Maunakea Spectroscopic Explorer (MSE) Update

By/par Patrick Hall, MSE Management Group Member
(Cassiopeia – Autumn/l’automne 2017)

The MSE Project Office staff continues its work in preparation for a System Conceptual Design Review by the end of the year. Mature drafts are being prepared of the four top level documents – Science Requirements, Observatory Architecture, Observatory Requirements and Operations Concept – together with technical budgets and cost and schedule estimates. Together, these documents describe the architectural, engineering and operational aspects of the entire MSE system and decompose the system into a set of subsystems that together meet the high level science goals of the facility. In related news, the geotechnical firm Fewell has confirmed the structural strength of the soil at the CFHT site is sufficient to support the new enclosure and telescope.

The MSE Management Group continues its work on a pre-construction phase Master MOU, also expected to be completed by the end of the year. This agreement will establish the framework within which existing and new MSE partners will proceed with the preliminary design of MSE.

It will be essential for Canada to contribute to the upcoming preliminary design work to maintain a significant share in the governance of the MSE project and ensure that scientific goals valuable to Canadian astronomers are prioritized in the design and operations. To that end, Canadian members of the MSE Management and Science Advisory Groups drafted a letter asking for NRC collaboration with universities and industry in conducting MSE design work at a level consistent with the recommendation of the 2016 Long-Range-Plan Mid-Term-Review. This letter was circulated widely in the Canadian astronomy community and accrued twenty-six co-signers before being delivered to NRC in early September. Follow-on discussions with NRC will inform upcoming preliminary design work funding applications. If you have not seen the letter but would like to see and perhaps co-sign it, contact Pat Hall.

The MSE website is mse.cfht.hawaii.edu. Questions or comments about MSE governance can be directed to your MSE Management Group Members, Greg Fahlman and Pat Hall. Scientific questions or comments can be directed to your MSE Science Advisory Group Members, Sarah Gallagher and Kim Venn.

Canadian Gemini Office News / Nouvelles de l’Office Gemini Canadien

By/par Stéphanie Côté (CGO, NRC Herzberg / OGC, CNRC Herzberg)
(Cassiopeia – Autumn/l’automne 2017)

La version française suit

John Blakeslee from the CGO becomes Gemini Chief Scientist!

After Laura Ferrarese being appointed Gemini Interim Director this year, it is now the turn of John Blakeslee from the CGO to receive a prestigious nomination. John has been appointed Gemini Chief Scientist! In this role he will be working along the deputy director and will be in charge of the important task of setting and implementing Gemini’s scientific goals and directions for the future, while working closely with the international user community. John will start working in this new role starting in November, staying based in Victoria until his departure in April to the Gemini South Base Facility in La Serena, Chile.

John has been an outstanding support astronomer as part of the Canadian Gemini Office for the last 10 years. He has given top-notch support to Canadian GMOS, Flamingos2 and GRACES users, and also has been providing for many years scientific leadership as the Canadian Gemini International TAC representative, while pursuing world-leading research in galaxy structure and evolution, supermassive black holes, the extragalactic distance scale, large-scale structure, globular cluster populations, and mentoring several PhD students along the way. The Canadian Gemini Office is very sad to see him go, but we wish him all the best in his news endeavors and are looking forward to working with him in his new role.

Gemini Proposals format changes

Starting with this semester 2018A, the format of the Canadian Gemini proposals sent to the Canadian TAC has been modified, in order to avoid unconscious gender bias effects. A recent study of CFHT and Gemini proposals sent to the Canadian Time Allocation Committee (CanTAC) over the last 10 cycles revealed that gender systematics are present in the mean proposal scores assigned by the CanTAC during the proposal review process (see poster by K.Spekkens at the last CASCA in Edmonton, p.84). It was found that that proposals submitted by female principal investigators (PIs) were rated significantly worse than those submitted by male PIs. In an effort to mitigate these effects the new proposal format will not reveal the name or gender (as far as it is guessable from the first name) of the PI on the first page as is the case now. The new format is similar to what has now been adopted for HST proposals and several other TACs. The proposal will instead list the name of the authors at the end of the proposal; the list of names will appear alphabetically with no indication of who is the PI; and the first names will be abbreviated to a single letter. The CGO has encouraged Gemini to develop this new proposal format and starting in 2018A all Gemini partners (except Chile) have now adopted the new format. Such measures have by now been adopted by granting committees in several other sciences and have shown to successfully get rid of gender bias effects.

When you fill in your proposal details in the new PIT for 2018A you will still be asked to identify yourself as the PI and give your full name as usual. This is necessary for the CGO and Gemini staff to communicate with you once the proposal is successful. However the proposal PDFs that are going to be shown to the CanTAC will follow the new format. Moreover the proposals sent to the 2 external referees (still used by CanTAC) will contain NO list whatsoever of investigators.

The proposal deadline is coming fast, on Friday September 29th , and we wish all our hopeful PIs (male or female or other) all the best for their 2018A proposals.

Recent Canadian Gemini Press Release

In August a team lead by Stéphane Vennes (Astronomical Institute in Ondrejov, Czech Republic) and including co-I Viktor Khalak (University of Moncton) reported on the discovery of what appears to be stellar shrapnel thrown away millions of years ago from a supernova explosion. This low-mass white dwarf (LP 40-365) was found by its high proper motion, being one of the fastest moving objects in the Milky Way, traveling at a velocity exceeding 550 km/s which is greater than the Galactic escape velocity. From Gemini GRACES spectra it was found that its peculiar atmosphere is composed almost exclusively of oxygen and neon with traces of sodium and magnesium but devoid of hydrogen or helium. This exotic surface composition indicates a catastrophic past involving a subluminous Type Ia supernova event. Type 1a supernovae are thought to have at their heart a white dwarf accreting matter dumped from its very close large companion until all this mass compresses the white dwarf to such high density and temperature that it triggers the thermonuclear explosion. It is thought that nothing survives this kind of explosion. However, a new class of models have been developed recently called subluminous Type 1a supernova also known as a Type Iax, that can leave a partially burnt remnant that is instantly ejected at high velocity. The unique object LP40-365 is the first observational evidence for such surviving bound remnant of a faint supernova. The paper published in Science is available here.

Join the thousands and thousands of Gemini Observatory followers on Facebook and Twitter: @GeminiObs.



John Blakeslee de l’OGC devient le Scientifique en Chef de Gemini!

Après que Laura Ferrarese ait été nommée directrice intérimaire de Gemini cette année, c’est le tour de John Blakeslee de l’OGC de recevoir une nomination prestigieuse. John a été nommé Scientifique en Chef de Gemini! Dans ce rôle, il travaillera avec le directeur adjoint et sera chargé de la tâche importante d’établir et de mettre en œuvre les objectifs et la direction scientifiques de Gemini pour l’avenir, tout en travaillant en étroite collaboration avec la communauté internationale des usagers. John commencera à travailler dans ce nouveau rôle à partir de novembre, en restant basé à Victoria jusqu’à son départ en avril pour le quartier général de Gemini-Sud à La Serena, au Chili.

John a été un astronome de soutien exceptionnel de l’Office Gemini Canadien depuis 10 ans. Il a donné un support hors-pair aux usagers canadiens de GMOS, Flamingos2 et GRACES, et a également fourni de nombreuses années de leadership scientifique en tant que représentant du Canada au TAC international de Gemini, tout en poursuivant une recherche de pointe dans la structure et l’évolution des galaxies, des trous noirs supermassifs, l’échelle de distance extragalactique, la structure à grande échelle, et les populations des amas globulaires, et en supervisant plusieurs étudiantes de doctorat en cours de route. L`Office Gemini Canadien est très triste de le voir partir, mais nous lui souhaitons tout le meilleur dans ses nouvelles fonctions et avons hâte de travailler avec lui dans son nouveau rôle.

Changement de format des demandes Gemini

À partir de ce semestre 2018A, le format des demandes Gemini canadiennes envoyées au Comité canadien d`allocation de temps (CanTAC) a été modifié afin d’éviter des effets de préjugés sexistes inconscients. Une étude récente des demandes TCFH et Gemini envoyées au CanTAC au cours des 10 derniers cycles a révélé que des différences systématiques selon les sexes sont présentes dans les scores moyens donnés par le CanTAC lors du processus d’examen des demandes (voir l’affiche par K.Spekkens à la dernière CASCA à Edmonton, p.84). Il a été constaté que les demandes soumises par des investigatrices principales (PI) ont été jugées nettement plus mauvaises en moyenne que celles soumises par des PIs masculins. Dans un effort pour atténuer ces effets, le nouveau format des demandes ne révélera pas ni le nom ni le genre (dans la mesure où il puisse être deviné par le prénom) du PI sur la première page, comme c’est le cas maintenant. Le nouveau format est similaire à ce qui a été adopté pour les demandes HST et plusieurs autres TACs. La demande énumèrera plutôt le nom des tous les auteurs à la fin de la demande; la liste des noms apparaîtra en ordre alphabétique sans indication duquel est le PI; et les prénoms seront abrégés à une seule lettre. Le CGO a encouragé Gemini à développer ce nouveau format de demandes et à partir de 2018A tous les partenaires Gemini (à l’exception du Chili) vont maintenant adopté le nouveau format. De telles mesures ont maintenant été adoptées par plusieurs comités de bourses dans plusieurs autres sciences et ont permis de se débarrasser efficacement des effets de préjugés sexistes inconscients.

Lorsque vous remplirez les détails de votre demande dans le nouveau PIT 2018A, vous devrez toujours vous identifier comme PI et donner votre nom complet comme d’habitude. Ceci est nécessaire pour que le personnel de l`OGC et Gemini puisse communiquer avec vous une fois la demande acceptée. Cependant, les fichiers PDF des demandes qui seront envoyés au CanTAC suivront le nouveau format. De plus, les demandes envoyées aux 2 arbitres externes (encore utilisés par CanTAC) ne contiendront aucune liste d`auteurs.

La date limite pour les demandes de temps arrive rapidement, le vendredi 29 septembre, et nous souhaitons bonne chance à tous nos usagers plein d’espoir (hommes ou femmes ou autres) pour leurs demandes 2018A.

Communiqué de presse canadien récent

En août, une équipe dirigée par Stéphane Vennes (Institut astronomique d’Ondrejov, République tchèque) et incluant le co-I Viktor Khalak (Université de Moncton) a rapporté la découverte de ce qui semble être un shrapnel stellaire éjecté il y a des millions d’années d’une explosion de supernova. Cette naine blanche de faible masse (LP 40-365) a été découverte par son mouvement propre élevé, étant l’un des objets les plus rapides de la Voie lactée, voyageant à une vitesse supérieure à 550 km/s ce qui est supérieure à la vitesse d’échappement de la Galaxie. Grâce aux spectres GRACES de Gemini, on a constaté que son atmosphère hors du commun est composée presqu`exclusivement d’oxygène et de néon avec des traces de sodium et de magnésium mais est dépourvue d’hydrogène ou d’hélium. Cette composition de surface exotique indique un passé catastrophique impliquant un événement supernova de Type Ia sublumineuse. Les supernovae de type 1a sont censées avoir à leur coeur une naine blanche accrétant la matière déversée par son très proche compagnon jusqu’à ce que cette masse comprime la naine blanche à une densité et à une température si élevées que cela déclenche l’explosion thermonucléaire. On pense que rien ne survit à ce genre d’explosion. Cependant, une nouvelle classe de modèles a été développée récemment appelée supernova de Type 1a sublumineuse, également appelée Type Iax, qui peut laisser un résidu partiellement brûlé qui est éjecté instantanément à grande vitesse. L’objet unique LP40-365 est la première preuve d’observation pour ce survivant d’une faible supernova. L`article publié dans Science est disponible ici.

Rejoignez les milliers et milliers de suiveurs de l’Observatoire Gemini sur Facebook et Twitter: @GeminiObs.

Square Kilometre Array (SKA) Update

By/par Bryan Gaensler, Canadian SKA Science Director
(Cassiopeia – Autumn/l’automne 2017)

For more information on the SKA, subscribe to the Canadian SKA email list, and visit the Canadian SKA WWW site.

SKA Science and Science Engagement

A very successful meeting on the topic “Canadian Radio Astronomy: Surveying the Present and Shaping the Future” was held over September 13-14, 2017, in Montréal (see Figure). More than 60 scientists and students from across Canada came together to discuss frontline research with current radio telescopes, the status of upcoming and planned facilities, and the community’s scientific priorities for the next generation of observatories such as the SKA and ngVLA. Presentations from the meeting can be downloaded from here.

Meeting participants.

Meeting participants.

An SKA lunch event was held in June 2017 at the CASCA annual meeting in Edmonton. Speakers covered the international landscape, NRC activities, and Canadian science activities, with significant time for questions and discussions. Copies of the presentations made at this session are available here.

The University of Toronto and the University of Cape Town jointly hosted a major science conference, “Fundamental Physics with the Square Kilometre Array”, held in Mauritius over May 1-5, 2017. The purpose of this meeting was to engage the theoretical physics (as opposed to astrophysics) community in the science case and design considerations for the full array. See physics presentations for copies of all presentations.

The Murchison Widefield Array (MWA) is the precursor of SKA-Low and is a powerful science facility in its own right (see MWA for details). Construction for MWA phase 2, which will improve the sensitivity of the array by an order of magnitude, is now nearing completion. Canada is a full member of the MWA project, with representation on the MWA Board. Any Canadian astronomers wishing to join the MWA Consortium and to consequently gain access to MWA data, software tools and science collaborations should contact Bryan Gaensler.

The SKA project maintains 11 international science working groups and another 2 focus groups. Membership of science working groups and focus groups is open to all qualified astronomers. If you are interested in joining one of these groups, please contact Bryan Gaensler.

ACURA Advisory Council on the SKA

The Association of Canadian Universities for Research in Astronomy (ACURA) coordinates activities and discussion on the SKA through the ACURA Advisory Council on the SKA (AACS); see the committees and working groups page for a listing of AACS membership. AACS meets several times per year, with its next meeting on October 13th, 2017. For further information or to propose AACS agenda items, please contact the AACS Chair, Bryan Gaensler.

SKA Technology Development

NRC Herzberg continues to be a major participant in pre-construction efforts for the SKA. Work on the Mid-Frequency Correlator/BeamFormer (MID.CBF) is proceeding at a vigorous pace towards its sub-element Critical Design Review (CDR) in March 2018. Canada’s proposed “Frequency Slice Architecture” (FSA) underwent a rigorous engineering change proposal (ECP) review by the SKA Project Office, and the feedback from the external review panel was very positive. As a result of this ECP review process, the FSA has now been formally accepted as the MID.CBF reference design. Procurement activities are under way to build actual prototypes to demonstrate this novel architecture in time for the sub-element CDR. The Canadian-led Central Signal Processor (CSP) consortium will hold its Critical Design Review in May 2018.

The design effort for SKA1-Mid’s Band 1 / Band 2 digitiser successfully passed its delta Detailed Design Review in August 2017. The next milestone is the production of two qualification models that will be mounted on the Chinese and German prototype antennas in January 2018. The digitiser sub-element Critical Design Review is now scheduled for April 2018.

Six additional Low-Noise Amplifiers (LNAs) were shipped to EMSS in South Africa in July 2017 for integration into the Band 2 receivers for SKA1-Mid. These LNAs plus two others shipped earlier are part of Canada’s contribution to SKA’s Dish Consortium.

The 2017 SKA Engineering meeting was held in Rotterdam, The Netherlands, in June 2017. Eleven Canadians attended, representing NRC and MDA.

SKA Regional Centres

Work continues in the SKA Regional Centre (SRC) Coordination Group, with representation from member countries/regions interested in hosting an SRC. The SRC Framework document has been officially accepted by the SKA office and the first draft of the SRC Requirements document has been submitted for review. The Requirements document describes the model for an alliance of collaborative interoperating regional centres to serve the international user community. The requirements cover 6 broad areas:

  • Governance: How the SRCs are made to function as an alliance and to work serving the needs of the SKAO and the user community;
  • Science Archive: Provision of an archive for the storage and curation of, and access to, SKA science data products;
  • Accessibility and Software Tools: How users will interact with the SRCs;
  • Data Processing: Generation and visualisation of science data products;
  • User Storage: Different capabilities for users, including scratch spaces and project collaboration spaces;
  • Network connectivity: Transfer of science data products from the Observatory into SRCs and between SRCs.

International SKA Activities

Canada is one of 10 member countries of the SKA Organisation, and is represented on the SKA Board of Directors by Greg Fahlman (NRC) and Bryan Gaensler (University of Toronto). The SKA Board met most recently in March 2017 (Perth, Australia), May 2017 (by videoconference) and July 2017 (The Hague, The Netherlands). A meeting of the SKA Members (at which Greg Fahlman represented NRC) took place in Perth in March 2017 (Perth) and May 2017 (videoconference). The SKA Board’s Executive Committee (of which Bryan Gaensler is a member) meets monthly. We note with sadness that the SKA Board Chair, Professor Giovanni Bignami, passed away unexpectedly in May 2017; a search committee (including Bryan Gaensler) is currently seeking a replacement.

Notable outcomes from the last two SKA Board meetings have included:

  • Conclusion of the SKA project’s cost control exercise, the aim of which was to identify a route to delivering SKA1 within the previously established cost cap of €674M (in 2016 euros). The “Design Baseline” for SKA1 was established in March 2015, and remains the longterm ambition of the project. The Board has now also approved the definition of a “Deployment Baseline” for SKA1. The Deployment Baseline corresponds to the telescopes currently deliverable at a funding level of €674M (2016 euros), and takes advantage of the scalable nature of interferometers. The final Deployment Baseline of SKA-1 will be defined in the SKA’s construction proposal and will include as much of the Design Baseline as can be afforded at that time. The current Deployment Baseline has been defined following an analysis from the SKA Office, in collaboration with the engineering design consortia and in consultation with the science community. See SKYBaseline for a comparison of the current Deployment Baseline and the Design Baseline.

    The scientific assessment from this process is that the current Deployment Baseline will provide transformational science capabilities. Furthermore, re-instatement of the omitted capabilities, up to the full restoration of the Design Baseline, is planned, either during or after the construction phase, should additional funding become available. Ongoing cost oversight will take place within the SKA Office’s regular activities. The Board now looks to the science community, and particularly to the SKA Science and Engineering Advisory Committee (SEAC) to regularly review the Deployment Baseline and to confirm its ability to deliver transformational science. Prof Kristine Spekkens from the Royal Military College of Canada is a member of the SEAC.
  • Consideration of a revised pre-construction schedule to incorporate the delays produced by the cost control project.
  • Updates from France, Germany, Portugal, Japan, Korea, Spain and Switzerland on their SKA-related activities and on their potential interest in participating in the SKA project.
  • Approval of a budget and business plan for the SKA Organisation (SKAO) through 2019, along with continued discussion of the corresponding financial contribution to be assigned to each member country in order to provide this funding.
  • Discussion of a draft mandate and terms of reference for an SKA Observatory Council Preparatory Task Force (CPTF). The CPTF will essentially form an interim council, consisting of those countries that have indicated they are willing to join the SKA Intergovernmental Organisation. The CPTF is expected to engage and negotiate with potential new Members and Associate Members of the SKA Observatory on matters pertaining to the terms of their accession or participation, prepare the SKA Observatory Initial Funding Schedule, and engage with the SKA Office and the SKA Board on SKA Observatory budgets, policies and procedures.
  • Ongoing discussion of finances, engineering reports, business development, site reports, communications, governance, operations, and transition planning from the current SKA Observatory (a UK company) into an Intergovernmental Organisation.
  • Ongoing overviews of the SKA Headquarters and Site Hosting agreements, and of the design and construction of the new SKA Headquarters at Jodrell Bank.

Upcoming SKA Board meetings will be in November 2017 (Italy), April 2018 (Sweden), and July 2018 (South Africa).

For further information on international SKA activities, see the latest SKA Newsletter and the bi-monthly SKA Bulletin.

CATAC Update on the Thirty Meter Telescope

By Michael Balogh (CATAC Chair)
(Cassiopeia – Autumn/l’automne 2017)

In July, the hearing officer considering the contested case hearing regarding TMT’s site permit on Mauna Kea issued her decision, that the permit should be granted under a number of conditions. The full report is available at https://dlnr.hawaii.gov/mk/files/2017/07/783-Hearing-Officers-Proposal.pdf. This was welcome news. The next step is for the Board of Land and Natural Resources to receive written and oral responses to these recommendations, and finally issue a decision on whether or not to approve the permit. This decision is expected in October. The decision may be appealed directly to the Hawaii Supreme Court within a 30-day window; if the Court decides to hear the case, they must give the matter priority and issue a decision within one year.

The only other pending legal issue is an appeal related to the vacating of consent for the UH-TIO sublease. A ruling on the appeal could come before the end of the year.

There is a generally optimistic sense that the prospects for construction in Hawai’i have greatly improved. There are still remaining issues, but the climate for resolving them has become much more constructive. The election of Harry Kim as mayor of Hawai’i County has changed the political dynamic. His vision of Maunakea as a “World Peace Park” is providing an opportunity for all interested parties to come together.

With the Project expected to obtain all necessary approvals for construction on ORM, as a backup site in the case Maunakea construction proves impossible, the site selection seems likely to be settled by early 2018. It remains true that the Project does not yet have sufficient committed funds to complete construction, a situation that has not been helped by the delay in the start of construction. At the CASCA meeting in May 2017, several people expressed a desire to learn more about the Project’s plans for managing this shortfall, and what the implications are for completion of construction. In response to this, we have invited Ed Stone (TIO Executive Director) and Gary Sanders (Project Manager) to address the CASCA community directly, via a 2 hour Webex session. This will take place at 3:30- 5:30pm, EDT, on September 26. All CASCA members are invited to participate. If you have previously participated in a CATAC Webex session, you will automatically receive an invitation to this discussion. If you would like to be added to the list of participants, please email luc.simard@nrc-cnrc.gc.ca. Slides will be made available to registered participants prior to the meeting; the presentation itself will be limited to ~30 minutes to leave plenty of time for your questions.

CATAC would like to remind you of the TMT Science Forum happening in Mysore, India Nov 7-9, 2017. The main purpose of this meeting is to discuss concepts for the next instrument to be built for TMT, after the first light instruments. The International Science Development Teams (ISDTs) will be leading these discussions, and we would like to thank ACURA for making funds available to help offset travel costs for Canadian University-based ISDT members and invited speakers. This activity is expected to continue after the Forum, culminating in a series of white papers that will be presented to the SAC, who will make a recommendation for funding studies of the next TMT instrument. The white papers will focus on the science aspects of possible capabilities, and will be due in March of next year. CATAC hopes to play a role here in consulting with the community to present our SAC members with a Canadian perspective. This is a critical activity for Canada and we welcome community engagement. Please contact CATAC (mbalogh@uwaterloo.ca), your SAC representatives (Tim Davidge, Bob Abraham, Stan Metchev, Doug Welch) or any of the ISDT members for more information.

Finally, CATAC member Christine Wilson (McMaster) has resigned from CATAC to make best use of the research time afforded by her recent Killam fellowship. We are grateful for her dedicated service and advice during her term on CATAC. We expect to appoint a replacement in short order.

Michael Balogh
Chair, CATAC

BRITE-Constellation Mission Update

By/par Gregg Wade, Canadian PI for BRITE
(Cassiopeia – Autumn/l’automne 2017)

BRITEpatch

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 22 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 build and is 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 fund mission operations.

3rd BRITE Science Conference

The 3rd conference devoted to presentation of BRITE-Constellation science and technical results took place from 7-11 August 2017 at Auberge du Lac Taureau in Québec, Canada. Thirty-two participants attended and delivered oral and poster presentations. The proceedings will be published by the Polish Astronomical Society.

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 Lac/Cyg field.
  • BRITE Lem (Poland): Lem observes with a blue filter. It is observing the Sagittarius (III) field. As implied by the numeral III, this is BRITE-Constellation’s 3rd revisit to this field.
  • BRITE Heweliusz (Poland): Heweliusz observes with a red filter. This satellite is observing the Pegasus field.
  • BRITE Austria (Austria): BRITE Austria observes with a blue filter. It is also observing the Sagittarius III field, along with the Cassiopeia II field.
  • UniBRITE (Austria): UniBRITE observes with a red filter. This satellite has been suffering from unpredictable resets of its on-board computer for several weeks, and is currently not acquiring observations.

The BRITE Constellation observing programme from early 2017 through early 2019 has been planned by the BRITE Executive Science Team (BEST), and details are available on the BRITE photometry Wiki page.

Recent Science Results

The variability of the BRITE-est Wolf-Rayet binary, γ2 Velorum I. Photometric and spectroscopic evidence for colliding winds” (Richardson et al. 2017, MNRAS 471, 2715):
Richardson et al. report the first multi-colour precision light curve of the bright Wolf-Rayet binary γ2 Velorum, obtained over six months with BRITE-Constellation. Combining these data with a huge new database of high-resolution optical spectra of the system, the authors revise the spectroscopic orbit and constrain the bulk properties of the colliding winds. We report a dependence of both the light curve and spectral line excess emission properties that scale with the inverse of the binary separation. Based on their analysis of the spectroscopic properties in combination with the photometry, they conclude that the phase dependence is caused only by excess emission in the lines, and not from a changing continuum. They also detect a narrow, high-velocity absorption component from the He I λ5876 transition, which appears twice during the orbit. Using smoothed-particle hydrodynamical simulations of the colliding winds (Fig. 1), the authors accurately associate the absorption from He I to the leading and trailing arms of the wind shock cone passing tangentially through the line-of-sight. The simulations also explain the general strength and kinematics of the emission excess observed in wind lines such as C III λ5696.

Fig. 1: Density (left), temperature (center), and line-of-sight velocity (right) of the hydrodynamic simulation of the colliding winds in γ2 Vel. The plane shown is rotated and inclined from the orbital plane such that the observer is directly to the right of the frame. At this phase, the WR star is on the right. The orbital motion is counterclockwise. From Richardson et al. (2017).

Fig. 1: Density (left), temperature (center), and line-of-sight velocity (right) of the hydrodynamic simulation of the colliding winds in γ2 Vel. The plane shown is rotated and inclined from the orbital plane such that the observer is directly to the right of the frame. At this phase, the WR star is on the right. The orbital motion is counterclockwise. From Richardson et al. (2017).

Short-term variability and mass loss in Be stars III. BRITE and SMEI satellite photometry of 28 Cygni” (Baade et al. 2017, A&A, in press):
Baade et al. report that, for decades, 28 Cyg has exhibited four large-amplitude frequencies: two closely spaced frequencies of spectroscopically-confirmed g modes near 1.5 c/d, one slightly lower exophotospheric (Štefl) frequency, and at 0.05 c/d the difference (∆) frequency between the two g modes (See Fig. 2). This top-level framework is indistinguishable from other Be stars, including η Cen. The circumstellar frequency is the only one that does not seem to be affected by the ∆ frequency. The amplitude of the ∆ frequency undergoes large variations; around maximum the amount of near-circumstellar matter is increased, and the amplitude of the Štefl frequency grows by some factor. During such brightenings dozens of transient spikes appear in the frequency spectrum, concentrated in three groups. Only eleven frequencies were common to all years of BRITE observations. They conclude that Be stars seem to be controlled by several coupled clocks, most of which are not very regular on timescales of weeks to months, but that function for decades. The combination of g modes to the slow ∆ variability and/or the atmospheric response to it appears significantly nonlinear. Like in η Cen, the ∆ variability seems the main responsible for the modulation of the star-to-disc mass transfer in 28 Cyg. A hierarchical set of ∆ frequencies may reach the longest timescales known of the Be phenomenon.

Fig. 2: BRITE frequency spectrum (in arbitrary units) of 28 Cyg. Top: 2015 (BRITE-Toronto and UniBRITE), bottom: 2016 (BRITE-Toronto). Arrows mark the identified frequencies. The dashed lines represent the local sum of mean power and 3 × σ (calculated after removal of the significant frequencies). Between 3.5 c/d and the nominal Nyquist frequency near 7.2 c/d, there is virtually no power. Frequency groupings occur at the approximate ranges 0.1-0.5 c/d, 1.0-1.7 c/d, and 2.2-3.0 c/d.

Fig. 2: BRITE frequency spectrum (in arbitrary units) of 28 Cyg. Top: 2015 (BRITE-Toronto and UniBRITE), bottom: 2016 (BRITE-Toronto). Arrows mark the identified frequencies. The dashed lines represent the local sum of mean power and 3 × σ (calculated after removal of the significant frequencies). Between 3.5 c/d and the nominal Nyquist frequency near 7.2 c/d, there is virtually no power. Frequency groupings occur at the approximate ranges 0.1-0.5 c/d, 1.0-1.7 c/d, and 2.2-3.0 c/d.

Conferences, Resources and Social Media

Conferences

As mentioned above, the 3rd BRITE Science Conference took place from 7-11 August 2017 at Auberge du Lac Taureau in Québec, Canada. Planning is underway for future meetings of the BRITE Executive Science Team (BEST) and the BRITE International Advisory Science Team (BIAST).

Resources

The BRITE Public Data Archive, based in Warsaw, Poland, at the Nikolaus Copernicus Astronomical Center, 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 now 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.

ALMA Matters

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From/de Gerald Schieven
(Cassiopeia – Autumn/l’automne 2017)

Cycle 5 Proposal Statistics

Observations for Cycle 5 begin October 1, 2017. A record 1661 proposals were submitted for Cycle 5 requesting almost 16,000 hours of 12-m Array time and more than 14,000 hours of ACA time. With approximately 7000 hours of available time (4000 for the 12-m Array), this yields an overall oversubscription rate of 4.3, similar to previous cycles. Thirty-nine proposals were submitted by Canadian PIs, which fared extraordinarily well in Cycle 5; nearly 10% of the 12-m Array time allocated to North American proposals had a PI or co-PI from a Canadian institution. Including both 12-m Array and ACA allocations, the fraction was over 24% of North American time.

Snow Impacts Cycle 4

The ALMA Observatory experienced back to back severe winter storms in May/June, making it difficult to recover the 12-m array for PI observations. This has had an even more detrimental impact on the relocation to long baselines. Many roads were blocked with 2 meters of snow, high winds often returned snow to the cleared locations, and snow often compacted into ice covering antenna pads. By early July ALMA had returned to routine observations utilizing the 7-m and Total Power Arrays, and 12-m Array PI observations resumed later in the month. By August long baseline observations had begun, though the largest configurations were further delayed to September due to a damaged power cable on the south arm.

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

(Cassiopeia – Autumn/l’automne 2017)

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

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

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

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

(Cassiopeia – Autumn/l’automne 2017)

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

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

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

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

(Cassiopeia – Autumn/l’automne 2017)

Angus

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

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

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

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

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

Maunakea Spectroscopic Explorer (MSE) Update

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

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

Video of the Telescope Structure Conceptual Design

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

More Conceptual Design Reviews

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

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

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

Other Activities

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

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

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

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