The Spatial Clustering of Ultraluminous Infrared Galaxies over 1.5 < z < 3

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Abstract
We present measurements of the spatial clustering of galaxies with stellar masses 1011 M☉, infrared luminosities 1012 L☉, and star formation rates 200 M☉ yr-1 in two redshift intervals: 1.5 < z < 2.0 and 2 < z < 3. Both samples cluster moderately strongly, with spatial correlation lengths of r0 = 6.14 ± 0.84 h-1 Mpc for the 2 < z < 3 sample and r0 = 5.36 ± 1.28 h-1 Mpc for the 1.5 < z < 2.0 sample. These clustering amplitudes are consistent with both populations residing in dark matter halos with masses of ~7 × 1012 M☉, which is comparable to that seen for optical QSOs at the same epochs. We infer that a minimum dark matter halo mass is an important factor for all forms of luminous, obscured activity in galaxies at z > 1, both starbursts and active galactic nuclei. Adopting plausible models for the growth of dark matter halos with redshift, the halos hosting the 2 < z < 3 sample will likely host poor to rich clusters of galaxies at z = 0, whereas the halos hosting the 1.5 < z < 2.0 sample will likely host L* elliptical galaxies or poor clusters at z = 0. We conclude that ultraluminous infrared galaxies (ULIRGs) at z ~ 2.5 likely signpost stellar buildup in galaxies that will reside in clusters at z = 0 and that ULIRGs at z ~ 1.7 signpost stellar buildup in sources that will either become L* elliptical galaxies or reside in poor clusters at z = 0.