Intergalactic Gas in Groups of Galaxies: Implications for Dwarf Spheroidal Formation and The Missing Baryons Problem
by
E. Freeland(OKC)
→
Europe/Stockholm
FA 32
FA 32
Description
Radio galaxies with bent jets are predominantly located in groups and
clusters of galaxies. We use bent-double radio sources, under the
assumption that their jets are bent by ram-pressure, to probe
intragroup medium (IGM) gas densities in galaxy groups. This method
provides a direct measurement of the intergalactic gas density and
allows us to probe IGM gas at large radii and in systems whose IGM is
too cool to be detected by the current generation of X-ray telescopes.
We find gas with densities of 10^(-4)-10^(-3) per cubic centimeter at
group radii from 15-700 kpc. A rough estimate of the total baryonic
mass in intergalactic gas is consistent with the missing baryons being
located in the IGM of galaxy groups. The neutral gas will be easily
stripped from dwarf galaxies with total masses of 10^6-10^7 solar
masses in the groups studied here. Indications are that IGM gas
densities in less-massive systems like the Local Group should be high
enough to strip gas from dwarfs like Leo T and, in combination with
tides, produce dwarf spheroidals.
