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Title: THE DELAY OF POPULATION III STAR FORMATION BY SUPERSONIC STREAMING VELOCITIES

Abstract

It has recently been demonstrated that coherent relative streaming velocities of order 30 km s{sup -1} between dark matter and gas permeated the universe on scales below a few Mpc directly after recombination. Here we use a series of high-resolution moving-mesh calculations to show that these supersonic motions significantly influence the virialization of the gas in minihalos and delay the formation of the first stars. As the gas streams into minihalos with bulk velocities around 1 km s{sup -1} at z {approx} 20, the additional momentum and energy input reduces the gas fractions and central densities of the halos, increasing the typical virial mass required for efficient cooling by a factor of three and delaying Population III star formation by {Delta}z {approx_equal} 4. Since the distribution of the magnitude of the streaming velocities is narrowly peaked around a non-negligible value, this effect is important in most regions of the universe. As a consequence, the increased minimum halo mass implies a reduction of the absolute number of minihalos that can be expected to cool and form Population III stars by up to an order of magnitude. We further find that the streaming velocities increase the turbulent velocity dispersion of the minihalomore » gas, which could affect its ability to fragment and hence alter the mass function of the first stars.« less

Authors:
;  [1];  [2];  [3]
  1. Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85740 Garching bei Muenchen (Germany)
  2. Institut fuer Theoretische Astrophysik, Zentrum fuer Astronomie der Universitaet Heidelberg, Albert-Ueberle-Strasse 2, 69120 Heidelberg (Germany)
  3. Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg (Germany)
Publication Date:
OSTI Identifier:
21578216
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 736; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/736/2/147; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMIC GASES; COSMOLOGY; HYDRODYNAMICS; MASS; NONLUMINOUS MATTER; STAR EVOLUTION; STARS; UNIVERSE; VELOCITY; EVOLUTION; FLUID MECHANICS; FLUIDS; GASES; MATTER; MECHANICS

Citation Formats

Greif, Thomas H., White, Simon D. M., Klessen, Ralf S., and Springel, Volker. THE DELAY OF POPULATION III STAR FORMATION BY SUPERSONIC STREAMING VELOCITIES. United States: N. p., 2011. Web. doi:10.1088/0004-637X/736/2/147.
Greif, Thomas H., White, Simon D. M., Klessen, Ralf S., & Springel, Volker. THE DELAY OF POPULATION III STAR FORMATION BY SUPERSONIC STREAMING VELOCITIES. United States. doi:10.1088/0004-637X/736/2/147.
Greif, Thomas H., White, Simon D. M., Klessen, Ralf S., and Springel, Volker. Mon . "THE DELAY OF POPULATION III STAR FORMATION BY SUPERSONIC STREAMING VELOCITIES". United States. doi:10.1088/0004-637X/736/2/147.
@article{osti_21578216,
title = {THE DELAY OF POPULATION III STAR FORMATION BY SUPERSONIC STREAMING VELOCITIES},
author = {Greif, Thomas H. and White, Simon D. M. and Klessen, Ralf S. and Springel, Volker},
abstractNote = {It has recently been demonstrated that coherent relative streaming velocities of order 30 km s{sup -1} between dark matter and gas permeated the universe on scales below a few Mpc directly after recombination. Here we use a series of high-resolution moving-mesh calculations to show that these supersonic motions significantly influence the virialization of the gas in minihalos and delay the formation of the first stars. As the gas streams into minihalos with bulk velocities around 1 km s{sup -1} at z {approx} 20, the additional momentum and energy input reduces the gas fractions and central densities of the halos, increasing the typical virial mass required for efficient cooling by a factor of three and delaying Population III star formation by {Delta}z {approx_equal} 4. Since the distribution of the magnitude of the streaming velocities is narrowly peaked around a non-negligible value, this effect is important in most regions of the universe. As a consequence, the increased minimum halo mass implies a reduction of the absolute number of minihalos that can be expected to cool and form Population III stars by up to an order of magnitude. We further find that the streaming velocities increase the turbulent velocity dispersion of the minihalo gas, which could affect its ability to fragment and hence alter the mass function of the first stars.},
doi = {10.1088/0004-637X/736/2/147},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 736,
place = {United States},
year = {2011},
month = {8}
}