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Spitzer 24micron Observations of Optical/Near-IR Selected Extremely Red Galaxies: Evidence for Assembly of Massive Galaxies at z approximately 1 - 2?We carried out the direct measurement of the fraction of dusty sources in a sample of extremely red galaxies with (R-K(sub s)) greater than or equal to 5.3 mag and K(sub s) less than 20.2 mag, using from the Spitzer Space Telescope. Combining deep 24 micrometers, K(sub s)- and R-band data over an area of approximately 64 sq.arcmin in the ELAIS N1 field of the Spitzer First Look Survey (FLS), we find that 50 +/- 60% of our ERO sample have measurable 24 micrometer flux above the 3(sigma) flux limit of 40 microns Jy. This flux limit corresponds to a SFR of 12 solar mass/yr at z approximately 1, much mo previous long wavelength measurement. The 24fJ,m-detected EROs have 24-to2.2 and 24-to-0.7micrometr flux ratios consistent with infrared luminous, dusty sources at z approx. 1, and an order of magnitude too red to be explained by an infrared quiescent spiral or a pure old stellar population at any redshift. Some of these 24 micrometer-detected EROs could be AGN, however, the fraction among the whole ERO sample is probably small, 10-20%, as suggested by deep X-ray observations as well as optical spectroscopy. Keck optical spectroscopy of a sample of similarly selected EROs in the FLS field suggests that most of the EROs in ELAIS Nl are probably at z approx. 1.
Document ID
20090007576
Acquisition Source
Jet Propulsion Laboratory
Document Type
Preprint (Draft being sent to journal)
External Source(s)
Authors
Yan, Lin
(California Inst. of Tech. Pasadena, CA, United States)
Choi, Philip I.
(California Inst. of Tech. Pasadena, CA, United States)
Fadda, D.
(California Inst. of Tech. Pasadena, CA, United States)
Marleau, F. R.
(California Inst. of Tech. Pasadena, CA, United States)
Soifer, B. T.
(California Inst. of Tech. Pasadena, CA, United States)
Im, M.
(Seoul National Univ. Korea, Republic of)
Armus, L.
(California Inst. of Tech. Pasadena, CA, United States)
Frayer, D. T.
(California Inst. of Tech. Pasadena, CA, United States)
Storrie-Lombardi, L. J.
(California Inst. of Tech. Pasadena, CA, United States)
Thompson, D. J.
(Caltech Optical Observatories Pasadena, CA, United States)
Teplitz, H. I.
(California Inst. of Tech. Pasadena, CA, United States)
Helou, G.
(California Inst. of Tech. Pasadena, CA, United States)
Appleton, P. N.
(California Inst. of Tech. Pasadena, CA, United States)
Chapman, S.
(Caltech Optical Observatories Pasadena, CA, United States)
Fan, F.
(California Inst. of Tech. Pasadena, CA, United States)
Heinrichsen, I.
(California Inst. of Tech. Pasadena, CA, United States)
Lacy, M.
(California Inst. of Tech. Pasadena, CA, United States)
Shupe, D. L
(California Inst. of Tech. Pasadena, CA, United States)
Squires, G. K.
(California Inst. of Tech. Pasadena, CA, United States)
Surace, J.
(California Inst. of Tech. Pasadena, CA, United States)
G., Wilson
(California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 24, 2013
Publication Date
September 27, 2004
Subject Category
Astronomy
Meeting Information
Meeting: Space Telescope Science Institute (STSCI) Mini Workshop Massive Galaxies over Cosmic Time
Location: Baltimore, MD
Country: United States
Start Date: September 27, 2004
End Date: September 29, 2004
Funding Number(s)
CONTRACT_GRANT: NASA-1407
Distribution Limits
Public
Copyright
Other
Keywords
galaxy evolution
galaxies
starbursts
infrared luminous
high-redshifts

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