The M33 globular cluster system with PAndAS data: the last outer halo cluster?

From National Research Council Canada

DOI	Resolve DOI: https://doi.org/10.1088/0004-637X/730/2/112
Author	Search for: Cockcroft, Robert; Search for: Harris, William E.; Search for: Ferguson, Annette M. N.; Search for: Huxor, Avon; Search for: Ibata, Rodrigo; Search for: Irwin, Mike J.; Search for: McConnachie, Alan W.¹; Search for: Woodley, Kristin A.; Search for: Chapman, Scott C.; Search for: Lewis, Geraint F.; Search for: Puzia, Thomas H.
Affiliation	National Research Council of Canada. NRC Herzberg Institute of Astrophysics
Format	Text, Article
Subject	galaxies: evolution; galaxies: halos; galaxies: individual (M33); galaxies: spiral; galaxies: star clusters: general; local group
Abstract	We use CFHT/MegaCam data to search for outer halo star clusters in M33 as part of the Pan-Andromeda Archaeological Survey. This work extends previous studies out to a projected radius of 50 kpc and covers over 40 deg(2). We find only one new unambiguous star cluster in addition to the five previously known in the M33 outer halo (10 kpc <= r <= 50 kpc). Although we identify 2440 cluster candidates of various degrees of confidence from our objective image search procedure, almost all of these are likely background contaminants, mostly faint unresolved galaxies. We measure the luminosity, color, and structural parameters of the new cluster in addition to the five previously known outer halo clusters. At a projected radius of 22 kpc, the new cluster is slightly smaller, fainter, and redder than all but one of the other outer halo clusters, and has g' approximate to 19.9, (g' - i') approximate to 0.6, concentration parameter c approximate to 1.0, a core radius r(c) approximate to 3.5 pc, and a half-light radius r(h) approximate to 5.5 pc. For M33 to have so few outer halo clusters compared to M31 suggests either tidal stripping of M33' s outer halo clusters by M31, or a very different, much calmer accretion history of M33.
Publication date	2011-03-10
Publisher	American Astronomical Society IOP Publishing
In	The Astrophysical Journal 730, no. 2, 112.
Language	English
Peer reviewed	Yes
NPARC number	19793789
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Record identifier	ca7a5dc5-ac7f-4380-b1ca-c3fe9170b239
Record created	2012-04-10
Record modified	2020-04-21

Date modified:: 2024-07-17