Claude Carignan
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Département de physique Université de Montréal
C.P. 6128, Succursale Centre-Ville Montréal, QC Canada H3C 3J7
Phone : +27 21 650 2395
Fax : +27 21 650 4547
Email: claude.carignan@umontreal.ca
Office : B-422
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Research field : Galactic kinematics and mass distribution
Description of the research project: 1. My main contribution to research in Astrophysics is the study of the mass distribution in late-type
spiral and dwarf galaxies carried out in the last twenty-five years (impact – number of citations :
Carignan & Freeman 1985 – 118 citations + 24 publications with more than 50 citations). This work
has clearly demonstrated that the contribution of dark matter to the total mass of dwarf galaxies
(∼90%) is much more important than in massive spirals (∼ 50%). Moreover, contrary to the situation
in spirals where dark matter contributes mainly in the outer parts, dark matter in dwarfs contributes
at all radii. This is clearly demonstrated for the galaxy DDO 154, now a prototype of its class
(number of citations : Carignan & Freeman 1988 –164; Carignan & Beaulieu 1989 – 182). Most of
this work was done using radio HI kinematical data.
2. The resolution reached by N-body simulations of the cosmic evolution of dark halos (NFW 1996 ; 1997)
allows one to predict the inner part of halo density profiles. In principle, these profiles could be directly
compared with the ones deduced from modeling the rotation curves. Unfortunately, the sensitivity of the
rotation curves to the exact density profile of the halos is quite low, and one must use the highest
sensitivity and the highest resolution possible to arrive at useful comparisons. Combining the high
spatial resolution of Fabry-Perot (FP) Hα data to the high sensitivity but low spatial resolution of HI
data, it is possible to show (Spano et al. 2008; Chemin et al. 2005; Côté et al. 2005; Blais-Ouellette et
al. 2004) that the simulations are predicting halo density profiles much more centrally concentrated
than what is observed.
3. In order to obtain high quality Hα kinematical data, a camera was specially developed (FaNTOmM:
Hernandez et al. 2003; Gach et al. 2002) to be able to work in photon counting mode with essentially
zero read-out noise. Using this instrument, surveys were carried out for barred spiral galaxies
(Hernandez et al. 2005), galaxies of the SINGS sample (Dicaire et al. 2008; Daigle et al. 2005) and a
sample of spirals in the Virgo Cluster (Chemin et al. 2005). Those observations were obtained at the
Observatoire du mont Mégantic (1,6m) and the Observatoire de Haute-Provence (1,93m) for the
objects requesting a large field and on the 4m-class CFHT and ESO (La Silla, Chile) for the more
distant objects. A similar FP instrument, GHαFaS, was also built for the WHT 4,3m telescope
(Carignan et al. 2008).
4. More recently, a CCD camera with zero read-out noise was developed based on an EMCCD chip
(Daigle et al. 2009; 2008; 2006; 2004). The first controller giving satisfactory results for this type of
chip (CCCP : a CCD Controller for Counting Photons), developed in collaboration with the
Laboratoire d'Astrophysique de Marseille (LAM) and the Québec company Photon etc (a spin-off of
our Laboratoire d'Astrophysique Expérimentale, LAE) was just breveted and the first one produced
sold to NASA. This also gave rise to a spin-off company called Nüvü Cameras who will
commercialize the new controller. This camera will unable to work in photon-counting mode with a
DQE > 80% (compared to 20% for FaNTOmM) and zero read-out noise with many applications in
other fields than Astrophysics. It was already chosen to equip two new instruments : the 3DNTT
(Marcelin et al. 2008) on the NTT in La Silla, Chile and the BTFi (Taylor 2010) on the SOAR
telescope, also in Chile.
5. It was always thought that dwarf spheroidal galaxies (dSph) were completely devoid of HI gas. This is
surely not true any more since our recent high sensitivity HI observations of dSphs in the Local Group
(Bouchard, Carignan & Staveley-Smith 2006) and in nearby groups (Beaulieu et al. 2006). Our first
detection was for the dwarf galaxy PHOENIX (Carignan, Demers & Côté 1991). Our calculations
showed that the gas mass measured was compatible with the mass loss rate expected from normal
giant stars, even if the galaxy was only retaining ~1% of the gas. Observations of Sculptor with the
Australia Telescope detected 20 000 solar masses of HI (Carignan et al. 1998). An interesting result
is that the HI is mainly in two clouds just outside the optical body of the dwarf. This can explain why
previous observations made with a 15' beam and centred on the galaxy could not detect any HI gas.
List of graduate students :
Member of the following committees
• | 2007-01 : Directeur-adjoint du Centre Observatoire du mont Mégantic |
• | 2007-01 : Membre du Canadian SKA Science Advisory Committee |
• | 2007-01 : Membre du conseil consultatif de HIA |
• | 2005-01 : Membre du Conseil d'Administration du télescope Canada-France-Hawaii |
• | 2003-01 to 2004-01 : Directeur de l'Observatoire du mont Mégantic |
• | 2002-01 : Membre du comité d'allocation du temps du Very Large Array |
• | 2000-01 : Membre du comité de subventions du programme FCAR-Équipes de recherche |
• | 1998-01 : Président du comité de radioastronomie de la CASCA |
• | 1998-01 : Directeur sur le Conseil de la CASCA |
• | 1997-01 : Membre du comité consultatif de HIA sur le futur de la radioastronomie |
Public outreach activities :
• 2009-06-27 : | ASTROLab du mont Mégantic (Notre-Dame-des-Bois) - Lumière sur la matière sombre |
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