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arXiv · 0705.2831

Multiwavelength study of massive galaxies at z~2. I. Star formation and galaxy growth

E. Daddi·M. Dickinson·G. Morrison·R. Chary·A. Cimatti·D. Elbaz·D. Frayer·A. Renzini·A. Pope·D. M. Alexander·F. E. Bauer·M. Giavalisco·M. Huynh·J. Kurk·M. Mignoli
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Abstract

Examining a sample of massive galaxies at 1.4 10^{11}L_sun, show a mid-IR excess which is likely due to the presence of obscured active nuclei, as shown in a companion paper. There is a tight and roughly linear correlation between stellar mass and SFR for 24um-detected galaxies. For a given mass, the SFR at z=2 was larger by a factor of ~4 and ~30 relative to that in star forming galaxies at z=1 and z=0, respectively. Typical ultraluminous infrared galaxies (ULIRGs) at z=2 are relatively 'transparent' to ultraviolet light, and their activity is long lived (~400 Myr), unlike that in local ULIRGs and high redshift submillimeter-selected galaxies. ULIRGs are the common mode of star formation in massive galaxies at z=2, and the high duty cycle suggests that major mergers are not the dominant trigger for this activity.Current galaxy formation models underpredict the normalization of the mass-SFR correlation by about a factor of 4, and the space density of ULIRGs by an orderof magnitude, but give better agreement for z>1.4 quiescent galaxies.

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E. Daddi, M. Dickinson, G. Morrison, R. Chary, A. Cimatti, D. Elbaz, D. Frayer, A. Renzini, A. Pope, D. M. Alexander, F. E. Bauer, M. Giavalisco, M. Huynh, J. Kurk, M. Mignoli. 2007-07-24. Multiwavelength study of massive galaxies at z~2. I. Star formation and galaxy growth. https://doi.org/10.1086/521818

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