Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-05-25
Astrophys.J.666:846-862,2007
Astronomy and Astrophysics
Astrophysics
18 pages, 15 figures. Accepted for publication in ApJ. Typos corrected and minor updates to Table 4/Fig.15 to match proofed ve
Scientific paper
10.1086/520035
We present the first results of a Spitzer IRAC (Infrared Array Camera) wide-field survey of the Coma cluster. The observations cover two fields of different galaxy densities; the first is a 0.733 deg^2 region in the core of the cluster (Coma 1), the second a 0.555 deg^2 off-center region located ~57 arcmin (1.7 Mpc) south-west from the core (Coma 3). The observations, although short 70-90 s exposures, are very sensitive; we detect ~29,200 sources at 3.6 micron over the total ~1.3 deg^2 survey area. We construct 3.6 micron galaxy luminosity functions (LFs) for each field using selection functions based on spectroscopic redshifts. At the bright end, the LFs are well modeled by a traditional Schechter function; [M^star (3.6 micron), alpha_1] = [-25.17, -1.18] and [-24.69, -1.30] for Coma 1 and Coma 3 respectively. However, at the faint end (M(3.6 micron) > -20.5), there is a steep increase in the LF slope in both fields indicative of large numbers of red dwarf galaxies. The reality of this population is examined using optical counterparts in SDSS data with optical color filtering (g-r<1.3). The steep increase can be modeled with a power-law function, with slopes of alpha_2 = -2.18 (Coma 1) and alpha_2 = -2.60 (Coma 3). A qualitative comparison with optical (B- and R-band) LFs shows that we are likely to be observing a larger population of dwarf galaxies in the near-IR, which may be a low-surface-brightness (LSB) population that IRAC is particularly sensitive to, or a population too red to be detected in existing optical surveys down to R~20.
Alexander Dave M.
Bauer Franz Erik
Hornschemeier Ann Elizabeth
Jenkins L. P.
Mobasher Bahram
No associations
LandOfFree
Uncovering the Near-IR Dwarf Galaxy Population of the Coma Cluster with Spitzer IRAC does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Uncovering the Near-IR Dwarf Galaxy Population of the Coma Cluster with Spitzer IRAC, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Uncovering the Near-IR Dwarf Galaxy Population of the Coma Cluster with Spitzer IRAC will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-679428