Observational Properties of Simulated Galaxies in Overdense and Average Regions at Redshifts z ≃ 6–12

Authors

Hidenobu Yajima, Tohoku University, Japan
Isaac Shlosman, University of KentuckyFollow
Emilio Romano-Díaz, University of Bonn, Germany
Kentaro Nagamine, Osaka University, Japan

Abstract

We use high-resolution zoom-in cosmological simulations of galaxies of Romano-Díaz et al., post-processing them with a panchromatic three-dimensional radiation transfer code to obtain the galaxy UV luminosity function (LF) at z ≃ 6–12. The galaxies are followed in a rare, heavily overdense region within a ∼5σ density peak, which can host high-z quasars, and in an average density region, down to the stellar mass of M_star ∼ 4 × 10⁷ M_⊙. We find that the overdense regions evolve at a substantially accelerated pace – the most massive galaxy has grown to M_star ∼ 8.4 × 10¹⁰ M_⊙ by z = 6.3, contains dust of M_dust ∼ 4.1 × 10⁸ M_⊙, and is associated with a very high star formation rate, SFR ∼ 745 M_⊙ yr^{− 1}. The attained SFR–M_star correlation results in the specific SFR slowly increasing with M_star. Most of the UV radiation in massive galaxies is absorbed by the dust, its escape fraction f_esc is low, increasing slowly with time. Galaxies in the average region have less dust, and agree with the observed UV LF. The LF of the overdense region is substantially higher, and contains much brighter galaxies. The massive galaxies are bright in the infrared (IR) due to the dust thermal emission, with L_IR ∼ 3.7 × 10¹² L_⊙ at z = 6.3, while L_IR < 10¹¹ L_⊙ for the low-mass galaxies. Therefore, ALMA can probe massive galaxies in the overdense region up to z ∼ 10 with a reasonable integration time. The UV spectral properties of discy galaxies depend significantly upon the viewing angle. The stellar and dust masses of the most massive galaxy in the overdense region are comparable to those of the sub-millimetre galaxy found by Riechers et al. at z = 6.3, while the modelled SFR and the sub-millimetre flux fall slightly below the observed one. Statistical significance of these similarities and differences will only become clear with the upcoming ALMA observations.

Document Type

Article

Publication Date

7-21-2015

Notes/Citation Information

Published in Monthly Notices of the Royal Astronomical Society, v. 451, no. 1, p. 418-432.

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Digital Object Identifier (DOI)

http://dx.doi.org/10.1093/mnras/stv974

Funding Information

This work has been supported under the International Joint Research Promotion Program by Osaka University. IS has benefited from the partial support by the NSF and STScI. STScI is operated by AURA Inc., under NASA contract NAS 5-26555. ERD thanks DFG for support under SFB 956. KN acknowledges the partial support by JSPS KAKENHI Grant Number 26247022.

Repository Citation

Yajima, Hidenobu; Shlosman, Isaac; Romano-Díaz, Emilio; and Nagamine, Kentaro, "Observational Properties of Simulated Galaxies in Overdense and Average Regions at Redshifts z ≃ 6–12" (2015). Physics and Astronomy Faculty Publications. 277.
https://uknowledge.uky.edu/physastron_facpub/277