NIRI Spectroscopy of the Extreme R-[24]$\ge$14 Red Galaxy Population
PI:
Arjun Dey
Co-I(s):
Kate Brand, Michael Brown, Vandana Desai, Emeric Le Floc'H, Buell Jannuzi, Casey Papovich, Tom Soifer, Dan Weedman
Abstract
We have recently discovered a sample of IR-luminous objects of extreme color
which may represent an early active phase in the formation of very
massive galaxies. These objects are optically extremely faint
($R\gtrsim 25$), but nevertheless bright at mid-infrared wavelengths.
Although only $<$1\% of the mid-IR
source population at bright fluxes ($F_{24\mu m}\gtrsim 0.8$mJy),
they are an increasing fraction of the source population at fainter
flux densities ($\gtrsim 10$\% at $F_{24\mu m}\approx 0.3$).
{\it Spitzer}/IRS spectra of the brightest sources (with $F_{24\mu
m} > 0.8$mJy) suggest redshifts $z\sim 2$. We propose to extend
our study of this population to fainter mid-IR flux densities
($F_{24\mu m}\approx 0.3$) currently beyond {\it Spitzer}'s reach. We
will obtain near-IR spectra of 7 of these objects
which are bright at $K$ and with $0.3 \le F_{24\mu m} < 0.8$ mJy in
order to determine their redshifts and investigate their spectral
properties. Constraints on the redshift distribution can help
determine whether or not this population is responsible for the
strong evolution observed in the mid-IR number counts.
Publications using this program's data
[data][ADS] Optical Line Diagnostics of z ~ 2 Optically Faint Ultraluminous Infrared Galaxies in the Spitzer Boötes Survey
[data][ADS] A Significant Population of Very Luminous Dust-Obscured Galaxies at Redshift z ~ 2
[data][ADS] The Star Formation Histories of z ~ 2 Dust-obscured Galaxies and Submillimeter-selected Galaxies