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Title: HEAVY DUST OBSCURATION OF z = 7 GALAXIES IN A COSMOLOGICAL HYDRODYNAMIC SIMULATION

Hubble Space Telescope observations with the Wide Field Camera 3/Infrared reveal that galaxies at z ∼ 7 have very blue ultraviolet (UV) colors, consistent with these systems being dominated by young stellar populations with moderate or little attenuation by dust. We investigate UV and optical properties of the high-z galaxies in the standard cold dark matter model using a high-resolution adaptive mesh refinement cosmological hydrodynamic simulation. For this purpose, we perform panchromatic three-dimensional dust radiative transfer calculations on 198 galaxies of stellar mass 5 × 10{sup 8}-3 × 10{sup 10} M{sub ☉} with three parameters: the dust-to-metal ratio, the extinction curve, and the fraction of directly escaped light from stars (f{sub esc}). Our stellar mass function is found to be in broad agreement with Gonzalez et al., independent of these parameters. We find that our heavily dust-attenuated galaxies (A{sub V} ∼ 1.8) can also reasonably match modest UV-optical colors, blue UV slopes, as well as UV luminosity functions, provided that a significant fraction (∼10%) of light directly escapes from them. The observed UV slope and scatter are better explained with a Small-Magellanic-Cloud-type extinction curve, whereas a Milky-Way-type curve also predicts blue UV colors due to the 2175 Å bump. Wemore » expect that upcoming observations by the Atacama Large Millimeter/submillimeter Array will be able to test this heavily obscured model.« less
Authors:
;  [1]
  1. Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States)
Publication Date:
OSTI Identifier:
22270719
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 776; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; ATTENUATION; CAMERAS; COLOR; COMPUTERIZED SIMULATION; COSMOLOGY; MAGELLANIC CLOUDS; MASS; METALS; MILKY WAY; NONLUMINOUS MATTER; RADIANT HEAT TRANSFER; RED SHIFT; RESOLUTION; STARS; TELESCOPES; THREE-DIMENSIONAL CALCULATIONS; ULTRAVIOLET RADIATION