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Role of galaxy mergers in cosmic star formation history



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Shi, Yong and Rieke, George and Lotz, Jennifer and Pérez González, Pablo Guillermo (2009) Role of galaxy mergers in cosmic star formation history. Astrophysical journal, 697 (2). pp. 1764-1783. ISSN 0004-637X

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Official URL: http://dx.doi.org/10.1088/0004-637X/697/2/1764


We present a morphology study of intermediate-redshift (0.2 < z < 1.2) luminous infrared galaxies (LIRGs) and general field galaxies in the GOODS fields using a revised asymmetry measurement method optimized for deep fields. By taking careful account of the importance of the underlying sky-background structures, our new method does not suffer from systematic bias and offers small uncertainties. By redshifting local LIRGs and low-redshift GOODS galaxies to different higher redshifts, we have found that the redshift dependence of the galaxy asymmetry due to surface-brightness dimming is a function of the asymmetry itself, with larger corrections for more asymmetric objects. By applying redshift-, infrared (IR)-luminosity- and optical-brightness-dependent asymmetry corrections, we have found that intermediate-redshift LIRGs generally show highly asymmetric morphologies, with implied merger fractions ~50% up to z = 1.2, although they are slightly more symmetric than local LIRGs. For general field galaxies, we find an almost constant relatively high merger fraction (20%-30%). The B-band luminosity functions (LFs) of galaxy mergers are derived at different redshifts up to z = 1.2 and confirm the weak evolution of the merger fraction after breaking the luminosity-density degeneracy. The IR LFs of galaxy mergers are also derived, indicating a larger merger fraction at higher IR luminosity. The integral of the merger IR LFs indicates a dramatic evolution of the merger-induced IR energy density [(1 + z)^~(5-6)], and that galaxy mergers start to dominate the cosmic IR energy density at z greater than or ~ 1.

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© 2009 The American Astronomical Society. All rights reserved.
We thank the anonymous referee for detailed comments. Support for this work was provided by NASA through contract 1255094 issued by JPL/California Institute of Technology. J.M.L. acknowledges support from Leo Goldberg Fellowship sponsored by the National Optical Astronomy Observatory. P.G.P.-G. acknowledges support from the Spanish Programa Nacional de Astronomía y Astrofísica under grants AYA 2006– 02358 and AYA 2006–15698–C02–02, and from the Ramón y Cajal Program financed by the Spanish Government and the European Union.

Uncontrolled Keywords:Luminous infrared galaxies; Ldss redshift surveys; Origins deep survey; Digital sky survey; Field galaxies; Stellar mass; Distant galaxies; Spitzer view; Evolution; Morphology
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:38653
Deposited On:29 Jul 2016 14:04
Last Modified:10 Dec 2018 15:05

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