Graduate Student Highlights

By Carter Rhea (Chair, CASCA Graduate Student Committee)
(Cassiopeia – Summer 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

Solar flares are sudden and intense releases of magnetic energy stored in the corona, causing the plasma to heat up to 10 million degrees Kelvin. The radiation and highly energetic particles emitted from these events can damage our satellite communication network and pose a health threat to astronauts. It has been suggested since the early 1990s, by E.T. Lu and collaborators, that solar flares are a manifestation of unobservable small scale magnetic reconnection processes that can be simulated by simple lattice models, called “avalanche models”. The goal of my master’s research project is to evaluate the predictive capabilities of these models in making solar flare forecasting. We first studied the stochastic behaviour of many avalanche models, and now are integrating data assimilation using X-ray observations of flares to improve our prediction methods.

Figure 1 – Cartoon of a physical interpretation of a coronal loop accumulating energy through the twisting of its footprints. (Strugarek et al. 2014)

Mallory Thorp — University of Victoria

Mallory’s research investigates how galaxies change as the result of a major galaxy merger, when two galaxies of comparable size interact and merge to form a single galaxy. To understand the kpc-scale changes resulting from a merger event, she uses Integral Field Spectroscopy (IFS) measurements from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. IFS provides a spectrum for every pixel on an image of a galaxy, allowing her to examine how spectral dataproducts like star-formation rate (SFR) vary across a galaxy.

Figure 2 contains 3 examples of post-merger galaxies from MaNGA (1st column), along with maps of their SFR surface density (2nd column). By comparing the maps of SFR from post-merger galaxies to those of isolated galaxies, she can quantify the change in SFR as the result of the merger event.

The 3rd column shows enhancements in SFR as a result of the merger in blue, whereas a deficit in SFR compared to an isolated galaxy are shown in red. On average post-mergers experience a galaxy-wide enhancement in SFR, like the 2nd and 3rd post-mergers. Variations from this, like the notable suppression of SFR in the outer regions of 1st post-merger, could indicate different progenitor qualities and orientations can alter how effectively star-formation is enhanced.

This work was completed by myself, under the supervision of Sara Ellison (both of us CASCA members!).

Figure 2

Lingjian Chen — Saint Mary’s University

My research is a galactic environment study. Dense galactic environments, such as galaxy groups and clusters, are thought to be formed through hierarchical mergers. Spatial distribution of satellite galaxies can be a good indicator for galaxy evolution in such environments.

We study the radial distribution of satellites around isolated massive central galaxies using data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (HSC-SSP) and the CFHT Large Area U-band Deep Survey (CLAUDS). Thanks to the large area, 6-band photometry and good depth of the combined survey, we were able to identify ~5000 centrals in a redshift range of 0.3<z<0.9 and also identify satellites around them down to stellar mass of 109.5 solar mass.

Our results show that satellite number density distribution can be described by an NFW profile (Navarro+1995, usually for mass density profile in dark matter halos) on scales greater than 100 kpc but deviates from it within that scale. This feature is seen out to z=0.9, it was previously found in studies at low redshift (e.g. Tal+2012). We have also investigated the dependence of the distribution on satellite and central properties such as mass and star-forming level. We concluded that the mechanism of shaping satellite distribution can probably be related to a combination of dynamic friction and tidal stripping when they are orbiting in the dark matter halo, but more detailed simulation or modelling are needed to understand better the physical process.

Figure 3 shows our satellite galaxy selection. Central galaxy is indicated by the yellow circle, potential satellites are circled in green, and red circle indicates our selection radius for satellites (700 kpc). Central galaxies were identified by mass and isolation criteria. Satellites were selected by photo-z difference and a circular aperture (basically a cylindrical selection centred on central galaxy). Number of satellites selected here were then corrected for contaminating background objects.

Figure 3

Figure 4 shows surface number density of satellite galaxies (averaged) around one central galaxy, after correction for background objects. The solid line is the best fit curve and can be separated into NFW component on large scale and Sersic component on small scale (dotted and dashed lines).

Figure 4

Farbod Jahandar — L’Université de Montréal

The main quest of Farbod’s work is unravelling the chemistry of our nearest stellar neighbours. This includes high-resolution observation and examination of M dwarfs as the most numerous type of star in our Galaxy and the smallest and coolest kind of star on the main sequence. Such an analysis impacts many fields of astrophysics, in particular, the determination of exoplanet radius that depends on a reliable estimate of the host radius that in turn depends on its chemical characteristics.

To achieve this goal, Farbod uses high-resolution data from the SPIRou instrument, which is one of the world-leading instruments at the Canada-France-Hawaii telescope. Then he uses chemical spectroscopy methods on the obtained data for the determination of the chemical abundance of different elements in the outer atmosphere of M dwarfs. This will be a critical component for a better understanding of the chemical evolution of M dwarfs and also can heavily contribute to chemical and dynamical improvements of the current synthetic stellar models.

Figure 5

Conferences and Carbon Footprints

By / par Sharon Morsink (University of Alberta)
(Cassiopeia – Summer / été 2020)

Authors: CASCA’s Sustainability Committee and Associates:
Sharon Morsink, Nicolas Cowan, Dennis Crabtree, Michael De Robertis, René Doyon, Vincent Henault-Brunet, Roland Kothes, David Lafrenière, Martine Lokken, Peter Martin, Christopher Matzner, Magdalen Normandeau, Nathalie Ouellette, Mubdi Rahman, Michael Reid, Joel Roediger, James Taylor, Robert Thacker, Marten van Kerkwijk

Canadians are responsible for CO2 emissions that are more than three times the annual global average of 4.8 tonnes per capita [1]. Most Canadian astronomers’ professional carbon footprint is dominated by air travel, and unlike telescope construction or rocket launches, flights — especially to conferences — are the immediate product of our individual choices. To reduce the environmental costs of our profession, we need real and desirable alternatives to jetting around to distant conferences.

Back in February, CASCA’s new Sustainability Committee was planning a virtual session for this year’s Annual General Meeting. But when the York meeting was cancelled due to the pandemic, an Online Organizing Committee was quickly assembled to plan a fully virtual conference. May’s online AGM, which was based around electronic posters and pre-recorded prize talks and community updates, drew 336 participants. We estimate that if everyone who participated from outside Ontario had flown in, the equivalent CO2 emissions would have been about 130 tonnes. (This may be an overestimate, as 43 respondents indicated on an exit survey that they would not have attended the in-person conference.)

The 2020 AGM was an interesting experiment, but how do we move forward? We aren’t advocating that all future conferences be completely virtual; we too would miss interacting with colleagues in person from time to time! Instead we would like to see the virtual options enhanced. We envision a future in which one would travel only to nearby conferences, and join remotely in most other cases. In the AGM exit survey (40% participation), about 60% of respondents reported missing the interactions that occur in person. Clearly, there is much work to be done to find effective and enjoyable ways to interact online with colleagues, but with improving text, video, and virtual reality options we believe this is possible. For instance, one could consider simultaneous physical meeting `hubs’ connected by a virtual link. Taking these points into consideration, the 2021 AGM organizers are already planning both in-person and remote ways to participate.

We encourage all astronomers to carefully consider how to minimize the impact of their research-related travel. In addition to being more selective about which conferences and meetings to attend in person, we recommend purchasing carbon offsets for those times when travel is needed. Not all institutions allow offsets to be reimbursed, and current NSERC spending rules for Discovery grants do not. Persistent advocacy is needed to change these policies, something which the Sustainability Committee will pursue. It is time for us to consider the environmental impact of our research, take stock of our own emissions, and plan a professional carbon budget in the same way that we plan a financial budget when managing our research grants.

[1] Hannah Ritchie and Max Roser (2017) – “CO₂ and Greenhouse Gas Emissions”. Published online at

CASCA’s New Sustainability Committee

By / par Chris Matzner (University of Toronto)
(Cassiopeia – Summer / été 2020)

Canada declared a national climate emergency a year ago and astronomy, like every profession, is beginning to face the challenge posed by the global climate crisis.  The problem is both an ethical and a practical one.  Ethically, we must recognize that the impacts of global heating – to which our professional activities contribute – will be the worst for those who have contributed the least to the problem:  the poor and marginalized in our own society, the Global South, and future generations worldwide.  Practically, we must find ways to live up to the commitments set out in the Paris Agreement: to cut greenhouse gas emissions in half by 2030, and reach net-zero by 2050 in order to avert irreversible and catastrophic climate change (ipcc).  

As members of CASCA’s new ad-hoc Sustainability Committee, our mandate is to encourage all Canadian astronomers to evaluate the environmental impacts of the practices of astronomy; to work with you on reducing them; and to provide sustainability-related resources for those engaged in teaching and outreach.  The Committee was created by the CASCA Board in early 2020, in response to the LRP white paper Astronomy in a Low-Carbon Future.  Its membership was drawn initially from that paper’s authors, with those involved in organizing the online version of the 2020 Annual General Meeting joining shortly thereafter. 

Now that the online AGM is over, we will work to: 

  • Plan and promote a virtual component to the 2021 AGM and other meetings to help members reduce their travel-related emissions;

  • Encourage and assist our fellow astronomers, and their institutions, to consider, track, review, and reduce their environmental impacts;

  • Build relationships with cognate committees in other fields and elsewhere in the world;

  • Advocate for changes in granting rules to acknowledge the environmental costs of doing research and permit climate-related costs like carbon offsets as eligible research expenses; and

  • Collect resources for effective astronomy teaching and outreach on topics related to sustainability and climate change.


We’re looking forward to engaging with you!  If you would like to get involved and join our roughly bi-monthly virtual meetings, please contact the committee chair, Chris Matzner.  

Sincerely yours, 

CASCA’s Sustainability Committee and Associates: Christopher Matzner, Nicolas Cowan, Dennis Crabtree, Michael De Robertis, René Doyon, Vincent Henault-Brunet, Roland Kothes, David Lafrenière, Martine Lokken, Peter Martin, Sharon Morsink, Magdalen Normandeau, Nathalie Ouellette, Mubdi Rahman, Michael Reid, Joel Roediger, James Taylor, Robert Thacker, Marten van Kerkwijk

Long Range Plan 2020 / Plan à long terme 2020

From Pauline Barmby, Bryan Gaensler (LRP2020 co-chairs PLT2020)
(Cassiopeia – Summer / été 2020)

La version française suit

From March to May 2020, the LRP2020 panel completed a series of consultations, culminating in the release of a set of draft recommendations and then a community discussion via Zoom at the 2020 CASCA AGM. We are grateful for all of the thoughtful feedback received both at the discussion session and via the feedback form.

Future plans involve incorporating this feedback, contacting specific individuals or groups for clarifications, and completing the report, including the introductory and concluding sections. The version of the LRP report that we are planning to release in the fall will be near-final; we do not plan a further round of community consultations. So that we can complete the report by the fall, we would like to receive any feedback by June 30, 2020 at the form linked above.

The LRP webpage contains a link to the draft recommendations document – see your CASCA email for the password – as well as a new page with links to all of the LRP2020 white papers and reports. The white papers are now also indexed in ADS.

The latest news on LRP2020 is available from the Slack workspace and our Twitter handle @LRP2020. The panel can be contacted at and the co-chairs at

De mars à mai 2020, le panel PLT2020 a achevé une série de consultations, aboutissant à la publication d’un ensemble de projets de recommandations puis une discussion communautaire via Zoom lors de l’AGA CASCA 2020. Nous sommes reconnaissants pour tous les commentaires réfléchis reçus à la fois lors de la session de discussion et via le formulaire de commentaires.

Les plans futurs consistent à intégrer ces commentaires, à contacter des individus ou des groupes spécifiques pour obtenir des clarifications et à compléter le rapport, y compris les sections d’introduction et de conclusion. La version du rapport LRP que nous prévoyons publier à l’automne sera presque définitive; nous ne prévoyons pas de nouvelle série de consultations communautaires. La version finale du rapport sera disponible en anglais et en français à la fin de l’année. Afin que nous puissions terminer le rapport d’ici l’automne, nous aimerions recevoir vos commentaires d’ici le 30 juin 2020 au formulaire ci-dessus.

La page Web LRP contient un lien vers l’ébauche du document de recommandations – voir votre courriel CASCA pour le mot de passe – ainsi qu’une nouvelle page avec des liens vers tous les livres blancs et rapports PLT2020. Les livres blancs sont désormais également indexés dans ADS.

Les dernières nouvelles sur PLT2020 sont disponibles sur l’espace de travail Slack et sur Twitter @LRP2020. Le panel peut être contacté à et les coprésidents à

President’s Message

By / par Sara Ellison (CASCA President)
(Cassiopeia – Summer / été 2020)

At the time of writing, I have been CASCA President for exactly one week! It is a role that I am meeting with both excitement and humility – the outgoing President, Rob Thacker, carried out his role with the utmost dedication, tirelessly working for our community and expertly navigating us through some choppy waters. So, whilst I am excited to receive the Presidential baton and continue the good work, Rob has left some rather big shoes to fill. Thank you Rob, on behalf of the Society, the Board and myself for your hard work to make the very best of our community.

The Board has some other new faces as well – we welcome Laura Parker (McMaster) and Julie Hlavacek-Larrondo (Montreal) as Directors, replacing Suresh Sivanandam and Rene Doyon. Thank you to Suresh and Rene for your valued service. The new Vice-President is Samar Safi-Harb (Manitoba), with whom I have worked in several capacities in recent years and am delighted to have as my wing-(wo)man. [As an aside, our Board is now 6/9 female!]. And finally, Bob Abraham completes his six year marathon on the Executive, having rotated through the Vice-President’s position, then to President and then to past-President. Bob – you have been an inspiration in the community, bringing wit and wisdom wherever you go. Thank you.

Since the last Newsletter in March, I think that there is not a one amongst us who hasn’t had their personal and professional lives turned upside-down by COVID-19. However, in times of crisis, our true natures rise to the fore and I am proud and inspired to live and work in a society (and Society!) that is characterized by compassion, community-mindedness and creativity. Across Canada, nightly serenades to front line workers, hearts in windows, poetry on lampposts and neighbourhood `caremongering’ have become the norm. We can be very proud that astronomers are amongst those in Canada who are seeking ways to support both professionals and the public alike in these challenging times. I wanted to highlight two examples of this, whose target audiences differ, but whose goals are united in serving communities whose regular ways of engaging have been interrupted by COVID.

First, under the ever-energetic leadership of Julie Bolduc-Duval, Discover the Universe (DU) launched a daily podcast (“astro-at-home”) aimed at children aged 8-12, delivered in both English and French, covering subjects as diverse as space robotics and the search for alien life. Many of us have school-aged children who have been home for months, adding another full time job to our lives (oh, the fun of having to retreat to a closet for a telecon!). Initiatives such as astro-at-home have not only been vital in keeping our young ones stimulated and educated, but is also a shining example of creating an opportunity out of a crisis. The astro-at-home podcasts are being delivered by a diverse crew of passionate communicators, who will surely be role models for the thousands of viewers that astro-at-home has attracted. My daughter and I were certainly amongst those so inspired.

A complementary initiative is CANVAS – the CANadian Virtual Astronomy Seminars. For researchers, the summer months normally mark the peak of the conference season, as we make our international pilgrimages to share the latest astronomical discoveries. Conference attendance is particularly important for our junior researchers, not only to advertise their work, but also to learn from others. Current travel bans obviously erase this opportunity. Spear-headed by Dennis Crabtree (NRC Herzberg), CANVAS aims to bring research talks to our home offices, by coordinating a national seminar program. By recording these presentations, which will have contributions from graduate students through professors alike, CANVAS will also provide a lasting legacy and enable research communication across the country, benefitting in particular smaller or more geographically remote centres of research. I hope that in the future CANVAS will be even more ambitious and recruit speakers from around the world – what a wonderful way to maximize scientific communication at low carbon cost.

As a society, we experienced a major milestone with this year’s AGM, the first to be hosted entirely virtually. Under the chairmanship of Michael De Robertis, some two years-worth of planning and hard work had already been invested by the York University team to host CASCA 2020. The decision to move the AGM online was made in mid-March, leaving the organizing committee a scant two months to overhaul the meeting. The Local Organizing Committee (LOC) was quickly re-shuffled to an Online Organizing Committee (OOC): Elaina Hyde, Paul Delaney, Michael De Robertis, June Parsons, Sharon Morsink, Carter Rhea, Dennis Crabtree, Chris Matzner, Maan Hani, James Taylor and Rob Thacker. It was truly a mammoth task to bring everything together on such a short timescale, but their Herculean efforts led to an AGM to be proud of – an extremely well attended meeting offered at low cost, with low carbon footprint and featuring several novel components such as iPosters, a Youtube channel for all of the prize talks and conference photos via Zoom. It may also be the only time you will get to see astronomers doing back-flips on the beach. Although CASCA 2020 was a virtual meeting by necessity, it was an excellent opportunity to experiment with technologies that might be blended with future meetings. Exploring such options is one of the primary mandates of CASCA’s newly minted Sustainability Committee (chaired by Chris Matzner). Whether it be virtual, or in person, I look forward to seeing you all next May in Penticton, where CASCA 2021 will be co-hosted by DRAO and UBC.

Despite all the upheaval of the past months, one effort that is seemingly unperturbed in its forward progress is the development of our Long Range Plan (LRP). Under the deft and indefatigable leadership of co-chairs Pauline Barmby (Western) and Bryan Gaensler (Toronto/Dunlap) a draft of the principal content was circulated to the Society in mid-May and discussed at a well-attended AGM session. The scope of the LRP is impressive, tackling not only research-driven topics, such as observatory facilities, supercomputing and data-management, but with a holistic perspective of our professional landscape. Equity and diversity, education and public outreach, funding and governance are all tackled, as well as recommendations pertaining to ethics, sustainability and indigenous matters. A reminder that the CASCA committee reports submitted for the AGM are publicly available here, and cover many of these topics, including the latest updates from facilities such as TMT and SKA. For now, Coalition lobbying activities are dormant, and a return to such activities is likely to be staged and require both flexibility and opportunism. But with the LRP on track for completion in the Fall, I am confident that whenever the opportunities do re-open, we will be ready for them.

Black Lives Matter and the day of action 10 June

We strongly voice our support for the Black Lives Matter movement and for elimination of systemic racism against Black and Indigenous Canadians. We are outraged at the deaths of so many individuals, most recently George Floyd, Chantel Moore, Regis Korchinski-Paquet, Jason Collins, Eishia Hudson and D’Andre Campbell, along with all the Black and Indigenous people in Canada, the USA, and elsewhere, who have not survived interactions with police.

Systemic racism exists in Canada, and our society has a long way to go to realize an equitable playing field for all Canadians. We stand with our Black and Indigenous members and their communities. As the wider Canadian community calls for change and for action, we offer our support for those struggling to end systemic racism, white supremacy, colonialism and police brutality. To create the change we want to see, it is incumbent upon each of us to educate ourselves, embrace and promote anti-racism in Canada, understand the impact of our astronomical research and facilities, act to dismantle barriers, and participate in social justice.

We are committed to improving the professional lives of members of the Canadian Astronomical Society. We know that racist language and behaviour exists in the working lives of many of our members, and that we must continuously commit to finding ways toward better representation, inclusion and equity.

As many of you already know, Wednesday June 10th has been designated as a day of action when academics are asked to focus their attention on education and action toward eliminating systemic racism and acknowledging that Black Lives Matter.

We have compiled below some links and resources that CASCA members can explore on this day of action. We encourage all CASCA members to take a stand against anti-Black racism this Wednesday and continue that stand in the future. There are many ways you can help, and all journeys begin with a single step.

Sara Ellison, CASCA President
Brenda Matthews, Chair, CASCA Equity & Inclusivity Committee

Join a movement:

Do some research:
Justice in June
CBC Radio
17 Years of Police Violence In Canada
A US/Canadian Race/Racism Reading List

Desmond Cole: ‘Canada insists on being surprised by its own racism’

Letters to America from Black Canadians