The clustering and abundance of star-forming and passive galaxies at $z\sim 2$

Abstract

We use the UKIDSS Ultra-deep survey (UDS), currently the deepest panoramic near infra-red survey, together with deep Subaru optical imaging to measure the clustering, number counts and luminosity function of galaxies at $z\sim 2$ selected using the BzK selection technique. We find that both star-forming (sBzK) and passive (pBzK) galaxies, to a magnitude limit of $K_{AB}<23$, are strongly clustered. The passive galaxies are the most strongly clustered population, with scale lengths of $r_0=15.0_{-2.2}^{+1.9}$h${}^{-1}$Mpc compared with $r_0=6.75_{-0.37}^{+0.34}$h${}^{-1}$Mpc for star-forming galaxies. The direct implication is that passive galaxies inhabit the most massive dark-matter halos, and are thus identified as the progenitors of the most massive galaxies at the present day. In addition, the pBzKs exhibit a sharp flattening and potential turn-over in their number counts, in agreement with other recent studies. This plateau cannot be explained by the effects of incompleteness. We conclude that only very massive galaxies are undergoing passive evolution at this early epoch, consistent with the downsizing scenario for galaxy evolution. Assuming a purely passive evolution for the pBzKs from their median redshift to the present day, their luminosity function suggests that only $\sim 2.5$ of present day massive ellipticals had a pBzK as a main progenitor.

8 pages, 7 figures, accepted for publication in MNRAS

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Cited by in corpus (11)

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• The evolution of galaxy clustering since z = 3 using the UKIDSS Ultra Deep Survey: the divergence of passive and star-forming galaxies
• Characterization and modeling of contamination for Lyman break galaxy samples at high redshift
• SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES) IV: Spatial clustering and halo masses of 450-$\mu$m-selected sub-millimeter galaxies
• Linking galaxies to dark matter haloes at $z\sim 1$ : dependence of galaxy clustering on stellar mass and specific star formation rate
• Angular clustering of z~2 star-forming and passive galaxies in 2.5 square degrees of deep CFHT imaging
• LARgE Survey. I. Dead Monsters: the Massive End of the Passive Galaxy Stellar Mass Function at Cosmic Noon
• A mass threshold in the number density of passive galaxies at z$\sim$2
• Morphology and structure of BzK-selected galaxies at z~2 in the CANDELS-COSMOS field
• An empirical model of the extragalactic radio background