Cassiopeia Newsletter – 2017 Autumnal Equinox

fall

In this issue:

President’s Message
ALMA Matters
BRITE-Constellation Mission Update
Update from the Canadian Space Agency (CSA) / Compte rendu de l’Agence spatiale canadienne (ASC)
CATAC Update on the Thirty Meter Telescope
CHIME First Light
Canadian Gemini Office News / Nouvelles de l’Office Gemini Canadien
Maunakea Spectroscopic Explorer (MSE) Update
Square Kilometre Array (SKA) Update
Dissertation: The Effects of Environment on the Atomic and Molecular Gas Properties of Star-Forming Galaxies
Dissertation: Lights in Dark Places: Inferring the Milky Way Mass Profile using Galactic Satellites and Hierarchical Bayes
Dissertation: Investigating Brown Dwarf Atmospheres: Gravity, Dust Content, Cloud Structure and Metallicity


Editors: Magdalen Normandeau & Joanne Rosvick

Cassiopeia is CASCA’s quarterly Newsletter, published on or near the solstices and equinoxes (March 21, June 21, September 21 and December 21). To submit a contribution please email cassiopeia.editors@gmail.com. All submissions must be received at least one week in advance to be published in the next edition. We accept plain text and Word documents. Note that the formatting of your document will not be preserved. Please include any images as attachments in your email, not embedded in the text. Please include URLs in parentheses next to the word or phrase that you wish to act as link anchors.

Cassiopeia est le bulletin d’information de la CASCA, publié quatre fois par année, aux solstices et aux équinoxes (21 mars, 21 juin, 21 septembre et 21 décembre). Pour soumettre un article, écrivez à cassiopeia.editors@gmail.com. Les soumissions doivent être reçues au moins une semaine avant la parution. Nous acceptons les fichiers en format texte (ascii) et Word. Veuillez noter que la mise-en-page de votre document ne sera pas conservée. Veuillez faire parvenir vos images en pièces jointes à votre courriel plutôt que de les insérer dans votre article. Pour les liens à des sites internets, veuillez inclure l’adresse entre parenthèses à côté du mot ou de la phrase devant servir d’ancre.


President’s Message

2014-06-27-Prof. Roberto Abraham

By/par Roberto Abraham, CASCA president
(Cassiopeia – Autumn/l’automne 2017)

Dear CASCA Members,

It’s been a busy summer! Here are some activities that have been going on over the past few months:

CHIME First Light

About two weeks ago, Kirsty Duncan, Minister of Science, installed the final piece of the Canadian Hydrogen Intensity Mapping Experiment (CHIME), triggering the official First Light for this exciting new radio telescope. Congratulations to the many people involved in CHIME at UBC, McGill, Toronto, and NRC.

CHIME is incredibly innovative and its science is hugely exciting, so it is no surprise to see that its First Light generated a lot of buzz in both the astronomical community and in the media. I can’t wait to see the exciting science it will produce. The process by which CHIME came into existence is also interesting because it is another success story for the CASCA Long-Range Plan process. I was on the LRP2010 committee (chaired by Chris Pritchet at the University of Victoria) and well remember the extensive discussions about CHIME that led to it being declared the top mid-scale priority in the plan. This prioritization evidently played an important role in securing its funding. I’m not a radio astronomer (yet), and I’m no lover of committees (in general), but I must say it is incredibly satisfying watching the CHIME team deliver the goods and knowing that the work the community put into LRP2010 helped make CHIME happen. By being organized, disciplined, and working together, harnessing the many strengths of both Canadian Universities and the NRC, we can build the groundwork for more Canadian success stories in astrophysics. And if you are getting the impression from this buildup that the Canadian community is starting to gear up for LRP2020, well, of course you’re right. Witness (for example) the very successful recent workshop held in Montreal last week on “Canadian Radio Astronomy – Surveying the Present and Shaping the Future”. So, please start thinking about what you want the future to look like, because the planning for LRP2020 will be starting quite soon.

TMT Progress

After nearly five months of hearing evidence, the contested case hearing for the Thirty Meter Telescope Project has concluded and State Hearings Officer and former Judge Riki May Amano has recommended that a permit be issued to the University of Hawaii to allow construction of the TMT. In parallel with this progress in the legal domain, support for the TMT has been growing in Hawaii. Oahu public support for TMT construction is now almost 80 percent, and the most recent polling indicates that Hawaii Island residents support the construction of the Thirty Meter Telescope by a nearly 2-to-1 margin. This is great news! Very serious consideration of the backup site (La Palma) continues but we now have many reasons to be optimistic about the prospect of TMT construction at our first-choice site in Hawaii. Challenges remain but this should not come as as a surprise to anybody. (Beyond a certain scale, essentially all ambitious scientific infrastructure projects have to deal with some combination of logistical, financial, and scheduling hurdles. The trick is to have a robust plan in place to manage the challenges.) CASCA members interested in learning how the TMT project is progressing, and on the plans for future instruments, should participate in the community Webcast with senior TMT management being organized by CATAC (see Michael Balogh’s CATAC report in this issue for details). Future webcasts will organized to help keep the community up to date on the considerable progress being made on the TMT.

Perhaps it is not out of place to remind ourselves that the privilege of observing on Mauna Kea has been a huge benefit to many of us. Let’s be grateful for, and respectful of, this privilege. Over the summer, I sat down with a couple of books and did some reading about the fascinating history of the people of Hawaii. Since I’ve been a regular visitor to the islands for 25 years, I’m truly ashamed that it took me this long to read a book on this subject. As the legal process winds down, I hope more astronomers take some time to learn more about the history of the islands. (Though it’s somewhat dated, I can recommend “Shoal of Time: A History of the Hawaiian Islands” by Gavan Daws. If you have other suggestions, please do email me with them.)

Space Science and the Canadian Space Agency

After years of talking about it on the James Webb Space Telescope (JWST) advisory committee, the JWST Early Release Science proposal deadline has come and gone. The selection committee is meeting in a few weeks and will divide about 500 hours worth of observing time between about 15 proposals, chosen from the 106 submitted. The JWST General Observer call for proposals will come out in two months with a proposal deadline of next March. The lesson you should draw from all this is that THE JWST ERA IS ALMOST HERE!

The Canadian Space Agency has played an important role in the development of the JWST mission and, when the spacecraft launches in 2018, I think that all Canadians will be justifiably proud to learn that a team of Canadian academic, governmental, and industrial scientists, engineers and technicians built one of JWST’s key instruments (the NIRISS spectrometer, whose Principal Investigator is René Doyon at the Université de Montréal), not to mention the critical Fine Guidance Sensor that points and guides the telescope.

Unfortunately, JWST will have a very limited lifetime. It is designed to have at least a five-year lifetime after launch, and carries only enough fuel to maintain orbital positioning for a little over ten years. Of course, most space-based endeavours have long lead times, and investments in space missions frequently begin to pay off many years into the future (and, when it comes to flagship missions, sometimes decades into the future). The spectacular near-term future we are anticipating with JWST is thus the product of investments begun many years ago. But what about the decades after JWST? We need to ensure that post-JWST Canada continues to innovate, lead, and inspire.

Operating in synergy with the CASCA Long Range Plan, and with a particular eye toward LRP2020, a number of Canadians have begun thinking about ways to lay out a roadmap to such an exciting post-JWST future. Professors Sarah Gallagher (Western) and Jeremy Heyl (UBC), working with graduate student Ilaria Caiazzo (UBC), have put together a very thoughtful white paper which I think everybody should read. This White Paper, together with the various Topical Team reports now being prepared by the CSA, show how space-based astrophysical research should operate in the country at a variety of levels, from low-cost, agile balloon-based missions that perform end-to-end experiments on a timescale relevant for the training of graduate students, to focused mid-scale missions that target high-risk/high-return subjects such as primordial gravitational waves from the first few moments after the Big Bang, all the way up to proposed participation in (and potentially leadership in) much more infrequent but highly ambitious facilities that will keep our astronomical research and space industrial communities vibrant long after JWST. The key to to this future is increased funding for the Canadian Space Agency, and the immediate audience for our recommendations is the government’s newly-formed Space Advisory Board. The Space Advisory Board’s first report, titled “Consultations on Canada’s Future in Space: What We Heard”, is now available here.

This report summarizes the feedback Space Advisory Board members received from stakeholders during the public consultations on Canada’s future in space. There are exciting plans, but how do we turn these plans into reality? By now you should not be surprised to learn that LRP2020 will be an important component in this. In the meantime, we need to keep delivering the message to the government. And this inevitably brings me to the my final topic: activities by the Coalition for Canadian Astronomy.

Coalition Activities

In late August, the Coalition for Canadian Astronomy prepared a pre-budget submission and submitted this to the government. There are two main recommendations in the submission:

Firstly, we offer a recommendation for increased funding for the Canadian Space Agency (CSA) that is very much in-line with the White Paper noted above. The Coalition believes Canada has the resources to achieve international leadership in space-based astronomy, matching its existing success in ground-based astronomy, and that such a future includes leadership in a future space mission.

Secondly, as noted by the report on the Fundamental Science Review (the Naylor Report), Canada needs a mechanism for funding “big science” projects, which tend to involve multiple international partners, have price tags in the billions, take years to conceive and build, and have lifespans measured in decades. The lack of such a funding mechanism could mean lost opportunities for Canadian astronomy in the future, including those priority projects identified in our pre-budget submission. Therefore, getting a nimble mechanism in place remains a top priority for the Coalition. You will be hearing more about formal CASCA Board support for the Naylor Report soon, along with some suggestions for things you can personally do to help draw attention to this important report.

In addition to providing the government with a formal document as part of the pre-budget submission process, we also wrote to Ministers Bains and Duncan on August 30 to reinforce the priorities noted above. The co-chairs of the coalition (myself, on behalf of CASCA, Don Brooks, on behalf of the Association of Canadian Universities for Research in Astronomy, and our industry co-chair Guy Nelson, CEO of Empire Industries) plan to visit Ottawa in October/November to follow-up on the priorities identified in this letter. As with our last visit to Ottawa, we will make an effort to meet with politicians on both sides of the bench.

Let me conclude this message by thanking you, on behalf of the CASCA Board, for your support of our society. We promise to work hard on your behalf. If you have any suggestions for things we could be doing better, please don’t hesitate to get in touch.

Roberto Abraham

Dr. Ingrid Stairs awarded the Rutherford Memorial Medal in Physics of the Royal Society of Canada

Dr Ingrid Stairs from the University of British Columbia has been awarded the 2017 Rutherford Memorial Medal in Physics from the Royal Society of Canada

CASCA is pleased to announce that Dr. Ingrid Stairs from the University of British Columbia has been awarded the 2017 Rutherford Memorial Medal in Physics from the Royal Society of Canada. The citation reads

“Ingrid Stairs is a leading world expert in finding and using radio emitting neutron stars (pulsars) to study and test theories of gravity. Pulsars, particularly those in binary systems, provide unique laboratories in which to study Einstein’s theory of gravity and any possible deviations from this theory. Professor Stairs has exploited this in numerous situations and continues to do so by developing sophisticated pulsar instrumentation.”

 

Update from the Canadian Space Agency (CSA) / Compte rendu de l’Agence spatiale canadienne (ASC)

By/par Denis Laurin, Senior Program Scientist, Space astronomy,
Space Exploration Development, Canadian Space Agency

(Cassiopeia – Autumn/l’automne 2017)

English version below

Opportunités pour études

Il y a presque un an, l’ASC avait accueilli de nombreux participants à l’Atelier canadien sur l’exploration spatiale (ACES 2016) à Montréal. Les résultats de l’atelier sont toujours disponibles sur le site FTP de l’ASC. Parallèlement à l’atelier, l’ASC a soutenu les équipes thématiques (ET), dont trois équipes en astronomie spatiale, quatre en exploration planétaire et une en santé spatiale. Les présidents des ET ont livré leurs rapports, qui seront condensés en un rapport sur les priorités scientifiques de l’exploration spatiale (ES) cet automne ou hiver par l’ASC. Les rapports des ET, tels que soumis par les présidents des ET, sont disponibles sur le site FTP mentionné ci-dessus. Ces produits de l’ACES et les rapports des ET seront des références clés pour les prochaines demandes de propositions (DDP) d’études de l’ASC en exploration. Un préavis de ces demandes d’études a été publié sur le site Web de Travaux publics (un message avait été envoyé le 31 mars aux membres de la CASCA afin d’informer la communauté de la publication de ce préavis.) L’ASC suit le plan annoncé. Déjà, une DDP pour une étude portant sur le concept CASTOR et une autre pour une contribution potentielle à LiteBIRD sont publiées. Des DDP pour des études de maturation scientifique et des études pour des concepts de missions suivront. Un message aux membres de la CASCA sera envoyé une fois que les DDP publiées. Encore une fois, les résultats de l’ACES et les rapports des ET guideront les sujets admissibles à ces études.

Un préavis pour un appel d’offre potentiel du programme de subventions VITES 2017 a été annoncé (http://www.asc-csa.gc.ca/fra/ao/2017-vites-preavis.asp) permettant un renvoi de commentaires et suggestions (date limite le 6 septembre).

JCSA comité consultatif mixte ASC et CASCA

Les membres du comité sont présentement:

  • Jason Rowe, Bishop U. (co-président)
  • Denis Laurin, CSA (co- président)
  • Chris O’Dea, U. du Manitoba
  • Renée Hlozek, U. de Toronto
  • Locke Spencer, U. de Lethbridge
  • Chris Willott, CNRC Herzberg
  • Daryl Haggard, U. McGill

La dernière rencontre a eu lieu après la CASCA à Edmonton. La prochaine réunion sera par télécom en novembre ou décembre.



Requests for Studies

Almost a year ago CSA hosted the Canadian Space Exploration Workshop (CSEW 2016) in Montreal. The output of the workshop is still available on the CSA FTP site. In parallel to the workshop, CSA supported Topical Teams (TT), with three teams in space astronomy, four in planetary exploration, and one in space health. The TT Chairs have delivered their reports, which will be condensed into a CSA Space Exploration (SE) science priorities report in the Fall or Winter. The TT reports, as submitted by the TT Chairs, are available on the FTP site mentioned above. These CSEW products and TT reports will be key references for upcoming CSA SE Studies Request for Proposals (RFP). An Advanced Notice (AN) of these Studies RFP was published on the Public Works website (a message was sent to CASCA emailer to inform the community of the publication of this AN on March 31.) CSA is following the announced plan. Already a study RFP targeting the CASTOR concept and a RFP for potential contribution to LiteBIRD are posted. Next are RFPs for Science Maturation Studies and for Mission Concept Studies. A message to CASCA emailer will be sent once the RFPs are posted. Again, the CSEW results and TT reports will guide the subjects eligible for these studies.

There was an Advanced Notice for a potential FAST 2017 grants AO (http://www.asc-csa.gc.ca/eng/ao/2017-fast-notice.asp), enabling feedback on the program (which closed 6 September).

JCSA the joint CASCA and CSA Consultation Committee

The current membership is comprised of:

  • Jason Rowe, Bishop U. (co-Chair)
  • Denis Laurin, CSA (co-Chair)
  • Chris O’Dea, U. of Manitoba
  • Renée Hlozek, U. of Toronto
  • Locke Spencer, U. of Lethbridge
  • Chris Willott, NRC Herzberg
  • Daryl Haggard, McGill U.

The last meeting was at CASCA in Edmonton. The next planned meeting will be by telecom in November or December.

CHIME First Light

By/par Cherry Ng, Andre Renard, and Seth Siegel
(Cassiopeia – Autumn/l’automne 2017)

CHIME, the $16M new Canadian radio telescope, saw its “First Light” on September 7th and was celebrated at a ceremony in Penticton, BC involving Federal Minister of Science, Kirsty Duncan.

The telescope is designed to simultaneously tackle major astrophysics and cosmology topics, including studying the nature of dark energy by making unprecedented maps of the distant universe, studying pulsars, and determining the origin of the mysterious phenomenon of Fast Radio Bursts.

Now that all the major components are in place, the first data from the instrument is starting to be collected. “After years of work it’s fantastic to finally see the graphs showing real sky data coming through the system on all channels.” says Nolan Denman, a graduate student at the University of Toronto, who produced the first light plots after an overnight session collecting data during the transit of Cygnus A (a nearby galaxy that is bright at radio wavelengths and is a useful source for calibrating the instrument). This new instrument will serve as a powerful tool to explore a number of interesting cosmological and astrophysical topics.

CHIME first light.  Cross-correlation of the signal measured by two CHIME antennas on different cylinders during the transit of Cygnus A.  Top panel shows the magnitude, real, and imaginary component of the cross-correlation.  Bottom panel shows the phase.  Radio waves from Cyg A reach the two antennas at slightly different times.  As the source moves across the sky, the delay between antennas changes.  This results in the fringe pattern observed in the real and imaginary component, with the envelope tracing out the antenna beam pattern.  Note that this is just one pair of antennas (or baseline) at a single frequency; in total CHIME measures the cross-correlation for over 2 million baselines at 1024 frequencies.

CHIME first light. Cross-correlation of the signal measured by two CHIME antennas on different cylinders during the transit of Cygnus A. Top panel shows the magnitude, real, and imaginary component of the cross-correlation. Bottom panel shows the phase. Radio waves from Cyg A reach the two antennas at slightly different times. As the source moves across the sky, the delay between antennas changes. This results in the fringe pattern observed in the real and imaginary component, with the envelope tracing out the antenna beam pattern. Note that this is just one pair of antennas (or baseline) at a single frequency; in total CHIME measures the cross-correlation for over 2 million baselines at 1024 frequencies.

Science

CHIME will probe the fundamental nature of dark energy, the mysterious agent invoked to explain the accelerated expansion of the universe. To accomplish this, it will produce a three-dimensional map of the 21-cm emission from neutral hydrogen that covers the entire northern sky and spans redshifts 0.8 to 2.5. This will enable a measurement of Baryon Acoustic Oscillations (BAO) in the large scale distribution of neutral hydrogen — a relic that originates from sound waves propagating in the baryon-photon plasma of the early universe. The size of the BAO feature will be used as a standard ruler to measure the expansion history of the universe during the epoch when dark energy generated the transition from decelerated to accelerated expansion.

Two further key science projects are currently under commissioning and will soon be conducted simultaneously alongside the cosmology experiment. These include a blind survey for Fast Radio Bursts (FRBs), energetic single pulses of radio emission arriving in random directions from unknown sources well beyond our galaxy. FRB appears to be a new class of radio transient with unknown astrophysical origin and have drawn a lot of attention among the astrophysics community. “There are currently more theories in the literature than the number of known FRB sources” said graduate student Utkarsh Giri at the Perimeter Institute. So far progress in resolving the mystery has been limited by the low survey efficiency of traditional single dish telescopes. With its huge field of view and broad frequency coverage, CHIME is a nearly ideal instrument for finding and studying many of these bursts. Like what McGill postdoc Emmanuel Fonseca said, “It has taken almost 10 years to observe 25 FRBs with different telescopes; CHIME is expected to detect 25 FRBs within one week of operation.” Pinning down the FRB event rate will be crucial for determining the origin of FRBs and all eyes are on CHIME to revolutionize the field.

The other commensal project that CHIME will carry out is pulsar timing. CHIME will monitor the pulses from all known pulsars in the Northern hemisphere visible from Penticton, every day. Among other things, this information will aid in the search for gravitational waves – travelling ripples in space-time – passing through our galaxy.

Instrumentation

CHIME is a transit telescope that surveys the northern half of the sky every day as the earth rotates. It is composed of four cylindrical reflecting surfaces that resemble snow-board half-pipes and have a total collecting area equivalent to five hockey rinks (8,000 square meters). It records the information from all the radio waves falling across its surface with over a thousand antennas. “These cloverleaf-shaped antennas are compact and have an excellent broadband coverage. They are made out of conventional low loss circuit boards and can be mass produced economically.”, said Meiling Deng, a graduate student at UBC who has led the design of these antennas.

CHIME at night.  The telescope consists of four parabolic cylinders that are 20 m wide and 100 m long with a focal length of 5 m.  The telescope has no moving parts, instead relying on the earth's rotation to move the sky across its field of view.  The focal line of each cylinder is populated with 256 dual-polarization antennas that feed into a custom 2048-input radio correlator.

CHIME at night. The telescope consists of four parabolic cylinders that are 20 m wide and 100 m long with a focal length of 5 m. The telescope has no moving parts, instead relying on the earth’s rotation to move the sky across its field of view. The focal line of each cylinder is populated with 256 dual-polarization antennas that feed into a custom 2048-input radio correlator.

The CHIME correlator is a sophisticated digital network and signal processing instrument that converts the massive amount of information that is contained in the radio waves incident on the cylinders into an image of the overhead sky. Measured in number of analog inputs (N=2048) squared times bandwidth (400 MHz), the CHIME correlator is the largest radio correlator in the world — and it was built for a comparatively low price. The correlator employs 128 field programmable gate arrays (FPGAs) to digitize the analog radio signals collected by the antennas and channelize their full bandwidth into 1024 narrow frequency bins. The FPGAs are interconnected through custom, full-mesh backplanes that enable a massive reorganization of 6.6 Terabit/second of data into the format required to compute the N2 correlation matrix of the signals measured by the antennas. The data is then transmitted over more than a thousand fiber optic cables to a supercomputer.

Using the data from the FPGAs, the CHIME supercomputer correlates the inputs into “visibility” matrices used to created detailed sky maps, and performs real-time beamforming which is used for the FRB and pulsar applications. This requires a huge amount of computing power, which was made possible thanks to the existence of low cost Graphics Processing Units (GPUs) from AMD, which were developed primarily for computer games, but are increasingly leveraged by scientists to perform complex calculations. In total CHIME has 1024 high end GPUs, spread out over 256 servers. Together they are able to perform over 7 quadrillion (a million billion) operations per second.

Undergraduate and graduate students played a key role in the assembly, testing, and on-site installation of the instrument. “My favourite part of working on CHIME has been interacting with all the wonderful people involved in this project. The team’s enthusiasm and devotion is contagious” said Emilie Storer, an undergraduate student at McGill who participated in the testing of FPGA motherboards.

People at work. (Top left) Postdoc Emmanuel Fonseca and summer intern Tristan Simmons raising feeds onto the focal line; (top right) Postdoc Cherry Ng connecting some of the 2048 50m-long coaxial cables; (bottom left) Graduate student Juan Mena Parra installing FPGA motherboards; (bottom right) Graduate student Nolan Denman assembling GPUs in the X-engine.

People at work. (Top left) Postdoc Emmanuel Fonseca and summer intern Tristan Simmons raising feeds onto the focal line; (top right) Postdoc Cherry Ng connecting some of the 2048 50m-long coaxial cables; (bottom left) Graduate student Juan Mena Parra installing FPGA motherboards; (bottom right) Graduate student Nolan Denman assembling GPUs in the X-engine.

Future of CHIME

CHIME is now in its commissioning phase, in preparation for science operations. This new telescope will bring Canada to the forefront of an emerging important and technically challenging domain of radio astronomy. More information on CHIME can be found here.

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.