DIFFUSE HOT GAS IN THE NGC-4261 GROUP OF GALAXIES

We have found diffuse X-ray gas in the group of galaxies containing the elliptical galaxy NGC 4261. This galaxy along with its associated companions are behind the Virgo cluster in the W-cloud. A recent analysis of the velocity structure in the Virgo region indicates that the W-cloud has similar to 30 members, most of which are low luminosity dwarfs. The hot X-ray emitting gas is centered about halfway between NGC 4261 and NGC 4264 and extends out to a radius of similar to 40' (620 kpc). The spectral data for the diffuse component are well fitted with a Raymond-Smith plasma model with a temperature of 0.85(-0.16)(+0.21) keV and abundance <0.08 times the solar value. Under the assumption that the diffuse gas is in hydrostatic equilibrium the total mass within 40' is 1.9 x 10(13) M(.). We estimate that the total baryonic mass of the hot gas and the galaxies is 20%-34% of the total mass in the central 40' radius of this group. This group of galaxies contains NGC 4273 which exhibits a ''bow shock'' morphology similar to that of NGC 2276, This is thought to occur when the ram pressure from the intragroup gas significantly perturbs the interstellar medium in a late-type galaxy. We show that this is unlikely in this group.