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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 730197.0, MPI für Astronomie / Publikationen_mpia
The quasar-LBG two-point angular cross-correlation function at z~4 in the COSMOS field
Authors:Ikeda, H.; Nagao, T.; Taniguchi, Y.; Matsuoka, K.; Kajisawa, M.; Akiyama, M.; Miyaji, T.; Kashikawa, N.; Morokuma, T.; Shioya, Y.; Enoki, M.; Capak, P.; Koekemoer, A. M.; Masters, D.; Salvato, M.; Sanders, D. B.; Schinnerer, E.; Scoville, N. Z.
Date of Publication (YYYY-MM-DD):2015
Title of Journal:The Astrophysical Journal
Issue / Number:2
Start Page:id. 138 (14 pp)
Audience:Not Specified
Abstract / Description:In order to investigate the origin of quasars, we estimate the bias factor for low-luminosity quasars at high redshift for the first time. In this study, we use the two-point angular cross-correlation function (CCF) for both low-luminosity quasars at -24\lt {M}1450\lt -22 and Lyman-break galaxies (LBGs). Our sample consists of both 25 low-luminosity quasars (16 objects are spectroscopically confirmed low-luminosity quasars) in the redshift range 3.1\lt z\lt 4.5 and 835 color-selected LBGs with {z}{LBG}\prime \lt 25.0 at z ∼ 4 in the COSMOS field. We have performed our analysis for the following two quasar samples: (1) the spectroscopic sample (the 16 quasars confirmed by spectroscopy), and (2) the total sample (the 25 quasars including 9 quasars with photometric redshifts). The bias factor for low-luminosity quasars at z ∼ 4 is derived by utilizing the quasar-LBG CCF and the LBG auto-correlation function. We then obtain the 86% upper limits of the bias factors for low-luminosity quasars, which are 5.63 and 10.50 for the total and the spectroscopic samples, respectively. These bias factors correspond to the typical dark matter halo masses, log ({M}{DM}/({h}-1{M}ȯ )) = 12.7 and 13.5, respectively. This result is not inconsistent with the predicted bias for quasars that is estimated by the major merger models.
Free Keywords:galaxies: active; large-scale structure of universe; quasars: general
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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