Category Archives: News and Announcements

By / par Gregg Wade (Canadian PI for BRITE)
(Cassiopeia – Spring / printemps 2019)

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 25 data releases to BRITE target PIs having already taken place, and many datasets available in the public domain from the BRITE public archive.

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, Bishop’s 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 operating BRITE satellites in the Constellation, collecting data on various sky fields in a coordinated programme to obtain well-sampled, longterm continuous (~6 months) light curves in both red and blue bandpasses.

As this issue of Cassiopeia went to press, here was the status of the sky assignments for the BRITE cubesats:

• BRITE Toronto (Canada): Toronto observes with a red filter. It is currently observing the Ori/Tau field, switching between the two fields each orbit.
• BRITE Lem (Poland): Lem observes with a blue filter. It is also observing the Ori/Tau field.
• BRITE Heweliusz (Poland): Heweliusz observes with a red filter. This satellite is observing CMa/Pup II field. As implied by the numeral ‘II’, the current campaign on this field represents a revisit of a previously-observed field.
• BRITE Austria (Austria): BRITE Austria observes with a blue filter. It is observing the Ori/Tau field and the Vel/Pup V field.
• UniBRITE (Austria): UniBRITE observes with a red filter. This satellite is also observing the Ori/Tau field and the Vel/Pup V field.

The BRITE Constellation observing programme from early 2017 through to early 2020 has been planned by the BRITE Executive Science Team (BEST), and details are available on the BRITE photometry Wiki page.

Recent Science Results

“Seismic modelling of early B-type pulsators observed by BRITE: I. θ Ophiuchi” (P. Walczak et al. MNRAS, in press). In this paper the authors analyse BRITE time-series observations of the well known β Cephei type star θ Ophiuchi. Seven previously known frequencies are confirmed and nineteen new frequency peaks are detected. In particular, high-order g modes, typical of the Slowly Pulsating B-type (SPB) pulsators, are uncovered. These low-frequency modes are also detected in the 7-year-long SMEI light curve. If g modes are associated with the primary component of θ Oph, then our discovery allows, as in the case of other hybrid pulsators, to infer more comprehensive information on the star’s internal structure. With this aim the authors perform in-depth seismic studies. To explain the mode instability in the observed frequency range a significant increase of the mean opacity in the vicinity of the Z-bump is needed. Moreover, constraints on mass, overshooting from the convective core and rotation are derived.

“Stellar masses from granulation and oscillations of 23 bright red giants observed by BRITE – Constellation” (Kallinger et al. A&A, in press). The study of stellar structure and evolution depends crucially on accurate stellar parameters. The photometry from space telescopes has provided superb data that allowed asteroseismic characterisation of thousands of stars. However, typical targets of space telescopes are rather faint and complementary measurements are difficult to obtain. On the other hand, the brightest, otherwise well-studied stars, are lacking seismic characterization. Aims: Our goal is to use the granulation and/or oscillation time scales measured from photometric time series of bright red giants (1.6≤Vmag≤5.3) observed with BRITE to determine stellar surface gravities and masses. Methods: We use probabilistic methods to characterize the granulation and/or oscillation signal in the power density spectra and the autocorrelation function of the BRITE time series. Results: We detect a clear granulation and/or oscillation signal in 23 red giant stars and extract the corresponding time scales from the power density spectra as well as the autocorrelation function of the BRITE time series. To account for the recently discovered non-linearity of the classical seismic scaling relations, we use parameters from a large sample of Kepler stars to re-calibrate the scalings of the high- and low-frequency components of the granulation signal. We develop a method to identify which component is measured if only one granulation component is statistically significant in the data. We then use the new scalings to determine the surface gravity of our sample stars, finding them to be consistent with those determined from the autocorrelation signal of the time series. We further use radius estimates from the literature to determine the stellar masses of our sample stars from the measured surface gravities. We also define a statistical measure for the evolutionary stage of the stars.

Fig. 1: Hertzsprung-Russell diagram including the red giants observed with BRITE – Constellation by Kallinger et al. (grey filled circles). The small dots show MIST stellar evolution models for solar composition with the mass colour coded. Blue filled circles mark stars for which solar-type oscillations have been identified in the BRITE-Constellation data.

“BRITE photometry of the massive post-RLOF system HD 149404G” (Rauw et al. 2019, A&A 621,15). HD 149404 is an evolved non-eclipsing O-star binary that has previously undergone a Roche lobe overflow interaction. Understanding some key properties of the system requires a determination of the orbital inclination and of the dimensions of the components. The authors used the BRITE-Heweliusz satellite to collect photometric data of HD 149404. Additional photometry was retrieved from the SMEI archive. These data were analysed using a suite of period search tools. The orbital part of the lightcurve was modelled with the nightfall binary star code. The Gaia-DR2 parallax of HD 149404 was used to provide additional constraints. The periodograms revealed a clear orbital modulation of the lightcurve with a peak-to-peak amplitude near 0.04 mag. The remaining non-orbital part of the variability is consistent with red noise. The lightcurve folded with the orbital period reveals ellipsoidal variations, but no eclipses. The minimum when the secondary star is in inferior conjunction is deeper than the other minimum, likely due to mutual reflection effects between the stars. Combined with the Gaia-DR2 parallaxes, the photometric data indicate an orbital inclination in the range of 23°-31° and a Roche lobe filling factor of the secondary larger than or equal to 0.96. The authors conclude that the luminosity of the primary star is consistent with its present-day mass, whereas the more evolved secondary appears over-luminous for its mass. It is confirmed that that the primary’s rotation period is about half the orbital period. Both features most probably stem from the past Roche lobe overflow episode.

Fig. 2: Top: Full de-trended BRITE lightcurve of HD 149404 obtained by Rauw et al. All 19 414 data points are shown (red) along with their error bars (black). Bottom: Same, but for the data averaged per spacecraft orbit. This lightcurve contains 708 data points.

Conferences, Resources and Social Media

Conferences

The BRITE team is spearheading the organization of a conference entitled “Stars and their Variability, Observed from Space”, to occur in Vienna, Austria from August 19 – 23, 2019. Preregistration is available on the conference website.

Resources

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 at brite.craq-astro.ca/.

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 to join BIAST, contact Canadian BRITE PI Gregg Wade: wade-g@rmc.ca.

Other News

BRITE-Austria and UniBRITE recently celebrated their 6th anniversary in orbit.

Fig. 3: An illustration of the accumulated statistics of the BRITE mission.

By / par John Hutchings (Astrosat Working Group member)
(Cassiopeia – Spring / printemps 2019)

Astrosat is now in its 4th year of operation. The orbit is stable and there are no power or datalink issues. One of the three LAXPC units is not operating, and sadly the UVIT NUV channel remains off in spite of numerous attempts to restart it. UVIT data processing and archiving are up to date, and incomplete datasets are being added. Currently cycle 6 proposals are being executed, along with newly instigated legacy proposals. There is a call for cycle 7 proposals out with a deadline of April 9. A new call for legacy proposals will follow later. Canadians are eligible for a 5% share of observing, and the information is available here. Joe Postma continues to be available for advice and assistance in proposal submission. CSA will continue to support Astrosat science with their grant program. We encourage you to make use of this excellent facility.

Many astrosat results were reported at the ASI meeting (Indian equivalent of CASCA) in February, and a 3 day conference at IIA was devoted to Astrosat research. See the image below for an example of UVIT’s image capabilities.

NGC 300 is a spiral galaxy that lies beyond the local group that contains the Milky Way and Andromeda. Its size in the sky is about that of the full moon, and is considered to be similar to the Milky Way. The UV image from UVIT (bottom image, from our observations with the Astrosat space telescope) reveals the many regions of young star-formation and nebulae within the spiral arms, whose details and ages tell the story of how this galaxy is evolving.
For comparison, the top image is in visible colours, from the ground, and includes the older, redder stars as well.

By / par Pauline Barmby and / et Bryan Gaensler (LRP2020 Co-Chairs / co-présidents PLT2020)
(Cassiopeia – Spring / printemps 2019)

La version française suit

LRP2020 will review the Canadian landscape for astronomy and astrophysics, and will produce a list of recommended priorities for the next decade. The resulting plan will serve as a single unified vision for the highest priority projects in astronomy in Canada over the period 2020 to 2030. See here for details and terms of reference. The process for Long Range Plan 2020 has begun, with appointment of the author panel and call for white papers. The panel members are:

• Pauline Barmby (Western University) – co-chair
• Matt Dobbs (McGill University)
• Bryan Gaensler (University of Toronto) – co-chair
• Jeremy Heyl (University of British Columbia)
• Natasha Ivanova (University of Alberta)
• David Lafrenière (Université de Montréal)
• Brenda Matthews (National Research Council) – ex-officio
• Alice Shapley (University of California Los Angeles – international member

The panel can be contacted at panel@lrp2020.groups.io and the co-chairs at chairs@lrp2020.groups.io.

White paper expressions of interest are due at UT 2300 on Apr 15th, 2019, via this link. Further information, including the LRP2020 timeline and statement of task, is available on this webpage, as well as on the Slack workspace.

Le PLT2020 fera un compte rendu des activités canadiennes en astronomie et en astrophysique et dressera une liste des priorités recommandées pour la prochaine décennie. Le plan qui en résultera servira de vision unifiée pour les projets d’astronomie les plus prioritaires au Canada entre 2020 et 2030. Voir ici pour obtenir des détails et le mandat. Le processus pour le Plan à long terme 2020 a commencé, avec la nomination du groupe d’auteurs et l’appel aux livres blancs. Les membres du panel sont :

• Pauline Barmby (Western University) – co-président
• Matt Dobbs (McGill University)
• Bryan Gaensler (University of Toronto) – co-président
• Jeremy Heyl (University of British Columbia)
• Natasha Ivanova (University of Alberta)
• David Lafrenière (Université de Montréal)
• Brenda Matthews (National Research Council) – ex-officio
• Alice Shapley (University of California Los Angeles – membre internationale

La groupe peut être contacté à panel@lrp2020.groups.io et les co-présidents à chairs@lrp2020.groups.io.

Les soumissions des manifestations d’intérêt pour livres blancs sont dues à 2300 UT le 15 avril 2019 , via ce lien. Vous trouverez des informations complémentaires, y compris le calendrier et l’énoncé de la tâche PLT2020 sur la page Web et à Slack.

(Cassiopeia – Spring / printemps 2019)

by Dr. Robin Arnason
Thesis defended on December 7, 2018
Department of Physics and Astronomy, Western University
Thesis advisor: Prof. Pauline Barmby

Abstract

X-ray binary stars are rare systems consisting of a black hole or neutron star and a main-sequence companion star. They are useful probes of galaxy properties and interesting laboratories for extreme physical conditions. In this thesis, I investigated the X-ray binary population of three galaxies in the Local Group.

The Sculptor Dwarf Spheroidal Galaxy offers the chance to study a primordial low-mass X-ray binary (LMXB) population in an isolated, low-metallicity environment. Combining X-ray, optical, and infrared observations, I have studied nine previously-identified and discovered four additional LMXB candidates in this galaxy. Of these candidates, all but one are either background galaxies or foreground stars, meaning that Sculptor is presently effectively devoid of bright LMXBs. If Sculptor is able to retain primordial LMXBs at a similar rate to globular clusters, it is likely that bright XRBs in globular clusters observed in the present day were dynamically formed.

The Andromeda Galaxy has the largest catalogue of Chandra-studied X-ray sources of any nearby galaxy. I have used this population to test a proof-of-concept method for identifying X-ray binary candidates using machine learning algorithms trained on known sources. After testing a variety of commonly used algorithms, I find that the best-performing random forest algorithm can identify X-ray binary candidates with 85% accuracy. I have identified 16 new strong X-ray binary candidates and find that 4 sources classified as X-ray binaries by this method coincide with star clusters identified by the Panchromatic Hubble Andromeda Treasury project.

The Milky Way’s X-ray binary population is the easiest to study but the most challenging for which to accurately measure distance. I have crossmatched Galactic X-ray binary catalogs to the second data release of the Gaia mission, finding candidate counterparts for 86 Galactic X-ray binaries. Distances to Gaia candidate counterparts are systematically smaller than those measured using Type I X-ray bursts, suggesting that these bursts do not consistently reach the Eddington limit. High-mass X-ray binaries are correlated with the Galaxy’s spiral arms and low-mass X-ray binaries are anti-correlated with the Galaxy’s spiral arms at a low level of significance.

By / par Patrick Hall (MSE Management Group Member)
(Cassiopeia – Spring / printemps 2019)

New Project Scientist, Deputy Project Scientist, and Project Spokesperson

The MSE project welcomed a new Project Scientist in January and a Deputy Project Scientist in February. Prof. Jennifer Marshall (Texas A&M) was appointed Project Scientist, and Dr. Andreea Petric (IfA/CFHT) was appointed Deputy Project Scientist.

Prof. Jennifer Marshall is an assistant professor in the Department of Physics and Astronomy at Texas A&M University.  Prof. Marshall’s scientific interests include the detailed kinematics and chemistry of satellite galaxies of the Milky Way, particularly those that have been discovered by the Dark Energy Survey.  As an astronomical instrument builder she led Texas A&M’s involvement in the Dark Energy Survey, producing the calibration systems that enable the unprecedentedly precise photometric measurements produced by the survey, and also in the HETDEX project, building the VIRUS spectrographs.  She is the co-PI of GMACS, the wide field multi-object spectrograph that will be a first-light instrument for the Giant Magellan Telescope. She is also the director of the REU Site in Astronomical Research and Instrumentation at Texas A&M, which brings talented undergraduates from other universities to conduct scientific research with Texas A&M astronomers each summer.

Dr. Andreea Petric is the Institute for Astronomy’s (IfA) resident astronomer at CFHT, where she is the instrument scientist for the wide field optical imager MegaCam. Dr. Petric obtained her PhD from Columbia University and was a Postdoctoral Scholar at Caltech and a Science Fellow at the Gemini Observatory before joining IfA. Dr. Petric’s research focus is on the formation and evolution of galaxies. She uses X-ray to radio data to study the impact of mergers and AGN feedback on the star formation rates in nearby galaxies and to study the interstellar medium content of quasars to understand the relationship between type 1 and type 2 QSOs. 

Meanwhile, former MSE Project Scientist Dr. Alan McConnachie was appointed as Project Spokesperson, responsible for developing and promoting an international base of support for MSE among partners and prospective partners. The MSE MG thanks Alan for all his work as Project Scientist and looks forward to working with Prof. Marshall, Dr. Petric and Dr. McConnachie in their new roles on the MSE project.

New MSE Website

The MSE project has a newly redesigned website. Keep an eye on the website (and on ArXiv) for an update to the MSE Detailed Science Case, coming soon!

Massively Multiplexed Spectroscopy with MSE: Science, Project and Vision

A very successful MSE meeting was held Feb. 26-28 in Tucson, AZ, hosted by NOAO in collaboration with MSE and CFHT. Copies of all the presentations from the meeting are available here. The meeting agenda covered the full range of scientific and technical aspects of MSE, including plans for the Design Reference Survey and for the development of the MSE Science Platform and the MSE partnership model.

Among the over 90 participants were scientists involved in the full range of current and upcoming wide-field spectroscopic surveys including SDSS, LAMOST, 2dF S^5, DESI, 4MOST, WEAVE, PFS, and more. Several fruitful discussion sessions focused on sharing lessons learned from the planning and execution of these surveys.

The eight MSE Science Working Groups held breakout sessions and presented summaries of their scientific and programmatic discussions to the full meeting. Numerous white papers discussed at the meeting have now been submitted for consideration by the Astro2020 decadal survey in the US; for example on tests of dark matter, on stellar astrophysics and exoplanet science, on cosmology, and on quasar reverberation mapping.

The Canadian community is encouraged to submit MSE-related white papers for the Long Range Planning exercise now underway (expressions of interest due April 15, 2019; white papers due September 30, 2019).

MSE Management Group and CFHT Board and SAC Meetings

The MSE Management Group (MG) held its annual full-day face-to-face meeting in Waimea, Hawaii, on December 10, 2018, with representatives from existing partners and two observers from prospective partners: Adam Bolton (NOAO) and Darren DePoy (Texas A&M). The MG heard a remote presentation from Richard Barvainis (NSF) about the Mid-Scale Research Infrastructure initiative, and discussed how MSE can best propose to this opportunity. The MG also held a useful discussion of possible partnership models for the construction, and operations phases of the project. Further details of the draft partnership model can be found in the Tucson meeting presentation by MSE MG Chair Andrew Hopkins.

Last but not least, the CFHT Board approved the following statement at its December 2018 meeting: “The Board resolves that the Maunakea Spectroscopic Explorer (MSE) is the scientific future of CFHT and affirms its intention to work towards an expanded MSE partnership to design, build and operate this transformational spectroscopic survey facility.” In addition, the CFHT Science Advisory Committee approved the following statement at its November 2018 meeting: “SAC endorses MSE as the scientific future of CFHT. SAC supports proceeding to the Preliminary Design Phase.”

CFI Proposal

Work led by U. Victoria Prof. Colin Bradley continues on a substantial request for University and industry partners to complete design work on many subsystems including the enclosure, the telescope structure, the fibre transmission system, the science calibration system, and others.

By / par Gerald Schieven (ALMA)
(Cassiopeia – Spring / printemps 2019)

Cycle 7 Call for Proposals

The Call for ALMA Cycle 7 Proposals has now been issued. Deadline for proposals is Wednesday 17 April at 13UT. It is anticipated that 4300 hours will be available for the 12m Array and 3750 hours for the Morita Atacama Compact Array (ACA). See the Call for Proposals for more information about the call and for links to useful documents. The Proposers’ Guide contains more information about the capabilities offered in Cycle 7.

If you’re relatively new to proposing for ALMA, you may be interested in attending an ALMA Proposal Writing Workshop at the University of Toronto on April 1. See below for details.

ALMA Proposal Writing Workshop

An ALMA Proposal Writing Workshop, to be held at the University of Toronto on April 1, is designed for all astronomers (including graduate students), in particular for those who do not regularly propose for time on r­­adio ­­telescopes but might be interested in one day using ALMA for their research.

The workshop will provide an overview of ALMA’s latest capabilities, a (very) brief discussion of interferometry fundamentals, ALMA-focused science talks, and a walkthrough of proposal preparation and ALMA simulator tools. The workshop is more than 2 weeks before the ALMA Cycle 7 deadline on April 17th. To register for the workshop, please visit the . Registration is free and lunch will be provided for registered participants. For more information, please see the workshop website, or feel free to email ALMA Ambassador Toby Brown.

Canadian ALMA Publication Statistics

By early 2019, barely 8 years since the start of Early Science, ALMA had already featured in over 1300 refereed publications. Canadian astronomers are continuing to make strong use of the facility and to make their mark in publications. In calendar year 2018 there were 49 refereed publications (13% of the total 380 in 2018) with authors/co-authors from Canadian institutions, of which 7 had a Canadian first author. Since 2012, when the first ALMA publication was released, 13% of ALMA publications have had at least one author/co-author from a Canadian institution, with 2.4% as first author.

Dear colleagues,

We are pleased to announce the call for white papers for the Canadian Astronomy Long Range Plan for 2020-2030 (LRP2020). Due dates are as follows:
* Expressions of interest: UT 2300 on Apr 15th, 2019, via https://casca.ca/?page_id=11595
* White papers: UT 2300 on Sep 30th, 2019 (instructions provided to those who submit EoIs)

LRP2020 will review the Canadian landscape for astronomy and astrophysics, and will produce a list of recommended priorities for the next decade. The resulting plan will serve as a single unified vision for the highest priority projects in astronomy in Canada over the period 2020 to 2030. See https://casca.ca/lrp2020 for details and terms of reference.

We now solicit white papers to inform the LRP2020 report. A white paper should be a self-contained description of a future opportunity for Canadian astronomy. A white paper will be most effective and useful if it concisely summarises an option that the LRP2020 panel should be considering for prioritisation.

White papers should adhere to the following guidelines:

EXPRESSIONS OF INTEREST: An expression of interest (EoI) must be submitted in advance of a full white paper. An EoI submission requires a title, a contact person, a proposed list of co-authors (optional) and a 2000-character summary, and is submitted entirely via a web form (see below).

SCOPE OF EoIs AND WHITE PAPERS: Topics may include (but are not limited to):
* new facilities, experiments and missions
* proposed upgrades to current facilities, experiments and missions
* science programs, science topics and science themes
* instrument design and development
* laboratory astrophysics
* high-performance computing
* data analysis, data management and data storage
* outreach, education and teaching
* state of the profession
* training, careers, demographics and professional development
* equity, diversity and inclusion

AUTHORSHIP: Each EoI and white paper must have a designated contact person. Anonymous submissions will not be considered and all submitted EoIs and white papers will be made public via the LRP2020 web site. Confidential supplementary material (e.g., budgets, proprietary technical information) can be submitted separately to the LRP2020 panel; the relevance of this material  should be described in the public submission. There are no restrictions on the affiliations of co-authors, and no limit on the number of co-authors. Note that the number of co-authors will not necessarily be taken as an indication of the level of community interest.

FORMAT AND LENGTH: Submissions may be made in English or in French.

White papers must be submitted as PDF files, capped at a length of ten 8.5”x11” pages (including figures, tables, references and appendices), with a minimum of 11-point font and 2-cm margins. Submissions must be in PDF format, and should not exceed a file size of 30 MB. Submissions not meeting these requirements will not be considered.

White papers are not required to contain a specific set of sections or headings. Depending on the content, the following topics may be appropriate to include:
* connection or relevance to Canada
* timeline
* cost
* description of risk
* governance / membership structure
* justification for private submission of supplementary information

SUBMISSION AND DUE DATES:
* EoIs: UT 2300 on Apr 15th, 2019, via https://casca.ca/?page_id=11595
* White papers: UT 2300 on Sep 30th, 2019 (instructions provided to those who submit EoIs)

PUBLICATION: All submitted EoIs and white papers will be posted as public documents on the LRP2020 web page (https://casca.ca/lrp2020). Teams wishing to submit supplementary confidential material will be able to indicate as such through the white paper submission process.

DISCUSSION AND QUESTIONS: We encourage open discussion on the coordination of EoIs and white papers using the LRP Slack workspace (see https://casca.ca/lrp2020 for links). Participants may use the existing topical channels, or to make new channels as appropriate. Questions about any aspect of the LRP2020 process can be posted on the #general channel on Slack, or sent by email to chairs@lrp2020.groups.io.

Pauline Barmby and Bryan Gaensler
LRP2020 Co-Chairs, on behalf of the LRP2020 Panel