2003ApJ...594L.107S -
Astrophys. J., 594, L107-L110 (2003/September-2)
The multiphase intergalactic medium toward PKS 2155-304.
SHULL J.M., TUMLINSON J. and GIROUX M.L.
Abstract (from CDS):
We study the cluster of H I and O VI absorption systems and the claimed detection of O VIII absorption from the intergalactic medium at z~0.0567, associated with a group of galaxies toward the BL Lac object PKS 2155-304. As measured by spectrographs on the Hubble Space Telescope, Far Ultraviolet Spectroscopic Explorer, and Chandra, this system appears to contain gas at a variety of temperatures. We analyze this multiphase gas in a clumpy-infall model. From the absence of C IV and Si III absorption in the Lyα clouds, we infer metallicities less than 2.5%-10% of solar values. The only metals are detected in two O VI absorption components, offset by ±400 km/s from the group barycenter (cz~16,600 km/s). The O VI components may signify ``nearside'' and ``backside'' infall into the group potential well, which coincides with the claimed O VIII absorption. If the claimed O VIII detection is real, our analysis suggests that clusters of strong Lyα and O VI absorbers, associated with groups of galaxies, may be the ``signposts'' of shock-heated metal-enriched baryons. Through combined UV and X-ray spectra of H I and O VI, O VII, and O VIII, one may be able to clarify the heating mechanism of this multiphase gas.
Abstract Copyright:
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Journal keyword(s):
Galaxies: Intergalactic Medium
Nomenclature:
[STG2003] QSO J2158-3013 abs N.NNNN N=1. [STG2003] abs A (Nos A-C).
Simbad objects:
1
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