vienna, Austria), in a Discussion Session entitled “Global Coordination of Ground-based Astronomy,” chaired by Debra Elmegreen. The panel included leads from the TMT, GMT, ELT, MSE, LSST and SKA.

Preparation for a CFI Proposal

As reported in the last MSE Update, planning preparations continue for a CFI proposal submission for the next round (anticipated in 2019). Discussions are underway regarding a pathfinder spectrograph to be deployed on an existing 4- or 8-meter class telescope to enable unique science while demonstrating that MSE engineering and technology requirements can be met. If you are interested in contributing to this effort, please contact CFI Project Manager for MSE Colin Bradley.

MSE Preliminary Design Phase

A version of the MSE Statement of Understanding suitable for signature has been circulated to all participants. The ACURA Board and Executive Director, Don Brooks, are reviewing the SOU with lawyers at UBC to determine if ACURA can join the SOU as the Canadian signatory. We anticipate a more substantial update on this issue in the Winter Solstice edition of e-Cassiopeia.

References for Further Information and Key Contacts

The MSE website is mse.cfht.hawaii.edu. Questions or comments about MSE governance can be directed to your MSE Management Group Members, Greg Fahlman and Pat Hall. Scientific questions or comments can be directed to your MSE Science Advisory Group Members, Sarah Gallagher and Kim Venn.

BRITE-Constellation Mission Update

By / par Gregg Wade (Canadian PI for BRITE)
(Cassiopeia – Autumn / l’automne 2018)

BRITEpatch

BRITE-Constellation is an international space astronomy mission consisting of a fleet of 20x20x20 cm nanosatellites dedicated to precision optical photometry of bright stars in two photometric colours. The mission continues in full science operations, with 25 data releases to BRITE target PIs having already taken place, and many datasets available in the public domain from the BRITE public archive.

The BRITE mission is a collaboration between Canadian, Austrian and Polish astronomers and space scientists. The Canadian partners represent University of Toronto, Université de Montréal, Bishop’s University, and Royal Military College of Canada. The mission was built, and the Canadian satellites operated by, the University of Toronto Institute for Aerospace Studies Space Flight Lab (UTIAS-SFL). The Canadian Space Agency funded the construction of the Canadian satellites, and continues to support their day-to-day operations.

Operations

There are five operating BRITE satellites in the Constellation, collecting data on various sky fields in a coordinated programme to obtain well-sampled, longterm continuous (~6 months) light curves in both red and blue bandpasses.

As this issue of Cassiopeia went to press, here was the status of the sky assignments for the BRITE cubesats:

  • BRITE Toronto (Canada): Toronto observes with a red filter. It is currently observing the Cygnus III and Cassiopeia III fields, switching between the two fields each orbit. As implied by the numeral ‘III’, the current campaigns on these fields represents revisits of previously-observed fields.
  • BRITE Lem (Poland): Lem observes with a blue filter. It is also observing the Cygnus III field.
  • BRITE Heweliusz (Poland): Heweliusz observes with a red filter. This satellite is observing the Cygnus III field, but will soon transition to another field (details TBD).
  • BRITE Austria (Austria): BRITE Austria observes with a blue filter. It is observing the Sagittarius IV and the Cassiopeia III fields.
  • UniBRITE (Austria): UniBRITE observes with a red filter. This satellite is currently observing the Cygnus III and Cassiopeia III fields.

The BRITE Constellation observing programme from early 2017 through to mid-2019 has been planned by the BRITE Executive Science Team (BEST), and details are available on the BRITE photometry Wiki page.

Recent Science Results

Figure 1: The two-month long BRITE light curve of V973 Sco (red filled circles) as recorded in 2015 in the red passband by BRITE-Heweliusz, along with the contemporaneous observations of phi 2 Lup (black diamonds, offset by 50 mmag for better visibility) showing no significant variability. From Ramiaramanantsoa et al. (2018).

“A BRITE view on the massive O-type supergiant V973 Scorpii: hints towards internal gravity waves or sub-surface convection zones” (Ramiaramanantsoa et al. 2018, MNRAS 480, 972). The authors report detection of stochastically-triggered photospheric light variations reaching ~40 mmag peak-to-valley amplitudes in the O8Iaf supergiant V973 Scorpii as the outcome of two months of high-precision time-resolved photometric observations with the BRITE nanosatellites. The amplitude spectrum of the time series photometry exhibits a pronounced broad bump in the low-frequency regime (<0.9 c/d) where several prominent frequencies are detected. A time-frequency analysis of the observations reveals typical mode lifetimes of the order of 5−10 days. The overall features of the observed brightness amplitude spectrum of V973 Sco match well with those extrapolated from two-dimensional hydrodynamical simulations of convectively-driven internal gravity waves randomly excited from deep in the convective cores of massive stars. An alternative or additional possible source of excitation from a subsurface convection zone needs to be explored in future theoretical investigations.

“Short-term variability and mass loss in Be stars IV. Two groups of closely spaced, approximately equidistant frequencies in three decades of space photometry of ν Puppis (B7-8 IIIe)” (Baade et al., submitted to A&A). In early-type Be stars, groups of nonradial pulsation (NRP) modes with numerically related frequencies may be instrumental for the release of excess angular momentum through mass-ejection events. Difference and sum/harmonic frequencies often form additional groups. The goal of this study is to find out whether a similar frequency pattern occurs in the cooler third-magnitude B7-8 IIIe shell star ν Pup. Time-series analyses are performed of space photometry with BRITE-Constellation (2015, 2016/17, and 2017/18), SMEI (2003–2011), and Hipparcos (1989-1993). Two IUE SWP and 27 optical echelle spectra spanning 20 years were retrieved from various archives. The optical spectra exhibit no anomalies or well-defined variabilities. A magnetic field was not detected. All three photometry satellites recorded variability near 0.656 c/d which is resolved into three features separated by ~0.0021 c/d. First harmonics form a second frequency group, also spaced by ~0.0021 c/d. The frequency spacing is very nearly but not exactly equidistant. Variability near 0.0021 c/d was not detected. The long-term frequency stability could be used to derive meaningful constraints on the properties of a putative companion star. The IUE spectra do not reveal the presence of a hot subluminous secondary. ν Pup is another Be star exhibiting an NRP variability pattern with long-term constancy and underlining the importance of combination frequencies and frequency groups. The star is a good target for efforts to identify an effectively single Be star.

Conferences, Resources and Social Media

Conferences

The BRITE Executive Science Team recently met in Wroclaw, Poland for two days of scientific and administrative discussions. Thirteen scientific presentations were delivered on topics ranging from BRITE CCD cosmetics to time-domain astronomy with BRITEs.

The proceedings of the third BRITE Science Conference – held at Lac Taureau, Canada in August 2017 – are available in printed form and online.

The BRITE team is spearheading the organization of a conference entitled “Stars and their Variability, Observed from Space”, to occur in Vienna, Austria from August 19 – 23, 2019. Preregistration is available on the conference website.

Resources

The BRITE Public Data Archive, based in Warsaw, Poland, at the Nikolaus Copernicus Astronomical Centre, can be accessed at brite.camk.edu.pl/pub/index.html.

The mission Wiki (including information on past, current and future fields) can be accessed at brite.craq-astro.ca/.

BRITE Constellation is on Facebook, at @briteconstellation.

The BRITE International Advisory Science Team

The BRITE International Advisory Science Team (BIAST), which consists of BRITE scientific PIs, technical authorities, amateur astronomers, and mission fans, advises the mission executive on scientific and outreach aspects of the mission. If you’re interested to join BIAST, contact Canadian BRITE PI Gregg Wade: wade-g@rmc.ca.

York University Update

By / par Paul Delaney
(Cassiopeia – Autumn / l’automne 2018)

Most astronomy Departments across Canada engage in Education and Public Outreach activities. It is important to build strong links with our communities for a variety of reasons, including stimulating the next generation of university students and enhancing the level of scientific literacy among the public.

At York University we have been steadily expanding our Outreach efforts for the past 30 years. A team of approximately 25 (mostly) undergraduate students routinely engages in weekly on-campus Public Viewing nights, a weekly radio program YorkUniverse (on astronomy.fm internet radio), a weekly Online Public Viewing experience, weekly tailored school tours (including observing opportunities weather permitting), summer camp presentations, special events such as Science Rendezvous (comet making, constellation tattoos, crater making), Science Literacy Week (sidewalk solar observing, comet making, public talks), community Star Parties, etc. These undergraduate students are trained in public speaking and are essentially ambassadors of science. In addition, as the Coordinator of this team of very enthusiastic students, I have become a focal point for local and national media, fielding interviews on a weekly basis covering a wide range of astronomy and space-science related stories.

The success of this Team recently led to a discussion between the former Dean of Science, Ray Jawarndhana, and Emeritus Professor and now Philanthropist, Dr. Allan I. Carswell. The result culminated in an announcement on August 9, 2018, of the creation of an Endowed Chair, the Allan I. Carswell Chair for the Public Understanding of Astronomy, to be held in the Department of Physics and Astronomy at York University. All our future Outreach efforts will be coordinated by this Chair whose efforts will expand and strengthen the activities of the Team, particularly to schools and local community groups. Perhaps most importantly, the Department of Physics and Astronomy and the Faculty of Science at York University demonstrate by the creation of this Chair a long-term commitment to Education and Public Outreach. I am honoured to have been chosen as the inaugural Chair.

An exciting addition to our enhanced commitment to Education and Public Outreach is the installation of a 1 m PlaneWave telescope in the Allan I. Carswell Observatory scheduled for this November. Apart from enhancing undergraduate and graduate education and research opportunities at York University, the new 1 m telescope will be accessible to the public once it has been commissioned.

All in all, 2019 promises to be an exceptional year for astronomy at York University.

NRC Herzberg News / Nouvelles du CNRC Herzberg

By / par Dennis Crabtree (NRC Herzberg)
(Contributions from David Andersen, Dean Chalmers, Jennifer Dunn, JJ Kavelaars)
(Cassiopeia – Autumn / l’automne 2018)

La version française suit

Management Changes at NRC Herzberg

There has been a series of changes in the senior management at NRC Herzberg which I will recap here:

  1. Luc Simard is now Director of the Astronomy Technology Directorate. Previously he held this position in an Acting capacity.
  2. Michael Rupen is the Acting Director of the Radio Astronomy Directorate.
  3. James di Francesco is the Acting Director of the Optical Astronomy Directorate.

VLASS Quick Look products now available via the Canadian Astronomy Data Centre

The CADC is working with the “Canadian Initiative For Radio Astronomy Data Analysis” (CIRADA.ca) to develop processes for the production of Advanced Data Products (ADP) from radio astronomy datasets. The CIRADA project is a precursor initiative for a Canadian SKA Regional Centre and will produce ADP for CHIME, MWA and the VLA Sky Survey (VLASS). The CADC is providing access to the original datasets for CIRADA within the CANFAR processing environment and will archive the ADP produced by CIRADA. An initial step in this activity has been to archive the Quick Look dataset produced by the VLASS project and present those observations via the CADC’s Advanced Search interface. There is no need to log in to access the CADC query or data retrieval for VLASS as all the metadata, and data, are public.

The 2-4 GHz VLASS is providing multiple epochs of spectral imaging of the northern sky using the eVLA, details can be found here. The first epoch of VLASS observations is now complete and an initial ‘Quick Look’ set of continuum images is available. The CADC is providing access to these public Quick Look images.

An interesting feature of the VLASS QL products is that they can be used as a background in the ‘View in Sky’ on the Results tab of CADC’s Advanced Search pages. This allows one to bring up the 2-4 GHz continuum image associated with the search result by selecting the VLASS1.1-QL as the image plane in the Sky View tool (which is based on Aladin Lite). We note that, due to the high-resolution nature of the VLASS QL products, only small scale features are visible in these images.

Virtual Reality at NRC Herzberg

Stimulated by the availability of a Virtual Reality (VR) model for the TMT, I (Dennis Crabtree) decided to explore VR for various uses at NRC Herzberg. After succeeding in purchasing the required equipment (engineering grade computer, gaming graphics card and an Oculus Rift headset) the TMT model was downloaded. The potential of VR for providing an immersive experience of our work was immediately evident.

For those who attended CASCA, you were able to view the TMT experience at either the TMT booth or the NRC-Herzberg table. At the table my co-op student, Dori Blakely (UVic), was also providing people with an experience aboard the ISS.

Our interpretive centre in Victoria, the Centre of the Universe, was closed in 2014. While this is now operated by the non-profit Friends of the DAO, it is only available for a limited time each year.

So why not create a Virtual Visitor Centre!

Over the rest of the summer Dori was able to develop an alpha version of a VR experience that could highlight our engineering work and science. This involved several aspects:

  1. Import the CAD/CAM models (SolidWorks and Autodesk Inventor) of instruments into the Unity development software.
  2. Identify and purchase a virtual museum asset from the Unity Store.
  3. Populate the virtual museum with images, video, and the imported instrument models.
  4. Provide the capability to ‘teleport’ into the detailed instrument model from within the museum context.
  5. Simply and fine tune the instrument models in order to achieve reasonable performance on the Occulus Rift.

There is still a lot of work required to make this a beta version which we plan on demonstrating at next year’s CASCA meeting and making available to anyone interested.

Figure 1 is a view of the interior of the Visitor Centre with the model of GHOST. Figure 2 shows the upper half of MSE in a display case.

Figure 1


Figure 2

We also purchased a new Oculus Go, which is a lower performance VR headset, but is totally portable as it does not require a computer. Dori managed to develop an app for the Go that allowed people to wander through a model of the GHOST Spectrograph that we are building for Gemini.

Thirty Meter Telescope (TMT) Instrumentation Update

The National Research Council (NRC) and its industrial and international partners have been advancing the designs of both NFIRAOS (the Narrow Field InfraRed Adaptive Optics System) and IRIS (InfraRed Imaging Spectrograph). Figure 3 shows NFIRAOS (blue) and IRIS (grey, on bottom) as viewed from the Nasmyth platform of TMT.

Figure 3


NFIRAOS successfully completed its Final Design Review in June, 2018. IRIS completed its Preliminary Design Review in September, 2017 and is in the midst of its own Final Design phase currently.

Figure 4


NFIRAOS (Figure 4) is the first-light facility Multi-Conjugate Adaptive Optics (MCAO) system for the Thirty Meter Telescope (TMT) which will provide stellar correction to up to 3 science instruments. To involve more of the Canadian community in TMT, and in particular NFIRAOS, NRC subdivided NFIRAOS into subsystems and subcontracted the final design of these subsystems to Canadian industry. The project has now engaged five Canadian industrial partners, ABB, INO, Dynamic Structures, Quantum Technology and Sightline Engineering to develop the final design of eight major NFIRAOS subsystems. Working with industry to develop designs to specifications was a new approach for the NRC team, and NFIRAOS has benefited greatly from these companies’ expertise and experience.

NFIRAOS will provide diffraction-limited performance in the J, H, and K band with 50% sky coverage at the Galactic Pole. The diffraction limit of TMT will provide much sharper images than any other ground or space-based telescope available today). Years of effort have been spent to ensure that TMT and NFIRAOS deliver images that on average will be the sharpest of any existing facility AO system. Sky coverage is, of course, also a key performance metric. For astronomers to be fully satisfied with TMT + NFIRAOS, they must be able to observe their key science programs. The laser guide stars, the use of MCAO, and the on-instrument near-infrared tip/tilt/focus sensors (OIWFSs) all contribute to achieving diffraction-limited performance 50% of the time at the North Galactic Pole. This sky coverage fraction increases dramatically for fields closer to the galactic plane where many more stars are available.

IRIS is the first-light client instrument of NFIRAOS. The IRIS team consists of groups at NRC, University of California Los Angeles, Caltech, University of California San Diego, University of California Santa Cruz, the National Astronomical Observatory of Japan and TMT. IRIS combines a “wide-field” Imager with an integral field spectrograph (IFS) and covers the 0.84 µm to 2.4 µm wavelength range. IRIS has been designed to take advantage of the diffraction-limit of TMT. The IRIS Imager uses four Teledyne Hawaii-4RG-10 detectors, which yield a total field-of-view (FoV) of 34 x 34 arcsec at a platescale of 4 milliarcseconds (mas). The IFS offers four spaxel scales ranging from 4 mas to 50 mas, and is capable of generating up to 14,000 simultaneous spectra within a filled rectangular pattern. The Imager and IFS are encased by the science cryostat, which provides the light-tight, cryogenic vacuum environment as required by the Imager and IFS subsystems. NRC is designing the three on-instrument wavefront sensors (OIWFS) mounted in a separate enclosure atop the science cryostat. These patrol the exterior perimeter of the two arc minute diameter field delivered by NFIRAOS and provide measurements of the tip/tilt, focus (TTF) and plate scale modes invisible to NFIRAOS and its laser guide stars (LGS). The OIWFS provides mechanical and thermal interfaces to NFIRAOS. NRC is also designing the support structure and rotator which support IRIS under NFIRAOS. The rotator enables IRIS to provide its own field de-rotation. The final component of IRIS that NRC is designing is the services cable wrap, which routes the cables from the inside of the OIWFS and science cryostat to the Nasmyth platform below the instrument and out to either the IRIS electronics cabinet or the TMT facility supplied services.

When the site for TMT is decided and construction resumes, NFIRAOS and IRIS will enter fabrication phases. A new integration facility will be built in Victoria to integrate both NFIRAOS and IRIS. Once the instruments have been thoroughly tested in Victoria, they will be shipped to TMT and be ready to observe at first light.

ngVLA Update

The next generation Very Large Array (ngVLA) is a NRAO led project to replace the existing Jansky Very Large Array with a new array with 10x the sensitivity, a frequency range from 1.2 to 116 GHz, longer baselines to give mas-resolution and a dense core for low surface brightness imaging. The project is currently developing a reference design to support a submission to the Astro2020 Decadal Survey. Canada, through NRC Herzberg, is contributing to the reference design with design studies of antennas and the correlator.

NRC Herzberg ngVLA Antenna Design Concepts, left-18m, right-6m.


The ngVLA will reference design calls for 244, Ø18m antennas and 19, Ø6m antennas. Working with contractors Minex Engineering and SED Systems NRC-HAA has developed costed reference designs for both sizes based on the Single-piece Rim-supported Composite (SRC) technology used in the DVA1 and 2 antennas.

The ngVLA requirement to operate up to 116GHz has required further development of the SRC concept in order to achieve the required surface accuracy and pointing. A successful concept design review was held at DRAO in May of this year with a panel of external and NRAO reviewers. Further development work is currently underway leading up to a Preliminary Design Review to be held in Socorro Oct. 3, 4.

NRC Herzberg is providing a costed reference design of a correlator/beamformer for the ngVLA, based on the Frequency Slice Architecture (FSA) and the TALON 14 nm FinFET FPGA technology developed for the SKA1 Mid correlator/beamformer. This architecture and technology is suitable and scalable now to the ngVLA’s 263 antennas, 28 GHz/pol of bandwidth, and up to 10,000 km baselines. However, since ngVLA construction isn’t until the mid-2020s at the earliest, cost and power will be less than using 2018 TALON technology.



Changements à CNRC Herzberg

Voici les faits saillants des changements survenus à la haute direction de CNRC Herzberg :

  1. Luc Simard a été confirmé comme directeur, Technologies d’astronomie, après avoir assuré l’intérim;
  2. Michael Rupen est directeur par intérim, Radioastronomie;
  3. James Di Francesco est directeur par intérim, Astronomie optique.

Les images Quick Look du relevé VLASS sont maintenant offertes par le Centre canadien de données astronomiques

En collaboration avec l’Initiative canadienne d’analyse des données de radioastronomie (CIRADA.ca), le CCDA travaille à développer des procédés pour produire des données évoluées (ADP, pour Advanced Data Products) à partir des données des observations radioastronomiques. Le projet CIRADA trace la voie pour l’établissement d’un éventuel Centre régional du SKA canadien et produira des données évoluées à partir des données du projet CHIME, du Murchison Widefield Array (MWA) et du VLA Sky Survey (VLASS). Le CADC donne au CIRADA un accès aux collections de données originales dans l’environnement de traitement de CANFAR et assurera la conservation des archives des données produites par le CIRADA. Une des premières étapes de ce projet a été l’archivage des données Quick Look produites par le projet VLASS et la présentation de ces observations au moyen de l’interface de recherche avancée du CADC. Il n’est pas nécessaire de posséder un compte d’utilisateur pour avoir accès à la plateforme de recherche de données du CADC pour avoir accès aux données du VLASS puisque toutes les métadonnées et les données sont publiques.

Le relevé du ciel VLASS dans la gamme 2-4 GHz fournit des images spectrales de plusieurs campagnes d’observation du ciel septentrional effectuées par l’instrument eVLA; pour en savoir plus : science.nrao.edu/science/surveys/vlass. La première campagne d’observation de VLASS vient de se terminer et un premier jeu d’images du continuum peut être consulté dans l’application Quick Look. Le CADC offre ces images appartenant au domaine public.

Fait intéressant, les images du VLASS formatées pour Quick Look peuvent servir d’arrière-plan dans la visualisation « Voir dans le ciel » sous l’onglet Résultats dans la fonction de recherche avancée des données du CADC. L’utilisateur peut ainsi invoquer image du continuum 2-4 GHz associé à un résultat de recherche en sélectionnant l’option VLASS1.1-QL comme plan image dans l’outil Sky View (dérivé de l’atlas Aladin Lite). En raison de la haute résolution des produits QL de VLASS, seuls les détails de petite dimension sont visibles dans ces images.

La réalité virtuelle à CNRC Herzberg

J’ai (Dennis Crabtree) décidé d’explorer les possibilités du modèle de réalité virtuelle (RV) du TMT pour CNRC Herzberg. Après avoir fait l’acquisition de l’équipement nécessaire (un ordinateur scientifique, une carte graphique pour le jeu et un casque de RV Oculus Rift), nous avons téléchargé le modèle virtuel du TMT dans notre environnement de RV. Dès la première utilisation, nous avons tout de suite constaté le potentiel de l’expérience immersive offerte par la réalité virtuelle pour notre travail.

Les personnes qui étaient à la conférence de la CASCA ont pu assister à l’expérience au kiosque du TMT ou à la table de CNRC-Herzberg où mon stagiaire, Dori Blakely (de l’Université de Victoria), donnait une démonstration à bord de la maquette de la Station spatiale internationale (SSI).

Le Centre d’interprétation de l’Univers à Victoria a officiellement fermé ses portes en 2014. Depuis, l’association Friends of the DAO a repris le flambeau à titre non lucratif, mais l’accès aux installations est limité à certaines périodes de l’année.

Alors pourquoi ne pas créer un centre de visite virtuel?

Au cours du reste de son stage d’été, Dori a développé une version alpha de l’expérience de réalité virtuelle pour mettre en valeur notre travail technique et scientifique. Le développement de ce projet suppose plusieurs étapes :

  1. Importer les modèles CAO/FOA (à l’aide des logiciels SolidWorks et Autodesk Inventor) des instruments dans la plateforme de développement Unity.
  2. Trouver et acheter une coquille de musée virtuel dans la boutique Unity Store.
  3. Verser les images, les séquences vidéo et les modèles d’instruments importés dans la coquille de musée virtuel.
  4. Programmer la capacité pour l’utilisateur de se « téléporter » dans le modèle d’instrument détaillé depuis le musée virtuel.
  5. Simplifie et affiner les modèles d’instrument pour donner un rendu acceptable dans la lunette du casque Oculus Rift.

Il y a encore beaucoup de travail à faire pour passer à la version bêta, que nous comptons présenter à la prochaine conférence de la CASCA l’an prochain et la rendre accessible à toutes les personnes désireuses d’en faire l’expérience.

VCC-1


MSE

La première image (VCC–1) montre une vue de l’intérieur du Centre virtuel réalisée avec le modèle du spectrographe GHOST. La seconde image (MSE) illustre la moitié supérieure de l’explorateur spectroscopique du Maunakea (MSE) dans une vitrine.

Nous nous sommes également procuré un nouvel Oculus Go, un casque de RV moins puissant, mais parfaitement portatif, puisqu’il ne nécessite pas d’être branché à un ordinateur. Dori est parvenu à développer une application pour ce casque permettant de déambuler à l’intérieur d’un modèle virtuel du spectrographe GHOST que nous construisons pour l’observatoire Gemini.

Nouvelles des instruments construits pour le Télescope de trente mètres

TMT 1


Les travaux entrepris par le Conseil national de recherches (CNRC) et ses partenaires industriels et internationaux pour la conception du NFIRAOS (le système d’optique adaptative infrarouge à champ étroit) et d’IRIS (le spectrographe à images infrarouges) ont progressé La TMT 1 montre une vue du NFIRAOS (en bleu) et IRIS (en gris, en bas) depuis la plateforme Nasmyth du TMT. L’examen final de conception du NFIRAOS s’est terminé en juin 2018 et l’examen de conception préliminaire d’IRIS a été mené à terme en septembre 2017, nous sommes maintenant à mi-parcours de la phase de conception finale de l’instrument.

TMT 2


Le NFIRAOS (TMT 2) est l’instrument d’optique adaptative multiconjuguée (OAMC) de première lumière du Télescope de trente mètres. Il pourra fournir un signal optique corrigé à un maximum de trois instruments scientifiques. Pour élargir la communauté des acteurs canadiens participant au projet du TMT, et au NFIRAOS en particulier, le CNRC a subdivisé l’instrument en sous-systèmes et donné le travail de conception finale en sous-impartition à des entreprises canadiennes. À l’heure actuelle, cinq partenaires industriels canadiens – ABB, INO, Dynamic Structures, Quantum Technology et Sightline Engineering – se partagent les contrats de conception des principaux sous-ensembles de NFIRAOS. Cette collaboration avec l’entreprise pour l’élaboration du cahier des charges de la conception est une nouvelle approche pour le CNRC, qui s’est avérée très profitable pour le projet grâce à la valorisation du savoir-faire et de l’expérience des partenaires de l’industrie.

Le NFIRAOS fournira aussi des images à la limite de diffraction dans les bandes J, H et K, avec une couverture du ciel de 50 % à partir du pôle galactique. Grâce à sa limite de diffraction, le TMT produira des images beaucoup plus nettes que tous les autres télescopes terrestres et même spatiaux existants aujourd’hui. Il a fallu des années d’efforts pour assurer que le TMT et le NFIRAOS produisent des images d’une netteté en moyenne supérieure à celle offerte par tout autre système d’optique adaptative. Évidemment, la couverture du ciel est un facteur important dans l’équation. Pour que les astronomes soient pleinement satisfaits du TMT conjugué au NFIRAOS, ils doivent pouvoir réaliser leurs principaux programmes d’observation. L’utilisation des étoiles guides laser, des systèmes d’optique adaptative multiconjuguée (OAMC) et des capteurs de basculement, d’inclinaison et de défocalisation en proche infrarouge sur instrument (OIWFS) contribuent à la réduction de la diffraction à 50 % du temps d’observation au pôle nord galactique. Le pourcentage de couverture du ciel s’accroît substantiellement pour les champs rapprochés du plan galactique, où la concentration d’étoiles est plus grande.

IRIS est l’instrument de première lumière du NFIRAOS. L’équipe d’IRIS est formée de groupes du CNRC, de Caltech, de l’Université de Californie à Los Angeles, à San Diego et à Santa Cruz, du National Astronomical Observatory japonais et du consortium du TMT. IRIS combine un imageur « grand champ » à un spectrographe à champ intégral (SCI) et couvre la gamme de longueurs d’onde de 0,84 µm à 2,4 µm. L’instrument est conçu en fonction de la limite de diffraction du TMT. L’imageur utilise quatre détecteurs Teledyne Hawaii-4RG-10, qui procurent un champ observé total de 34 × 34 secondes d’arc à une résolution de 4 millisecondes d’arc (mas). Le SCI offre quatre échelles de pixels spectraux (ou spaxels pour space et pixel) allant de 4 mas à 50 mas, et peut réaliser jusqu’à 14 000 spectres en une seule pose à l’intérieur d’un modèle rectangulaire plein. L’imageur et le spectrographe sont encapsulés dans un cryostat, soit une enceinte à vide étanche à la lumière assurant les températures cryogéniques indispensable au fonctionnement des deux sous-systèmes. Le CNRC est chargé de concevoir les trois capteurs de front d’onde sur instrument (OIWFS) qui seront montés dans une enceinte distincte posée sur le cryostat scientifique. Ces capteurs surveillent le périmètre extérieur d’un champ d’un diamètre de 2 minutes d’arc produit par le NFIRAOS et fournit les paramètres de mesure dans trois dimensions [basculement, inclinaison et focale] et les modes d’échelle que le NFIRAOS ne peut voir ainsi que ses étoiles guides laser. L’OIWFS assure les interfaces thermomécaniques avec le NFIRAOS. Le CNRC travaille aussi la conception de la monture et du mécanisme de rotation d’IRIS, qui est installé sous le NFIRAOS. Ce mécanisme procure une capacité de contre-rotation de champ à IRIS. Le CNRC est également chargé de concevoir la composante finale d’IRIS, soit les enroulements des câbles de service, qui partent de l’intérieur de l’OIWFS et du cryostat scientifique pour se connecter à la plateforme Nasmyth sous l’instrument et repartent vers l’enceinte de l’électronique d’IRIS ou les services sur place du TMT.

Lorsque le lieu où le TMT sera érigé aura été déterminé et que les travaux de construction auront repris, le NFIRAOS et IRIS entreront dans la phase de fabrication. Une nouvelle installation sera construite à Victoria pour réaliser l’intégration du NFIRAOS et d’IRIS. Après les essais complets des deux instruments à Victoria, ils seront envoyés au site du TMT où ils seront prêts à capter leur première lumière.

Nouvelles du ngVLA

L’interféromètre de prochaine génération Very Large Array (ngVLA) est un projet mené par l’observatoire américain NRAO pour remplacer le télescope existant, le Jansky Very Large Array, avec un instrument possédant 10 fois la sensibilité de l’ancien, fonctionnant dans la gamme de fréquences de 1,2 à 116 GHz, à des bases maximisant la résolution et possédant un cœur dense pour réaliser des images de surfaces à faible luminosité. L’équipe de projet travaille actuellement à l’élaboration d’une conception de référence pour l’inclure dans la proposition relative au projet de relevé décennal Astro2020. Le Canada, par l’entremise de CNRC Herzberg, participe à cette étape en fournissant les études de conception des antennes et du corrélateur.

La conception de référence du ngVLA comprend 244 antennes de 18 m de diamètre et 19 antennes de 6 m de diamètre. En collaboration avec les sociétés Minex Engineering et SED Systems, CNRC Herzberg a préparé des conceptions de référence chiffrées pour les deux modèles d’antennes utilisant la technologie de réflecteurs composites à pièce unique fixés sur disque (SRC) utilisée pour le réflecteur DVA1 et deux antennes.

Conceptions des antennes du ngVLA élaborées par CNRC Herzberg, à gauche, réflecteur de 18 m, et à droite, réflecteur de 6 m.


Comme le ngVLA doit fonctionner à la fréquence de 116 GHz, il a fallu retravailler le concept SRC pour réaliser la géométrie de surface et la précision de pointage requises. L’OFR a procédé à un examen de conception du concept en mai dernier avec la participation d’un comité externe et d’évaluateurs du NRAO. Des travaux supplémentaires sont actuellement en cours en préparation de l’examen de conception préliminaire qui aura lieu à Socorro, les 3 et 4 octobre prochains.

CNRC Herzberg doit fournir une conception de référence chiffrée d’un ensemble corrélateur-conformateur de faisceaux pour le ngVLA, reposant sur l’architecture à fréquence de découpage (FSA) et la technologie FPGA FinFET 14 nm de TALON développée pour le corrélateur-conformateur de faisceaux moyenne fréquence de SKA1. L’architecture et la technologie conviennent au projet et pourront être adaptées aux 263 antennes du ngVLA, fonctionnant dans la gamme de 28 GHz/POL et compatibles avec des bases de 10 000 km. Comme la construction du ngVLA ne débutera pas avant le milieu de la décennie 2020 dans le meilleur des cas, les coûts et la puissance requise devraient être inférieurs à ce qu’exige la technologie TALON de 2018.

ALMA Matters

ALMAlogo

From / de Gerald Schieven
(Cassiopeia – Autumn / l’automne 2018)

New Horizons Conference Pre-registration Open


Pre-registration is now open to the conference: “New Horizons in Planetary Systems”, to be held in Victoria from 13-17 May 2019. Pre-registration and more information is available here. Registration and abstract submission will open in October.

The meeting is planned to have a broad scope, including planetary systems in formation within protoplanetary disks, minor objects in the solar system, debris disks and exoplanets. Experts will be asked to provide insights from all these fields to enhance our understanding of how planets form and evolve. Though co-organized by NRAO and the NRC Herzberg millimetre astronomy group, the meeting is not ALMA-centric, and has a strong focus on the impact of the New Horizons mission flyby of a KBO in January 2019, plus experts from TESS and other facilities who will be asked to provide a multi-chromatic picture of the current understanding in their fields. Invited speakers have been asked to provide broadly accessible talks.

Confirmed invited speakers include:

Diana Dragomir (MIT Kavli Inst): Early results from the TESS mission
Brett Gladman (UBC): theory of planet formation
Grant Kennedy (U Warwick): debris disk constraints on planet formation
Heather Knutson (Caltech): exoplanet atmospheric composition
Emmanuel Lellouch (Observatoire de Paris): solar system objects, constraints on formation
Karin Öberg (Harvard U): protoplanetary disk composition and chemistry
John Spencer (SWRI): New Horizons KBO flyby: first results
Zhaohuan Zhu (UNLV): protoplanetary disk structure

We will also host a public talk on New Horizons by Deputy Mission Scientist Kelsi Singer (SWRI).

Canadian Cycle 6 ALMA Allocations

Projects with PIs from Canadian institutions were again disproportionately successful in obtaining time in Cycle 6. Allocations were announced at the end of July. Of the 44 Canadian PI proposals submitted (a record), 10 were awarded 217 hours of high priority time (17 (for 323 hours) including grade C “fallback” projects). This represents 9.7% of the North American allocation of high priority time. Though lower than the fraction allocated in Cycle 5 (partly due to Canadian participation in a Large program), this is significantly higher than in Cycles 1-4. Note that Canada has a 7.246% stake in the North American share of ALMA.

Globally, there were Canadian (i.e. investigators from Canadian institutions) on 19.4% of all proposals that were awarded high priority time.

There were 27 unique Canadian PIs and 93 individuals as PI or coI proposing for ALMA this cycle; both these numbers are record highs for all cycles.

ALMA Development Roadmap

ALMA is approaching completion of its initially envisaged capabilities and, within the first five years of operations, the original fundamental science goals of ALMA have been essentially achieved. The ALMA Board established a Working Group to develop a strategic vision and prioritize new capabilities for the Observatory out to 2030 as part of the ALMA Development Program. The ALMA Board approved the resulting ALMA Development Roadmap in November 2017, which you can download from here.

According to the vision in the Board-approved Roadmap, the current development priorities as based on scientific merit and technical feasibility, are:

  • to broaden the receiver IF bandwidth by at least a factor two, and
  • to upgrade the associated electronics and correlator.

These developments will advance a wide range of scientific studies by significantly reducing the time required for blind redshift surveys, spectral scans, and deep continuum surveys. In order of scientific priority, receiver upgrades are recommended for intermediate (200-425 GHz), low (< 200 GHz), and high (> 425 GHz) frequencies.

Dissertation: Étude sous-millimétrique de l’interaction entre le magnétisme et la turbulence dans les milieux interstellaires / Submillimetre study of the interaction between magnetism and turbulence in interstellar media

(Cassiopeia – Summer / été 2018)

SimonPic
by / par Simon Coudé
Thesis defended on February 19, 2018
Université de Montréal / University of Montréal
Thesis advisor: Dr. Pierre Bastien

The English version follows

Abstract
L’astronomie sous-millimétrique est une fenêtre unique pour l’étude des propriétés physiques d’une grande variété d’environnements interstellaires, des pouponnières d’étoiles de notre Galaxie aux jets relativistes issus de noyaux galactiques actifs. Grâce en particulier aux observations polarimétriques, il est même possible d’étudier les effets de l’interaction entre le magnétisme et la turbulence sur la dynamique de ces milieux. Cette thèse présente les résultats d’une étude sous-millimétrique dont l’objectif est de caractériser les propriétés physiques et la dynamique d’une sélection de régions de formation d’étoiles et de jets extragalactiques à partir d’observations continues, spectroscopiques et polarimétriques obtenues au télescope James-Clerk-Maxwell (JCMT).

Nous avons d’abord quantifié l’effet de la contamination moléculaire sur les observations du nuage moléculaire géant d’Orion A obtenues à 450 µm et 850 µm avec la caméra SCUBA-2. À l’aide de mesures spectroscopiques effectuées avec le spectromètre HARP de la raie moléculaire 12CO J=3-2, nous avons identifié un échantillon de 33 sources dont le flux à 850 µm est fortement contaminé par des flots moléculaires environnants. Nous avons finalement montré que cette contamination mène à une sous-estimation de l’indice spectral d’émissivité β obtenu à partir du ratio des flux mesurés à 450 µm et 850 µm.

Dans le cadre du programme BISTRO au JCMT, nous avons utilisé le polarimètre POL-2 afin de caractériser le champ magnétique dans la région de formation d’étoiles Barnard 1 du complexe moléculaire de Persée. Nous avons d’abord déterminé l’orientation sur le plan du ciel du champ magnétique à partir de la carte de polarisation linéaire obtenue à 850 µm. Nous avons aussi calculé une valeur de 1.05 ± 0.92 pour le rapport entre les composantes turbulentes et ordonnées de l’énergie magnétique. Grâce aux observations de la raie moléculaire C18O J=1-0 obtenues au FCRAO, nous avons enfin appliqué la technique de Davis-Chandrasekhar-Fermi afin d’évaluer l’amplitude du champ magnétique à ~20 µG.

Avec l’équipe de mise en marche de POL-2, nous avons détecté avec succès la polarisation à 850 µm dans le coeur protostellaire CB 68. Nous avons ainsi déterminé l’orientation dans le plan du ciel du champ magnétique à l’intérieur de cet objet, que nous avons ensuite comparé avec les données SCUPOL dans la littérature. Additionnellement, nous avons mesuré une diminution de la fraction de polarisation en fonction de l’intensité totale, ce qui pourrait être expliqué par des effets de dépolarisation le long de la ligne de visée.

Finalement, nous avons mené la première campagne avec POL-2 afin d’étudier la variabilité temporelle de la polarisation linéaire à 850 µm vers quatre noyaux galactiques actifs: 3C 84, 3C 273, 3C 279 et 3C 454.3. Nous avons mesuré une variation significative de la fraction et de l’angle de polarisation pour 3C 84, 3C 273 et 3C 279 sur une période de 9 mois. Cette variabilité supporte la présence de cellules turbulentes magnétisées à l’intérieur de chocs permanents le long des jets relativistes issus de l’accrétion de matière sur les trous noirs supermassifs au centre de ces galaxies.



Submillimetre astronomy is a unique window for the study of the physical properties of a large variety of interstellar environments, from the stellar nurseries of our Galaxy to the relativistic jets from active galactic nuclei. With polarimetric observations in particular, it is even possible to study the effects of the interaction between magnetism and turbulence on the dynamics of these environments. This thesis presents the results from a submillimetre study which goal was to characterise the physical and dynamical properties of a selection of star-forming regions and extragalactic jets using continuum, spectroscopic and polarimetric observations from the James Clerk Maxwell Telescope (JCMT).

We have first quantified the effect of molecular contamination on SCUBA-2 observations at 450 µm and 850 µm of the Orion A giant molecular cloud. With spectroscopic measurements using the HARP spectrometer of the 12CO J=3-2 molecular line, we have identified a sample of 33 sources for which the 850 µm flux is highly contaminated by nearby molecular outflows. Finally, we have shown that this contamination leads to an underestimation of the emissivity spectral index β derived from the 450 µm to 850 µm flux ratio.

As part of the BISTRO survey at the JCMT, we have used the POL-2 polarimeter in order to characterise the magnetic field in the Barnard 1 star-forming region in the Perseus molecular cloud complex. We have inferred the plane-of-sky orientation of the magnetic field from the linear polarisation map obtained at 850 µm. We have also calculated a value of 1.05 ± 0.92 for the turbulent-to-ordered magnetic energy ratio. With FCRAO observations of the C18O J=1-0 molecular line, we have also applied the Davis-Chandrasekhar-Fermi method in order to evaluate the amplitude of the magnetic field to be ~20 µG.

With the POL-2 commissioning team, we have successfully detected the 850 µm polarisation in the CB 68 protostellar core. We have then inferred the plane-of-sky orientation of the magnetic field within this cloud that we have then compared to previously published SCUPOL observations. Additionally, we have measured a diminution in the fraction of polarisation as a function of total intensity, which could be explained by depolarisation effects along the line-of-sight.

Finally, we have lead the first POL-2 campaign to study the temporal variability of the 850 µm linear polarisation towards four active galactic nuclei: 3C 84, 3C 273, 3C 279 and 3C 454.3. We report significant variability in the fraction and angle of polarisation for 3C 84, 3C 273 and 3C 279 over a period of 9 months. This variability supports the presence of magnetised turbulent cells within standing shocks along the relativistic jets originating from the accretion of matter on the central supermassive black holes of these galaxies.

Update on CASTOR

By / par Patrick Côté (NRC Herzberg Astronomy & Astrophysics Research Centre)
(Cassiopeia – Summer / été 2018)

Background

The Cosmological Advanced Survey Telescope for Optical and ultraviolet Research (CASTOR) is a proposed Canadian-led space telescope that has been in detailed study by the Canadian Space Agency (CSA) since 2011. The mission concept was developed in response to LRP2010, which identified Canada’s top priorities in space astronomy as “…significant involvement in the next generation of dark energy missions — ESA`s Euclid, or the NASA WFIRST mission, or a Canadian-led mission, the Canadian Space Telescope.” A detailed concept study for CASTOR was completed in 2012. Subsequent CSA-sponsored technical studies, undertaken between 2013 and 2017, further developed the mission concept by retiring sources of technical risk. In 2015, the mid-term review of LRP2010 recommended that the CSA immediately launch a Phase 0 study for CASTOR.

Design

CASTOR is a 1-m telescope that uses a three-mirror-anastigmat design to deliver Hubble-like image quality (FWHM ~ 0.15”) over a wide field of view (0.5 deg x 0.5 deg) — nearly a hundred times larger than that of Hubble’s cameras. Complementing the Euclid and WFIRST missions, CASTOR would operate at UV/blue-optical wavelengths using dichroics to image simultaneously in three pass-bands that span the 0.15-0.55 micron region. CASTOR would also offer strong synergies with LSST by providing superior resolution and point-source sensitivity at blue-optical wavelengths, as well as direct access to the UV region. The latter will become a critical capability in the coming decade when HST will likely cease operations. In short, CASTOR would be a powerful vehicle for both surveys and Guest Observer programs, and would provide Canadian astronomers with a unique and strategic capability in the coming decade.

Status

In the fall of 2017, CSA commissioned an extended Science Maturation Study (SMS) for the CASTOR mission that began in January 2018. The 14-month study, which will conclude in March 2019, will revise and update the CASTOR concept with an emphasis on the science case. Eight science working groups have been formed to explore scientific opportunities across a broad range of fields, from the cosmology to the solar system, with an eye towards updating the scientific requirements and optimizing the observing plan. Technical work is addressing all aspects of the mission design, including mission architecture, opto-mechanical design (including a possible spectrographic capability), satellite bus and launch options, ground segment requirements, and mission implementation plan.

The study — which will lead to an improved understanding of mission cost, schedule and risk, and involve an exploration of possible international partnerships and collaborations — is being led by Honeywell Aerospace (Ottawa), in collaboration with ABB Engineering (Quebec) and Magellan Aerospace (Winnipeg). The science team that consists of nearly 60 researchers at 17 Canadian universities and institutes. The study also involves major international partners — currently the Jet Propulsion Laboratory (JPL) and the Indian Institute of Astrophysics, who have been our partners in Astrosat, and are responding to an ISRO call for Astrosat2 proposals.

For more information on the CASTOR mission, see the project website.

To get involved in CASTOR, please contact Patrick Côté (scientific) or Alan Scott (technical).

News from the JCMT

By / par Chris Wilson, McMaster University (JCMT Board member for Canada)
(Cassiopeia – Summer / été 2018)

The JCMT continues to produce exciting new science results, with many results from the Large Programs appearing in the past 6 months. I’d like to particularly highlight the amazing results from the Canadian built polarimeter POL2 on SCUBA-2, including the first observations of the magnetic field structure inside the “Pillars of Creation” from the BISTRO Large Program (see Pattle et al., 2018, ApJL, in press, ArXiv: 1805.11554 and Ward-Thompson et al., 2017, ApJ). Pierre Bastien (Montreal) also presented a poster on POL-2 results at the recent CASCA meeting. The first generation Gould Belt Survey with SCUBA-2 is being very productive and publishing lots of papers, with good Canadian participation and leadership. There is also a major Canadian role in the new transient large program with some exciting papers published recently.

Magnetic field vectors  in the “Pillars of Creation” in the M16 nebula are shown overlaid on a 3-colour HST image from Hester et al. (1996). The data were obtained at 850 microns with the POL2 instrument mounted in front of SCUBA-2 on the JCMT. Figure from Pattle et al. (2018, ApJL, in press).

Magnetic field vectors in the “Pillars of Creation” in the M16 nebula are shown overlaid on a 3-colour HST image from Hester et al. (1996). The data were obtained at 850 microns with the POL2 instrument mounted in front of SCUBA-2 on the JCMT. Figure from Pattle et al. (2018, ApJL, in press).

Canadian PI observing time on the JCMT continues to be very oversubscribed, although the oversubscription rate in the most recent semester (18B) was lower than previous semesters. This drop may reflect the uncertainty in future Canadian participation in the JCMT (see below), or simply proposer fatigue caused by the high oversubscription rate.

The East Asian Observatory (EAO) currently has a 5-year agreement to operate the JCMT that ends in February, 2020. Recently, the EAO Board decided that they wish to continue to operate the JCMT for a second 5-year term. They would welcome continued participation by their U.K. and Canadian partners, and are also looking for additional partners from Asia and beyond.

As a result of this extended commitment by the EAO, the observatory is planning for upgrades to the existing instrumentation. The current 230 GHz receiver will be replaced with a newer, more sensitive receiver within the next year. Active investigations are underway for replacements for both SCUBA-2 and the 345 GHz array receiver HARP-B. Assistant Director Jessica Dempsey gave a talk about the future instrumentation plans at the JCMT at the recent CASCA meeting in Victoria.

The current Canadian university funding runs out February 2019. We will be looking for options to continue to fund JCMT operations, but none are currently obvious. The NSERC RTI program that has funded the Canadian operations contribution from February 2017-February 2019 did not run a competition in 2017. It remains to be seen whether it will be resurrected for the 2018 competition this fall given the new infusion of money from the Federal Government to the granting councils. The CADC currently operates the archive for the JCMT and about half of our PI observing time is tied to this CADC contribution. Whether this situation will continue if university funding for the JCMT ends remains to be confirmed. Another opportunity we are exploring is whether a CFI proposal could fund a contribution to the new instruments on the JCMT in return for continued PI access by Canadian researchers.

If operational funding from Canada lapses completely, Canadian astronomers will continue to be members of and have access to the existing Large Programs on the JCMT. Whether this courtesy would be extended at the next large program call (likely sometime in 2020) remains to be seen.