Dissertation: The Dynamical Evolution of Classical Be Stars

(Cassiopeia – Spring / printemps 2022)

by / par Dr. Keegan C. Marr
Thesis defended on February 11, 2022
Department of Physics and Astronomy, University of Western Ontario
Thesis 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.

ALMA Matters

ALMAlogo

By / par Gerald Schieven (ALMA)
(Cassiopeia – Spring / printemps 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 click here for registration page

Proposal Preparation and the Review Process 31 March @ noon EDT click here for registration page

ALMA Basics and Cycle 9 Capabilities 05 April @ 2pm EDT click here for registration page

Proposal Preparation and the Review Process 05 April @ 4pm EDT click here for registration page

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.

Report from the LCRIC

By / par Chris Wilson (LCRIC chair)
(Cassiopeia – Spring / printemps 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.

BRITE-Constellation Mission Update

By / par Gregg Wade (on behalf of the Canadian BRITE Team)
(Cassiopeia – Spring / printemps 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.

BRITE orbital-mean magnitudes of WR24 from the 36-Car-II field as a function of the Heliocentric Julian Date, after subtraction of the median, showing the stochastic photometric variability of this star.

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.

Square Kilometer Array (SKA) Update

By / par Kristine Spekkens (Canadian SKA Science Director) and the AACS
(Cassiopeia – Spring / printemps 2022)

Artist’s impression of the SKA, combining elements from South Africa and Australia from left to right in the image. Photos of real hardware have been blended with realizations of the future SKA antennas. Image credit: SKA Observatory.

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:

Registration & Abstract Submission: 13th Canada-France-Hawaii Telescope Users’ Meeting

Registration remains open and abstract submission is now open for the 13th Canada-France-Hawaii Telescope Users’ Meeting to be held remotely with limited in-person participation at the Observatoire Astronomique de Strasbourg, May 9-11, 2022.

Meeting sessions will cover the following topics:

  • The future of CFHT and Maunakea Spectroscopic Explorer (MSE)
  • CFHT’s current operating instruments and future plans
  • LP and PI science at CFHT
  • CFHT Communications and Outreach

Deadline for abstract submission : March 15 2022

https://www.cfht.hawaii.edu/en/news/UM2022/2ndannouncement.php

ngVLA Update

By Erik Rosolowsky (U Alberta), Joan Wrobel (NRAO)
(Cassiopeia – Winter 2021)

In early November, the US Decadal Review released its rankings, identifying the design and construction of the ngVLA as one of the three top priorities for US astronomy over the coming decade. This is particularly big news for the Canadian community since the ngVLA was also recognized as one of the top priority ground-based facilities in the Canadian Astronomy Long Range Plan 2020-2030. This recommendation was conditional “pending a positive recommendation on this project from the US Astro2020 Decadal Survey,” which has now happened.

Our LRP recommends that Canada pursues scientific and technical leadership in the development of the ngVLA. To that end, Brenda Matthews (NRC) has recently agreed to serve as the co-Chair of the refreshed ngVLA Science Advisory Council (SAC). The SAC is the interface between the scientific community and the Project Office. Since the SAC’s formation in 2016 its members have provided invaluable guidance and feedback on many aspects of the ngVLA. With the Project now past the critical US Decadal review, the SAC is being reformed under this new leadership. We are also grateful to James DiFrancesco (NRC) who has served on the SAC since its inception and is now rotating off. Our community is also fortunate to have Lewis Knee and Michael Rupen (NRC) on the Technical Advisory Council for the ngVLA, presenting a strong presence in the technical leadership.

If you are excited about the ngVLA, one way you can get involved in the community is to attend the meeting Computational Astrophysics in the ngVLA Era: Synergistic Simulations, Theory, and Observations at the Flatiron Institute in New York (June 7-9, 2022).

CRAQ Summer School Announcement

By Robert La Montagne
(Cassiopeia – Winter 2021)

The Centre for Research in Astrophysics of Quebec (CRAQ) is announcing its annual Summer School, which will be held on June 15-17, 2022 in Montreal, Quebec.

This year’s topic will focus on Cosmology. This 3-day school will introduce cutting-edge observational probes of cosmology such as the Cosmic Microwave Background (CMB), intensity mapping, and gravitational lensing, with hands-on analysis examples including CMB mapmaking, MCMC parameter estimation, and machine learning. Instructors will include Adrian Liu, Cynthia Chiang, Matt Dobbs, Katelin Schutz, Jon Sievers (McGill University), Yashar Hezaveh, and Laurence Perreault Levasseur (Université de Montréal).

The CRAQ Summer School is principally aimed at graduate students in the field of physics, astronomy, and astrophysics, although students who have completed an undergraduate program in physics will also be accepted.

There is no registration fee. However, we cannot offer traveling funds or cover lodging expenses.

The Centre for Research in Astrophysics of Quebec promotes employment diversity, inclusion and equity. We encourage applications from women, visible and ethnic minorities, Indigenous peoples, persons with disabilities, and persons of any sexual orientation or gender identity. We will consider providing travel funds for individuals from these communities if they cannot attend the summer school otherwise. Please contact us using the email address below.

Additional information about the program, registration and accommodation will be available soon on this site: craq-astro.ca/summerschool.

Email contact: Summer.School@craq-astro.ca

BRITE-Constellation Mission Update

By / par Catherine Lovekin (on behalf of the Canadian BRITE Team)
(Cassiopeia – Winter / hiver 2021)

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 finished a campaign in Cygnus, and is now being set up on the Vela Puppis field.
  • 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 is currently observing the Orion field.
  • BRITE Austria (Austria): BRITE Austria observes with a blue filter. It has recently wrapped up a campaign in Orion, and is now on hold while its orbit takes it through eclipse. It is expected to resume observations in mid-December.
  • UniBRITE (Austria): Currently out of order.

The BRITE Constellation observing program is currently set through early 2022. Details of the observing plan will be available on the BRITE photometry Wiki page.

Recent Science Results

“Five years of BRITE-Constellation photometry of the luminous blue variable P Cygni: properties of the stochastic low-frequency variability (Elliott et al., arXiv:2110.12056)

Luminous Blue Variables (LBVs) are massive stars that are likely to be a transitionary phase between O stars and hydrogen-free classical Wolf-Rayet stars. The variability of these stars has been an area of study for both professional and amateur astronomers for more than a century. This paper presents five years of precision photometry of the classical LBV P Cygni taken with the BRITE-Constellation nanosatellites. The authors use the BRITE data to search for periodicities that could elucidate the drivers of variability for these stars. These data show some long-timescale variability over the course of all six calendar years of observations, but the frequencies needed to reproduce the individual light curves are not consistent from one year to the next. These results likely show that there is no periodic phenomenon present for P Cygni, meaning that the variability is largely stochastic. This suggests the variability is being caused by internal gravity waves similar to those seen in other massive stars, with P Cygni exhibiting a larger amplitude and lower characteristic frequency than the main-sequence or blue supergiant stars previously studied. These results show evidence that LBVs may be an extrapolation of the blue supergiants, which have previously been shown to be an extension of main-sequence stars in the context of the stochastic low-frequency photometric variability.

The BRITE flux, after subtracting off the global mean, with units of parts per thousand (ppt) (left) and the Fourier amplitude spectrum (right) for the 2014 data from BRITE. Each peak used in our analysis is highlighted with a different color in the Fourier spectrum, and then the fit is overplotted on the photometry with the corresponding color for that term and all previous terms. The final four-frequency fit is then used to calculate the (𝑂 −𝐶) that is shown on the bottom panel of the photometry. Fits including the first four frequencies are shown on the left plot: 1 term (red dashed line), 2 terms (dotted blue line), 3 terms (dash-dot green line), 4 terms (solid pink). Vertical lines on the right plot indicate the frequency added to each term.

Conferences, Resources, and Social Media

Conferences

The BRITE team does not plan to host any conferences at this time.

Resources and Social Media

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

The mission Wiki (including information on past, current and future fields) can be accessed 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 Konstanze Zwintz, the chair of BEST at konstanze.zwintz@uibk.ac.at.

CATAC Update on the Thirty Meter Telescope

By Michael Balogh (CATAC Chair)
(Cassiopeia – Winter / hiver 2021)

Recent News

The US Decadal report, released in November, clearly recognized the scientific excellence and importance of the US Extremely Large Telescope (ELT) Program, and TMT in particular. Furthermore, it lays out clear steps and milestones that the project must achieve in the next few years. Specifically, the report notes that “it will be necessary for NSF to commence with an external review with a target completion in 2023, in order to evaluate the financial and programmatic viability of both proposed U.S. ELT projects”. If states further that a decision for US federal investment should be predicated on several things, including final site selection and agreed-upon commitments from partners “for all of the necessary capital and operations money, pending only NSF investment”. This is certainly a challenge for TMT, but the clarity is very welcome, and the viability of the project is going to come rapidly into focus over the next two years.

CATAC is aware that if NSF becomes a TMT partner, this will have an impact on Canada’s share and opportunity for scientific and technological leadership. All avenues must be explored to maintain a significant share in the telescope, to fulfil our own Long Range Plan recommendation that “this participation be at a level that provides compelling opportunities for Canadian leadership in science, technology and instrumentation”. Astro2020 provides a clear roadmap and timeline that will help all partners, including Canada, to secure the resources necessary to satisfy their own ambitions. CATAC has begun working closely with GAC as they explore how to fulfil the LRP recommendation to ensure Canada has access to a VLOT in case of delays to, or failure of, TMT.

Site Update

The University of Hawaii released a draft plan for Mauna Kea in September, and held a period of open consultation after its release. Among other things, the draft calls for the number of astronomical sites at the summit to be reduced from fourteen to nine. The Caltech Submillimeter Observatory and Hōkū Keʻa decommissioning process is already underway, and the VLBA antenna will be decommissioned prior to 2033. A process is outlined to identify the remaining two facilities by the end of 2025. The sites of the decommissioned facilities will not be available for future astronomy use. The site on ORM remains a viable alternative for TMT, and CATAC reiterates that it remains scientifically acceptable.

The Maunakea legislative working group established by the Hawaii House of Representatives has been active through most of the year. Their mandate is to propose a new management structure for the mountain. There is information, including meeting notes, available on their web page. Their report is anticipated for late December 2021 or early 2022.

The site on Roque de los Muchachos Observatory (ORM) in La Palma remains a viable alternative for TMT, and CATAC reiterates that it remains scientifically acceptable. However, in August of this year, an appeal by environmental group Ben Magec to annul the land concession for TMT was successful. This decision has been appealed to a higher court.

TMT Science Forum

Canada was looking forward to hosting the next TMT Science Forum, in Vancouver in 2022. Due to the continued travel uncertainty associated with the pandemic, as well as the delay of Astro2020 and the imminent launch of JWST, it was decided to postpone this event until 2023.

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)
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)
Kim Venn (TIO Governing Board, 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)