1994/06/16 by H. J. Mo · 3 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galactic halo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Luminosity #Physics #RADIUS #Redshift #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1093/mnras/269.1.l49
14 pages,1 figure,uuencoded,compressed,ps file,accepted by MNRAS
arxiv created 1994/06/16 · openalex publication_date 1994/07/01 · arxiv updated 2016/06/08 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Motivated by recent observation of Lanzetta et al. that most luminous galaxies at low redshifts produce \lya absorption at impact parameter l\lsim 160 \kpch, we propose that these absorbers are clouds confined by the pressure of ambient hot gas in galactic haloes. We determine the properties of this hot gas and of the absorption systems on the basis of observational and theoretical constraints. The absorbing clouds need to be replenished on about one orbital time (∼ 109 yrs) in the galactic halo. The pressure and temperature of the gas at radius r∼ 100\kpc are P=(10-100)\rm cm-3 K, T=10(5.5-6.5)\rm K. The model requires that about 10 per cent of the gas in low-redshift galactic haloes is in the hot phase. Such gas in galactic haloes emits x-ray with bolometric luminosity of the order 1037-40\rm erg s-1. The plausibility for such gas to exist in current models of galaxy formation is discussed.