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Detection of a stellar halo in NGC 4244

Published online by Cambridge University Press:  01 December 2006

A. Seth ,
R. de Jong  and
J. Dalcanton
A. Seth
Affiliation:
Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02139 email: aseth@cfa.harvard.edu
R. de Jong
Affiliation:
Space Telescope Science Institute
J. Dalcanton
Affiliation:
University of Washington
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Abstract

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We present the preliminary detection of a stellar halo in the nearby, edge-on galaxy, NGC 4244. Using data from the Hubble Space Telescope's Advanced Camera for Surveys (HST/ACS), we have examined number counts of red giant branch (RGB) stars along the minor axis of the galaxy out to 10 kpc, with a limiting surface brightness of μR ∼ 31 mag/arcsec2. At distances more than 2.5 kpc above the disk, a second stellar component is clearly visible. This component is well fit by either an exponential or a power law. The best-fit exponential scale height is similar to the scale length of the galaxy disk, suggesting that we are indeed detecting a halo component. Furthermore, the color of the RGB stars above 2.5 kpc are significantly bluer than those in the disk, suggesting a more metal-poor population. Outside the local group, this finding represents one of the first detections of a resolved stellar halo in a spiral galaxy.

Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 2 , Symposium S241: Stellar Populations as Building Blocks of Galaxies , December 2006 , pp. 523 - 524
Copyright
Copyright © International Astronomical Union 2007

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