Cassiopeia Newsletter – Vernal Equinox 2022
- angabela
- Mar 24, 2022
- 31 min read
Updated: Aug 23, 2025
Date: March 26. 2022
In this Issue:
President’s Message
ALMA Matters
BRITE-Constellation Mission Update
Update on CASTOR
CATAC Update on the Thirty Meter Telescope
Canadian Initiative for Radio Astronomy Data Analysis (CIRADA)
Report from the LCRIC
Maunakea Spectroscopic Explorer (MSE) Update
ngVLA Update
Report from the SKA
Dissertation: The Dynamical Evolution of Classical Be Stars
Editor: Joanne Rosvick
Cassiopeia is CASCA’s quarterly Newsletter, published on or near the solstices and equinoxes (March 21, June 21, September 21 and December 21).
To submit a contribution please email cassiopeia.editors@gmail.com. All submissions must be received by the due date (usually 2 weeks in advance of publication) to be published in the next edition. I accept plain text and Word documents. Note that the formatting of your document will not be preserved. Please include any images as attachments in your email, not embedded in the text. Please include URLs in parentheses next to the word or phrase that you wish to act as link anchors.
President’s Message
By Rob Thacker (CASCA President)(Cassiopeia – Spring 2022)
On Some Difficult Questions for CASCA
I will centre myself often in this dialogue as identity matters, and I want to emphasize that I’m writing to encourage broader thought, these are obviously my personal views on how I believe organizations should function. I may ask some difficult questions, but they are meant to be general rather than focused, and to lead introspection.
That many of you may well find some of statements I make easier to be framed by me as a (hopefully perceived) compassionate and unthreatening white cis-gender man, also helps to position this dialogue. I’ve never considered myself an activist, but I am married to a person who is deaf, who has had to fight for so many things in their life that I can almost remember where the furrows on her brow come from. I also work with many colleagues who consider themselves activists. That simple statement about not seeing myself as an activist perhaps encapsulates my inherent whiteness, namely, to not see myself for what I am.
I wrote a President’s message in 2019 on the close proximity of CASCA to government, the high costs of the projects we are now involved in and the responsibility it places on our community. While one can argue Canada is normally a small player in major international projects, the reality is the size of those projects are becoming massive. I concluded that essay by saying “It’s one thing to say that knowledge from astronomy benefits everyone, but there’s a growing onus on astronomers to make connections that fulfil that promise.”
How far have we come?
Each of you will have a different viewpoint and answer. That is the nature of community.
I’ve been asked why it was important to run the leadership panel this past November, and, other than the fact a promise was made to do that, I think it speaks to the fundamental value of dialogue. With CASCA being a (not-for-profit) corporation, ultimate authority and legal responsibility sits with the Board to determine what is appropriate. That said, I think with most of us being used to working in university collegial governance we would expect support for discussion over difficult topics, that is one of the key things universities are meant to do. However, we have a clear organizational dissonance right now, as the Letters Patent for the Society has a distinctly different flavour to a university act, which usually include statements around freedom and respect, for example. To be more explicit, we don’t have a Senate, we don’t have an Appeals Board, and multiple other structures. CASCA simply does not operate under the same principles as most universities.
What about when discussions get heated? Could we have “civility codes of conduct” to avoid offense and discomfort as distinct from equity-driven codes of conduct employed in conference environments? Obviously, this has been a major discussion on campuses for some time now. But despite our differences from a university structure, I strongly feel we should continue to follow CAUT guidelines to resist imposing any such legislation. David Robinson, CAUT Executive Director, has spoken extensively about how while a goal of civil and respectful dialogue is laudable, when policies are put in place to regulate speech and behaviour then free expression can be put at risk. These issues become most prominent during protest and dissent. CAUT usually highlights the 2014 Capilano University protest as an example where the creation of a statue was ruled as harassment of the university President, which in turn was seen as a clear violation of academic freedom and freedom of expression in a follow-on review.
To be clear: CASCA has a moral and legal obligation to ensure its operation is free from discrimination and harassment, but, at least in my view, we cannot enshrine an intrinsic right to never be offended or uncomfortable. As to the standard of this statute, that is a challenge, and one I will admit is very difficult to determine. Legally, we fall back to the reasonable and competent assessment, but from a social justice perspective that can be argued to be insufficient.
Consequently, as someone that works as a union Lead Negotiator, I am (personally) resistant to any policy which intimidates and silences by inappropriate methods of behaviour control that can be used to oppress, as the 2014 Capilano University case shows. Moreover, I wholly admit it is easy for me to say these things as someone that is implicitly a member of an empowered group and there are complicating factors, for example although many of our members have academic freedom, not all do. Arguments between individuals with academic freedom vs those without it can have an inherent imbalance. Please try to be mindful of this issue. Members of CASCA do not all have the same workplace rights.
Above all, I want to remind everyone that without questioning our values we can easily perpetuate dominant ideologies without being aware of it. There is no question that systemic white supremacy is pervasive within academia, even documents on diversity, which may have been written with good intentions, frequently centre whiteness as “normal.” Similarly, we’ve all seen the benefits of dual anonymous reviews in astronomy, we know biases are present.
This winter term I’ve been enrolled in a course “Indigenous Knowledges and Relations” co-taught by Michelle Paul and Benita Bunjun. One of the key questions we are asked as students is a moral one, namely: “Could you learn all the material in this course and still be someone that doesn’t value Indigenous Knowledges and actively works against them?” the answer is obviously that yes, you could. Why would someone? From self-interest, to systemic bias, to conscious racism we can name different possibilities. Education is but one part of a broader issue – indeed I’m currently working with Reconciliation Education to put this in place for the current and future CASCA Boards – but we have to fully process the moral and ethical questions that are implicit within that knowledge.
All of this discussion has been building to highlight one key fact about how we respond to ethical questions: it is ultimately an individual reaction. CASCA can make ethical statements about what it supports as a Society, but it is down to individual members to take those statements and incorporate them in their actions. Not everyone will come to same conclusions, we know that individuals in communities have different viewpoints. Nonetheless, I feel the single most important recommendation in the LRP is that every Canadian astronomer make a personal commitment to inclusion and reflect that in their personal ethics and values.
With that I call on everyone in the Society to be welcoming, generous and open. We are a community that is focused on education. When we argue, make it about learning, rather than mere winning.
Astronomy is important, but we don’t make the world a better place by discovering things about the universe. We make it a better place by truly sharing that discovery with all the people that make it possible, and working together with respect and true partnership.
Coalition Update
Over the past few months Coalition activities have focused strongly around the Square Kilometer Array. As many of you are aware the project continues to move ahead rapidly, please refer to the excellent updates being provided by Kristine Spekkens and the AACS. The cooperation agreement has been a great way to keep Canadian participation moving forward, but it is clear we need to signal a clear intent to the project to shift to full participation before the agreement ends in March 2023. With the agreement only having been signed last November it might seem unusual to have to be back discussing the issue with the Government so quickly, we are mindful of that issue!
I want to express a personal note of thanks to all the members of Coalition that have participated in the many meetings we’ve had in this first quarter. The community should be aware that some of our industry partners support the Coalition and participate in briefings despite not necessarily being involved in construction of a given project, in that sense the Coalition is a true partnership. That is an important and valuable interrelationship. However, I am most thankful to Kristine Spekkens for her amazing efforts in support of education around the SKA and contributions to discussions with key decision-makers.
I’m delighted to say that these meetings have gone well so far. We’ve been able to address many questions about the project and how it fits with several different Government priorities. I am hopeful that we will indeed see a commitment to the project in the time frame that the SKAO needs. It would be a tragedy if the cooperative agreement ended up becoming an off-ramp for our participation.
So long…
I will be stepping down as Interim President at the AGM as I need to lead what will likely be a very difficult negotiation for my fellow faculty members at SMU. As I write this message, I am quite literally minutes away from giving another faculty update. Juggling responsibilities since January has been a headache! Bylaw 9.1 allowed me to work in this position from last August until the next round of CASCA elections, and those will be soon upon us. We are diligently working to prepare a slate of nominations and I am happy to say we are over half-way there at this point, nominations will be presented soon.
I want to thank everyone in the Society for the conversations we’ve had over the past few months, and all the time and work you have committed to the Society, especially those serving on committees and/or the Board. I also thank our staff, Jessica and Don for all the great help they have provided, and Joanne for her continued work as Editor of Cassiopeia.
It has been an honour to serve you all.
My parting thought to each of you: Be gentle with yourself.
Rob
ALMA Matters
By Gerald Schieven (ALMA)(Cassiopeia – Spring 2022)
Cycle 9 Call for Proposals
On March 24, the Joint ALMA Observatory will issue its call for proposals (CfP) for the Cycle 9 period of 1 October 2022 through 30 September 2023. The deadline for proposals will be 21 April, 2022 at 15UT. Proposals are to be submitted using the Cycle 9 Observing Tool (OT), available through the ALMA Science Portal. A full list of science capabilities and other information can also be found on the Science Portal.
Proposals are being solicited for the 12-m Array in all configurations (with maximum baselines from 0.16 km to 16.2 km), and for the ACA (including the 7-m and TP Array). Note that there will NOT be a supplemental call for stand-alone ACA proposals (i.e. those requiring just the 7-m and TP Arrays) during Cycle 9. All such proposals should be submitted during the normal call with deadline 21 April.
Once again, proposals will be submitted using the dual-anonymous procedure, which requires that PIs write their proposals in a way that preserves anonymity. In addition, all proposals requesting less than 50 hours on the 12-m Array, or 150 hours on the ACA in stand-alone mode, will be reviewed through the distributed peer review system.
Some the new capabilities being offered in Cycle 9 include:
High-frequency and long-baseline observations, including Band 8 in configurations up through C-10, Band 9 in configurations up through C-9, and Band 10 in configurations up through C-8. For the first time, observations can be requested for angular resolutions as small as 9 milliarcseconds at 600µm (500 GHz).
Solar Total Power regional mapping scans in bands 3, 5, 6, and 7
VLBI continuum observations in Band 7
VLBI spectral line observations in Band 3
Webinars for Novice Users (and those wishing a refresher)
A series of webinars will be held in late March and early April on ALMA basics and capabilities, and on proposal preparation and review. Registration is free.
Talk | Date | Registration Link |
ALMA Basics and Cycle 9 Capabilities | 30 March @ 4pm EDT | |
Proposal Preparation and the Review Process | 31 March @ noon EDT | |
ALMA Basics and Cycle 9 Capabilities | 05 April @ 2pm EDT | |
Proposal Preparation and the Review Process | 05 April @ 4pm EDT |
These webinars are being organized by the ALMA Ambassadors, a program that provides some funding to young researchers, in exchange for organizing an ALMA workshop in your home area. This program is open to grad students and post-docs in any university or research institute in North America. Stay tuned to the CASCA exploder to be notified of the next deadline to apply for this program.
In addition to the webinars, Observing with ALMA – A Primer provides a basic introduction to radio interferometry, ALMA, its capabilities, and examples of science projects that could be observed with ALMA. The goal of the document is that, with all the basic information in one place, and a few examples of how to plan a science observation, this document can help all astronomers become familiar with ALMA’s capabilities and to start planning their own ALMA observations.
BRITE-Constellation Mission Update
By Gregg Wade (on behalf of the Canadian BRITE Team)(Cassiopeia – Spring 2022)
BRITE-Constellation is an international space astronomy mission consisting of a fleet of 20x20x20 cm nanosatellites dedicated to precision optical photometry of bright stars in two photometric colours. The mission continues in full science operations, with 38 datasets available in the public domain from the BRITE public archive. As of April of 2020, all data is made public as soon as decorrelation is complete, with no proprietary period.
The BRITE mission is a collaboration between Canadian, Austrian and Polish astronomers and space scientists. The Canadian partners represent University of Toronto, Université de Montréal, Mount Allison University, and Royal Military College of Canada. The mission was built, and the Canadian satellites operated by, the University of Toronto Institute for Aerospace Studies Space Flight Lab (UTIAS-SFL). The Canadian Space Agency funded the construction of the Canadian satellites, and continues to support their day-to-day operations.
Operations
There are five BRITE satellites in the Constellation, which work together to obtain well-sampled, long term continuous (~6 months) light curves in both red and blue band passes across a variety of sky fields.
As this issue of Cassiopeia went to press, the assignments of the BRITE nanosats were:
BRITE Toronto (Canada): This satellite observes with a red filter. It is currently observing the Vel-Pup VIII field. (As indicated by the roman numeral, Vel-Pup is a BRITE legacy field being observed for the 8th time.
BRITE Lem (Poland): Lem observes with a blue filter, but is currently idle due to unresolved stability issues.
BRITE Heweliusz (Poland): Heweliusz observes with a red filter. It has recently finished observing the Orion VIII field and is being set up on the Cru-Car IV field.
BRITE Austria (Austria): BRITE Austria observes with a blue filter. It has recently completed observing the Orion VIII field.
UniBRITE (Austria): Currently out of order.
The BRITE Constellation observing program is currently set through mid-2022. Details of the observing plan will be available on the BRITE photometry Wiki page.
Recent Science Results
“A study of stochastic photometric variability in the winds of Galactic Wolf-Rayet stars” (Lenoir-Craig et al., ApJ 925, 79)
In order to explore how the ubiquitous short-term stochastic variability in the photometric observations of Wolf-Rayet (WR) stars is related to various stellar characteristics, we examined a sample of 50 Galactic WR stars using 122 lightcurves obtained by the BRIght Target Explorer-Constellation, Transiting Exoplanet Survey Satellite and Microvariability and Oscillations of Stars satellites. We found that the periodograms resulting from a discrete Fourier transform of all our detrended lightcurves are characterized by a forest of random peaks showing an increase in power starting from ~0.5 day-1 down to ~0.1 day-1. After fitting the periodograms with a semi-Lorentzian function representing a combination of white and red noise, we investigated possible correlations between the fitted parameters and various stellar and wind characteristics. Seven correlations were observed, the strongest and only significant one being between the amplitude of variability, α0, observed for hydrogen-free WR stars, while WNh stars exhibit correlations between α0 and the stellar temperature, T∗, and also between the characteristic frequency of the variations, νchar, and both T∗ and v∞. We report that stars observed more than once show significantly different variability parameters, indicating an epoch-dependent measurement. We also find that the observed characteristic frequencies for the variations generally lie between -0.5 < log n < 0.5, and that the values of the steepness of the amplitude spectrum are typically found in the range -0.1 < log g < 0.5. We discuss various physical processes that can lead to this correlation.
Conferences, Resources, and Social Media
Conferences
The BRITE team does not plan to host any conferences at this time.
Resources
The BRITE Public Data Archive, based in Warsaw, Poland, at the Nikolaus Copernicus Astronomical Centre, can be accessed here.
The mission Wiki (including information on past, current and future fields) can be accessed here.
BRITE Constellation is on Facebook, at @briteconstellation
The BRITE International Advisory Science Team
The BRITE International Advisory Science Team (BIAST), which consists of BRITE scientific PIs, technical authorities, amateur astronomers, and mission fans, advises the mission executive on scientific and outreach aspects of the mission. If you’re interested in joining BIAST, contact Dr. Catherine Lovekin, the chair of BEST.
Update on CASTOR
By Patrick Côté, John Hutchings (NRC Herzberg Astronomy & Astrophysics Research Centre)(Cassiopeia – Spring 2022)
The CASTOR project continues to move forward as the Long Range Plan’s highest priority in space astronomy for the 2020s.
The ongoing CSA technical (STDP) study contract continues to make good progress. A recent review detailed the design and performance of the Fast Steering Mirror that will perform the fine guiding for the observatory. The recently launched James Webb Space Telescope utilizes the same guiding system, so there is significant heritage in this capability. Other work on the detectors and payload opto-mechanical issues continues.
The long-awaited Phase 0 study contract is underway as of March 8. This study overlaps the STDP work, and both studies will wrap up about one year from now. The prime deliverable from the Phase 0 study will be a fully characterized and thoroughly planned mission concept, with agreed partnerships, that can move immediately into the flight Phases A to E. It is hoped that partnership details and agreements with ISRO, JPL, and UK will be formulated during this time. The Phase 0 study consists of an industrial contract (led by Honeywell Aerospace) and a science team contract (led out of NRC/HAA), and now is formally a joint project between CSA and NRC. Science working groups (SWGs) and work contracts are in place with several Canadian universities.
The CASTOR and Indian INSIST teams continue to work on a common design and hold regular meetings. The partner teams also include JPL and UK, whose participation in the STDP and Phase 0 work are being formalized.
The ACURA board and the Coalition are fully informed and are carrying the message from Universities to the government to prepare for flight approval and funding. We welcome colleagues to join in SWG and outreach activities.
For more information on the mission, see the main page here.
CATAC Update on the Thirty Meter Telescope
By Michael Balogh (CATAC Chair)(Cassiopeia – Spring 2022)
TMT Canada Information Session
In advance of the CASCA AGM, CATAC will be hosting a community Webinar to provide an update on TMT. This will take place on Thursday, May 12 at 3pm EDT. A registration link will be circulated shortly to the CASCA email list; registration is open to CASCA members only. A rough outline of the agenda is:
Time (EDT) | |
3:00-3:25pm | CATAC update on next steps following Astro2020, including the NSF process and the role of the Board and partners during this process |
3:25-4:05pm | Project Manager Fengchuan Liu will provide an update on TMT, including technology development and the situation in Hawaii |
4:05-4:30pm | Discussion and questions from participants |
The meeting will not be recorded, though some slides may be made available. If you want to attend but cannot make that time, we are considering hosting a second (identical) session the following day, May 13 at 3pm EDT. This will only occur if there is sufficient demand. If you cannot attend on May 12, but can on May 13, send an email to mbalogh@uwaterloo.ca to register your interest.
Recent News
We are pleased to announce that David Andersen (NRC) is the new science instrumentation group leader. He takes over from Eric Chisolm (another Canadian), who has taken a senior leadership position with Amazon’s Center for Quantum Computing (CQC).
Fengchuan Liu transitioned from acting Project Manager to Project Manager in November 2021. He is resident in Hilo, Hawaii and over the past year he has had many opportunities to listen and learn from members of the community.
Following the top ranking in the US Decadal report, the next step is for the project to be accepted into the Major Research Equipment and Facilities Construction (MREFC) budget, after which it will become an official project of the NSF. The process and timeline from there is described in detail in NSF’s Large Facilities Manual. NSF’s funding for the construction or modification of facilities constitutes a Federal Action that triggers compliance with several statutes, including the National Environmental Policy Act (NEPA), the National Historic Preservation Act (NHPA) and the Endangered Species Act. Compliance with NEPA includes providing opportunities for public input on issues such as potential environmental impacts and ways to avoid, minimize, and/or mitigate adverse impacts, and will require completion of an Environmental Impact Statement (EIS).
In preparation for this process, the NSF has engaged in informal discussions with various parties, including TIO partners. It should be expected that partnership with the NSF at a significant level may impact many aspects of the project including partner shares, governance, operations and instrumentation planning. As we noted in our last eCass article, CATAC is working closely with GAC as they explore how to fulfil the LRP recommendation to ensure Canada has access to a Very Large Optical Telescope (VLOT), at a level that provides compelling opportunities for Canadian leadership in science, technology and instrumentation.
Site Update
As we noted in our last article, the University of Hawaii bill that is currently before the House of Representatives. This bill would establish the creation of a new body for managing the summit. This body would be made up of ten voting members (three of which serve ex-officio). The bill requires that four of the seven non-ex officio members be Native Hawaiian residents of the county of Hawaii, with a preference for Native Hawaiian residents of the county of Hawaii for all seven non-ex officio members. There would be no representative from the astronomical community on this authority. The bill was passed by the House on March 8, and received by the Senate on March 10. The current status of the bill can be followed here.
Instrumentation
A good description of the first-light and subsequent instrumentation planning for TMT is available on their website. CATAC has been revisiting and revising our recommendations on post-first-light instrumentation, released in 2019. Despite the delay in construction start for TMT, and the progress made by ELT, the planned instrumentation development for TMT is still competitive. WFOS (Wide Field Optical Spectrograph) and MODHIS (high resolution, AO-assisted NIR spectrograph) are first light capabilities that ELT will not have on the current projected timeline. HROS (high resolution optical spectrograph) remains a high priority for the next instrument – and while there is competition from a similar instrument (ANDES, formerly known as HIRES) on ELT, there is still scope for HROS to be deployed on a comparable timescale. Current, Canadian-led work on GIRMOS (for Gemini) and NIRPS (ESO 3.6m) paves the way for future TMT instruments TIRMOS and NIRES-B, respectively. Finally, we note that ELT is deferring development of the Planetary Camera and Spectrograph (PCS), to further develop the science case and technology (see article here). Careful and appropriate phasing of TMT’s Planetary System Instrument (PSI) could therefore enable TMT to achieve some of this exciting science well before the ELT.
While the pace of GMT instrument development appears to be significantly behind that of TMT, that has the potential to change with NSF involvement. Since the US community will have access to both GMT and TMT, this may inform NSF priorities regarding instrumentation on the two telescopes. It is too early to be sure what the implications might be for Canada and the TMT, but it is an issue that CATAC is watching closely.
CATAC Membership
Michael Balogh (University of Waterloo), Chair, mbalogh@uwaterloo.ca
Bob Abraham (University of Toronto; TIO SAC)
Stefi Baum (University of Manitoba)Laura Ferrarese (NRC)
David Lafrenière (Université de Montréal)
Harvey Richer (UBC)
Kristine Spekkens (Royal Military College of Canada)
Kim Venn (University of Victoria)
Luc Simard (Director General of NRC-HAA, non-voting, ex-officio)
Don Brooks (Executive Director of ACURA, non-voting, ex-officio)
Rob Thacker (Acting CASCA President, non-voting, ex-officio)
Stan Metchev (TIO SAC, non-voting, ex-officio)
Tim Davidge (TIO SAC Canadian co-chair; NRC, observer)
Greg Fahlman (NRC, observer)
Update on Canadian Initiative for Radio Astronomy Data Analysis (CIRADA)
By Bryan Gaensler (U. Toronto, CIRADA Director)(Cassiopeia – Spring 2022)
The Canadian Initiative for Radio Astronomy Data Analysis (CIRADA), a pilot project for Canada’s planned Square Kilometre Array Regional Centre, is producing science-ready public data products for large surveys being conducted with three telescopes: the Very Large Array (VLA), the Australian Square Kilometre Array Pathfinder (ASKAP), and the Canadian Hydrogen Intensity Mapping Experiment (CHIME). These products (e.g., images, cubes, time series spectra, catalogues, databases, alerts, pipeline algorithms, and software tools) utilise Canadian Advanced Network for Astronomical Research (CANFAR) services and will be searchable and usable by professional astronomers and the general public, through the Canadian Astronomy Data Centre (CADC). Users of our science-ready data products will be able to leverage for viewing images data and tabular catalogues directly through our portal. Currently our services include:
A “Quicklook Catalogue” of 1.7 million radio sources from the first epoch of the VLA Sky Survey (VLASS) including a second version that contains data on sidelobe probabilities, as well as the software pipelines that were used to generate the catalogues along with detailed user manuals. Next steps: Our team is currently in the process of producing an updated version of the catalogue using updated first epoch images that have had astrometry corrections made as well as a first catalogue using images from the second epoch. Both catalogues will be available in Q2 2022. We are also planning to co-release a VLASS Single Epoch catalogue when the first 1000 square degrees become available in Q3 2022.
pyink, developed in collaboration with Dr. Tim Galvin, a tool that simplifies the preprocessing and analysis that is required to train a self-organising map (SOM) using PINK. pyink can be used (i) to produce catalogues of double and multiple radio sources, (ii) to classify radio sources as either complex or simple sources, (iii) to find source orientations, and (iv) as an annotation tool. Next steps: Our team has recently hired a new developer to explore opportunities to use this tool to expand the identification of complex sources.
An Image Cutout Provider that allows astronomers to quickly visualise data from multiple surveys (VLASS Quicklook, GLEAM, FIRST, NVSS, WISE, PanSTARRS, SDSS I-II) at a given position in the sky and to download the data for further analysis. (PLEASE NOTE THAT THE ASTROMETRIC ERRORS THAT WERE PREVIOUSLY REPORTED ARE NOW RESOLVED.) Next steps: We are in the process of extending the application of our cutout provider for use with RACS, VLASS Single Epoch, and VCSS.
The RM-Tools software package for radio polarimetry analysis, including 1D and 3D RM synthesis, RM-clean and QU fitting on polarised radio spectra. Next steps: Our team is currently adding complementary tools and working on an RM Standards package which will be released in the coming months. We are collaborating with POSSUM scientists, CADC and the Australian Square Kilometre Array Regional Centre on a pipeline to mosaic, re-tile, re-grid and perform ionospheric corrections on POSSUM cubes that can be used to generate Faraday depth cubes and other science-ready data products using the RM synthesis tools.
Hydra: a source finder comparison and analysis tool that can be used to compare multiple source-finding algorithms on radio continuum data along with examples and detailed instructions.
A mock-cube generator suite that can be used to generate realistic data cubes for a single galaxy model, or a suite of galaxy models generated from standard scaling relations. Next steps: Our team is coordinating efforts with the WALLABY survey to co-release pilot observations of the Hydra, Norma, and NGC 4636 fields and rotating disk models which will be accessible for download or for use with CADC TAP services through our portal
An alpha-version of the VLASS Transient Marshal is currently being readied for testing, with a full release planned before the end of the year.
Access to all of CIRADA’s services, software tools and data products is available at cirada.ca.
Report from the LCRIC
By Chris Wilson (LCRIC chair)(Cassiopeia – Spring 2022)
The Long Range Plan Community Recommendations Implementation Committee (LCRIC) has continued to meet weekly over the past 3 months. Our primary focus has been on developing draft documents for LRP2020 Recommendation #1 (on Land and Consent) and Recommendation #46 (on an Indigenous Engagement Committee), as well as organizing the second in our series of webinars. We are also beginning to work on an LCRIC-focused session for the 2022 CASCA AGM.
Building on our work at the end of 2021, the LCRIC has held significant internal discussions around LRP2020 Recommendation #1, which focuses on issues of land and consent. We have produced a short document that we have passed along to the CASCA Board for their consideration and feedback.
The LCRIC has also had sustained discussions around LRP Recommendation #46, which envisages establishing a new CASCA committee, an Indigenous Engagement Committee. Among the items we are discussing is the scope of this committee, how it should interact with other existing CASCA committees, what types of persons would be appropriate and useful members of this committee, and how to fund the committee’s activities. We aim to develop a draft document with some ideas that we will share with the CASCA Board in the next 3 months.
We have also been working to organize our second webinar, titled “Including Indigenous Voices in Astronomy Education”. This webinar is now scheduled for 4-5:30 pm Eastern Time on Thursday, March 31, 2022 and will be held via zoom. The goal of this webinar is to share with CASCA members ideas and actions that they can use to support Indigenous knowledges, include Indigenist methods, and to be inclusive of Indigenous students in their classes. Panelists include: Jason Bazylack, Samantha Lawler, Ismael Moumen, and Laurie Rousseau-Nepton. There will be time for audience members to ask questions of the panelists. All participants are expected to follow the event’s Code of Conduct and pre-registration is required. An announcement of this webinar was circulated on the CASCA email exploder in mid-March.
Looking ahead, over the next 3 months, LCRIC is planning to meet with the Sustainability Committee and the Graduate Student Committee to discuss LRP2020 recommendations in their areas of interest. Finally, we will continue our initial work on an implementation timeline for the LRP2020 societal recommendations, with a focus on goals over the next 1 to 3 years.
The LCRIC recognizes that transparency and consultation are very important as our community moves forward to implement the recommendations of the LRP. We will be seeking input from a diversity of perspectives, recognizing that astronomy and astronomers exist with a broader societal context. We welcome feedback and comments at any time, via the Public Discussion page or by email to one of the LCRIC members. Communications will be kept confidential if requested.
Maunakea Spectroscopic Explorer (MSE) Update
By Patrick Hall (MSE Management Group Member)(Cassiopeia – Spring 2022)
MSE and Astro2020
MSE and wide-field optical spectroscopy faired well in last year’s Astro2020 report (“Pathways to Discovery in Astronomy and Astrophysics for the 2020s”, U. S. National Academies of Sciences, Engineering, and Medicine 2021). The report reads, in part:
“Recommendation: The National Science Foundation (NSF) Division of Astronomical Sciences (AST) should create three tracks within the AST Mid-Scale Innovations Program … The strategic priorities track is an essential addition to the existing mid-scale program structure to ensure that it is responsive to decadal and community strategic priorities. The survey has identified one top priority for this element, a time-domain astrophysics program, and two co-equal areas – highly multiplexed spectroscopy and radio instrumentation. … There is very strong support for massively multiplexed spectroscopy across many sectors of the science community. … A dedicated facility would of course provide advantages over relying solely on existing infrastructure. Most glaring is the lack of high spectral resolution (R~20,000) multi-object spectrographs. … MSE and SpecTel presented plans to the panel for such a mode. … In all cases, the United States could envision playing a significant role in these projects through a MSRI-2-level investment, which could provide up to about 20 percent of the cost of a project like MSE, SpecTel, or up to about 50 percent of MegaMapper, perhaps split with DOE.”
From the MSE collaboration’s official statement, available here:
“The 2010 decadal plan highlighted the need for large telescopes and deep imaging surveys to explore the universe,” said Jennifer Marshall, MSE Project Scientist and associate professor at Texas A&M University. “We have built the MSE science case over the past decade with the understanding that multi-object spectroscopy is the natural follow-up to those large projects.”
Strengths encompass two of three of Astro2020’s priorities for mid-sized projects: time domain astronomy and highly multiplexed optical spectroscopy. The MSE detailed science case outlines the compelling science that MSE will execute, much of which falls within the three main science themes identified by Astro2020: “Worlds and Suns in Context” (exoplanets), “New Messengers and New Physics” (transient astrophysics), and “Cosmic Ecosystems” (the evolution of galaxies).
Regarding the State of the Profession, one of the committee’s recommendations is that “the astronomy community should work with representatives from local communities to define a Community Astronomy model of engagement that advances scientific research while respecting, empowering and benefiting the local community.” The MSE collaboration welcomes this recommendation, along with the other recommendations regarding diversity, equity and inclusion, broadening the academic pipeline, and working with our indigenous and local communities here in Hawai’i.
The CFHT board is “committed to the Maunakea Spectroscopic Explorer as the future of the facility. The Board is confident that, following deeply rooted CFHT practices, the MSE project will be respectful of our privilege to share the cosmos from Maunakea, and will continue CFHT’s long-standing history of engaging the Hawai’i Island community.”
MSE Pathfinder
MSE/CFHT plan to propose to NSF to develop an end-to-end Pathfinder: a multi object spectrograph fed at prime focus from the Canada France Hawaii Telescope. It will utilize the MSE spectrograph design and a scaled down fiber positioner (approximately 800 fibers) using the same technology as the fiber positioner for MSE.
The goal of the Pathfinder will be to retire many of the high-level technical risks for MSE by demonstrating on-sky the ability of the major hardware and software components of MSE, with the end result of an initial science product being produced and shared with the community. Construction of either the optical or the near-IR arms of the MSE spectrographs would achieve these goals. It is envisioned that the proposal to NSF will be led by MSE/CFHT, with co-investigators from US universities and NOIRLab.
The Pathfinder fibers will subtend one arcsecond on the sky but because of CFHT’s smaller aperture will be one-third the physical diameter of the fibers for MSE. Thus, the spectrographs offer the possibility of spectral resolution two or even three times that delivered for MSE (10,000 or potentially 15,000 instead of 5,000). A rough estimate of sensitivity is that the Pathfinder will reach AB=22 at wavelengths longer than 400 nm at SNR=2 per resolution element in one hour.
MSE/CFHT are actively seeking input on science projects for both the optical and near-IR Pathfinder options. Key projects are envisioned to be galactic archeology, stellar spectroscopy for abundances and stellar evolution studies, and time-domain astrophysics (specifically, follow-up of transients to demonstrate the dynamic scheduling capabilities that will be possible with MSE).
If you are interested in the MSE Pathfinder, you can receive updates by joining the MSE Science Team at mseinfo@mse.cfht.hawaii.edu.
MSE/WFMOS and CFI
In parallel to the pathfinder efforts, Canadian proponents of WFMOS (Wide-Field Multi-Object Spectroscopy) are submitting a CFI proposal to obtain funding for a targeted set of conceptual and preliminary design needs widely applicable to all potential 10-meter-class WFMOS facilities, including but not limited to MSE. CFI envelope funding have been allocated at York, Waterloo, UBC, Toronto, Saint Mary’s, Western and Manitoba.
The proposal encompasses work on WFMOS facility enclosures, on software needed for end-to-end survey design & implementation, near-real-time survey optimization, and data reduction & analysis, and on the fiber-optic multiplexing systems and spectrographs required to meet the stringent scientific requirements of these facilities. Questions regarding the proposal can be directed to Pat Hall.
MSE Project Scientist
Prof. Jennifer Marshall plans to step down as Project Scientist later this year. She states, “I have thoroughly enjoyed working with all of you for the past three years, and going forward I fully intend to stay very engaged with the project and with all of you.”
The MSE Project office is now seeking nominations for a new Project Scientist. The detailed job description can be found here.
While the position is unpaid, there are financial and other benefits that come with the position, including the potential for MSE to provide funding for travel, summer salary support, and teaching buyout. Partial-time candidates will be fully considered. The position is open to mid-career and senior scientists. “The next Project Scientist will have the benefit of getting to work with the very excellent leadership team in the Project Office, which has been a pleasure for me. I have thoroughly enjoyed serving in this position and I’m sure my successor will also–as you all know, MSE is a great project!”
Your MSE Representatives for Canada
MSE Science Advisory Group Members: Ting Li (U Toronto) and Kim Venn (U Victoria)
MSE Management Group Members: Laura Ferrarese (HAA) and Patrick Hall (York U)
Canada is also represented among the MSE Science Team Working Group Leads by Prof. Ting Li (U. Toronto, Astrophysical Tests of Dark Matter WG co-Lead) and Prof. Will Percival (U. Waterloo, Cosmology WG co-Lead).
ngVLA Update
By Erik Rosolowsky (U Alberta)(Cassiopeia – Spring 2022)
After support from the US Decadal, the ngVLA project is beginning the next phase of its development: creating a fully costed design and a well developed science plan. Canada, along with Mexico and Japan, remains highly engaged as an international partner in the ngVLA planning process. Currently, the project is recruiting new members to the Science Working Groups and developing the next steps for what the next decade of National Radio Astronomy (NRAO) facilities looks like.
VLA/VLBA to ngVLA Transition Advisory Group
The NRAO has begun the process of developing a plan to transition from the operation of the Very Large Array (VLA) and Very Long Baseline Array (VLBA) to the ngVLA (see news article here). This activity will be led by the community-based “VLA/VLBA to ngVLA Transition Advisory Group”. Guided by the scientific opportunities planned for the coming decade, the Group will be charged to develop, quantitatively assess, and evaluate a finite number of possible VLA/VLBA to ngVLA transition options that can be prioritized on their scientific promise, cost and technical/personnel impacts. Nominations for the panel recently closed and the Group’s summary report is anticipated to be completed in early 2023.
Computational Astrophysics in the ngVLA Era: Synergistic Simulations, Theory, and Observations
This conference will be held 7-9 June 2022 at the Simons Foundation’s Flatiron Institute in Manhattan, New York, USA. The in-person conference will bring together theoreticians, modellers, and observers to discuss the computational astrophysics and observational challenges for the next generation of observatories, focusing on the ngVLA. The participation of early career scientists is particularly encouraged. Abstracts for oral presentations are due 1 April 2022.
Square Kilometer Array (SKA) Update
By Kristine Spekkens (Canadian SKA Science Director) and the AACS(Cassiopeia – Spring 2022)
The SKA project continues to develop rapidly, with the construction phase for SKA Phase 1 (= SKA1) now well underway. The SKA will deliver a range of scientific, technical, and societal benefits, with the latter framed through the lens of the UN Sustainable Development Goals. In particular, the project is committed to building partnerships with Indigenous and local communities at the remote sites where the dishes and antennas will be located. The SKA Construction Proposal and Observatory Delivery Plans detail the project science drivers, technical requirements and anticipated broader impacts, SKA Prospectus summarizes these aspects, and the SKA Canada website gives up-to-date Canada-specific information.
SKA1 construction is staged into “Array Assemblies” (AA’s). The first 6-station array for SKA1-Low in Australia and 4-dish array for SKA1-Mid in South Africa (= AA0.5) are planned for 2024, science verification observations with the first scientifically competitive arrays of 64 SKA1-Low stations and 64 SKA1-Mid dishes (= AA2) are set to begin in 2026, and operations readiness reviews for the telescope design baselines (= AA4) are expected by 2028. Nine months into the construction phase, construction tender and procurement is a project office focus, with over two dozen contracts now awarded to SKA Member States.
Significant progress towards securing long-term commitments to the SKA Observatory (SKAO) by partner countries have also been made in recent months. In January, Switzerland became the first country to accede to the SKAO Convention as a Member State, joining the seven founding Member States Australia, China, Italy, the Netherlands, Portugal, South Africa, and the United Kingdom. The eight current Member States are responsible for project governance, with voting rights on the SKAO Council.
Project partners that are not SKAO Members are designated as SKAO Council Observers, and are witness to SKAO Council meetings. Given Switzerland’s recent accession to the SKAO Convention, eight Observer countries remain: Canada; France; Germany; India; Japan; South Korea; Spain; and Sweden. Many Observers are completing their internal processes to become Member States and gain governance rights. Since October 2021, the SKAO has signed short-term cooperation agreements with research institutions in Canada, France, India, and Sweden to allow for the continued technological and scientific participation of these partner countries until they make long-term participation decisions and complete related processes.
The cooperation agreement between NRC and the SKAO allows Canada’s scientific and engineering communities to continue participating in the project — most notably in the delivery of the AA0.5 SKA1-Mid correlator developed by NRC-HAA and industry partner MDA — while membership in the SKAO is given full consideration by the federal government. Canada’s long-term participation in the SKA requires a commitment to construction and operations beyond the cooperation agreement, and this commitment is needed well before the agreement expires in early 2023 to maintain our leading role in SKA1-Mid correlator work. The Coalition for Canadian Astronomy is hard at work to raise awareness of the requisite governmental decisions and timelines.
There are a number of ways in which Canadian astronomers can get involved in the SKA. For example, SKA Science Working Groups are accepting new members, and there are regular calls for participation in SKA Science Data Challenges. Material from the recently completed SKA Regional Centre Training Events and an upcoming special session on artificial intelligence in radio astronomy at the European Astronomical Society Annual Meeting also provide opportunities to prepare for the massive data streams that the SKA will generate.
Now that the construction phase has begun a significant ramp-up in staffing across the project is also underway, and many scientists, engineers, software designers, and support and administrative personnel are being hired. Individuals from all nationalities are welcome to apply. Those interested should keep an eye on the SKAO Recruitment Portal, which includes a “job alert” tool to set up personalized emails filtered by field of expertise, location, duration, and employment type.
For more information and updates on Canada and the SKA:
subscribe to the Canadian SKA email list by sending a blank email to all+subscribe@skacanada.groups.io
visit the Canadian SKA website
Dissertation: The Dynamical Evolution of Classical Be Stars
by Dr. Keegan C. Marr
Thesis defended on February 11, 2022
Department of Physics and Astronomy, University of Western OntarioThesis advisor: Prof. Carol E. Jones
Abstract
This thesis focuses on the evolution of the disks of two classical B-emission (Be) stars, 66 Ophiuchi and Pleione, and on the thermal structure for disks tilted out of the star’s equatorial plane.
We used a hydrodynamic code to model the disk of the Be star 66 Ophiuchi. Observations from 1957 to 2020 were compiled to follow the growth and subsequent dissipation of the disk. Our models are constrained by new and archival photometry, spectroscopy and polarization observations. Using Markov chain Monte Carlo methods, we confirm that 66 Oph is a B2Ve star. We constrain the density profile of the disk before dissipation using a grid of disk models. At the onset of dissipation, the disk has an equatorial density of ρ(R) = 2.5 × 10-11 (R/R∗)-2.6 g cm-3. After 21 years of disk dissipation, our work shows that 66 Oph’s outer disk remains bright in the radio. We find an isothermal disk with constant viscosity with an α = 0.4 and an outer disk radius of ~115 stellar radii, best reproduces the dissipation. We determined the interstellar polarization in the direction of the star in the V-band is p = 0.63 +/- 0.02% with a polarization position angle of θIS ~ 85.7 +/- 0.7°. Using the Stokes QU diagram, we find the intrinsic polarization position angle of 66 Oph’s disk is θint ~ 98 +/- 3°.
We acquired Hα spectroscopy from 2005 to 2019 that shows Pleione has transitioned from a Be phase to a Be-shell phase. We created disk models which successfully reproduce the transition from Be to Be-shell with a disk model that varies in inclination while maintaining a constant, equatorial density of ρ(R) = 3 × 10-11 (R/R∗)-2.7 g cm-3, and an Hα emitting region extending to Rout = 15Req. We use a precessing disk model to follow variability in disk inclination over 120 years. The best-fit disk model precesses with an inclination between ∼25° and ∼144° with a period of ∼80.5 years. Our precessing models match some of the observed variability but fail to reproduce all of the historical data available. Therefore, we propose an ad-hoc model based on our precessing model and recent disk tearing simulations of similar systems. In this model, a single disk is slowly tilted to an angle of 30° from the stellar equator over 34 years. Then, the disk is torn by the companion’s tidal torque, with the outer region separating from the innermost disk. The inner disk returns to the stellar equator as mass injection remains constant. The outer disk precesses for ∼15 years before gradually dissipating. This model reproduces all the variability trends, repeating every 34 years.
Our research on Pleione led to a detailed investigation of the thermal structure of tilted disks. For this research, we modelled the radiative transfer in tilted disks self-consistently. We constructed disk models for a range of spectral types, rotation rates and disk densities. We find as the tilt angle increases to 60, the minimum disk temperature of our B0 V star model, with W = 0.95 and ρ0 = 10-11 g cm-3, can increase up to ∼114%, while the maximum disk temperature decreases by up to ∼8%. When W = 0.7, the changes in disk temperature for the same model are smaller, and at lower density the disk temperature increases globally. In the B2 V model, both the disk temperature and ionization fraction globally increase. In the B5 V and B8 V models, the disk temperature globally decreases, but increases around ∼10Req. The ionization fraction increases as modest changes to the disk temperature allow it to exceed the hydrogen ionization temperature. Overall, we find that the trends in the disk temperature and ionization fraction with the disk tilt angle greatly depend upon the stellar spectral type.
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