Dissertation: Investigating Brown Dwarf Atmospheres: Gravity, Dust Content, Cloud Structure and Metallicity

(Cassiopeia – Autumn/l’automne 2017)

by Kendra Kellogg
Thesis defended on July 13, 2017
Department of Physics and Astronomy, Western University
Thesis advisor: Dr. Stanimir Metchev

Abstract
Brown dwarfs are the lowest mass products of star formation. Their low masses don’t allow them to sustain, or sometimes even begin, the thermonuclear processes that provide stars with internal energy and the thermal pressure necessary to maintain hydrostatic equilibrium. Thus, their radii and effective temperatures decrease as they age, continually changing their spectral classification. However, it is now a well-known fact that the spectral appearance of ultra-cool dwarfs is governed by more than just temperature. Factors such as gravity, metallicity and cloud distribution play an important role in the structure and composition of ultra-cool dwarf atmospheres and ultimately their spectra.

Pinning down the effects of some of the contributing factors to the structure and evolution of brown dwarf atmospheres has been the goal of my thesis research. Through a joint positional and colour cross-match of optical, near-infrared and mid-infrared all-sky surveys, I have identified 20 new brown dwarfs with “peculiar” photometric colours which are candidates for having unusual atmospheric properties. I have determined that a number of these objects have atypical surface gravities and/or atmospheric dust content using near-infrared spectroscopic observations. I have also determined the timescales for the various peculiarities by comparing these objects to the population of “normal” objects. In addition, I have studied in detail a few of the most peculiar objects in order to understand how conditions on individual objects affect their atmospheric structure and composition.

Dissertation: Lights in Dark Places: Inferring the Milky Way Mass Profile using Galactic Satellites and Hierarchical Bayes

(Cassiopeia – Autumn/l’automne 2017)

by Gwendolyn Eadie
Thesis defended on July 18, 2017
Department of Physics and Astronomy, McMaster University
Thesis advisor: Dr. William Harris

Abstract
Despite valiant efforts by astronomers, the mass of the Milky Way (MW) Galaxy is poorly constrained, and not known within a factor of two. A range of techniques have been developed and different types of data have been used to estimate the MW’s mass. One of the most promising and popular techniques is to use the velocity and position information of satellite objects orbiting the Galaxy to infer the gravitational potential, and thus the total mass. Using these satellites, or Galactic tracers, presents a number of challenges: 1) much of the tracer velocity data are incomplete (i.e. only line-of-sight velocities have been measured), 2) our position in the Galaxy complicates how we quantify measurement uncertainties of mass estimates, and 3) the amount of available tracer data at large distances, where the dark matter halo dominates, is small. The latter challenge will improve with current and upcoming observational programs such as Gaia and the Large Synoptic Survey Telescope (LSST), but to properly prepare for these data sets we must overcome the former two. In this thesis work, we have created a hierarchical Bayesian framework to estimate the Galactic mass profile. The method includes incomplete and complete data simultaneously, and incorporates measurement uncertainties through a measurement model. The physical model relies on a distribution function for the tracers that allows the tracer and dark matter to have different spatial density profiles. When the hierarchical Bayesian model is confronted with the kinematic data from satellites, a posterior distribution is acquired and used to infer the mass and mass profile of the Galaxy.

This thesis walks through the incremental steps that led to the development of the hierarchical Bayesian method, and presents MW mass estimates when the method is applied to the MW’s globular cluster population. Our best estimate of the MW’s virial mass is M(vir) = 0.87 x 1012 Solar masses with a 95% credible range of (0.67 – 1.09) x 1012 Solar masses. We also present preliminary results from a blind test on hydrodynamical, cosmological computer-simulated MW-type galaxies from the McMaster Unbiased Galaxy Simulations. These results suggest our method may be able to reliably recover the virial mass of the Galaxy.

Dissertation: The Effects of Environment on the Atomic and Molecular Gas Properties of Star-Forming Galaxies

(Cassiopeia – Autumn/l’automne 2017)

Angus

by Angus King Fai Mok
Thesis defended on July 31, 2017
Department of Physics and Astronomy, McMaster University
Thesis advisor: Dr. Christine Wilson

Abstract
Where a galaxy is located has a strong effect on its properties. The dense cluster environment is home to a large population of red, quiescent elliptical galaxies, whereas blue, star-forming, spiral galaxies are common in lower-density environments. This difference is intricately linked to the ability of the galaxy to form new stars and therefore ultimately to the fuel for star formation, the atomic and molecular gas. In this thesis, I use two large JCMT surveys to explore the effects of environment on the atomic gas, molecular gas, and star formation properties of a large sample of nearby gas-rich galaxies.

From the NGLS and follow-up studies, I select a sub-sample of 98 HI-flux selected spiral galaxies. I measure their total molecular gas mass using the CO J=3-2 line and combine this data with measurements of their total atomic gas mass using the 21-cm line and star formation rate using attenuation-corrected H-alpha luminosity. I find an enhancement in the mean H2 mass and a higher H2-to-HI ratio for the Virgo Cluster sample. Virgo Cluster galaxies also have longer molecular gas depletion times (H2/SFR), which suggests that they are forming stars at a lower rate relative to their molecular gas reservoirs than non-Virgo galaxies.

Next, I collect VLA 21 cm line maps from the VIVA survey and follow-up VLA studies of selected galaxies in the NGLS. I measure the surface density maps of the atomic gas, molecular gas, and star formation rate in order to determine radial trends. I find that the H2 distribution is enhanced near the centre for Virgo Cluster galaxies, along with a steeper total gas (HI + H2) radial profile. I suggest that this is due to the effects of moderate ram pressure stripping, which would strip away low-density gas in the outskirts while enhancing high-density gas near the centre. There are no trends with radius for the molecular gas depletion times, but the longer depletion times for the Virgo Cluster sample is still present.

Finally, I use 850 micron continuum observations for 105 star-forming galaxies and CO J=2-1 line observations for 35 galaxies in the initial data release (DR1) of the JINGLE survey. I match the JINGLE galaxies to a SDSS group catalogue and measure environmental parameters such as the host halo mass, environment density, and location in phase space. I find that the molecular gas masses estimated from the 850 micron and CO J=2-1 line observations are well-correlated. The H2-to-HI ratio and the molecular gas depletion times do not appear to vary with stellar mass. I did not find any significant variation with environment in the DR1 sample, but I will apply this framework to the full JINGLE sample once the complete dataset is available.

Maunakea Spectroscopic Explorer (MSE) Update

MSE_final

By/par Patrick Hall, MSE Management Group Member
(Cassiopeia – Summer/été 2017)

As discussed at the CASCA meeting, the Maunakea Spectroscopic Explorer (MSE) project has just wrapped up a series of subsystem conceptual design reviews.

Video of the Telescope Structure Conceptual Design

The conceptual design for MSE’s telescope structure by the Spanish firm IDOM has passed its review with flying colours. The 11.25m aperture MSE will fit within a structure only slightly wider than currently exists at CFHT. Details and a video of IDOM’s mount for MSE are available at this link.

More Conceptual Design Reviews

Many MSE partners and work packages delivered conceptual designs for review in Waimea and elsewhere this quarter:

  • Enclosure (Empire Dynamic Structures), held in Port Coquitlam, BC.
  • High Resolution Spectrograph (NIAOT, Nanjing). The Project Office welcomed the NIAOT team, including the Director of NIAOT, for this 2 day review.
  • Fiber Positioning Systems (a competitive study between teams from AAO, UAM and USTC).
  • Fiber Transport System (Herzberg Institute together with Fibertech Optica, Canada).
  • Real Time Software Architecture (staff at CFHT).
  • Top-End Assembly (INSU-DT and GEPI, France).
  • Low Resolution Spectrographs (CRAL, France) in Lyon, France.

With the completion of the subsystem conceptual design reviews, the next step is to undertake a project-wide system conceptual design review and then a cost review. The Project Office staff are now shifting gears from reviewing designs to preparing material for review, and plan to defend the system design in the last quarter of 2017.

Other Activities

The MSE Management Group held its 2017Q1 meeting by telecon. The components of a Design Phase Master Agreement are under discussion. Such an agreement would spell out past and planned pre-construction contributions from each partner and the corresponding science return in terms of access to MSE survey data as compensation for those contributions.

Canadian astronomers with questions or comments about MSE or MSE governance can contact their MSE MG members, Greg Fahlman and Pat Hall).

The MSE Science Advisory Group began the year by reviewing the MSE Science Requirements Document and prioritizing the first light science capabilities for a nominal 2026 first light. The results of this discussion by the SAG will inform the prioritization of different system elements in the upcoming project-wide system conceptual design and cost reviews.

Canadian astronomers with scientific questions or comments about MSE can contact their MSE SAG members, Kim Venn and Sarah Gallagher.

President’s Message

2014-06-27-Prof. Roberto Abraham

By/par Roberto Abraham, CASCA president
(Cassiopeia – Summer/été 2017)

CASCA AGM

Many of us have just returned from a very successful CASCA Annual General Meeting in Edmonton. This was a terrific meeting and we owe our colleagues in Alberta our thanks for putting it together. This year’s CASCA AGM featured some wonderful talks (Dicke’s Superradiance, which I’d not even heard of before the meeting, turns out to be a really interesting thing) and interesting discussion sessions. Several of these sessions focused on topics of great significance for our community, such as the space astronomy funding situation and progress in the construction of the Thirty Meter Telescope. We all look forward to more interesting talks and more stimulating discussion at the 2018 CASCA AGM in Victoria.

CATAC

As I described in my last President’s Message, a major focus of the CASCA Board’s recent activity has been to put into place a formal advisory structure for Canadian participation in the Thirty Meter Telescope project. I’m pleased to be able to report that the CASCA-ACURA TMT Advisory Committee (CATAC) was put into place at the start of this year, and many of you were able to witness it in action at the CASCA AGM. CATAC is being led by Prof. Michael Balogh (Waterloo), and in my opinion he has done an extraordinarily good job managing this new committee.

The specific terms of reference for CATAC are carefully spelled out in a formal document, but the gist is that CATAC has two major roles:

  1. This committee continuously assesses progress in the TMT project, making sure that TMT meets the scientific, technical and strategic goals set out in the Long-range Plan, and it feeds this information to the LRP Implementation Committee.
  2. It acts as a conduit for consulting with and informing the community about the state of the TMT project.

An initial very significant activity of CATAC has been to provide CASCA and ACURA with a detailed assessment of the strengths and weaknesses of constructing TMT on La Palma, in the form of a detailed report. The report is, I think, a model for these kinds of things. It even got written up in Nature! The findings and the recommendations in this report make for important reading and I think you should take a look at it. The high-level summary is that building TMT on Mauna Kea is clearly the preferred option for our community, but building TMT on La Palma would still result in a very exciting telescope that would deliver transformational science for the Canadian astronomical community. Some of the disadvantages of La Palma cannot be overcome (e.g. its lower altitude limits performance at longer mid-infrared wavelengths), but others can be overcome by careful planning and an appropriate funding model. The various trade-offs, strengths and weaknesses in the project are described in detail in the report… please check it out.

By creating CATAC and populating it with astronomers with different areas of expertise, and trying to be inclusive with respect to institutional geography, gender and career stage, CASCA and ACURA have set in place a credible and representative structure for community-based feedback and advice. I think this committee is firing on all cylinders (thanks again, Michael Balogh and everybody serving on CATAC) and it’s really impressive to see it work. CATAC meets frequently (approximately weekly by telecon, though in between there is considerable discussion via email and via the Slack groupware system) and it has succeeded in spreading TMT expertise and engagement over many institutions. In my opinion this aspect of the committee’s activity will have an even more enduring impact than its first report, because the more Canadians get involved in the project, the more they feel a sense of ownership in it, at least if our community’s feelings about CFHT can be taken as a guide. For this reason, I was particularly pleased by CATAC’s decision to open four meetings to CASCA members, via Webex. These open meetings included presentations by key people in the TMT project. Armed with this information, members of the community provided thoughtful advice to CATAC, who discussed this at length and synthesized the community’s feedback into the final report. This activity has already had an impact, with more thinking at the project level now being focused on hardware (such as an adaptive secondary mirror) and operational models (such as an adaptive queue) that are of particular importance to the Canadian community.

Advancing the Long Range Plan

The long description above might give you the impression that the CASCA Board did nothing but focus on TMT this year. This is far from true! We were kept busy by many other things. For example, the federal government solicited feedback from us on a number of matters of relevance to the astronomical community, and CASCA, acting in partnership with ACURA and Industry as part of the Coalition for Canadian Astronomy, responded in the following ways:

  • The Coalition provided written input to Canada’s Innovation Agenda, and to the federal government’s Fundamental Science Review Panel. The Coalition also provided a pre-budget submission the federal government, noting the commitment needed to fulfil the aspirations in the Long Range Plan.
  • On behalf of the Coalition, I met with the Fundamental Science Review Panel in Calgary. Once again, the emphasis was on the items in the Long Range Plan.
  • Last Fall, the Coalition mailed out a summary of the conclusions of the CASCA Mid-Term Review to all MPs. This Spring we sent each MP a beautifully-printed copy of the full review.

In addition to providing feedback to specific requests from the government, we also acted in a pro-active manner in a number of ways. For example:

  • On behalf of the Coalition, I flew to Ottawa to meet with representatives from the Aerospace Industry Association of Canada to consider ways in which CASCA could partner with them on topics of mutual interest.
  • On May 9 the coalition co-chairs (Don Brooks, Guy Nelson and I) traveled to Ottawa and met with Genevieve Tanguay (VP, Emerging Technologies, NRC), John Burnett (Director of Policy, Office of the Minister of Science), and Marilyn Gladu (Conservative Party Science Critic).

These latter meetings were particularly useful, not only for informing government about our aspirations in the LRP, but also for hearing back from them about ways we could better align ourselves with top-level national goals (an important component in our success). For example, in our discussions with NRC we discussed challenges to do with Compute Canada and the Canada Foundation for Innovation (which has not clearly understood the close linkage between University-based and NRC-based researchers), and we learned that NRC needs help with outreach and public communications. I think that CASCA members should try hard during our outreach activities to communicate how success in Canadian astronomy is at least partially a function of a close partnership between NRC, Universities, and Industry. I hope you can help by touching upon this theme when describing our activities to the general public.

In the coming months the CASCA Board and its various committees will continue to work hard on your behalf. There are a few big-ticket items coming up, and I expect we will be focusing considerable energy on advocacy for the space astronomy and radio astronomy portions of the Long Range Plan, and on a professional climate survey being prepared by the Equity and Inclusivity Committee.

Let me conclude by apologizing yet again for a somewhat overlong President’s Message, and on behalf of the CASCA Board, I extend to you our very best wishes for a healthy, happy, and productive summer.

NRC Herzberg News / Nouvelles du CNRC Herzberg

From/de Dennis Crabtree (NRC-Herzberg)
Avec l’apport de/With contributions from Chris Willott

(Cassiopeia – Summer/été 2017)

La version française suit

These reports will appear in each issue of E-Cass with the goal of informing the Canadian astronomical community on the activities at NRC Herzberg.

Feedback is welcome from community members about how NRC Herzberg is doing in fulfilling our mandate to “operate and administer any astronomical observatories established or maintained by the Government of Canada” (NRC Act).

Canadian Time Allocation Committee (CanTAC)

CanTAC met in May to discuss and rank CFHT and Gemini proposals for semester 2017B. The meeting was hosted by Stanimir Metchev at Western. The CanTAC SuperChair for this meeting was Ingrid Starirs (UBC), while the Galactic panel chair was Stanimir Metchev (Western) and the Extragalactic panel chair was Eric Steinbring (NRC Herzberg). Dennis Crabtree continues to serve as the technical secretary.

The full list of CanTAC members for the May meeting was:

Galactic Extragalactic
Laurent Drissen (Laval) Peter Capak (Caltech)
Christopher Johns-Krull (Rice) Pat Cote (NRC)
Stanimir Metchev (Western) Julie Hlavacek-Larrondo (Montreal)
Els Peeters (Western) Adam Muzzin (York)
Leslie Rogers (Chicago) Eric Steinbring (NRC)
Samar Safi-Harb (Manitoba) Ludo van Waerbake (UBC)

For Semester 2017B CanTAC received 27 CFHT proposals (17 Galactic and 10 Extragalactic) and 36 Gemini proposals (21 Galactic and 15 Extragalactic). The subscription rates were 2.41 for CFHT, 1.91 for Gemini North and 1.90 for Gemini South.

NRC Herzberg commissioned a study of gender systematics in CanTAC grades. CFHT and Gemini proposal grades over 10 recent proposal cycles were analyzed by a social sciences PhD student at Queens under the supervision of Kristine Spekkens. The analysis shows that except for faculty principal investigators (PIs), proposals submitted by female PIs were rated significantly worse than those submitted by male PIs.

To address this issue we will be changing the format of Gemini and CFHT proposals. In the future, all investigators will be listed alphabetically and the PI will not be identified.

JWST Update

This summer the James Webb Space Telescope will undergo its final cryo-vacuum test at Johnson Space Center, Houston. The telescope, including the science instrument module, will be subjected to a range of thermal and optical tests. This 93 day long test program will verify models and performance specifications to ensure that the telescope performs as designed.

At the same time astronomers across the globe are gearing up to prepare JWST science programs. The Director’s Discretionary Early Release Science (DD-ERS) program will use about 500 hours of time early in Cycle 1 to provide example science use cases of a range of instrument modes. This data will have zero proprietary time so prospective users will be well informed of instrument capabilities in advance of the Cycle 2 Call for proposals. The Cycle 1 General Observer Call for proposals is due for release in November this year. This is a significant milestone for the community as they plan proposed JWST observations.

There are many ways to prepare yourself for writing JWST proposals. The Space Telescope Science Institute (STScI) has extensive and increasing documentation. Also available are a set of observation planning tools including the Astronomer’s Proposal Tool (APT), Exposure Time Calculator (ETC) and target visibility tools. This fall the Canadian JWST team, led by PI Rene Doyon, will organise several events aimed at Canadian JWST users including university visits and webinars. The recent announcement at the CASCA meeting in Edmonton of science support funding for JWST users from the Canadian Space Agency is very welcome and will allow the Canadian community to get the most science out of our national investment in the facility.

JWST will be launched into a halo orbit around L2 on an Ariane V rocket in October 2018.

JWST being prepared for cryo-vacuum testing in the Apollo era Chamber A at Johnson Space Center, Houston. NASA (Chris Gunn)

JWST being prepared for cryo-vacuum testing in the Apollo era Chamber A at Johnson Space Center, Houston. NASA (Chris Gunn)



Les rubriques qui suivent reviendront dans chaque numéro du bulletin et ont pour but de tenir les astronomes canadiens au courant des activités de CNRC Herzberg, Astronomie et astrophysique.

Les commentaires des astronomes sur la manière dont CNRC Herzberg, Astronomie et astrophysique s’acquitte de sa mission, c’est-à-dire « assurer le fonctionnement et la gestion des observatoires astronomiques mis sur pied ou exploités par l’État canadien » (Loi sur le CNRC), sont les bienvenus.

Comité canadien d’attribution du temps d’observation (CanTAC)

Les membres du CanTAC se sont entretenus en mai afin d’examiner et d’ordonner les demandes du semestre 2017B se rapportant aux observatoires CFHT et Gemini. Stanimir Metchef, de l’Université Western, était l’hôte de la rencontre. Ingrid Starirs (UBC) a agi à titre de super-présidente à l’occasion, Stanimir Metchev (Université Western) présidant le Groupe galactique et Eric Steinbring (CNRC Herzberg), le Groupe extragalactique. Dennis Crabtree continue de servir de secrétaire technique au Comité.

La liste complète des membres du CanTAC qui ont assisté à la réunion de mai est la suivante :

Groupe galactique Groupe extragalactique
Laurent Drissen (Laval) Peter Capak (Caltech)
Christopher Johns-Krull (Rice) Pat Cote (NRC)
Stanimir Metchev (Western) Julie Hlavacek-Larrondo (Montreal)
Els Peeters (Western) Adam Muzzin (York)
Leslie Rogers (Chicago) Eric Steinbring (NRC)
Samar Safi-Harb (Manitoba) Ludo van Waerbake (UBC)

Le CanTAC a reçu 27 demandes pour le CFHT (17 du Groupe galactique et 10 du Groupe extragalactique) ainsi que 36 demandes pour l’observatoire Gemini (21 du Groupe galactique et 15 du Groupe extragalactique), pour le semestre 2017 B. Les taux d’adhésion se chiffraient à 2,41 pour le CFHT, à 1,91 pour Gemini Nord et à 1,90 pour Gemini Sud.

Le CNRC Herzberg a commandé une étude sur le temps d’observation octroyé par le CanTAC, selon le sexe. Sous la supervision de Kristine Spekkens, un doctorant en sciences sociales de l’Université Queens a examiné les demandes de temps d’observation pour le CFHT et l’observatoire Gemini accordées au cours des dix derniers cycles. L’analyse révèle que, si l’on fait exception des chercheurs principaux (CP) attachés à une faculté, les demandes soumises par les CP de sexe féminin reçoivent une note beaucoup plus basse que les demandes présentées par les CP de l’autre sexe.

Afin d’y remédier, on modifiera le format des demandes pour l’observatoire Gemini et le CFHT. Dorénavant, les chercheurs seront énumérés par ordre alphabétique et le CP ne sera pas identifié.

Nouvelles du JWST

Cet été, le télescope spatial James Webb (JWST) subira ses derniers essais sous vide et sous zéro au Johnson Space Center de Houston. Le télescope et son module d’instruments scientifiques seront soumis à une batterie de tests thermiques et optiques. Le programme d’essais de 93 jours servira à vérifier les modèles ainsi que les spécifications de rendement pour s’assurer que le télescope fonctionne bien de la façon dont il est censé le faire.

Parallèlement, les astronomes du monde entier se préparent en vue des programmes scientifiques du JWST. Ainsi le programme DD-ERS (Director’s Discretionary Early Release Science ou programme discrétionnaire du directeur sur la diffusion hâtive des données) disposera d’environ 500 heures d’observation au début du premier cycle, de manière à illustrer la façon dont les instruments peuvent être utilisés à des fins scientifiques dans divers modes. Puisqu’aucun droit d’exclusivité ne s’applique aux données résultant de ces observations, les utilisateurs auront une bonne idée des capacités des instruments avant que s’amorce le deuxième cycle de demandes de temps d’observation. L’appel à projets pour les observations générales du premier cycle devrait avoir lieu en novembre, cette année. Il s’agit d’un jalon marquant pour les astronomes qui planifient d’utiliser le JWST pour leurs observations.

On peut se préparer de nombreuses façons à la rédaction d’une demande pour le JWST. Ainsi, le Space Telescope Science Institute (STScI) propose une documentation abondante, qui ne cesse d’augmenter. On y trouvera aussi divers outils facilitant la planification des observations, y compris l’APT (Astronomer’s Proposal Tool — outil de rédaction des demandes d’astronomie), l’ETC (Exposure Time Calculator – calculatrice du temps d’exposition) et des aides pour calculer la visibilité de la cible. Cet automne, l’équipe canadienne du JWST, pilotée par René Doyon, organisera plusieurs activités à l’intention des utilisateurs canadiens du JWST, notamment des visites à l’université et des webinaires. L’annonce que l’Agence spatiale canadienne financera les activités scientifiques des utilisateurs du JWST, faite récemment à la réunion de la Société canadienne d’astronomie, à Edmonton, est certainement la bienvenue et permettra aux astronomes canadiens d’exploiter scientifiquement au mieux les sommes que l’État a injectées dans l’installation.

Le JWST sera lancé sur son orbite en halo autour du point de Lagrange L2 au moyen d’une fusée Ariane V, en octobre 2018.

Préparation du JWST en vue des essais sous vide et sous zéro à la chambre A du programme Apollo, au Johnson Space Center de Houston. NASA (Chris Gunn)

Préparation du JWST en vue des essais sous vide et sous zéro à la chambre A du programme Apollo, au Johnson Space Center de Houston. NASA (Chris Gunn)

Report from the CASCA/ACURA TMT Advisory Committee

By Michael Balogh (CATAC Chair)
(Cassiopeia – Summer/été 2017)

CATAC’s first report to ACURA and CASCA has been made publicly available, at http://casca.ca/wp-content/uploads/2017/03/CATAC-Report-Final.pdf. This report is the result of broad consultation with the community, members of the TMT project office, experts in adaptive optics, site testing and computational fluid dynamics, and Directors and users of telescopes on the Canary Islands. The report includes a quantitative comparison of the capabilities of TMT on its preferred site on Maunakea (MK13N), relative to the alternative site (Observatorio del Roque de los Muchachos, ORM) and the other 30-m class facilities under development: ELT and GMT. In summary we find that TMT is most capable and competitive if it can be constructed as planned on MK13N. However, if it proves necessary to move to ORM, TMT will still deliver transformative science that will meet the needs of the majority of the Canadian community. We made the following specific recommendations, which are worth repeating here:

  1. Given that ELT will be located at a better site, with a substantial aperture advantage, competitiveness now and in the future for TMT will require extracting the maximum from instrumentation and operations. Innovation will be of fundamental importance. A robust development budget with stable funding commitments is also essential. Operations must include an adaptive queue, and should allow observing flexibility. Canadian participation in a VLOT that fails to meet these basic national facility requirements should not be considered.

  2. TMT@MK13N offers significant competitive advantages relative to ELT. In particular it is expected to outperform ELT in the UV and MIR, while remaining competitive for visible and NIR observations. Therefore the site on MK should not be given up prematurely. The decision to move to ORM should only be made once it is clear that construction on MK will delay the project significantly relative to ELT, or fail to attract the necessary funding. As both the realistic timeline for ELT and the funding opportunities for TMT remain uncertain, we should proceed with caution.

  3. The broader Canadian community should be engaged in a project to which we are dedicating so many resources. We should aim to have ~5 Canadians on each science team. They should be representative in terms of geography, institution, gender, and career stage. While all Canadian researchers are encouraged to apply, CATAC (or LRPIC) should also develop a list of specific individuals to approach to apply for ISDT membership well before the next call (January 2018). LRPIC should investigate whether there exist mechanisms within the Canadian funding ecosystem to support ISDT activities, or whether a new allocation should be sought, perhaps by ACURA.

We presented a summary of our findings at this year’s CASCA meeting in Edmonton. From the ensuing discussions (during both the CATAC lunch meeting and the LRPIC/CATAC meeting the following morning) we took away the following:

  • The community remains strongly supportive of TMT on Maunakea. A move to ORM would generally be disappointing. However, when asked directly, no one stated that they would be unable to achieve significant scientific progress with TMT if it were located on ORM. This is strong affirmation that the alternative site will be acceptable to the Canadian community.
  • The community is dissatisfied with the TMT project’s transparency regarding its financial planning and overall viability. Little or no information about how the Board is dealing with the financial shortfall is available, and this lack of communication has resulted in some skepticism in the community regarding the project’s ability to complete construction.
  • The Canadian astronomical community is aware of the conflicting interests on Maunakea, and respects the legal process that is being undertaken in Hawai’i. There is an understandable desire to act ethically.

CATAC agrees that the TMT project office and Board need to be more forthright in their communications with the community. To encourage this, we would like to hold our next public Webex meeting on the financial status of the project, and we will invite one or more representatives of the project to lead with a presentation and be available for following discussion.

Finally, we would like to thank and congratulate those of you who answered our call to participate in the International Science Development Teams. As of this writing, 18 individuals have responded to fill 23 positions (with five individuals serving on more than one ISDT). Including those already participating, we anticipate at least 35 ISDT positions filled by 28 Canadians. This is a great improvement and a better reflection of what this telescope means to our community.

The TMT Science Forum is being held in Mysore, India on November 7-9, 2017. We would like to encourage especially those participating in the ISDTs to consider attending. We are still working on identifying sources of partial financial support, but now recognize that may not be possible before this meeting. We hope many of you will still be able to attend.

As always, CATAC is happy to hear from you at any time. Please email mbalogh@uwaterloo.ca if you have questions for us, opinions or advice relevant to our mandate, or indeed information that you think might be useful to CATAC. Our website is now hosted on the CASCA site and we will keep this updated with upcoming meetings, events and documents.

CATAC Members:

  • Michael Balogh (University of Waterloo) Chair
  • Sarah Gallagher (Western University), Vice-Chair
  • Stefi Baum (University of Manitoba)
  • Chris Wilson (McMaster University)
  • David Lafrenière (Université de Montréal)
  • Harvey Richer (UBC)

Observers:

  • Greg Fahlman (General Manager of NRC-HAA, non-voting, ex-officio)
  • Don Brooks (Executive Director of ACURA, non-voting, ex-officio)
  • Bob Abraham (CASCA President, non-voting, ex-officio)
  • Doug Welch, (Science Governor for Canada on TIO Governing Board, non-voting, ex-officio)
  • Tim Davidge (NRC)
  • Luc Simard (NRC)

Looking Back at CASCA-2017

CASCA_Badge_Back

By/par Erik Rosolowsky, on behalf of the LOC
(Cassiopeia – Summer/été 2017)

The astrophysics group at the University of Alberta was pleased to host the 2017 Annual General Meeting of the Canadian Astronomical Society. The meeting was held in Edmonton, Alberta from May 29 to June 1, 2017, and over 200 members of the Canadian astronomical community attended. The full details of the meeting, including the conference program remain available at casca2017.ca. In addition to several prize lectures by the 2017 CASCA awardees, invited speakers covered topics ranging from engaging public outreach, to planetary energy budgets, to next generation instruments. Over 70 junior researchers presented their research in poster and oral contributions, showcasing the next great results to come out of the community. Fiona Harrison, Principal Investigator of the NuSTAR mission, delivered the Helen Sawyer Hogg lecture to meeting attendees and the public on “From Spinning Black Holes to Exploding Stars: A New View of the High Energy Universe.”

Several additional activities happened associated with the CASCA meeting including a full-day workshop for graduate students, this year focusing on writing scientific papers. In addition to faculty members, the graduate students heard from Leslie Sage, editor at Nature (and CASCA press officer), who spoke about the publication process, and Christina Hwang of the University of Alberta libraries, who spoke about data access and management. The Education and Public Outreach Committee organized an excellent workshop for local educators, expanding and enriching their ongoing effort to connect our community with the science educators. There were two special sessions to present information about Canadian participation in Very Large Optical Telescopes, in particular the Thirty Metre Telescope. These sessions featured broad-ranging discussion about the circumstances surrounding our next great telescope project. The CASCA Board, the Joint Committee on Space Astronomy, and the Association of Canadian Universities for Research in Astronomy, all held their annual face-to-face meetings.

In addition to oral and poster prizes presented to the students in attendance, the LOC initiated a hopefully-continuing tradition of awarding a poster prize to the best post-PhD contributor. At this meeting, the SOC/LOC prioritized junior scientists for oral contributions and we instituted the prize to encourage senior scientists to present their research through a poster presentation. This year’s inaugural winner was Jason Rowe (Montréal/Bishop’s). Awards for students were presented to:

  • Best student oral presentation (as judged by the Board): (tie) Gwendolyn Eadie (McMaster) & Anna Ordog (Calgary)
  • Best student poster presentation (as judged by the Board): Megan Tannock (Western)
  • Best student oral presentation (as judged by the students): Gwendolyn Eadie (McMaster)
  • Best student poster presentation (as judged by the students): Farbod Jahandar (Victoria)

We would like to thank attendees for coming to the meeting. Your attendance is ultimately what makes these annual meetings a success. In particular, we would like to thank those members of the community who support their students to travel to and attend CASCA meetings. By convening and deliberating on scientific and policy questions, we strengthen our community and advance our broader scientific goals.

What Telescopes Do Canadians Use?

By/par Dennis Crabtree (NRC Herzberg)
(Cassiopeia – Summer/été 2017)

I maintain a database of publications based on data obtained from a large number of telescopes. The database contains the basic publication information (journal, year, volume, page), as well as other information retrieved from NASA ADS. This includes the unique bibliographic identifier – the bibcode.

ADS’s new Bumblebee interface allows for a search of the full text of the article but the feature I make use of for this study is the ability to search the affiliation field. By searching for papers that include “Canada”, I can select papers with at least one author based at a Canadian institution, i.e., the Canadian papers.

Once I have the list of Canadian papers, including the bibcode, I correlate the list of Canadian papers with the list of observatory papers. This identifies the Canadian papers based on data from each of the telescopes.

Figure 1 below shows both the number of Canadian papers for each telescope for the period 2011 – 2015, and the percentage of that telescope’s papers that are Canadian. For example, there were 268 Canadian CFHT papers during this period, which is approximately 40% of the papers from CFHT. (A large number of papers based on CFHT data use archival data so one would not expect the percentage of Canadian papers to necessarily match our percentage of CFHT).

Figure 1 The number of Canadian papers based on data from various telescopes for the period 2011-2015 as well as the percentage of each telescope’s papers that are Canadian. While Canada provides direct support for ALMA, CFHT and Gemini, Canadians utilize data from many more telescopes via international collaborations.

Figure 1 The number of Canadian papers based on data from various telescopes for the period 2011-2015 as well as the percentage of each telescope’s papers that are Canadian. While Canada provides direct support for ALMA, CFHT and Gemini, Canadians utilize data from many more telescopes via international collaborations.

Figure 2 compares the average impact per paper for papers that have at least one Canadian author with that of all papers from each telescope. For almost all of the telescopes included, Canadian papers have higher impact per paper than the average paper from the same telescope. The reason for this remarkable result is again that Canadians are great collaborators. The average number of authors on Canadian papers is larger than the average number of authors on all papers for each telescope. Since there is a strong correlation of impact with the number of authors on a paper, it is not surprising that Canadian papers have higher impact.

Figure 2 The average impact per paper for Canadian papers on each telescope compared to the impact per paper for all papers.

Figure 2 The average impact per paper for Canadian papers on each telescope compared to the impact per paper for all papers.

Using Archived Data in Course Projects: A Call for Collaboration

By/par Magdalen Normandeau (UNB)
(Cassiopeia – Summer/été 2017)

There is a wealth of easily accessible archived data and databases that provide opportunities to give our undergrad students a taste of real data and a sense of the puzzle-solving involved in doing astronomy. However, coming up with a good project is time-consuming. Also, if one is not an expert in the particular subfield, there is the danger of introducing some serious error in the process of trying to craft something that is tractable in the context of a course.

I propose that we help each other – and our students – by collaborating on the elaboration of course projects and in-class activities that use publicly available data. I offer to coordinate the effort both by collecting the materials and finding a way to distribute them. Also, I offer to provide assistance, consultation and feedback on the pedagogical side (worrying about teaching effectiveness is what I do now rather than worrying about the impact of Wolf-Rayet stars on the surrounding ISM).

If you are interested in creating a project this summer, please email me (mnormand@unb.ca) the following information:

  • Your name and the names of anyone else who helps you on this project
  • Your institution(s)
  • The database that you intend using
  • The level for which you will be designing.
    • I have in mind intro astro for physics students at the 2nd or 3rd year level, but you should feel free to specify something else. Given the wealth of resources available for general education astro, my tendency is to design something for students with a stronger science background, the potential future astrophysicists.
  • The scope of project that you have in mind
    • A term project worth a substantial fraction of their final grade? One of a few projects scattered throughout the term? Part of a weekly or biweekly assignment? An in-class activity?

If two or more people propose similar projects, I’ll put them in touch with each other to avoid duplication of effort.

I doubt I’ll get any takers on this, but it’s worth a shot!