Récipiendaire de la Médaille Richer 2021 – Dr. Renée Hložek

CASCA a le plaisir de nommer Dr. Renée Hložek comme récipiendaire de la Médaille Richer 2021. Dr. Hložek a obtenu son DPhil à l’Université Oxford en tant que Boursière de Rhodes et est présentement Assistante Professeure à l’institut Dunlap et au département d’Astronomie et d’Astrophysique à l’Université de Toronto. Elle est une experte reconnue en cosmologie théorique et observationnelle, à la fois dans l’étude du fond micro-ondes cosmologique, des structures à grande-échelle et de la cosmologie transitoire. Elle détient une position de leader dans multiples collaborations internationales, incluant l’observatoire Simons, le télescope cosmologique Atacama, le Consortium Canadien Euclid et l’observatoire Vera Rubin. Joignant ses réalisations en recherche avec la formation d’un grand nombre d’étudiants depuis son arrivée à Toronto, elle a réhaussé le profil et l’impact de la communauté Canadienne de Cosmologie. Dr. Hložek a recu le prix de mérite du Doyen de la Faculté de l’Université de Toronto en 2017 et 2018 et a été élue Boursière Mondiale CIFAR-Azrieli ainsi que Compagnon de Recherche Alfred P. Sloan.

CASCA a le plaisir de récompenser les efforts de Dr. Renée Hložek’s avec ce prix.

Récipiendaire du prix de la Conférence R.M. Petrie Prize pour 2021: Dr. Heino Falcke

CASCA a le plaisir de nommer Dr. Heino Falcke comme récipiendaire du prix de la Conférence R.M. Petrie Prize pour 2021. Dr. Falcke est professur de Physique des Astroparticules et d’Astronomie Radio à l’Institut des Mathématiques, Astronomie et Physique des Particules de la faculté des Sciences à l’Université Radboud. Durant des décennies, il a été un leader international dans la poursuite de l’imagerie de l’ombre d’un trou noir à l’aide de l’interférométrie à très longue base. Ces efforts ont culminés en l’imagerie stupéfiante du trou noir supermassif dans M87 par le Event Horizon Telescope (EHT). Dr. Falcke est membre de l’Académie Royale des Arts et Sciences des Pays-Bas et a gagné le Prix de Percée en Physique Fondamentale en 2019 comme membre de la collaboration EHT.

CASCA est honoré de donner la Conférence Petrie Prize a Dr. Falcke

Récipiendaire de la Médaille J.S. Plaskett 2021: Dr. Ziggy Pleunis

CASCA a le plaisir de nommer Dr. Ziggy Pleunis comme récipiendaire de la Médaille J.S. Plaskett 2021 pour la thèse de doctorat la plus remarquable en astronomie et astrophysique. Dr. Pleunis a complété sa thèse de PhD en 2020 sous la supervision de Prof. Victoria Kaspi à l’Université McGill et ira bientôt à l’Université de Toronto comme Compagnon Dunlap. Sa thèse, intitulée “Fast radio burst detection and morphology with the CHIME telescope” représente un ensemble de contributions majeures au nouveau champ de recherche des Fast Radio Bursts en astronomie. Dr. Pleunis a contribué à tous les aspects du projet FRB du télescope CHIME; l’instrumentation, les logiciels, l’observation, l’analyse et l’interprétation scientifique. Au-delà de CHIME, il a aussi fait plusieurs avancées scientifiques en utilisant le LOw Frequency Array (LOFAR), de la découverte d’un FRB à basse fréquence à l’étude de Pulsars millisecondes.

CASCA a le plaisir de récompenser les réalisations de Dr. Pleunis avec ce prix. De plus, nous tenons à souligner les thèses exceptionnelles de tous les finalistes: Dr Ryan Cloutier, Dr Maan Hani, Dr Eric Koch, Dr Ian Roberts et Dr Kaja Rotermund.

Récipiendaire du prix Qilak Award 2021: Dr. Jayanne English

CASCA a le plaisir de nommer Dr. Jayanne English comme récipiendaire du prix Qilak Award 2021. Dr. English a obtenu son PhD à l’Australian National University et est présentement Professeure Associée en Astronomie à l’Université du Manitoba. Sur plusieurs décennies, Dr. English a mise à profit sa formation artistique (à l’Ontario College of Art and Design University) pour construire un programme de sensibilisation unique qui marie art et science. Elle a promu l’utilisation de techniques artistiques et de design pour influencer comment l’imagerie en astronomie est faite par les professionnels et les amateurs passionnés. Durant son mandat de deux ans de coordinatrice du projet Hubble Heritage, elle a mené la production d’images parmi les plus iconiques du Hubble Space Telescope, dont certaines ont été vues par des milliards de personnes. En combinant des données optiques avec des observations radios, Dr. English a récemment reçue la deuxième place au National Radio Astronomy Observatory 2020 Visualization Award pour son image HST-VLA, composite superbe de la galaxie NGC 5775. En collaboration avec la compositrice Nicole Lizee, elle a produit ‘’Colliding Galaxies : Colours and Tones’’, une intégration unique de l’astronomie et de la musique électronique. En conceptualisant et enseignant des cours tels que ‘’The Art of Scientific Visualization’’, Dr. English a aussi entrainé une nouvelle génération d’experts en visualisation astronomique, garantissant ainsi que son travail aie des effets multiples sur une communauté plus large.

CASCA à le plaisir de récompenser les efforts du Dr. Jayanne English avec ce prix.

Récipiendaire du Prix Martin 2021: Dr Sara Ellison

CASCA a le plaisir de nommer Dr. Sara Ellison comme récipiendaire du Prix Martin 2021. Dr. Ellison a obtenu son PhD à l’Université Cambridge et est présentement Professeure de Physique et d’Astronomie à l’Université de Victoria. Dr. Ellison est une leader internationale à la fois dans l’étude de lignes d’absorption QSO à haut décalage vers le rouge et dans la fusion de galaxies dans l’Univers local. Ses champs de recherche sont variés. Comme expérimentaliste, Dr. Ellison a mené de multiples programmes d’observation au travers du spectre électromagnétique, des Rayons-X aux ondes radios en passant par le visible. Comme théoricienne, elle a complémenté son travail observationnel avec des simulations sur une variété d’échelles de longueurs et des techniques à la fine pointe de la technologie, telle que le Machine Learning. Sa recherche a eu un impact majeur, réunissant plus de 11500 citations au total, avec plusieurs de ses travaux sur la métallicité des galaxies et la fusion/interactions des galaxies considérés comme définitifs dans le domaine. Dr. Ellison a reçu le Prix Annie Jump de la American Astronomical Society en 2004, le Prix d’Excellence en Recherche de la Faculté de Science de l’Université de Victoria en 2009, la Rutherford Memorial Medal en Physique de la Société Royale Canadienne en 2014 et la Médaille d’argent pour Excellence en recherche REACH en 2020.

CASCA à le plaisir de récompenser les réalisations de Dr. Ellison avec ce prix.

President’s Message

By / par Sara Ellison (CASCA President)
(Cassiopeia – Spring / printemps 2021)

Happy 50th Birthday CASCA! Yes, 2021 is a special year for CASCA, as we mark our half century as a Society. For those interested in a potted history of the Society, a short summary of the background leading up to CASCA’s founding, and its early years, can be found here.

The AGM offers the ideal (virtual) venue to celebrate our 50th anniversary, and several CASCA groups/committees are organizing commemorative activities. Gordon Walker (one of CASCA’s original charter members), will give a talk at the AGM banquet reflecting on 50 years of CASCA and Canadian astronomy. The AGM organizers are also inviting all charter members (many of whom are still current members – see here for a full list) to submit video recollections, sharing their memories and perspectives from those early years. For the charter members who are unfortunately no longer with us, the Heritage Committee (Chaired by Elizabeth Griffin) will be compiling short biographies in memory of our founding colleagues. In addition to this reflection upon the past, we also want to look forwards to the next half century. The Graduate Student Committee (Chaired by Carter Rhea) will be reaching out to current graduate students and postdocs to invite them to make “futurecast” videos, speculating what Canadian astronomy will look like at our 100th anniversary in 2071. Highlights from these futurecasts will also be shared at the AGM banquet. Finally, as you will have seen via the CASCA email exploder, a competition is currently open to submit an anniversary themed Zoom background that can be used during our virtual meeting in May. Submissions are due by April 20, and may be uploaded here.

Anniversary celebrations are just one facet of our AGM, which is coming up in less than 50 days (May 10-14). Dennis Crabtree and his team have been working feverishly on preparations for a stimulating and diverse meeting, that blends science, socializing and societal priorities and promises to be a conference unlike any you have attended in the past! The roster of invited speakers is nearing completion and will likely be posted on the CASCA2021 website by the time you read this. Speaker highlights include a public lecture by Nobel Laureate Andrea Ghez and an indigenous cultural awareness session given by Bob Joseph (author of « 21 Things You Didn’t Know About the Indian Act », a copy of which will be given free to all participants). The deadline for abstract submission has now passed and 147 abstracts were received for oral contributions across the scientific, EPO, and EDI/Sustainability categories. The deadline for applications for dependent care support has been extended to April 15. Although the deadline for general registration extends until May 3, the Organizing Committee encourages people to register early for the conference as some information will be sent to only registered attendees via the Whova platform.

On the lobbying and engagement front, the Coalition for Canadian astronomy has been very active this last quarter. A commitment for membership and funding in the SKA is urgently needed (see the article by Kristine Spekkens on behalf of the AACS in this newsletter edition for further updates on the SKA). Since the SKA Observatory, an inter-governmental treaty-based organization, came into force in February, Canada’s lack of formal commitment (via membership and funding) means that our status within the project has effectively been reduced to “observer”, with no means to provide scientific, technical or governance input. Moreover, if we have not joined SKAO by July 2021 we will likely lose the highly desirable, and valuable, correlator contract provisionally allocated to Canada. Given this, our political and bureaucratic outreach has been focused on SKA membership and funding through much of Q4 2020 and Q1 of 2021, with a particular focus on the Ministers and Departments of Finance and Innovation, Science and Industry.

A commitment to the SKA might be made in the Federal budget itself. At present, there is no date for the 2021 budget, and the Prime Minister recently announced that the budget will not be in March or early April. If so, and based on the House of Commons calendar, the next earliest opportunity is the week of April 12, though it could be even later as on March 12 the Prime Minister said the budget date will be announced “in the coming weeks.” Regardless, assuming that it is within the 4-6 weeks that begin on April 12, the budget could set the stage for a late-May or June election. While all parties are suggesting they do not want an election, all are also getting ready, with candidate nominations picking up steam, campaign personnel starting to get appointed, and platform development underway. Regardless of the timing of the budget and a possible 2021 election, the messaging to decision-makers has focused on the fact all SKA partners except Canada have now formally or informally committed to the project and that a failure by Canada to do so by July will strongly compromise our return on investment.

The availability of our Long Range Plan 2020-2030 has been very timely in our engagement efforts, and is providing a valuable tool to signal our coordinated strategy for the next decade. As you know, the basic text of LRP2020 has been available on CASCA’s website since December 2020. The completion of the fully typeset+graphics version should be available in electronic version within a few weeks and a message will be posted to the CASCA exploder to alert our membership to its availability. Printed copies are expected about a month beyond the electronic version, at which point the Coalition will organize a mass mailing to targeted Ministers, MPs, Senators, and Departmental stakeholders, along with a cover letter from the Coalition for Canadian Astronomy, highlighting the major project opportunities in the LRP, such as SKA and CASTOR.

In addition to the pressing need for SKA funding, the CASTOR mission is also very much in need of our commitment. The next 9-12 months are critical, as the project intends to seek government approval in early 2022 and secure Canadian leadership in the mission. The Space Technology Development Program (STDP) study will start this month or next, and the call for a Phase 0 study is expected in the summer. More detail is available in the CASTOR update in the current newsletter, and there will be a dedicated Town Hall Session as part of the AGM (May 13). Students and postdocs are particularly encouraged to get involved in these efforts, as CASTOR promises to a flagship for Canadian space astronomy in the coming decade, with opportunities across the fields of astronomy, aeronautics, software development hardware design and manufacture.

Update on CASTOR

By / par Patrick Côté, John Hutchings (NRC Herzberg Astronomy & Astrophysics Research Centre)
(Cassiopeia – Spring / printemps 2021)

CASTOR continues to move forward to fulfil its ranking as the top LRP2020 priority for space astronomy. The following steps have been taken in the past quarter.

  1. The substantial technical (STDP) contract is in final stages of being signed, and is expected to kick off officially by early April. The work will advance vital mission technology and retire risks in a) advancing the opto-mechanical design for the 1m off-axis wide-field telescope; b) designing and testing the large focal plane array concept with flight-like detectors; c) lab-testing the proposed fast-steering mirror for fine guiding; d) incorporating and adding detectors to the multi-slit spectrograph in design in India; and e) developing the concept for bright-star precision photometry of exoplanet transits. The work will be in close partnership with the Indian and JPL teams.
  2. Formal discussions are now under way between CSA and ISRO on a joint mission. The agreed concept is that of CASTOR, and an initial proposed split of the hardware and operation responsibilities has been agreed, subject to more detailed discussions. Along with the anticipated detector involvement by JPL, this will form the basis of a Canada-led proposal for funding from the government. ISRO will work in close step in a proposed schedule that will see CASTOR launched in late 2027.
  3. Plans are evolving for involving the Universities via ACURA, consultation with the government via the Coalition, and outreach activities within the CASTOR science team. CASTOR will have a town-hall event (on Thursday May 13) at the upcoming virtual CASCA Annual Meeting. Talks have been given by CASTOR team members at meetings in UK and India.
  4. CSA is on track to approve and begin a phase 0 study in parallel with the technical contract work, to refine costs and detail moving into a funded phase A-E sequence to take CASTOR to launch and operation.

This year will be an important one in defining the partnership and pitching the mission to government. With its wide range of science capability, it will be a major facility for the astronomy community, and those interested in joining in are encouraged. In particular, there exist numerous opportunities for student participation; for more information, students are encouraged to attend the CASCA town hall session and/or the CaTS (Canadian Telescope Seminar) talk in June, which will be dedicated to CASTOR.

More information on the mission may be found here.

President’s Message

By / par Sara Ellison (CASCA President)
(Cassiopeia – Winter / hivers 2020)

The Long Range Plan is out! This final report represents two years of effort in our community to examine the state of our professional activities and ambitions from both a scientific and societal perspective. Hundreds of people in our community have contributed in a variety of ways to the generation of this finished product, ranging from co-authoring white papers, attending town hall meetings and dedicated AGM sessions, to providing feedback to the panel along the journey. A broad message of gratitude is therefore due to the entire community for your engagement and collaboration. As a Society, we owe our greatest thanks to the LRP panel for the immense undertaking of leading this process: Pauline Barmby, Matt Dobbs, Bryan Gaensler, Jeremy Heyl, Natasha Ivanova, David Lafreniere, Brenda Matthews and Alice Shapley. The French version of the LRP, as well as the typeset version with full figures and design and hard copies, are expected early in the new year.

As alluded to in my last President’s message, the next challenge in the LRP process is its implementation, and the Board (with input from the current LRPIC, as well as LRP co-chairs) has been laying out the strategy for this next step. Oversight and monitoring of both existing and future facilities will remain in the remit of our current CASCA committees: the Ground-based Astronomy Committee (GAC, currently chaired by Stefi Baum) and the Joint Committee on Space Astronomy (JCSA, currently chaired by Locke Spencer). In order to tackle the broad ranging community-based LRP recommendations, CASCA will create a new committee, the LRP Community Recommendations Implementation Committee (LCRIC), whose portfolio will encompass the societal-level aspects of the plan, including equity, indigenous matters, outreach and sustainability. The LCRIC will work to generate an actionable implementation plan from the LRP’s recommendations, working with existing CASCA committees and striking new working groups as needed to convert the recommendations into reality over the next decade. We are just beginning the first steps in establishing this new LCRIC, but I am delighted to announce that Christine Wilson (McMaster University) has agreed to be the inaugural Chair. Given their remit, the new LCRIC, in partnership with the GAC and JCSA, will replace the previous LRPIC – I thank John Hutchings and his team for their wisdom and tireless efforts over many years.

The top (unfunded) large facilities in the LRP are the SKA and CASTOR. As discussed in my September message, the SKA is reaching a critical point with the IGO expected to take over the project imminently. Securing membership and funding for Canada has been at the top of CASCA’s agenda of effort over the last few months. I have been working closely with Kristine Spekkens (Canadian SKA Science Director) and Gilles Joncas (AACS Chair) to prepare the ground for the Coalition’s lobbying activities. These activities are now well underway with a positive first meeting with officials from ISED, and more in the planning stages. In collaboration with ACURA, the AACS has also mobilized its university connections, with several VPR briefings already completed across the country. I encourage you to look at the Canadian SKA webpage, which hosts a wealth of material on the project, its science aspirations, industry connections and societal impacts. In particular, I point you to a handy 4-page summary of the project in the Canadian context, in case you have the opportunity to discuss the project in your broader networks.

With an anticipated launch in the late 2020s, there is also significant on-going progress on planning for the CASTOR space telescope. A more complete report is provided by Pat Côté in this Edition, but the long-awaited CSA technical study request for proposals (STDP RFP) has now been issued (and, by the time you read this, closed), representing a significant step in the preparatory process. CASTOR is one of seven “Priority Technologies” in this call, and there are five different work packages within the CASTOR study. The CSA has also started working a mission development plan for CASTOR: i.e., a summary of timelines, budget requirements, milestones and action items that mark the path towards launch later this decade. CASTOR represents a truly unique and exciting component in Canada’s astronomy portfolio – the potential for a Canada-led UV-optical space telescope will not only bring terrific science returns, as well as showcasing and supporting our national expertise in several technology domains, but it will generate tremendous excitement and pride in the general public, inspiring the next generation of budding scientists and engineers.

On the digital infrastructure side, the New Digital Research Infrastructure Organization (NDRIO) is ramping up to eventually replace Compute Canada. Unlike Compute Canada, NDRIO is funded directly by ISED, and CASCA is an Associate Member (as is CADC). NDRIO held its first AGM at the end of September, at which the inaugural Researcher Council (RC) was announced. Erik Rosolowsky (U of A) was one of approximately 20 appointees on the new RC. Despite this success, it is the responsibility of our broader community to engage with NDRIO and communicate our needs. Notably, astronomy represents ~5% of Compute Canada users but uses ~20% of its resources. Our success as a field therefore critically relies on effective and appropriate DRI. NDRIO has outlined several steps in its initial consultation process on needs assessment within the broader community. Several white papers are under preparation within our astronomy community in response to the first step in this call. A user survey is also expected in the near future – please take the time to complete this survey when it comes your way!

Preparations for the CASCA 2021 AGM (May 10-14) continue apace – since CASCA was founded in 1971, this will be our 50th birthday party! The SOC and OOC have developed an exciting scientific and social program for CASCA 2021. With the release of the LRP, and the broad reaching issues it has assessed, the SOC has chosen a theme that will align with the LRP2020’s goals: « Canadian Astronomy: Dialing It Up To 11 ». The SOC has selected a roster of invited speakers and the invitations will have been sent by the time you read this. The organizing committees have scored quite the coup with securing recent Nobel laureate Professor Andrea Ghez to present the Helen Sawyer Hogg Public Lecture. Two other ‘evening’ events have been planned. There will be a games night featuring the popular game ‘Among Us’ and the CASCA Banquet will feature « CASCA Has Talent » – a chance for CASCA members to demonstrate their non-astronomy skills. The OOC is also working on integrating daily social interactions; it won’t be quite the same as being together in Penticton, but it sounds like it will be a lot of fun nonetheless! Watch this space in the new year for more details and registration.

President’s Message

By / par Sara Ellison (CASCA President)
(Cassiopeia – Autumn / l’automne 2020)

It’s back to school time – and for a semester the like of which we have never seen before! First of all, a warm welcome to all of the new members of our community – graduate students, postdoctoral fellows and professors alike. It is not an easy time to be starting a new position of any kind, or moving to a new place. Although we are fortunate that our profession is largely conducive to remote working, activities such as collaboration meetings, classroom interactions and student-supervisor exchanges all play a critical role in our daily work lives. Engaging our new community members will be critical in the months ahead. I encourage every one of us to think about how we can reach out to the new people in our departments (and beyond!) to make them feel welcome and included. I also want to take this opportunity to remind you that new graduate students can join CASCA for free for their first year, so please encourage your new peers/students to take advantage of this.

The Long Range Planning (LRP) process is reaching its crescendo. The main facility recommendations have now been released ahead of the full report, in order that they can be a ready tool for lobbying and funding efforts that will start to ramp up through the Fall. The full report content is expected to be released in mid-November (a reminder that there is a dedicated set of LRP web pages hosted on casca.ca, including the schedule for the next six months). Although the release of the LRP’s report represents the final lap of an (ultra?) marathon for the LRP panel, it is just the start of our work as a community. Converting the LRP’s recommendations into reality (whether that be funding new facilities, or improving astronomy’s professional climate) should be an effort in which we all engage. The CASCA Board will, of course, be reviewing the implementation process once the full report comes out. This will certainly include coordination with our Society’s committees, for example to discuss recommendations specific to topics such as equity, diversity, public outreach and sustainability. There has also already been discussion with (and within) the current LRP Implementation Committee (LRPIC, Chaired by John Hutchings), who have overseen the last decade of progress, on how we can most effectively monitor, support and facilitate recommendations. Beyond these official structures, the actions and voices of individual community members (i.e. you!) will be equally vital in converting the LRP’s recommendations into a reality. Every one of us can enact recommendations concerning our professional climate.

One of the LRP-recommended facilities which demands our immediate efforts is the Square Kilometre Array (SKA; see the latest newsletter update here), in which Canada has been a key player since its inception. The SKA is currently going through a major transformation into an inter-governmental organization (IGO) with partner countries signing a convention for membership. This process is already well underway, with 7 countries having already signed the convention, with 3 of them fully ratified. The convention will come into full force when five countries (including the 3 hosts: Australia, South Africa and the UK) have ratified, which is expected by mid-2021. Canada is not currently amongst these signatories. In order that Canada can continue to play a major leadership role in the SKA project, our membership status, and a funding commitment, are urgently needed. For example, Canada has recently been awarded a conditional contract for the mid-frequency central signal processor, one of the largest contracts awarded to date. However, this contract is conditional on our future commitment to the project, and needs to be finalized by the middle of next year. We should all be taking the opportunity to talk about the importance of SKA and other future facilities, both within our universities and to our broader contacts. Without awareness, there can be no action.

There has been much discussion about whether it is a lost cause to consider lobbying for new facility funding in the midst of the world’s current crisis. However, I see reasons to be hopeful. Our federal government, and funding agencies, have already shown willingness to dig into their rainy day coffers. The return to Parliament will be kicked off with a Speech from the Throne on September 23 and is expected to focus on a roadmap out of the pandemic. Word from Ottawa is that the Liberals are in Big Thinking (and spending!) mode, seeking to lay out a new vision to transform Canada in a post-pandemic world, without any immediate concerns for the fiscal deficit. Several of the highly ranked LRP facilities may offer appeal in this regard, both for their scientific and economic benefits. For example, The Cosmological Advanced Survey Telescope for Optical and ultraviolet Research (CASTOR; see the updates from Pat Côté in the 2020 Summer Solstice newsletter as well as this one) mission offers excellent opportunities for industrial partnership and technology development. As a telescope that is envisioned to be Canadian-led, CASTOR will have a field of view 100 times that of Hubble and provide the best ever view of the UV universe, and will therefore be both a cutting edge astronomical facility, as well as a source of national pride and inspiration.

In the last newsletter, Taylor Kutra, Martine Lokken and Hilding Neilson reported their positive experiences in taking/offering a mini-course on astronomy and colonization in Canada. I am delighted to hear that, this coming Fall, Hilding will be offering this course to our CASCA membership on a virtual platform. It behooves all of us to recognize and be educated on the issue of colonization, both in the context of astronomy and in Canada in general. Hilding’s course is a (currently) unique opportunity within our profession to learn from a First Nation professional astronomer with first hand understanding of the challenges and issues. As noted in the afore-mentioned newsletter article, such a course is long overdue. Now, thanks to Hilding’s community offering, one more step is being taken to disseminate this education. An announcement will be forthcoming on the CASCA exploder with more details, including the registration process.

Finally, an update on the AGM. As you all know, the original plan for 2021 was to host the CASCA AGM in Penticton, BC. However, upon discussion with the Penticton LOC (Chaired by Michael Rupen), due to on-going uncertainty over COVID-19 restrictions, we have decided that the 2021 AGM should be planned to be virtual. Since the 2022 AGM has already been confirmed to be hosted by Waterloo, Penticton aims to welcome us eventually in 2023. The online organizing committee (OOC) for CASCA 2021 is being led enthusiastically by Dennis Crabtree, and is planned for the week that had been originally identified for the Penticton meeting (May 10-14). In news from south of the border, the American Astronomical Society (AAS) is also offering its winter meeting virtually and has offered CASCA members the opportunity to attend at AAS member registration fee level. If you would like to take advantage of this opportunity, keep an eye out for the announcement on the CASCA email exploder in the near future, where we will be providing instructions on how to obtain the relevant discount code that can be used for web registration.

Graduate Student Highlights

par Carter Rhea (Chair, CASCA Graduate Student Committee)
(Cassiopeia – été 2020)

Each month, the GSC highlights the work of an outstanding Canadian graduate student by sharing their work with our members. Since the launch in February of 2020, we have highlighted four students from around the country.

Follow us on Twitter, Instagram, and Facebook under the handle casca_gsc.

Christian Thibeault — L’Université de Montréal

Les éruptions solaires sont des tempêtes de rayonnement provoquées par la libération d’énergie magnétique provenant de la couronne solaire. Ces éruptions posent un danger pour les astronautes et peuvent causer des perturbations importantes sur les communications satellites (incluant les systèmes GPS). Il a été proposé par E.T Lu et ses collaborateurs que les éruptions solaires sont le produit d’une réaction en chaîne inobservable de reconnexions magnétiques à petite échelle. Cette cascade de petits évènements peut être simulée avec un simple modèle sur réseau, appelé « modèle d’avalanche ». Le but de mon projet de maîtrise est d’évaluer le potentiel de ces modèles à faire des prédictions à court terme des éruptions solaires. Nous avons tout d’abord étudié le comportement stochastique de plusieurs modèles d’avalanche, et sommes maintenant en train d’intégrer l’assimilation de données sur des observations de rayon X (GOES) des éruptions solaires pour améliorer nos prédictions.

Figure 1 – Représentation imagée de l’interprétation physique d’une boucle coronale qui accumule de l’énergie par rotation de sa base. (Strugarek et al. 2014)

Mallory Thorp — University of Victoria

Comme une chercheuse en Astronomie, elle enquête comment changent-ils les galaxies au cause d’une fusion majeure galactique — ça se passe quand deux galaxies d’au peu près la même taille s’interagissent y se fusionnent en une unique galaxie. Pour meilleure comprendre ces changements d’un ordre de grandeur de quelques kiloparsecs, elle utilise les measures de la Spectroscopie de Champs Intégral (IFS – Integral Field Spectroscopy en anglais) d’enquête La Cartographie des Galaxies Proches à l’Observatoire d’Apache Point (MaNGA – Mapping Nearby Galaxies at Apache Point Observatory en anglais). L’IFS lui fournit une spectre pour chaque pixel d’une image d’une galaxie qui nous permet d’examiner comment les produits-de-données spectrales — comme le taux de formation stellaire (SFR — Stellar Formation Rate en anglais) — se changent à travers une galaxie.

On peut voir dans le figure 2 trois exemples de galaxies post-fusion de MaNGA (première colonne) et leurs cartes de densité surfacique de SFR (deuxième colonne). En comparant les cartes de SFR de galaxies post-fusion avec les galaxies isolées, nous pouvons quantifier le changement en SFR à la suite de fusion. La troisième colonne montre l’augmentation de SFR causée par une fusion en bleue, tandis qu’un déficit est visualisé en rouge. En moyenne, les galaxies post-fusion éprouvent une augmentation à travers la galaxie entière en SFR (voir les deuxième et troisième fusions). Les variations de ça, comme l’étouffement de SFR en les régions lointaines de la première galaxie post-fusion, peut-être indiquer comment les qualités progénitures distinctes et orientations modifient l’efficacité de la formation des étoiles.

Cette travaille-là était complétée par moi-même sous la direction de Sara Ellison (Nous deux sommes les membres de CASCA!)

Figure 2

Lingjian Chen — Saint Mary’s University

Dans ma recherche, j’étudie l’environnement galactique. Les environnements denses, tels que les groupes et les amas de galaxies, sont formés, en partie, par les fusions hiérarchiques. La distribution de galaxies satellites nous indique comment les galaxies dans cet environnement évoluent.

Nous étudions la distribution radiale des satellites autour de galaxies centrales en utilisant les données de Hyper Suprime-Cam (HSC) Subaru Strategic Program (HSC-SSP) et le télescope de Canada-France-Hawaii (CFHT) Large Area U-band Deep Survey (CLAUDS). Grâce à cette région étendue, la photométrie de 6-bandes et la profondeur du survey, nous pouvons identifier plus que 5000 centres dans un décalage vers le rouge entre 0,3 et 0,9. En plus, nous pouvons identifier les satellites qui sont en orbite autour de galaxies centrales.

Nos résultats nous indiquent que la distribution de densité de satellites est bien décrite par un profil NFW (Navarro-Frenk-White 1995, qui est normalement utilisé pour décrire le profil de densité de matière sombre) en une échelle plus grande que 100 kiloparsec à un décalage vers le rouge bas (e.g. Tal +2012). Nous avons enquêté en plus la dépendance de la distribution entre les satellites et les propriétés de la galaxie centrale. Nous trouvons que le mécanisme qui forme la distribution de satellites est relié fortement au frottement dynamique et le décapage des étoiles. Cependant, on a besoin de faire plus de simulations détaillées.

Le figure 3 démontre les galaxies de type satellite. La galaxie centrale est indiquée par un cercle jaune, les galaxies de type satellite potentielles sont indiquées par un cercle vert, et le rayonnement de sélection est indiqué en rouge (700 kpc). Les galaxies centrales étaient identifiées par leur masse et les critère d’isolation. En utilisant la différence en photo-z et une région circulaire, on a choisi les galaxies de type satellite. Le numéro des galaxies de type satellite montré ici était corrigé par les objets de fond.

Figure 3

Le figure 4 montre la densité superficielle des galaxies de type satellites (la moyenne) autour une galaxie centrale après la correction pour les objets de fond. La ligne solid démarque la meilleur ajustement et peut être séparée en deux composantes: la composante NFW au grandes échelles et la composante Sersic au petites échelles.

Figure 4

Farbod Jahandar — L’Université de Montréal

Farbod Jahandar travaille à débrouiller les mystères chimiques de nos étoiles voisines. Pour faire ça, il étudie les observations à haute résolution des naines étoiles de type spectral M qui sont les étoiles les plus nombreuses dans notre galaxie et sont les étoiles les plus petites et les plus froides sur la séquence principale. Cette analyse a un impact puissant sur plusieurs domaines en astronomie; en particulier, ça nous permet de déterminer le rayon d’une exoplanète. Le rayon d’une exoplanète dépend sur le rayon de l’étoile hôte qui est une fonction de ses propriétés chimiques! Pour réussir, Farbod utilise les données à haute résolution proviennent de l’instrument SPIROU qui est situé sur le télescope Canada-France-Hawaii.

Puis, Farbod utilise les techniques diverses de la spectroscopie chimique sur les données obtenues pour calculer les abondances chimiques des éléments différents dans l’atmosphère des naines étoiles de type spectral M. Cela est important pour comprendre l’évolution chimique de ces étoiles. En plus, cette étude va contribuer fortement à améliorer les modèles synthétiques stellaires qui existent.

Figure 5