Where are the z=4 Lyman Break Galaxies? Results from Conditional Luminosity Function Models of Luminosity-dependent Correlation Functions

Abstract

Using the conditional luminosity function (CLF) -- the luminosity distribution of galaxies in a dark matter halo -- as a way to model galaxy statistics, we study how z=4 Lyman Break Galaxies (LBGs) are distributed in dark matter halos. For this purpose, we measure luminosity-dependent clustering of LBGs in the Subaru/XMM-Newton Deep Field by separating a sample of 16,920 galaxies to three magnitude bins in i'-band between 24.5 and 27.5. Our models fits to data show a possible trend for more luminous galaxies to appear as satellites in more massive halos. The satellite fraction of galaxies at z=4 in these magnitude bins is 0.13 to 0.3, 0.09 to 0.22, and 0.03 to 0.14, respectively, where the 1 sigma ranges account for differences coming from two different estimates of the z=4 LF from the literature. To jointly explain the LF and the large-scale linear bias factor of z=4 LBGs as a function of rest-UV luminosity requires central galaxies to be brighter in UV at z =4 than present-day galaxies in same dark matter mass halos. Moreover, UV luminosity of central galaxies in halos with total mass greater than roughly 10^{12} M_sun must decrease from z=4 to today by an amount more than the luminosity change for galaxies in halos below this mass. This mass-dependent luminosity evolution is preferred at more than 3 sigma confidence level compared to a pure-luminosity evolution scenario where all galaxies decrease in luminosity by the same amount from z=4 to today. The scenario preferred by the data is consistent with the ``down-sizing'' picture of galaxy evolution.

13 pages, 9 figures; accepted for publication in Mon. Not. Roy. Astron. Soc.; low resolution figures submitted here. A pdf file with high resolution figures available at http://www.cooray.org/Cooray-Ouchi.pdf

References in corpus (2)

• Subaru Deep Survey V. A Census of Lyman Break Galaxies at z=4 and 5 in the Subaru Deep Fields: Photometric Properties
• Definitive Identification of the Transition between Small- to Large-Scale Clustering for Lyman Break Galaxies

Cited by in corpus (9)

• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• Galaxy Evolution from Halo Occupation Distribution Modeling of DEEP2 and SDSS Galaxy Clustering
• z~7-10 Galaxies in the HUDF and GOODS fields, and their UV Luminosity Functions
• The Clustering and Host Halos of Galaxy Mergers at High Redshift
• An improved limit on the neutrino mass with CMB and redshift-dependent halo bias-mass relations from SDSS, DEEP2, and Lyman-Break Galaxies
• Clustering of the IR Background Light with Spitzer: Contribution from Resolved Sources
• COSMOS2020: UV selected galaxies at $z\ge 7.5$
• Probing the Diffuse Lyman-alpha Emission on Cosmological Scales: Lyα Emission Intensity Mapping Using the Complete SDSS-IV eBOSS Survey
• Constraining galaxy-halo connection with high-order statistics