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Title: SIMULATIONS OF EARLY BARYONIC STRUCTURE FORMATION WITH STREAM VELOCITY. I. HALO ABUNDANCE

Abstract

It has been recently shown that the relative velocity between the dark matter and the baryons (v{sub bc}) at the time of recombination can affect the structure formation in the early universe. We statistically quantify this effect using large cosmological simulations. We use three different high-resolution sets of simulations (with separate transfer functions for baryons and dark matter) that vary in box size, particle number, and the value of the relative velocity between dark matter and baryons. We show that the total number density of halos is suppressed by {approx}20% at z = 25 for v{sub bc} = 1{sigma}{sub vbc}, where {sigma}{sub vbc} is the variance of the relative velocity, while for v{sub bc} = 3.4{sigma}{sub vbc} the relative suppression at the same redshift reaches 50%, remaining at or above the 30% level all the way to z = 11. We also find a high abundance of 'empty halos', i.e., halos that have gas fraction below half of the cosmic mean baryonic fraction f-bar{sub b}. Specifically, we find that for v{sub bc} = 1{sigma}{sub vbc} all halos below 10{sup 5} M{sub Sun} are empty at z {>=} 19. The high abundance of empty halos results in significant delay in themore » formation of gas-rich minihalos and the first galaxies.« less

Authors:
 [1];  [2]
  1. CIERA, Northwestern University, Evanston, IL 60208 (United States)
  2. IPMU, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)
Publication Date:
OSTI Identifier:
22016239
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 747; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; BARYONS; COMPUTERIZED SIMULATION; COSMOLOGICAL MODELS; COSMOLOGY; DENSITY; GALACTIC EVOLUTION; GALAXIES; NONLUMINOUS MATTER; RECOMBINATION; RED SHIFT; STATISTICS; TRANSFER FUNCTIONS; UNIVERSE

Citation Formats

Naoz, Smadar, Yoshida, Naoki, and Gnedin, Nickolay Y., E-mail: snaoz@northwestern.edu. SIMULATIONS OF EARLY BARYONIC STRUCTURE FORMATION WITH STREAM VELOCITY. I. HALO ABUNDANCE. United States: N. p., 2012. Web. doi:10.1088/0004-637X/747/2/128.
Naoz, Smadar, Yoshida, Naoki, & Gnedin, Nickolay Y., E-mail: snaoz@northwestern.edu. SIMULATIONS OF EARLY BARYONIC STRUCTURE FORMATION WITH STREAM VELOCITY. I. HALO ABUNDANCE. United States. https://doi.org/10.1088/0004-637X/747/2/128
Naoz, Smadar, Yoshida, Naoki, and Gnedin, Nickolay Y., E-mail: snaoz@northwestern.edu. Sat . "SIMULATIONS OF EARLY BARYONIC STRUCTURE FORMATION WITH STREAM VELOCITY. I. HALO ABUNDANCE". United States. https://doi.org/10.1088/0004-637X/747/2/128.
@article{osti_22016239,
title = {SIMULATIONS OF EARLY BARYONIC STRUCTURE FORMATION WITH STREAM VELOCITY. I. HALO ABUNDANCE},
author = {Naoz, Smadar and Yoshida, Naoki and Gnedin, Nickolay Y., E-mail: snaoz@northwestern.edu},
abstractNote = {It has been recently shown that the relative velocity between the dark matter and the baryons (v{sub bc}) at the time of recombination can affect the structure formation in the early universe. We statistically quantify this effect using large cosmological simulations. We use three different high-resolution sets of simulations (with separate transfer functions for baryons and dark matter) that vary in box size, particle number, and the value of the relative velocity between dark matter and baryons. We show that the total number density of halos is suppressed by {approx}20% at z = 25 for v{sub bc} = 1{sigma}{sub vbc}, where {sigma}{sub vbc} is the variance of the relative velocity, while for v{sub bc} = 3.4{sigma}{sub vbc} the relative suppression at the same redshift reaches 50%, remaining at or above the 30% level all the way to z = 11. We also find a high abundance of 'empty halos', i.e., halos that have gas fraction below half of the cosmic mean baryonic fraction f-bar{sub b}. Specifically, we find that for v{sub bc} = 1{sigma}{sub vbc} all halos below 10{sup 5} M{sub Sun} are empty at z {>=} 19. The high abundance of empty halos results in significant delay in the formation of gas-rich minihalos and the first galaxies.},
doi = {10.1088/0004-637X/747/2/128},
url = {https://www.osti.gov/biblio/22016239}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 747,
place = {United States},
year = {2012},
month = {3}
}