INFRARED SPECTROGRAPH SPECTROSCOPY AND MULTI-WAVELENGTH STUDY OF LUMINOUS STAR-FORMING GALAXIES AT z {approx_equal} 1.9

Journal Article · Mon Jul 20 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/700/1/183; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21313887

Huang, J -S; Lai, K; Younger, J D; Fazio, G G ^[1]; Faber, S M; Koo, D ^[2]; Daddi, E ^[3]; Laird, E S ^[4]; Omont, A ^[5]; Wu, Y ^[6]; Bundy, K ^[7]; Cattaneo, A ^[8]; Chapman, S C ^[9]; Conselice, C J ^[10]; Dickinson, M ^[11]; Egami, E ^[12]; Im, M ^[13]; Le Floc'h, E ^[14]; Papovich, C ^[15]; Rigopoulou, D ^[16]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. University of California Observatories/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)
3. Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, DAPNIA/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex (France)
4. Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom)
5. Institut d'Astrophysique de Paris-CNRS, 98bis Boulevard Arago, F-75014 Paris (France)
6. IPAC, California Institute of Technology, 1200 E. California, Pasadena, CA 91125 (United States)
7. Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada)
8. Astrophysikalisches Institut Potsdam, an der Sternwarte 16, 14482 Potsdam (Germany)
9. Institute of Astronomy, Cambridge, CB3 0HA (United Kingdom)
10. University of Nottingham, School of Physics and Astronomy, Nottingham NG7 2RD (United Kingdom)
11. NOAO, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
12. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
13. Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of)
14. IfA, University of Hawaii, Honolulu, HI 96822 (United States)
15. George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics, Texas A and M University, College Station, TX 77843-4242 (United States)
16. Department of Astrophysics, Oxford University, Keble Road, Oxford, OX1 3RH (United Kingdom)

We analyze a sample of galaxies chosen to have F{sub 24{mu}}{sub m} > 0.5 mJy and satisfy a certain IRAC color criterion. Infrared Spectrograph (IRS) spectra yield redshifts, spectral types, and polycyclic aromatic hydrocarbons (PAH) luminosities, to which we add broadband photometry from optical through IRAC wavelengths, MIPS from 24-160 {mu}m, 1.1 mm, and radio at 1.4 GHz. Stellar population modeling and IRS spectra together demonstrate that the double criteria used to select this sample have efficiently isolated massive star-forming galaxies at z {approx} 1.9. This is the first starburst (SB)-dominated ultraluminous infrared galaxies (ULIRG) sample at high redshift with total infrared luminosity measured directly from FIR and millimeter photometry, and as such gives us the first accurate view of broadband spectral energy distributions for SB galaxies at extremely high luminosity and at all wavelengths. Similar broadband data are assembled for three other galaxy samples-local SB galaxies, local active galactic nucleus (AGN)/ULIRGs, and a second 24 {mu}m-luminous z {approx} 2 sample dominated by AGN. L{sub PAH}/L {sub IR} for the new z {approx} 2 SB sample is the highest ever seen, some three times higher than in local SBs, whereas in AGNs this ratio is depressed below the SB trend, often severely. Several pieces of evidence imply that AGNs exist in this SB-dominated sample, except two of which even host very strong AGN, while they still have very strong PAH emission. The Advanced Camera for Surveys images show that most objects have very extended morphologies in the rest-frame ultraviolet band, thus extended distribution of PAH molecules. Such an extended distribution prevents further destruction PAH molecules by central AGNs. We conclude that objects in this sample are ULIRGs powered mainly by SB; and the total infrared luminosity density contributed by this type of objects is 0.9-2.6 x 10{sup 7} L{sub sun} Mpc{sup -3}.

• OSTI ID: 21313887
• Journal Information: Astrophysical Journal, Vol. 700, Issue 1; Other Information: DOI: 10.1088/0004-637X/700/1/183; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
CAMERAS
COLOR
COSMOLOGY
ENERGY SPECTRA
GALAXIES
LUMINOSITY
MORPHOLOGY
PHOTOMETRY
POLYCYCLIC AROMATIC HYDROCARBONS
RED SHIFT
SPECTROSCOPY
STARS
ULTRAVIOLET RADIATION