GAS DEPLETION IN LOCAL GROUP DWARFS ON {approx}250 kpc SCALES: RAM PRESSURE STRIPPING ASSISTED BY INTERNAL HEATING AT EARLY TIMES

Journal Article · Sun May 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/732/1/17· OSTI ID:21574663

Nichols, Matthew; Bland-Hawthorn, Joss ^[1]

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1. Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

A recent survey of the Galaxy and M31 reveals that more than 90% of dwarf galaxies within 270 kpc of their host galaxy are deficient in H I gas. At such an extreme radius, the coronal halo gas is an order of magnitude too low to remove H I gas through ram pressure stripping for any reasonable orbit distribution. However, all dwarfs are known to have an ancient stellar population ({approx}> 10 Gyr) from early epochs of vigorous star formation which, through heating of H I, could allow the hot halo to remove this gas. Our model looks at the evolution of these dwarf galaxies analytically as the host-galaxy dark matter halo and coronal halo gas build up over cosmic time. The dwarf galaxies-treated as spherically symmetric, smooth distributions of dark matter and gas-experience early star formation, which sufficiently heats the gas, allowing it to be removed easily through tidal stripping by the host galaxy, or ram pressure stripping by a tenuous hot halo (n{sub H} = 3 x 10{sup -4} cm{sup -3} at 50 kpc). This model of evolution is able to explain the observed radial distribution of gas-deficient and gas-rich dwarfs around the Galaxy and M31 if the dwarfs fell in at high redshift (z {approx} 3-10).

• OSTI ID: 21574663
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 732; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
HEATING