Modèle d’évolution de galaxies pour simulations cosmologiques à grande échelle

Dr. Benoît Côté

Dr. Benoît Côté

Par/by Benoît Côté
Thèse défendue le 18 décembre 2014; Thesis defended on December 18th 2014
Département de physique, université Laval
Directeurs de thèse/thesis advisors: Hugo Martel & Laurent Drissen (U. Laval)

Résumé (English version follows)

Nous présentons un modèle semi-analytique (MSA) conçu pour être utilisé dans une simulation hydrodynamique à grande échelle comme traitement de sous-grille afin de générer l’évolution des galaxies dans un contexte cosmologique. Le but ultime de ce projet est d’étudier l’histoire de l’enrichissement chimique du milieu intergalactique (MIG) ainsi que les interactions entre les galaxies et leur environnement. À l’heure actuelle, le MSA inclut tous les ingrédients né- cessaires pour reproduire l’évolution des galaxies de faible masse et de masse intermédiaire. Cela comprend l’accrétion du halo galactique et du MIG, le refroidissement radiatif, la for- mation stellaire, l’enrichissement chimique et la production de vents galactiques propulsés par l’énergie mécanique et la radiation des étoiles massives, mais exclut l’effet d’un noyau actif galactique qui n’est important que pour les galaxies plus massives. La physique des bulles interstellaires est appliquée à chaque population d’étoiles qui se forme dans le modèle afin de relier l’activité stellaire à la production des vents galactiques propulsés par l’énergie mé- canique. Nous utilisons des modèles stellaires à jour pour générer l’évolution de chacune des populations d’étoiles en fonction de leur masse, de leur métallicité et de leur âge. Cela per- met d’inclure, dans le processus d’enrichissement, les vents stellaires des étoiles massives, les supernovae de Type II, Ib et Ic, les hypernovae, les vents stellaires des étoiles de faible masse et de masse intermédiaire sur la branche asymptotique des géantes ainsi que les supernovae de Type Ia. Avec ces ingrédients, notre modèle peut reproduire les abondances des éléments C, N, O, Na, Mg, Al, Si, S, Ca, Cr, Mn, Ni, Cu et Zn observées dans les étoiles du voisinage solaire. De manière plus générale, notre MSA peut reproduire la relation actuelle observée entre la masse stellaire des galaxies et la masse de leur halo de matière sombre. Il peut aussi reproduire la métallicité, la quantité d’hydrogène et le taux de formation stellaire spécifique observés dans les galaxies de l’Univers local en fonction de leur masse stellaire. Notre mo- dèle est également consistant avec les observations suggérant que les galaxies de faible masse sont davantage affectées par la rétroaction stellaire que les galaxies plus massives. De plus, le modèle peut reproduire les différents comportements, soit oscillatoire ou stable, observés dans l’évolution du taux de formation stellaire des galaxies. Tous ces résultats démontrent que notre MSA est suffisamment qualifié pour traiter l’évolution des galaxies de faible masse et de masse intermédiaire à l’intérieur d’une simulation cosmologique à grande échelle.


Abstract

We present a semi-analytical model (SAM) designed to be used in a large-scale hydrodynamical simulation as a sub-grid treatment in order to generate the evolution of galaxies in a cosmolog- ical context. The ultimate goal of this project is to study the chemical enrichment history of the intergalactic medium (IGM) and the interactions between galaxies and their surrounding. Presently, the SAM takes into account all the ingredients needed to compute the evolution of low- and intermediate-mass galaxies. This includes the accretion of the galactic halo and the IGM, radiative cooling, star formation, chemical enrichment, and the production of galactic outflows driven by the mechanical energy and the radiation of massive stars, but excludes the effect of an active galactic nucleus which is only important for more massive galaxies. The physics of interstellar bubbles is applied to every stellar population which forms in the model in order to link the stellar activity to the production of outflows driven by mechanical energy. We use up-to-date stellar models to generate the evolution of each stellar population as a function of their mass, metallicity, and age. This enables us to include, in the enrichment process, the stellar winds from massive stars, Type II, Ib, and Ic supernovae, hypernovae, the stellar winds from low- and intermediate-mass stars in the asymptotic giant branch, and Type Ia supernovae. With these ingredients, our model can reproduce the abundances of C, N, O, Na, Mg, Al, Si, S, Ca, Cr, Mn, Ni, Cu, and Zn observed in the stars located in the solar neigh- borhood. More generally, our SAM reproduces the current stellar-to-dark-halo mass relation observed in galaxies. It can also reproduce the metallicity, the hydrogen mass fraction, and the specific star formation rate observed in galaxies as a function of their stellar mass. Our model is also consistent with observations which suggest that low-mass galaxies are more affected by stellar feedback than higher-mass galaxies. Moreover, the model can reproduce the periodic and the stable behaviors observed in the star formation rate of galaxies. All these results show that our SAM is sufficiently qualified to treat the evolution of low- and intermediate-mass galaxies inside a large-scale cosmological simulation.

Madawaska Highlands Observatory Corp.

By Frank Roy, founder and CEO

WFT_Montage

Company Expects to Complete Financing in 2014

The company is expecting to close its financing for the facility shortly. As part of that effort, the company has launched an Initial Crowd Offering (ICO) on Optimized Capital Markets listing service.

The offering can be viewed on the Optimize Capital Markets OCMX website.

Optimize Capital Markets, our exclusive financial agent, is a Bay Street firm, leading the next generation of Investment Banking Firms through its Institutional Corporate Finance Team coupled with its Institutional Crowdfunding Marketplace. Optimize Capital Markets launched its operations in September of 2009 out of Toronto but has since expanded its operations to include Quebec, Alberta, and British Columbia. Optimize Capital Markets and its marketplace, the OCMX, connects institutional and accredited investors directly with businesses seeking financing transactions and other investment opportunities.

The company is very excited about the ICO. Reaction from investors has been extremely positive and very encouraging.

Science Partner

The company is interested in a single science partner. Up to 100 hours per year (about 10% of the available science time) would be made available to our partner. The company is looking for long term commitments. The Wide-Field-Telescope is expected to become operational Q4/2017. Partners from anywhere in the world will be considered. The partner may also be a consortium. Please contact us for more information.

Documents and eNewsletter

Distances from Major Universities in Southern Canada and the North-East USA

The proximity of 13 Canadian Universities within 600 Km is very advantageous to these institutions in terms of easy accessibility and travel convenience. This represents 55% of Canadian Universities which are members of ACURA. Queen’s and Trent Universities are a two hour drive, a day’s return trip. Four Universities [Toronto, York, McGill and Montréal] are within 3.5 hours travel. McMaster and Waterloo are within 4.5 hours and Western and Sherbrooke are within 6 hours. Université Laval in Québec City is seven hours away.

The Universities of Ottawa and Carleton are within 120 Km. They currently offer introductory courses in astronomy and astrophysics. We expect that with the proximity of a nearby major astronomical observatory they may want to offer more advanced courses and degrees.

The facility is also within 8 hours of twenty-eight US universities. We expect strong interest from these institutions due to their proximity.

The X-ray View of Galaxies in Compact Groups and the Coma Cluster Infall Region

By/par Tyler D. Desjardins
Thesis defended on July 30th 2014; Thèse défendue le 30 juillet 2014
University of Western Ontario
Thesis advisor/directrice de thèse: Sarah C. Gallagher

Abstract

In this thesis, we have explored what information may be gleaned from X-ray observations of galaxies in dense environments. We use X-ray observations from XMM-Newton and the Chandra X-ray Observatory, and multi-wavelength ancillary data, to investigate the X-ray emission of galaxies. First, we study the distribution and properties of the intragroup diffuse X-ray emission in compact groups (CGs) of galaxies. From a sample of 19 CGs, we find the morphology of hot gas in low-mass groups is varied, and most systems have hot gas (if any) associated with only individual members. The galaxy-linked hot gas is coupled with high star formation rates (SFRs), while only CGs with high baryonic masses have substantial hot gas linked to the group environment. It is high-mass CGs that also agree well with the observed scaling relations between diffuse X-ray luminosity (LX), gas temperature, and velocity dispersion predicted and observed in galaxy clusters, indicating that the hot gas in only massive CGs is virialized. We also investigate the relations between LX, SFR, and stellar mass from individual members of CGs and the infall region of the nearby Coma galaxy cluster, which is the only environment that has a mid-infrared galaxy color distribution similar to CGs. The Coma galaxies agree with the scaling relations between LX, SFR, and stellar mass from the literature within uncertainties, while the CG members often show an X-ray excess. We also used our multi-wavelength observations to identify active galaxies in the Coma infall sample and find that the fraction of active galaxies is similar to the CG environment. From our observations of the diffuse X-ray emission in CGs, we find it unlikely that the intragroup hot gas is responsible for the rapid transformation of galaxies from star-forming to quiescent. While the fraction of nuclear activity in Coma infall and CG galaxies is similar, which may reflect the influence of multi-galaxy gravitational interactions, the X-ray emission from individual galaxies in the two environments is also markedly different.

Nouvelles du CNRC Herzberg

Par Dennis Crabtree, Directeur de l’Observatoire fédéral d’astrophysique (par intérim) & Directeur du programme d’astronomie optique (par intérim)
avec des contributions par Alan McConnachie, James Hesser, Gary Hovey, Gordon Lacy, Kei Szeto

Les rubriques qui suivent reviendront dans chaque numéro et ont pour but de tenir les astronomes canadiens au courant des activités de CNRC Herzberg.

Les commentaires des astronomes sur la manière dont CNRC Herzberg accomplit sa mission, c’est-à-dire « assurer le fonctionnement et la gestion des observatoires astronomiques mis sur pied ou exploités par l’État canadien » (Loi sur le Conseil national de recherches), sont les bienvenus.

Intrusion informatique au CNRC

Le 29 juillet, le CNRC révélait avoir détecté puis confirmé une intrusion informatique dans son infrastructure de TI. Des mesures ont été adoptées sur-le-champ pour protéger les données du CNRC et celles de ses clients et intervenants par l’isolement des actifs informationnels et l’arrêt des serveurs, dont plusieurs de CNRC Herzberg renfermant des données confidentielles.

Grâce à quelques solutions de rechange majeures, nous avons cependant réussi à maintenir la majorité de nos services. Selon les estimations, les activités de CNRC Herzberg devraient revenir à la normale vers la mi-octobre.

Reprise des activités de vulgarisation à l’OFA

Les démarches amorcées par la collectivité à l’été 2013 ont finalement porté des fruits. Les groupes concernés, alarmés par la conclusion du programme de vulgarisation mis en place au Centre de l’Univers, sur la colline de l’observatoire, ont coopéré avec le CNRC pour qu’une partie des activités soit restaurée durant l’été 2014. Le mouvement s’est enclenché avec les pétitions en ligne organisées par Don Moffatt (interprète à l’OFA dans les années 1990) et Lana Popham, députée de la circonscription dans laquelle se trouve l’observatoire. En novembre 2013, la députée Popham a rassemblé les représentants de la communauté à l’OFA pour une réunion cruciale à laquelle assistaient Dan Wayner, vice-président du CNRC, Greg Fahlman et Jim Hesser. L’ambiance s’est avérée propice à un débat constructif avec la direction de l’observatoire et du CNRC, si bien que les discussions ont débouché sur deux projets pilotes qui ont remporté un vif succès et permis la réintroduction d’activités pédagogiques en astronomie et de vulgarisation pour le public durant l’été 2014.

Le CNRC a mis le bâtiment qui abrite le Centre de l’Univers à la disposition du programme Science Venture (SV) de l’Université de Victoria pour la tenue de camps hebdomadaires en astronomie et en sciences spatiales à l’intention des élèves de la 3e à la 5e année (5 séances) ainsi que de la 6e à la 8e année (3 séances), en juillet et en août. Ces camps se sont ajoutés à la programmation estivale régulière du SV, sur le campus de l’université, et constituaient une audacieuse tentative en vue de mettre sur pied un programme pilote hors campus. Cent quarante-quatre places sur les 185 disponibles (78 %) ont trouvé preneur (les filles composant 24 % du total). La directrice de programme du SV, Melisa Yestrau, a déclaré : « Les parents et les campeurs n’ont pas tari d’éloges sur l’emplacement du camp et les activités au programme. »

Les membres de la SRAC installent leurs télescopes pour la population à la dernière séance d’observations publique de 2014 (6 septembre). (Photo : J. Hesser)

RASC members setting up their personal telescopes for public view on the last public observing session for 2014 (6 September). (Photo: J. Hesser)

Parallèlement, le CNRC a conclu une entente pilote avec le Victoria Centre de la Société royale d’astronomie du Canada afin qu’il assume la responsabilité des soirées d’observation publiques durant sept samedis, entre juillet et le début de septembre. La SRAC a totalement pris en charge la programmation et assuré l’interaction avec la population, le CNRC mettant des commissaires à sa disposition pour veiller à la sécurité générale sur les lieux et surveiller l’accès à ceux-ci, ainsi qu’un opérateur chevronné du télescope Plaskett. Le CNRC a aussi appris à quatre membres de la SRAC à utiliser le télescope en toute sécurité. Des bénévoles de la SRAC ont apporté leurs propres télescopes pour les observations nocturnes et servi de guides pour la visite de la coupole. Deux mille deux cent deux personnes ont saisi l’occasion et affiché un enthousiasme communicatif pour l’activité. Don Moffatt et Lana Popham ont apporté leur soutien pendant tout l’été. De plus, Don a obtenu de la flûtiste Martina Peladeau et du guitariste Ian Bezpalko qu’ils enchantent le public de leurs prestations sous la coupole du télescope Plaskett en début de soirée, plus de la moitié des samedis prévus.

Nous tirerons des enseignements de ces activités et verrons ce sur quoi ils débouchent en 2015, mais, face au succès remporté cette année, l’engouement des deux groupes de la communauté est déjà apparent et on souhaite persévérer dans cette voie.

Antenne parabolique de vérification de 15 m (DVA1)

L’antenne parabolique de vérification n° 1 du CNRC pour le SKA

L’antenne parabolique de vérification n° 1 du CNRC pour le SKA

Le CNRC a commencé à tester son antenne parabolique de vérification de 15 m (DVA1), prototype novateur destiné au Réseau d’un kilomètre carré (SKA). Cette antenne est optimisée pour une production industrielle, à faible coût, mais à rendement élevé – des exigences primordiales pour les antennes du SKA. L’antenne offset grégorienne a été mise au point en collaboration avec le Technology Development Program des États-Unis (US-TDP). Une de ses principales innovations est que les réflecteurs primaire et secondaire, soutenus en périphérie, sont des monocoques en composites et fibres de carbone conçues à l’Observatoire fédéral de radio-astrophysique du CNRC, près de Penticton. Ces réflecteurs d’une seule pièce sont moulés avec précision par infusion sous vide, processus qui donne un réflecteur précis qu’on peut fabriquer industriellement à un coût modique.

Les deux réflecteurs ont été mesurés et leurs dimensions respectent la taille idéale à 0,89 mm (réflecteur primaire) et 0,2 mm (réflecteur secondaire) près. En perfectionnant les moules, l’équipe du CNRC a montré qu’il est possible de couper ces erreurs de moitié, de manière à obtenir des réflecteurs qui fonctionneront à 20+ GHz et auront une stabilité à toute épreuve, peu importe la température, le vent et la charge, comparativement à ceux fabriqués de la manière usuelle.

Première observation du Soleil @ 11,75-13,25 GHz

Première observation du Soleil @ 11,75-13,25 GHz

Les essais sur la DVA1 vont bon train. La première observation du Soleil dans la bande Ku a été réalisée au début d’août et les relevés pour l’holographie, le pointage et la température de l’antenne devraient s’achever cet automne.

Exploreur spectroscopique du Mauna Kea (MSE)

Le MSE (appelé auparavant ngCFHT) avance rondement et est maintenant entré dans la phase de construction, qui durera environ 3 ans et demi. Cette phase est pilotée par le tout nouveau Bureau de projet. Voici les principaux progrès réalisés au cours des derniers mois.

  • Constitution d’une équipe scientifique actuellement composée d’une soixantaine de membres, dont dix du Canada. En font aussi partie des personnes de l’Australie, de Chine, de France, d’Hawaï, d’Inde, du Japon, des États-Unis continentaux et d’autres pays. Les équipes scientifiques se sont mises au travail en août et des livres blancs ont été sollicités en vue d’alimenter les activités scientifiques.
  • Formation d’une direction scientifique avec des chercheurs d’Australie (Andrew Hopkins), du Canada (Michael Balogh), de France (Nicolas Martin) et d’Inde (Gajendra Pandey) comme contacts, auxquels s’ajouteront bientôt des représentants d’autres pays partenaires. Le groupe dirigera l’équipe scientifique en collaboration avec Alan McConnachie, scientifique responsable du projet.
  • Classement du MSE dans la tranche des projets de développement les plus prioritaires de l’ébauche de la nouvelle Prospective quinquennale de France (grosso modo, l’équivalent du plan à long terme français). Le MSE et le TCFH continuent de s’impliquer dans l’élaboration de la Prospective.
  • Mise en place d’une grande partie de l’infrastructure de base requise pour faire fonctionner le Bureau de projet, dont le siège se situe à Waimea.
  • Analyse des difficultés et des possibilités liées aux permis pour le MSE dans le contexte du Plan général d’aménagement du Mauna Kea.
  • Visites et discussions importantes avec nos collègues de Chine, de République de Corée, de Taïwan et du Japon en prévision d’un partenariat éventuel dans le développement futur du TCFH et du MSE, ainsi que préparation d’une visite en Inde cet automne.

N’hésitez pas à communiquer avec les personnes mentionnées ci-dessous si vous avez la moindre question au sujet du projet MSE.

  • Scientifique responsable du projet MSE (Alan McConnachie; mcconnachie@mse.cfht.hawaii.edu),
  • Gestionnaire de projet (Rick Murowinski; murowinski@mse.cfht.hawaii.edu)
  • Directeur exécutif du TCFH (Doug Simons; simons@cfht.hawaii.edu)

Visitez le site Web du MSE à mse.cfht.hawaii.edu pour en savoir plus et connaître les dernières nouvelles.

NFIRAOS

L’équipe du NFIRAOS n’a pas chômé ces derniers mois afin d’inciter l’industrie canadienne à amener les sous-systèmes optomécaniques du NFIRAOS au stade du concept final, à temps pour la révision prévue à la fin de 2016. Les entreprises canadiennes construiront (fabriqueront, assembleront et testeront) éventuellement ces sous-systèmes puis les livreront à CNRC Herzberg pour qu’il les intègre avant leur remise à l’observatoire du TMT.

Voici la liste prévue des sous-systèmes confiés en sous-traitance pour le NFIRAOS en 2014 et 2015.

  1. Miroirs à paraboloïdes hors axe (OAP) et leurs supports – on a besoin de six unités au total.
  2. Changeur de diviseur de faisceau (DF) avec diviseurs de faisceau scientifique et technique, diviseur de faisceau pour la partie visible du spectre et leurs supports – le DF scientifique sépare les ondes infrarouges, employées pour la science, de la lumière visible saisie par le capteur à front d’onde (WFS) et les relaie aux instruments clients. Le DF de la lumière visible sépare les ondes captées par le WFS en trajet des étoiles guides laser (LGS) et trajet naturel de la lumière visible dans le WFS pour la détection du front d’onde des étoiles guides naturelles (NGS). Le changeur de DF assure la permutation avec le DF technique pour faciliter l’assemblage et l’intégration du NFIRAOS.
  3. Miroir de renvoi aux instruments (ISM), support et système de rotation – l’ISM réfléchit la lumière infrarouge scientifique vers les instruments clients qu’elle alimente. Le système de rotation dirige la lumière vers les ports des instruments situés au sommet, sur les côtés et au bas du NFIRAOS.
  4. Montage des simulateurs de source – il groupe les éléments qui produiront la lumière artificielle pour les NGS, les LGS et l’étalonnage astrométrique. Les composants optomécaniques comprennent un masque à sténopés juxtaposés, un miroir de renvoi pouvant être déployé pour les sources des NGS, un chariot pour les sources des LGS, la structure générale de soutien et l’équipement employé pour contrôler les déplacements.
  5. Banc du trajet des LGS – il comprend les éléments d’optique, leurs supports et les dispositifs optomécaniques du trombone, des miroirs de relais, des diaphragmes de champ, des collimateurs et des six barillets optiques servant d’interface aux détecteurs fournis par le TMT, ainsi que la structure générale de soutien du banc de trajet et l’équipement connexe employé pour contrôler les déplacements.
  6. Banc du VNW – il comprend les éléments d’optique, leurs supports et les dispositifs optomécaniques pour l’ensemble des miroirs de renvoi, l’unité de sélection des étoiles, le compensateur de dispersion atmosphérique, le diaphragme de champ, les miroirs à orientation rapide, le bloc de commutation ainsi que le barillet optique des NGS servant d’interface au détecteur fourni par le TMT, le capteur du front d’onde véritable (TWFS), la structure générale de soutien du banc du VNW et l’équipement connexe employé pour contrôler les déplacements.
  7. Montage du capteur de front d’onde à haute résolution (HRWFS) et de l’appareil photo d’acquisition (ACQ) – il comprend les éléments d’optique, les supports et les dispositifs optomécaniques permettant la saisie du front d’onde à haute résolution, l’imagerie à basse et à haute résolution avec le détecteur commun pour la totalité du champ de vision du NFIRAOS et l’équipement connexe employé pour contrôler les déplacements; il comprend aussi la structure générale de soutien qui servira à monter le HRWFS et l’ACQ sur le port latéral.
  8. Générateur de turbulences – il comprend les éléments d’optique, les supports et les dispositifs optomécaniques qui permettront de déployer les écrans de phase pour les turbulences et de passer d’une position à l’autre, la structure générale de soutien et l’équipement connexe employé pour contrôler les déplacements.

La figure ci-dessous illustre les sous-systèmes optomécaniques décrits ci-dessus. La conception coûtera globalement 1,7 million de dollars pour les huit projets, le montant de chacun variant de 90 000 $ à 300 000 $, selon sa complexité. La construction quant à elle coûtera au total 8,5 millions, soit de 300 000 $ à 3 millions de dollars, toujours selon la complexité du travail.

image005

Sous-systèmes optomécaniques du NFIRAOS

Sous-systèmes optomécaniques du NFIRAOS

Chaque contrat comporte au moins deux étapes : la conception et la construction, la seconde faisant l’objet d’un marché à prix fixe exécutoire une fois la conception définitive du sous-système achevée. Une réunion d’information publique, le 28 août, portait sur notre plan d’affermage et avait pour but de recueillir les commentaires des fournisseurs éventuels. Six entreprises y assistaient.

Réflecteurs du Meerkat

CNRC Herzberg a conclu un marché avec General Dynamics Satcom (GD Satcom) en vue de la fabrication de deux réflecteurs secondaires de 4 m de diamètre. Nous devrions transférer notre technologie à l’entreprise pour qu’elle fabrique les soixante-deux réflecteurs restants. Les deux premiers réflecteurs ont été construits à Penticton et livrés avant la fin de l’exercice financier de 2013-2014. Ils avaient été faits à partir d’un bloc unique de fibres de carbone infusées sous vide. L’écart-type pour la surface était de 0,1 mm dans les deux cas, ce qui est nettement en dessous de la spécification technique (é.-t. de 0,245 mm). Ces réflecteurs constituent une solution de rechange très simple et très légère (<100 kg) à la méthode de fabrication classique, qui fait appel à de nombreux éléments métalliques (le moule leur donne la forme requise, si bien qu’aucun ajustement supplémentaire n’est nécessaire). Leur masse plus faible signifie que la structure de soutien pourra être encore plus allégée et que leur manutention s’en trouvera elle aussi facilitée. La phase suivante nécessitera un voyage à Johannesburg, en Afrique du Sud, afin de former une équipe locale qui fabriquera les unités restantes.

Chemical Abundances of Local Group Globular Clusters

By/par Charli Sakari
Thesis defended on July 31st 2014; Thèse défendue le 31 juillet 2014
University of Victoria
Thesis advisor/directrice de thèse: Kim Venn

Abstract

Detailed chemical abundances of globular clusters in the Milky Way and M31 (the Andromeda Galaxy) are presented based on analyses of high resolution spectra. The unusual Milky Way cluster Palomar 1 (Pal 1) is studied through spectra of individual red giant branch stars; these abundances show that Pal 1 is not a classical globular cluster, and may have been accreted from a dwarf satellite of the Milky Way. The Milky Way globular clusters 47 Tuc, M3, M13, NGC 7006, and M15 are studied through their integrated light (i.e. a single spectrum is obtained for each cluster) in order to test high resolution integrated light analyses. The integrated abundances from these clusters reproduce the average abundances from individual stellar analyses for elements that do not vary within a cluster (e.g. Fe, Ca, and Ni). For elements that do vary within the clusters (e.g. Na and Mg) the integrated abundances fall within the observed ranges from individual stars. Certain abundance ratios are found to be extremely sensitive to uncertainties in the underlying stellar populations, such as input models, empirical relations to determine atmospheric parameters, interloping field stars, etc., while others (such as [Ca I/Fe I]) are largely insensitive to these effects. With these constraints on the accuracy and precision of high resolution integrated light analyses, detailed abundances are obtained for seven clusters in the outer halo of M31 that were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS) and are likely to have originated in dwarf galaxy satellites. Three clusters are relatively metal rich ([Fe/H] > -1.5) for their locations in the outer halo; their chemical abundances suggest that they likely originated in one or more fairly massive dwarf satellites. The other four are more metal-poor, and may have originated in less massive dwarf satellites. These results indicate that the Milky Way and M31 have both experienced some amount of accretion from dwarf satellites, though M31 may have had a more active accretion history.

Message from the CASCA president

By Chris Wilson, CASCA president

Hi, everyone,

The start of term is upon us, with all the work that entails, and so this will be just a short report to update you on some of the things that have been going on over the last three months. More information on many of these topics is available elsewhere in this newletter or in the society web pages.

First, I would like to welcome Joanne Rosvick and Magdalen Normandeau as our new Cassiopeia editors! I am very grateful to them for taking this on and I look forward to working with them.

The Mid Term Review (MTR) is now underway with the solicitation of White Papers in preparation for the town hall meetings that will occur early in 2015. The panel has already requested a number of reports from CASCA committees and individuals involved in proposed or established facilities and missions. But any member of the community is welcome to submit a white paper. Length will be as in the LRP – 4 pages text maximum. Up to 5 additional figures allowed. Deadline for submissions is 28 November 2014. Please see the MTR part of the CASCA web site for more details.

Lobbying efforts for the Thirty Meter Telescope (TMT) are well underway. A thoughtful article by Ivan Semeniuk on the TMT appeared in the Globe & Mail in late July and generated additional media coverage. A number of CASCA members wrote letters to their MPs and to Minister Ed Holder, under whose department the TMT falls, and many or all of us received replies from the Minister’s office in August. Individual CASCA members have also been busy meeting with their university Presidents and/or Vice-Presidents research to update them on the TMT issue and I can report that the TMT was discussed at the U15 meeting of university presidents in August. Also in August, the Coalition for Canadian Astronomy made a Pre-Budget Submission on the TMT to the House of Commons Standing Committee on Finance. I think it is safe to say that TMT as a project and an issue is now quite well-known both within the government and in the universities. We are continuing to raise the issue of TMT with the government this fall. Ultimately, though, we will only know whether or not we are successful in getting funding for TMT when the 2015 federal budget is announced. In the meantime, keep an eye out for the TMT Ground-Breaking ceremony which will happen on October 7 and is supposed to have a live-stream which we hope to link to the CASCA web site.

The Long Range Plan Implementation Committee is continuing its monitoring of the broad suite of activities underway in our community. The Canadian CCAT construction proposal will meet with an expert CFI panel on September 29. A complication to the Canadian effort was the failure of NSF to provide partial funding for CCAT through its recent MSIP program. However, the CCAT team continues to be hopeful that new partners will join the telescope to allow its construction in a timely manner. There is an update on progress with the Maunakea Spectroscopic Explorer elsewhere in this issue and so I will not say anything more about that here. The ACURA Advisory Committee on the SKA has a new chair (Bryan Gaensler) and is being expanded to nine members in anticipation of accelerated developments with that project over the next couple of years.

In the wider world, the International Astronomical Union (IAU) has started on an ambitious program to reform its Commission structure with a deadline of October 15, 2014. Also, the deadline for proposing for an IAU Symposium for 2016 is now October 31, 2014.

And last but not least, two of our society’s members have been honoured this past month. Harvey Richer from UBC has been elected as a Fellow of the Royal Society of Canada. Christian Marois from NRC Herzberg has been elected to the College of New Scholars of the Royal Society of Canada. Congratulations to both Harvey and Christian on a well-deserved award.

ACURA News

By Ernie Seaquist, ACURA Executive Director

Introduction

This is the sixth issue of the semi-annual newsletter for E-Cass readers. The intention is to keep the community up to date on the activity of ACURA. ACURA is the Association of Canadian Universities for Research in Astronomy, with a membership of 20 universities. ACURA exists to promote the interests of Canadian university astronomers, including the highest priority LRP projects requiring funding by the Federal Government. The current projects of interest to ACURA are the TMT and the SKA. ACURA also maintains an active role in advancing the interests of its member institutions in the governance of federally supported astronomy, currently undertaken by NRC.

ACURA is primarily concerned with the promotion of its two highest priorities – the Thirty Meter Telescope (TMT) and the Square Kilometre Array (SKA) following the ground based priorities for world observatories in the LRP. In the past few months it has also discussed with NRC and CFI the complex issue of sources of operational support for astronomy national facilities which by parliamentary mandate fall under NRC’s responsibility. More on these issues below.

Activity on the Thirty Meter Telescope (TMT)

On July 28, 2014 the TMT partnership, now incorporated as the TMT International Observatory (TIO), announced the formal start of construction on the Mauna Kea site, following final approvals on the site sublease by the University of Hawaii and the state. This was accompanied by a press release issued by the TMT and an article in the Globe and Mail here in Canada. There will be a Ground-Breaking (GB) ceremony at the site on October 7, followed by a reception at Waikoloa attended by many invitees across the international TMT community.

The TMT partners (now designated as Members) signed onto the project are now China, Japan, Caltech and UC, with India expected to join at about the time this letter reaches press. The Government of Canada has not yet announced a decision on whether Canada will be a Member. In the interim Canadian interests in TMT are represented by ACURA’s status as an Associate Member respecting its past contributions, signifying its intent for Canada to become a Member, and its agreement to continue with in-kind contributions to TMT. These contributions will be provided to TMT by NRC Herzberg through an agreement between ACURA and NRC. Associate Members are present at Board meetings but have no vote. The Associate Member status is in place for one year (until Spring 2015) at which point TIO, in light of the (anticipated) decision by Canada, will undertake a second decision whether to proceed with construction. This decision may be influenced by whether Canada joins, and permits existing Members to withdraw at this stage without financial penalty should they decide to do so. India and NSF (through AURA) are also Associate Members because of their existing contributions and expectations to participate. As an Associate Member, Canada will have representation at the GB ceremonies, mainly through ACURA. NRC will also be represented by a member of its senior administration, respecting NRC’s current and past contributions to TMT.

Meanwhile ACURA and its Coalition partners (CASCA and Industry) have continued their activity in support of joining TMT. On the ACURA side, the focus is on promoting support from the presidents of ACURA universities, and on meetings with Industry Canada and the Department of Finance. We have also made, together with the Coalition, a pre-budget submission to the House Committee on Finance on August 6, detailing the funding needed for Canada to join the project.

Throughout the Coalition interactions with government on TMT we have been advised to consider use of the forthcoming Canada First Research Excellence Fund (CFREF) recently announced by the Federal Government. This fund, to be used for supporting excellence in research within the universities beginning early next year, will ramp up slowly ($50M in the first year) and will total $1.5B over 10 years. However, ACURA, following advice from some of its member institutions, considers it premature to plan the use of this fund for TMT until we understand how the fund will be implemented, and until universities have had a chance to consider TMT together with their other priorities. The fund is certainly inappropriate and insufficient to cover the cost of the enclosure ($150M) needed to cover Canada’s contribution of the TMT enclosure within the first few years. Accordingly, the basic strategy will be to continue to push for the full cost ($300M over 10 years) to join in TMT.

Activity related to the Square Kilometre Array (SKA)

Activity here in the past six months has been to finalize the transformation of the Canadian SKA Consortium Board to the new ACURA Advisory Council on the SKA (AACS). As such it will be a standing committee of the ACURA Board. The ACURA Board has now approved both the terms of reference and the position of Council chair which will be Bryan Gaensler. Bryan will be arriving from Australia to take up a position as director of the Dunlap Institute at the University of Toronto in January, 2015, and will then also begin his role as Council chair. Bryan is also ACURA’s nomination to NRC for the currently vacant Canadian scientific director position on the international SKAO Board. We are fortunate to have Bryan at the helm in both SKA positions.

Funding for operating national facilities in Canadian astronomy

Recently the JCMT community raised a concern that the CFI declared an application for operational support of JCMT after withdrawal of NRC support this year as ineligible. The argument is that JCMT is a national facility and falls under the responsibility of NRC. This ruling has implications for any facility of national scale that has, or has had, support from NRC, and obviously reduces flexibility to support Canadian astronomy. Follow-up discussions by ACURA with CFI and NRC indicated that the restriction is imposed by Industry Canada, leaving the agencies with no flexibility in this area. Both CFI and NRC recognize that this “balkanization” of funding astronomy facilities is unhealthy and potentially problematic downstream for facilities that have had any connection with NRC. CHIME was raised as an example of a project that might be ineligible because it is sited at DRAO. At the last regular meeting between ACURA and NRC in May it was resolved that NRC will consider discussing this issue with all agencies, possibly by resurrecting the (currently inactive) Agency Committee on Canadian Astronomy (ACCA) this fall. The ACCA contains representatives from NRC, CFI, NSERC and CSA. ACURA intends to follow developments in this area and to continue to argue for flexibility in how national facilities are supported.

A Few Words from the Editors / Message des rédactrices en chef

PhotoForEcassHello! I’m pleased to be a part of the CASCA website team, and am looking forward to co-editing the CASCA newsletter with Magdalen. I would like to thank Brian Martin for taking care of this task for so many years, and past-president Laura Ferrarese for assisting us in our new role!

In this and future issues, you will find articles updating you on current as well as new projects in Canadian astronomy, and abstracts of recent (successfully defended) PhD dissertations. We are happy to be including these in the newsletters. Happy reading!

Joanne Rosvick

Magdalen Normandeau Bonjour membres de la CASCA! C’est avec grand plaisir que j’entreprends, en compagnie de Joanne, la rédaction du bulletin Cassiopeia. Je tiens à remercier Brian Martin qui a veillé à cette tâche pendant tant d’années.

Dans cette parution, vous trouverez les habituels et importants articles au sujet des divers projets dans lesquels la communauté canadienne est impliquée, mais en plus, vous aurez le plaisir de lire les résumés des thèses doctorales défendues depuis le solstice d’été.

Bonne lecture!

Magdalen Normandeau

JCMT Update

By Doug Johnstone, Associate Director JCMT

Countdown! September has arrived and I am now in the last month of my secondment to the Joint Astronomy Centre as Associate Director JCMT. It is hard to believe that two years have passed so very quickly, and of course, there still seems to be a great deal left to accomplish before the end of the month, including this Newsletter piece.

As usual, in this update I will describe recent events at the JCMT, including progress within the JCMT Legacy Surveys, a recap of Semester 14A, and the present status of the JCMT Science Archive. For details on the on-going efforts to transfer the JCMT to an East Asian consortium, please refer to the article in the Summer Solstice edition (June 2014) on the ‘Continuing Evolution of the JCMT’, by Gary Davis, Director of the JAC.

The showcase science programme at the JCMT remains the JCMT Legacy Survey (JLS), covering debris disks, star formation near and far within our Galaxy, nearby Galaxies, and cosmology. Over the last nine months we have managed to increase the completion fraction of the survey, from about 50% to over 75%, despite a dismal winter for sub-millimetre observing on Maunakea. All six of the SCUBA-2 legacy surveys now have a majority of their observations in hand, with the debris disk survey reaching 100% completion in August. Our recent efforts to streamline the observing process and extend observing into the morning hours through limited remote operations have clearly paid off. Of course it also helps when the nightly fault rate for the telescope drops well below 5% of clear-sky time – an impressive threshold for a twenty-seven year old telescope with complex cryogenic and superconducting instrumentation. Kudos and mahalo to the dedicated JAC staff!

We anticipate that JLS observations will be taken throughout much of the Fall as negotiations continue with the East Asian consortium, soon to be known as the East Asian Observatory (EAO), on the smooth transfer of the telescope. Looking further into the future, it is clear that large legacy surveys will be a continuing tradition at the JCMT, and Canadians are being asked to help define these priorities. A number of us will be taking part in a meeting in the UK near the end of September where new and expanded surveys for the JCMT will be developed. Christine Wilson (McMaster) continues to lead the Canadian effort for continued JCMT involvement beyond the NRC Herzberg era.

As Semester 14A nears conclusion, a bittersweet moment for Canada was reached on Thursday, August 13th with the last night of Canadian observing under NRC Herzberg management. Both JAC Director Gary Davis and I were there to mark the occasion, along with UBC graduate student Todd Mackenzie (see attached photo). Todd’s connection to the JCMT started while an undergraduate student. Working as a co-op student at NRC Herzberg with James Di Francesco and me, he helped produce SCUBA Legacy images and catalogues. Now Todd is using SCUBA-2 data as part of his PhD thesis, under the direction of Douglas Scott. Despite having to note the end of an era, I am pleased to announce that Canadian PI’s did extremely well with their share of the flexible telescope time this last semester. Six of the seven top proposals in the Canadian queue obtained at least 95% of their requested observing time. The outlier proposal was, unfortunately, a target of opportunity that simply did not trigger.

In the 2013 Winter Solstice edition I discussed the importance of the JCMT Science Archive (JSA) as part of the legacy of the JCMT. This effort, a collaboration between the JAC and the CADC at NRC Herzberg in Victoria, has been extremely active over the last year. Regular JSA users will have already noticed the simplified interface through which they now search the archive. For those daunted by this change, a helpful primer on searching the JSA is available on the JAC web-page (follow the link from the JCMT landing page at the CADC). Further JSA effort includes a plan for the uniform reduction and cataloguing of all public JCMT SCUBA-2 data residing in the archive. Initial pipeline processing for this effort is now underway and these legacy data products should start to become available through the archive in late Spring 2015. Together with the individual JCMT Legacy Survey team reductions, which are specially designed to pick out science-goal specific features such as point sources or extended structure, these uniformly reduced data products will provide a lasting legacy for the JAC era at the JCMT.

It feels extremely strange to be saying good-bye to the JCMT at this time. This is especially true given that I have spent the last few months working closely with the Director to help secure a long-term future for the JCMT through its transfer to EAO, espousing my admiration and respect for the telescope, its staff, and its community at every opportunity. Just last week I was in Japan at an NAOJ JCMT workshop and next week I will be in the UK to help design future legacy surveys. It is my great hope that despite my formal departure, I will continue to be intimately involved with the JCMT, both as a scientist, making use of its fantastic instrumentation, and as an advocate, providing support and constructive criticism to the new management. Long live the JCMT.

Todd Mackenzie, Doug Johnstone, and Gary Davis in the JCMT control room on the last night of Canadian observing under NRC management. (Photo Credit: T. McLaughlin)

Todd Mackenzie, Doug Johnstone, and Gary Davis in the JCMT control room on the last night of Canadian observing under NRC management. (Photo Credit: T. McLaughlin)

ALMA Update

By Chris Wilson, Canadian ALMA Project Scientist
with material from the NRAO newsletters and the ALMA web site

ALMA Current Status

ALMA construction continues to wind down. In late June, 2014, the final ALMA antenna was taken up to the high-level site 5000 meters above sea level. Its arrival completes the complement of 66 ALMA antennas on the Chajnantor Plateau in the Atacama Desert of northern Chile. Images and video of the antenna move can be found at http://www.almaobservatory.org/

The ALMA Phasing Project team, with support from the Extension and Optimization of Capabilities (EOC) Team, the ALMA Department of Engineering, and the ALMA Department of Computing, integrated the new hydrogen maser into the ALMA system. This is an important milestone toward incorporating ALMA as a Very Long Baseline Interferometry array element. Tests have shown the maser performance is excellent, and it has replaced the rubidium clock as the ALMA time standard.

The August weather at Chajnantor was very good, as is usual for the austral winter, and the high frequency campaign made good use of the resulting excellent high frequency transparency. Multiple objectives were met, including the imaging of Uranus with 29 array elements at ALMA Band 10 (350 microns, 810 GHz) by the EOC team. The EOC team also demonstrated the transfer of phase information from lower frequencies, where calibrators are brighter and more densely distributed, to higher frequencies. Simultaneous sub-arraying within the main 12 m array was demonstrated for the first time, a key goal for achieving simultaneous EOC and Early Science operations.

On September 1, 2014, the EOC Team started the Long Baseline Campaign and will continue commissioning-type observations through the end of November. This critical campaign is essential for Cycle 3 proposed capabilities and will test the calibration and imaging characteristics of ALMA out to baselines of at least 10 km. All ALMA Early Science Observations (both Cycle 2 and carryover Cycle 1 programs) have been halted until the end of the campaign. This break in Early Science observing is needed because of the time required to move antennas out to the largest configurations and the fact that once the antennas are spread out to 5-10 km, the antennas remaining nearer the center of the array are not sufficient to populate any of the Cycle 2 configurations.

ALMA Cycle 2 progress

Results of the Cycle 2 proposal review process were sent to the PI on April 9, 2014 and the full list was released May 2, 2014. A full listing of the 353 highest priority proposals is available here. More recently, a detailed report on the outcome of the ALMA Early Science Cycle 2 Proposal Review Process has become available. The report describes the proposal review process, proposal statistics and regional distributions as well as the proposal distribution across science categories and receiver bands. The report can be downloaded as a pdf document here.

Cycle 2 observing began in a higher resolution configuration, with a longest baseline of 650 m, and is planned to cycle into larger configurations as the austral winter progresses. As noted above, all ALMA Early Science Observations have been halted until the end of the long baseline campaign. Early Science observations are scheduled to resume in December 2014 in array configuration C34-3. Observations in array configuration C34-1 are expected to begin in January 2015.

PIs and Co-Investigators can consult the Project Tracker for information on the execution of an accepted project. PIs can also modify their user profile at the Science Portal to receive e-mail notifications whenever a component of a project is first observed, fully observed, or successfully processed.

Archival and Science Verification Data

All the data from Cycle 0 Early Science projects have been delivered. The data are made publicly available via the ALMA archive as the one-year proprietary period expires. A total of 109 of the 116 Cycle 0 projects are available in the ALMA Science Archive; only a few projects are still within their proprietary period. Twenty-five of the 69 North American high priority Cycle 1 projects have been fully delivered and two-thirds of the highest-ranked NA Cycle 1 projects have seen deliveries of some data.

Data for two new ALMA Science Verification targets were released on September 7, 2014. The targets are (1) the evolved star VY Cma observed in water maser lines in Bands 7 (~850 microns) and 9 (~450 microns) and demonstrating ALMA capabilities on 1-3 km baselines and (2) Comet Lemmon observed in the HCN line in Band 6 (~1.1 mm) and demonstrating Doppler tracking of ephemeris targets. All Science Verification targets are listed on the Science Verification web page and the data sets are available through the ALMA Science Portal.

ALMA software news

CASA release 4.2.2 is now available from the CASA homepage: http://casa.nrao.edu/.This is a patch release of CASA 4.2.0/4.2.1 to introduce SIGMA and WEIGHT columns defined according to channel width and integration time. The patch also adds the plotms capability to export iterated plots in multiple files. A detailed description of the CASA visibility weighting scheme can be found at http://casa.nrao.edu/Memos/CASA-data-weights.pdf. CASA, the Common Astronomy Software Applications (CASA) package, is being developed by NRAO, ESO, and NAOJ and is used for the offline reduction and analysis of both ALMA and VLA data. CASA is fully scriptable. Full support is provided for ALMA and VLA but almost any data that can be written in uvfits format can be imported and reduced in CASA (for example, CARMA, SMA, ATCA).

ALMA has begun routine data reduction using the automated pipeline. The pipeline is now the principle means of data calibration and flagging for PI projects at ALMA. Previously, all ALMA data were reduced manually by ALMA’s team of scientists around the globe. For example, for North American projects the data have been reduced by staff scientists at the North American ALMA Science Center (NAASC) at NRAO Headquarters in Charlottesville and in Victoria, Canada, and at the Joint ALMA Observatory in Santiago, Chile. This transition to pipeline processing comes at a critical time when the ALMA data rate is high and continuing to grow. The pipeline is essential to allowing the ALMA observatory to cope with the current and anticipated future data rates. The pipeline has been developed by a dedicated team of engineers and scientists (including, from 2002-2010, C. Wilson as the sub-system scientist) with the aim of being able to handle the majority of ALMA observing projects. Some non-standard modes will continue to need manual reduction. The pipeline currently handles flagging and calibration while the imaging step continues to be done manually. The imaging portion of the pipeline is still under development and testing.

ALMA Meetings

There are two workshops and one major ALMA meeting planned in the next year:

“Revolution in Astronomy with ALMA: The Third Year” will be held from December 8-11, 2014, in Tokyo, Japan. Registration is still open and the deadline for abstracts for posters and registration is October 15, 2014. The web site is http://www.almasc2014.jp/.

A NAASC workshop on “The Filamentary Structure in Molecular Clouds” is being held 10-11 October 2014 in Charlottesville Virginia. Registration is now closed but there is a waiting list. The conference web site is https://science.nrao.edu/science/meetings/2014/filamentary-structure/.

“Dissecting Galaxies Near and Far” is the subject of a workshop to be held March 23-27, 2015 in Santiago, Chile. Preliminary information is available on the conference web site, http://www.eso.org/sci/meetings/2015/Galaxies2015.html.

Information

A good source for monthly updates on the ALMA project is the electronic NRAO newsletter
http://science.nrao.edu/enews/. And don’t forget the ALMA observatory web site http://www.almaobservatory.org/ which contains wide range of information about the observatory, including details about science and technology, infrastructure, and geographical location.

An email list has been created for Canadian astronomers interested in ALMA. This moderated list will periodically send out updates on ALMA’s status, news of software releases, notices of upcoming ALMA science meetings and workshops, etc., which would be of interest to Canadian astronomers. Those who wish to be subscribe to the alma-users list are encouraged to visit the web page http://lists.astrosci.ca/mailman/listinfo/alma-users/ or send an email to Gerald.Schieven(at)nrc-cnrc.gc.ca.