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Contribution to unresolved infrared fluctuations from dwarf galaxies at redshifts of 2-3

Chary, Ranga-Ram and Cooray, Asantha and Sullivan, Ian (2008) Contribution to unresolved infrared fluctuations from dwarf galaxies at redshifts of 2-3. Astrophysical Journal, 681 (1). pp. 53-57. ISSN 0004-637X. doi:10.1086/588576.

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In order to understand the origin of clustered anisotropies detected in Spitzer images between 3.6 and 8 μm, we stack the Spitzer IRAC/Great Observatories Origins Deep Survey (GOODS) images at pixel locations corresponding to faint, z_(AB) ~ 27 mag, optical sources with no obvious IR counterparts. We obtain a strong detection of the sources with a stacked median flux at 3.6 μm of 130 ± 5 nJy above the background. The wealth of multiwavelength imaging data in GOODS enables a similar stacking analysis to be undertaken at various wavelengths between the ultraviolet and near-infrared bands. We obtain strong stacked detections of these optically faint sources over the entire wavelength range, which places constraints on the average properties of these sources. We find that the flux spectrum of the median, stacked source is consistent with a L less than or similar to 0.03L_*, _(UV) galaxy with a 90% confidence interval for the redshift of 1.9-2.7. These sources produce a 3.6 μm absolute background intensity between 0.1 and 0.35 nW m^(−2) sr^(−1), and the clustered IR light could account for ~30%-50% of fluctuation power in the IR background at 4' angular scales. Although the exact redshift distribution of these sources is unknown, these galaxies appear to contain 5%-20% of the comoving stellar mass density at z ~ 2.5.

Item Type:Article
Related URLs:
URLURL TypeDescription
Chary, Ranga-Ram0000-0001-7583-0621
Cooray, Asantha0000-0002-3892-0190
Additional Information:© 2008 The American Astronomical Society. Received 2007 November 13, accepted for publication 2008 March 25. We thank Mark Dickinson for helpful suggestions. We also acknowledge the contributions of various members of the GOODS team, who are associated with key aspects of data processing and handling. This research was funded by NASA grant NNX 07AG43G, NSF CAREER grant AST 06-45427, award number 1310310 from Spitzer for Archival Research, and program number HST-AR-11241.01-A by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.
Group:TAPIR, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NSFAST 06-45427
Spitzer Science Center1310310
Subject Keywords:diffuse radiation: infrared; galaxies: large-scale structure of the universe
Issue or Number:1
Record Number:CaltechAUTHORS:20090618-195535830
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Official Citation:Contribution to Unresolved Infrared Fluctuations from Dwarf Galaxies at Redshifts of 2-3 Ranga-Ram Chary, Asantha Cooray, and Ian Sullivan 2008 ApJ 681 53-57 doi: 10.1086/588576
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14412
Deposited By: Joy Painter
Deposited On:27 Aug 2009 00:11
Last Modified:08 Nov 2021 23:11

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