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Extragalactic Source Counts at 24 Microns in the Spitzer First Look Survey

Marleau, Francine R. and Fadda, D. and Storrie-Lombardi, L. J. and Helou, G. and Makovoz, D. and Frayer, D. T. and Yan, L. and Appleton, P. N. and Armus, L. and Chapman, S. and Choi, P. I. and Fang, F. and Heinrichsen, I. and Im, M. and Lacy, M. and Shupe, D. and Soifer, B. T. and Squires, G. and Surace, J. and Teplitz, H. I. and Wilson, G. (2004) Extragalactic Source Counts at 24 Microns in the Spitzer First Look Survey. Astrophysical Journal Supplement Series, 154 (1). pp. 66-69. ISSN 0067-0049. doi:10.1086/422584.

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We present the Spitzer Multiband Imaging Photometer 24 μm source counts in the Extragalactic First Look Survey (FLS) main, verification, and European Large Area ISO Survey N1 fields. Spitzer's increased sensitivity and efficiency in large areal coverage over previous infrared telescopes, coupled with the enhanced sensitivity of the 24 μm band to sources at intermediate redshift, dramatically improve the quality and statistics of number counts in the mid-infrared. The FLS observations cover areas of 4.4, 0.26, and 0.015 deg^2, respectively, and reach 3 σ depths of 0.11, 0.08, and 0.03 mJy. The extragalactic counts derived for each survey agree remarkably well. The counts can be fitted by a super-Euclidean power law of index α = -2.9 from 0.2 to 0.9 mJy, with a flattening of the counts at fluxes fainter than 0.2 mJy. Comparison with infrared galaxy evolution models reveals a peak's displacement in the 24 μm counts. This is probably due to the detection of a new population of galaxies with redshift between 1 and 2, previously unseen in the 15 μm deep counts.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Fadda, D.0000-0002-3698-7076
Storrie-Lombardi, L. J.0000-0002-5987-5210
Helou, G.0000-0003-3367-3415
Frayer, D. T.0000-0003-1924-1122
Yan, L.0000-0003-1710-9339
Appleton, P. N.0000-0002-7607-8766
Armus, L.0000-0003-3498-2973
Im, M.0000-0002-8537-6714
Lacy, M.0000-0002-3032-1783
Shupe, D.0000-0003-4401-0430
Squires, G.0000-0002-1977-5717
Surace, J.0000-0001-7291-0087
Teplitz, H. I.0000-0002-7064-5424
Additional Information:© 2004 The American Astronomical Society. Received 2004 March 29; accepted 2004 May 13. We thank A. Noriega-Crespo for useful discussions and the referee M. Malkan for insightful comments. We are grateful to H. Dole and A. Franceschini for providing us with their model predictions. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. Support for this work was provided by NASA through an award issued by JPL/Caltech.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:galaxies: statistics — infrared: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20170327-153742897
Persistent URL:
Official Citation:Francine R. Marleau et al 2004 ApJS 154 66
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75443
Deposited By: Tony Diaz
Deposited On:27 Mar 2017 23:24
Last Modified:15 Nov 2021 16:33

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