Archives de la catégorie : Nouvelles et annonces

(Cassiopeia – Spring/printemps 2017)

by Mohammed Hassan Abdallah
Thesis defended in September 2016
Department of Physics and Astronomy, University of Calgary
Thesis advisor: Dr. Dennis Leahy

Abstract

We study the time dependence of the energy spectra (i.e. of the spectral model parameters, and the interpretation) of the X-ray binary system Hercules X-1/HZ Hercules (Her X-1/HZ Her) over the superorbital/35-day cycle. The results are discussed separately in two parts: one for the data during the main high state and one for the data obtained during low state and short high state. We made use of data collected by RXTE/PCA instrument in the standard-2 mode during the period from July,1996 to August of 2005 (MJD = 50290 to 53584) acquired as a result of 23 study proposals for observing the HZ Her/Her X-1 system. Observations made while the system was in anomalous low state (ALS) were removed, as the ALS are believed to be caused by a change in the status of the disc which results in disappearance of the 35-day superorbital cycle. In our data there are two anomalous low states (MJD = 51226:4 to 51756:9 & MJD = 52950:6 to 53159:4). Due to the rapid change of count rates and energy spectra during eclipse and dips periods, we remove these periods from our analysis. The main results during main high state are directly linked to the disc precession and its effect in occulting the central source and surrounding emission regions, while results obtained for the low state and short high state are related to the changing visibility of the irradiated face of HZ Her which contributes to the observed spectra by the reflected emission off of its heated face.

By/par Bryan Gaensler, Canadian SKA Science Director
(Cassiopeia – Spring/printemps 2017)

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

“Canadian Radio Astronomy: Surveying the Present and Shaping the Future”

A meeting will be held over September 13-14, 2017, in Montréal to assess the present and future landscape of Canadian radio astronomy, defined broadly to span the frequency range from ~50 MHz to ~100 GHz, utilising instruments such as CHIME, the JVLA, ALMA, the various SKA pathfinders and precursors, and more. The meeting will be an opportunity for the entire Canadian astronomy community (including students and postdocs) to present and discuss their frontline research with current radio facilities, the status of planned facilities, and the community’s scientific priorities for the next generation of observatories such as the ngVLA and SKA. There will be a strategy session on the afternoon of the second day, where we will have an initial discussion on possible radio contributions to the next Long Range Plan. To register, please fill out this form by March 31st, 2017.

Canadian SKA Pre-Construction Activities

NRC Herzberg has continued its work on pre-construction for the SKA1-Mid correlator/beamformer (CBF), the single pixel feed digitisers, and the band 2 and band 5 low noise amplifiers, with the focus remaining on completing Critical Design Reviews by December 2017.

The Mid.CBF and Low.CBF teams initiated discussions to see if there was a possibility of converging the NRC and CSIRO/ASTRON correlator/beamformer designs and of sharing development pieces. The functional requirements for SKA1-Mid and SKA1-Low are sufficiently different that full convergence is not possible, but the teams have agreed to share design pieces.

The single pixel feed digitisers will undergo a Detailed Design Review (DDR) within the Dish Consortium over January 30-31, 2017 prior to building pre-production units for on-site testing later this year.

The band 2 low-noise amplifier (LNA) specifications have been ratified by the Dish Consortium, and the band 2 feed design from EMSS South Africa passed its DDR in Nov 2016. NRC is proceeding to supply LNAs for the pre-production units for on-site testing. The band 5 change request to split the 3:1 band into two 1.85:1 bands 5A and 5B was approved, and prototype LNAs are being prepared by NRC for consideration in a competitive design of these split bands.

The construction and operating cost review, mandated from the SKA Board, is being led by SKAO with nine ‘streams’ of examination:

• Reuse of precursor or pathfinder designs
• Alternative antennas
• Reduced operating model
• Critical review of consortia cost estimates
• Review of identified cost reduction options
• Over-specified requirements
• Over design
• Explore SDP savings
• Procurement model

The consortia are supporting this effort, and went through full day cost reviews discussions in February 2017, leading to recommendations to the SKA Board meeting in March 2017.

Canadian SKA Science Activities

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

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 (bgaensler@dunlap.utoronto.ca).

The 2016 SKA Engineering meeting was held in Stellenbosch in October 2016. Twelve Canadians attended, representing NRC, CADC, and MDA. The 2016 SKA Science meeting was held in Goa in November 2016. Six Canadians attended, representing Toronto, NRC, McGill ,and Calgary. The 2017 SKA Engineering meeting will be held in Rotterdam in June 2017.

CFI Proposal on Radio Astronomy Data Services

A $9.4M funding proposal has now been submitted to the 2017 round of the CFI Innovation Fund program, with the goal of developing the tools and infrastructure needed to support a Canadian SKA Data Centre. The proposal is entitled “Unlocking the Radio Sky with Next-Generation Survey Astronomy”, and is a partnership between U. Toronto (lead), U. Alberta, UBC, U. Manitoba, Queen’s U., McGill U., CADC and NRAO, along with selected other international collaborators. If successful, the proposal will fund 14 staff and $3.6M of equipment over five years, through which the proposing team will derive and archive advanced data products for major new surveys with the VLA, CHIME and ASKAP. Results are expected in around June 2017.

Murchison Widefield Array

The Murchison Widefield Array (MWA) is one of three designated SKA precursors. Construction is now well advanced for MWA phase 2, which will improve the sensitivity of the array by an order of magnitude. The legal process to add the University of Toronto as a partner to MWA phase 1 is now complete, providing Canada with one seat on the MWA Board as part of a North American consortium. Bryan Gaensler has taken up this seat and is participating in Board meetings. The next step is to establish a new legal framework for MWA phase 2, in which Canada will participate in its own right rather than in partnership with the USA. The process of developing the relevant documentation has commenced.

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 skatelescope.ca/canada-and-the-ska/committees-working-groups/ for a listing of AACS membership. AACS meets several times per year, with its next meeting in June, 2017. For further information or to propose AACS agenda items, please contact the AACS Chair, Bryan Gaensler (bgaensler@dunlap.utoronto.ca).

SKA Regional Centres

In 2016, the SKA Board endorsed the concept of SKA Regional Centres (SRCs) as its preferred model for meeting and managing the challenges posed by the extremely high data rates, data volumes and data analysis requirements of SKA Phase 1. As such, the essential functions of a network of SRCs are to:

• provide access to SKA data products, subject to SKA data access policies;
• provide the computational resources for processing, including science analysis and data visualisation;
• provide a common platform for the continued development and certification of software and data analysis tools;
• provide a long-term science archive for SKA data products; and
• provide local user support to their communities.

The SKA Office has now established an SKA Regional Centre Coordination Group (SRCCG), with representation from member countries/regions interested in hosting an SRC. The responsibilities of the SRCCG include defining a minimum set of requirements for individual SRCs, developing an accreditation process for the SRCs, developing a process to ensure that software tools are interoperable across the SRC network, and investigating models for the future governance of the collaborative network of SRCs. The SRCCG began monthly meetings in September 2016; Séverin Gaudet (NRC) has been appointed as the Canadian representative.
To provide input to the SRCCG and to shape a vision for an SRC in Canada, the AACS has formed a Canadian SKA Regional Centre Advisory Committee (CSRCAC), chaired by Erik Rosolowsky (U. Alberta). CSRCAC has now established its terms of reference, and held its first meeting in February 2017. A range of initial issues have been discussed, including consultation with the local astronomical community, the need to engage with other Canadian stakeholders (CANARIE, Compute Canada, CADC, CFI), and the potential for collaboration with other countries/regions.

International SKA Lanscape

The SKA Board (for which Greg Fahlman and Bryan Gaensler are the two Canadian directors) met most recently in July 2016 and November 2016; both meetings were held at SKA HQ at Jodrell Bank, UK). A meeting of the SKA Members (at which Greg Fahlman represented NRC) took place via videoconference in December 2016. The SKA Board’s Executive Committee (of which Bryan Gaensler is a member) meets monthly.

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

• A decision to undertake a review of the existing SKA design and to explore and capitalise on a range of cost-saving measures, in order to ensure the delivery of SKA1 against the defined cost cap of €674M (2016 Euros). This includes drawing on cost reduction options already identified and further exploiting potential cost-saving and risk-reduction technology developments and solutions provided by SKA precursor and pathfinder facilities. This work is being performed under the guidance of a Cost Update Subcommittee (CUS) of the Board, comprising all SKA Board Science Directors. The CUS aims to preserve the transformational science capabilities of SKA1, while minimising impact on the project schedule and allowing expansion of the telescopes as additional funding becomes available. The SKA Office will present preliminary recommendations on a cost update to the March 2017 Board meeting.
• Extensive ongoing discussion of a proposed budget and business plan for the SKA Organisation (SKAO) through 2019 and into the transition into an intergovernmental treaty organisation (IGO).
• Consideration of a staged construction plan for SKA1.
• Approval of the top-level principles governing SKA operations, including recognition of the advantages of appointing CSIRO and SKA South Africa as preferred bidders for the operation of the two telescope sites in Australia and South Africa, respectively.
• Receipt of a comprehensive review from the SKA Management Review Panel, and initiation of activity to implement the resulting recommendations.
• Consideration of an SKA Observatory Development Program, aimed at pursuing advanced instrumentation for future SKA upgrades.
• Discussion of the formation of a new international Phased Array Feed technology consortium.
• Ongoing overviews of the SKA Headquarters and Site Hosting agreements, and of the design and construction of the SKA Headquarters.
• Ongoing discussion of costing, scheduling, construction plans, engineering reports, operations plans, hosting agreements, and transition planning from a company limited by guarantee into an intergovernmental organisation (IGO).

The SKA Board meetings for 2017 will be in March, July and November.

Negotiations to form an IGO to replace the current SKA Organisation are ongoing. Negotiation meetings have taken place in Rome in October 2015, January 2016, April 2016, September 2016 and February 2017. Canada has not participated in these negotiations, but Gilles Joncas (ACURA) and Greg Fahlman / Sean Dougherty (NRC) have attended these meetings as observers. If the Canadian government decides not to participate in the IGO, an alternative option for Canadian astronomy is associate membership in the SKA IGO. Note that at present associate membership is a poorly understood concept, envisioned as a matter of negotiation between the IGO Council and the petitioning State.

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

By John Hutchings (NRC)
(Cassiopeia – Spring/printemps 2017)

ISRO’s Astrosat observatory is in regular operations and all instruments are working well. The UVIT telescopes, for which Canada supplied the photon-counting detectors, are performing well above spec and have no sign of degradation after 18 months in orbit. The accompanying image shows the centre of M31 in the FUV (roughly 150nm wavelength), from a program of Denis Leahy. The hot population around the nucleus, dust clouds, and young clusters in the spiral arms, are evident. Other Canadian observing programs range from X-ray binaries to star-forming galaxies, AGN, and galaxy clusters.

Refinements in drift correction and distortion corrections by CSA’s science support, Joe Postma, are producing matched images with 0.9” to 1.0” resolution in various filters, and the ability to do time analysis of fluxes. UVIT and the three X-ray instruments all observe together, allowing for multi-wavelength investigations. Canada has guaranteed 5% of observing time, and cycles will be for a full year, beginning this October. Expect a call for proposals around June. Astrosat will also be open for a quota of international proposals in future, and discussions are under way for a single TAC process. Proposal pressure from India remains high.

From/de John Hutchings
(Cassiopeia – spring/printemps 2017)

LRPIC holds discussions monthly, or more often when needed, and is active on emails to keep current with LRP developments. The group of members and observers includes the following: R. Thacker, M. Sawicki, M. Dobbs, N. Murray, R. Abraham, M. Balogh, B. McNamara, C. Wilson, C. Heinke, I. Stairs, S. Ellison, JJ Kavelaars, and J. Hutchings. This group ensures direct participation in activities of JCSA, GAC, AACS, CATAC, CASCA, and the Coalition, as well as connection with several individual LRP projects.

At present there are several issues of concern and uncertainty within the LRP, with particular implications for TMT (CATAC, potential alternatives), SKA (significant cost cap problems, treaty formation, non-treaty members, regional data centres), MSE (completion of design reviews this year, Maunakea issues and alternatives), and space astronomy (future commitments, input to government space policy, Treasury Board submissions), where WFIRST and CASTOR are currently under close scrutiny.

As noted in recent CASCA mailings, LRPIC will announce details of an open Webex meeting in April, and also a session at the CASCA meeting in Edmonton. This is an important time for Canadian astronomy and the LRPIC wishes to encourage as many people as possible to attend these discussions.

By/par Patrick Hall, MSE Management Group Member
(Cassiopeia – Spring/printemps 2017)

The MSE project continues to move ahead. The major focus of the MSE project office in the first quarter of 2017 has been to prepare for an extensive set of subsystem conceptual design reviews in Spain, Canada, Hawaii, and France in the second quarter of 2017. Components to be reviewed are the telescope structure, the enclosure, the high resolution spectrograph, the fibre transmission system, two fibre positioner system concepts, the top end assembly, and the low/moderate resolution spectrograph. A project-wide system conceptual design review and cost review will follow later in 2017.

On Maunakea, the geotechnical firm Fewell have completed drilling sample boreholes beneath CFHT to assess the structural strength of the soil; results are pending. The activity was monitored by ASM Affiliates for any archeological issues; none were found.

The MSE Science Advisory Group has been appointed. The SAG is charged with advising the MSE Project Scientist on any and all aspects of the science-related development of MSE. Its members are: Andrew Hopkins (Australia), Kim Venn and Sarah Gallagher (Canada), Zhao Gongbo and Peng Yingjie (China), Nicolas Martin and Olivier Le Fèvre (France), Brent Tully and Ken Chambers (Hawaii), Gajendra Pandey (India), and Arturo Manchado (Spain). The first charge to the SAG has been to review the MSE Science Requirements Document – available at http://mse.cfht.hawaii.edu/docs/ – and prioritize the science capabilities for first light. Their report is expected for the April 3 meeting of the Management Group.

From/de David Naylor, University of Lethbridge (naylor@uleth.ca)
and/et Doug Johnstone, NRC-Herzberg (doug.johnstone@nrc-cnrc.gc.ca)
(Cassiopeia – Spring/printemps 2017)

Overview

Image obtained from www.ir.isas.jaxa.jp/SPICA/SPICA_HP/index-en.html

SPICA is an ESA/JAXA observatory class mission that is currently under review by ESA as part of its Cosmic Vision M5 call. SPICA will provide imaging, spectroscopic and polarimetric capabilities in the 5 to 350 μm wavelength range. SPICA features a ~2.5 m class telescope cooled to a temperature less than 8 K. The combination of a new generation of ultra-sensitive detectors and effectively zero background emission from the telescope, will allow astronomers to achieve sky-limited sensitivity over this wavelength range for the first time. SPICA will, therefore, be over two orders of magnitude more sensitive than Herschel, and will cover the full wavelength range between 5 and 350 μm, including the missing octave between 28 – 55 μm, which lies outside of both the Herschel and JWST domains. Not only will SPICA be the only observatory of its era to bridge the wavelength gap between JWST and ALMA, but it will enable unique science on galaxies, star-forming molecular clouds, and protoplanetary disks. Science that will be complementary to and not accessible with ALMA alone.

Canadian Participation

Canada was a founding member of the team that proposed the SPICA/SAFARI instrument and since 2007, with support from the CSA, Prof. David Naylor has served as the Canadian SPICA co-I, charged with establishing a potential role for Canada in this mission. Since 2007, the Lethbridge team, building on its leading role in the SPIRE instrument on Herschel, has been contributing to the SAFARI instrument design and development (e.g. building a test facility, evaluating mechanisms and metrology components for use at cryogenic temperatures, developing a SAFARI instrument simulator etc.).

Ian Veenendaal, PhD student and NSERC Alexander Graham Bell scholarship recipient installing a cryogenic FTS in the test facility cryostat at the University of Lethbridge.

As a result of these efforts a unique opportunity exists for Canada to lead the development of one of the most critical components of the SAFARI instrument, the high resolution spectrometer. The design is based on a Fourier transform spectrometer (FTS; Martin-Puplett configuration), which is not only an area of academic strength, but also a recognized signature industrial technology (ABB) in Canada. If the SPICA mission is pre-selected by ESA in the M5 call (results expected in summer 2017) and Canada decides to seize the opportunity presented by the high resolution spectrometer, it will be making one of the larger contributions of the consortium to the mission, which will in turn confer a greater scientific return to Canadian scientists. Although the SAFARI consortium constitution is still under development, the Canadian science return on investment will be at least twice that of the Herschel/SPIRE (i.e., at least 2 co-Is and 10 associate scientists). With one third of the total SPICA observing time expected to be awarded to the instrument teams (guaranteed time), the return on Canada’s investment in SPICA will be significant. While Prof. Naylor represents Canada on the SPICA/SAFARI board and oversees Canada’s technical contributions to the project, it is foreseen that the second co-I would have an astronomical focus. Dr Doug Johnstone, with support from the NRC-Herzberg Astronomy and Astrophysics, has attended several consortium meetings and is currently serving in this capacity. Several other Canadian scientists have also contributed to the development of the science case for SPICA. In total 22 scientists from across Canada supported the SPICA proposal submitted to the ESA M5 call.

Key SPICA Science

SPICA as planned has three science instruments. The SMI instrument covers the 12-36 μm range with varying spectral resolution from R=50-30000. Additionally, SMI provides mid-IR imaging capabilities. The SAFARI grating spectrometer covers the range 34-230 μm at R=300 or, using the Canadian-led FTS, at R=3000-10000. Finally, an imaging polarimeter, POL, operates at 100, 200, and 350 μm. Together, these three instruments, integrated with a cold telescope, provide an extremely sensitive view of (1) the evolution of galaxies over cosmic time, (2) the formation and evolution of planetary systems (through to debris disks), and (3) the interaction between turbulence and magnetic fields in star-forming molecular clouds. Through the precise measurements of a forest of fine-structure lines and dust features, the co-evolution of AGN and galaxies will be investigated, the processes which regulate both star formation and the baryon cycle in galaxies will be explored, the composition and abundance of metals, dust, and ices over cosmic time will be delineated, and some of the earliest, most luminous galaxies in the Universe will be revealed. SPICA will provide robust gas mass estimates in the inner parts of planet-forming disks using HD and water lines, while the high spectral resolution observations will allow for measurement of the rate at which disk material is eroded due to, for example, photo-evaporation, and detailed dust features will be analysed to extract mineralogical information, including the Fe/Mg ratio in olivines and pyroxenes, in these exo-Solar systems. In between the galactic and protoplanetary disk scales, SPICA spectral maps of fine structure lines will reveal the location of shocks within star-forming molecular clouds and quantify the importance of turbulence and turbulent energy dissipation, while extremely sensitive polarimetric imaging will uncover the role of magnetic fields throughout these regions. In short, SPICA’s instrumentation and extreme sensitivity will provide the astronomical community with an entirely unique view of the mid- to far-infrared Universe.

A Brief History of SPICA and Current Mission Status

• 2007 – M-class JAXA-led mission with ESA telescope. ESA undertook a telescope design study. JAXA changed launcher which impacted telescope size.
• 2011/2012 – JAXA undertook ‘Risk Mitigation Phase’ which determined mission costs exceeded current ESA contribution. ESA partnership needed to increase.
• 2014 – joint JAXA/ESA CDF mission study. SPICA becomes an ESA-led mission, but no longer qualifies as a “mission of opportunity” must now go into competition.
• 2015 – Japan passes Mission Definition Review for SPICA.
• October 2016 – European/Japanese SPICA proposal submitted to ESA M5 call.
• February 2017 CSA provides letter of support to ESA for Canadian participation in SPICA.
• Summer 2017 – ESA selects M5 missions to move to study phase.
• Summer 2019 – ESA down selects M5 mission.
• Launch 2028?

Next Steps

If, as anticipated, ESA selects SPICA in the M5 process then CSA funding will be required for the phase A study to raise the maturity of the high resolution spectrometer to TRL 6. Funding will also be required to enable the Canadian science team to participate in SPICA science meetings and guide the development of the science program. As a founding member of the SAFARI consortium, Canada is ideally positioned to exploit this world class facility. To date Canada’s contributions have been primarily technical in nature. Once the project is selected, however, as was the case for Herschel and Planck, it is important that funding be made available to prepare to exploit the science from this mission.

Individuals with interest in SPICA are welcome to contact David Naylor or Doug Johnstone for further information and to add their names to the ‘SPICA Supporters’ mailing list. For further details on Canada’s contributions to SPICA see: research.uleth.ca/spica/

From/de Gerald Schieven
(Cassiopeia – Spring/printemps 2017)

Cycle 5 Call for Proposals

The ALMA Observatory will be issuing the Call for Cycle 5 Observing Proposals on March 21, 2017. Proposals may be submitted through the ALMA Science Portal (almascience.org). The deadline for proposals will be 15UT (11am EDT, 8am PDT) on April 20, 2017. New capabilities include a minimum of 43 antennas in the 12-m Array and 10 antennas in the 7-m Array, a full complement of receivers from Band 3 through 10, covering the full range of wavelengths available from ground-based telescopes from ~3.6 mm to 0.3 mm (84 GHz – 0.95 THz), full Stokes polarimetry at Bands 3 through 7, maximum baselines of 16 km at Bands 3 through 6, and many more. Please see the Proposer’s Guide on the ALMA Science Portal for full details.

An ALMA proposal preparation workshop will be held at the University of Toronto on March 30, hosted by ALMA Ambassador Chelsea Sharon (McMaster). For more information, consult the web page. A similar workshop was held at UBC on March 8, hosted by the Millimetre Astronomy Group from NRC Herzberg.

An ALMA Archive Preview Tool

Canadian ALMA proposers and users should be aware that while the ALMA archive does not yet have preview images of archived dataset, the Japanese Virtual Observatory has been archiving the fits files that are delivered as part of the ALMA packages to PIs. The data on the JVO site are publicly available datasets only and provide an excellent way to search public ALMA products and look at fits images of the datasets. This capability will allow you to judge whether a dataset is worth downloading from the ALMA archive itself, and the fits files may contain enough information to utilize them to help in your proposal preparation, without even downloading data from the ALMA archive itself. The ALMA FITS archive on JVO can be accessed at jvo.nao.ac.jp/portal/alma/archive.do. Searches can be done on targets, project codes or proposal titles, as well as coordinates and frequency. The ALMA archive is accessed at almascience.nrao.edu/aq/.

Call for Development Study Proposals

Have an idea for an instrument, software tool, or observing technique, that could be used to enhance the science from ALMA? Funding is available to develop such ideas. A Call for Study Proposals was issued on March 7, with a deadline of 1 May 2017 at 23:59 EDT. Up to US$200k for one year is available for general development studies, or up to US$400k for 2 years for strategic studies, i.e. those which support in-depth studies aligned with certain development priorities (see go.nrao.edu/Roadmap_for_ALMA). For full details about the call, see https://go.nrao.edu/ALMA_Cycle5_Development.

Band 3 Update

The NRC-supplied ALMA Band 3 suite of 73 receiver cartridges continues to operate reliably at the observatory site. Cartridge 12, an early production-phase cartridge, has been returned to HAA with a fault that developed in one of the low noise amplifiers (LNAs) – this is the first cartridge to be returned for repair since December 2014. The cartridge is currently in our lab and the LNA will be inspected and repaired.

HAA is working on various projects to improve the performance of the Band 3 cartridges. A solution for improving the total power stability by periodically de-fluxing the SIS mixer junctions has been developed and is being tested on one cartridge at ALMA. The hardware work to upgrade the cartridges is straightforward and can be done at the observatory.

HAA is also pursuing research into more significant upgrades to Band 3 through North American ALMA Development funding. Ongoing is a study to develop improved sideband-separating (2SB) assemblies. These offer the potential of improving a number of performance measures, such as sideband rejection and LO signal distribution. Potential future upgrade initiatives include doubling the IF bandwidth of the cartridges – in conjunction with proposed signal transport and correlator upgrades, this would provide a major boost in continuum sensitivity and permit wider spectral windows for line work.

From/de Gregg Wade, Canadian BRITE PI
(Cassiopeia – spring/printemps 2017)

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

The most recent Call for Proposals closed on 01 December 2016, and 15 new proposals for observation were evaluated.

More information about the mission is available on our website: www.brite-constellation.at. General inquiries about BRITE Constellation should be directed to the BEST Chair, Andrzej Pigulski, Univ. Wroclaw, Poland (pigulski@astro.uni.wroc.pl) or to Canadian PI Gregg Wade, RMC (wade-g@rmc.ca).

Operations

There are five operating BRITE satellites in the Constellation, collecting data on various sky fields in a coordinated programme to obtain well-sampled, long-term 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 has recently completed observations of the Auriga/Perseus field, and continues to observe the Vela/Pictoris field. The Arae/Scorpius field has recently been introduced as the new switch field.
• BRITE Lem (Poland): Lem observes with a blue filter. It has recently completed observations of the Auriga/Perseus field and continues on the Vela/Pictoris field. The next switch will be to the Sagittarius field when it comes into range in late March.
• BRITE Heweliusz: Heweliusz observes with a red filter. This satellite is observing the Carina field and potential switch fields are under investigation. One potential option is Lyra/Herculis.
• UniBRITE (Austria): UniBRITE observes with a red filter. It has completed the Orion field and continues on the Carina field. The next switch will be Sagittarius when it comes into range in late March.
• BRITE Austria (Austria): BRITE Austria observes with a blue filter. It has completed the Orion field and continues on the Vela/Puppis field. The next switch will be Sagittarius when it comes into range in late March.

The BRITE Constellation observing programme from early 2017 through mid-2018 has been planned by the BRITE Executive Science Team (BEST), and details are available on the BRITE photometry Wiki page.

Recent science results

Artist’s conception of Iota Orionis.
Credit: Danielle Futselaar

“The Most Massive Heartbeat: An In-depth Analysis of iota Orionis” (Pablo et al. 2017, MNRAS, in press): BRITE observations of iota Orionis have revealed tidal interactions between the hot components of this massive 29d period binary system. The tidal distortions of the stars lead to a unique photometric signatures known as a “Heartbeat”, due to qualitative similarities to the “normal sinus rhythm” signal of an electrocardiogram. Pablo et al. model the BRITE photometry in tandem with ground-based spectroscopy to measure the masses and radii of the components, revealing iota Ori to be the most massive known heartbeat system. In addition, they report the unprecedented discovery of multiple tidally induced oscillations in the O-type primary star, from which they empirically estimate the tidal circularization rate. This discovery was recently covered in the popular press.

Conferences, resources and social media

The 3rd BRITE Constellation Science Conference will be hosted in Canada in August 2017. The conference, entitled “New scientific and technical achievements with BRITE”, will take place at the Auberge du Lac Taureau, located 2.5h north of Montréal, from 6-10 August. The first announcement is imminent.

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

The mission Wiki includes information on past, current and future fields.

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.