Detection of a Stellar Halo in NGC 4244
Abstract
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 mu_R ~ 31 mag/arcsec^2. 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.
Cite
@article{arxiv.astro-ph/0701704,
title = {Detection of a Stellar Halo in NGC 4244},
author = {Anil Seth and Roelof De Jong and Julianne Dalcanton and the GHOSTS team},
journal= {arXiv preprint arXiv:astro-ph/0701704},
year = {2009}
}
Comments
To appear in the proceedings of IAUS 241: Stellar Populations as Building Blocks of Galaxies