Joint Chandra/XMM-Newton Observation of NGC1407/1400 complex

The nearby dark group centered on NGC 1407 is notable for a nearby bright galaxy(NGC 1400) with a velocity differing by at least 1200 km/s. This large velocitydifference, plus controversy over these two galaxiesa?? respective distances,hasled to a wide range of mass estimates for this group. Our analysis of XMMNewtondata reveals an extended region of enhanced surface brightness near NGC 1400which may be a cold front. We also find that the hottest regions lie betweenNGC 1400 and 1407, suggesting that their atmospheres are colliding. We propose..text on Chandra cut .. a 30 ks XMM pointing covering the east side of NGC1407 to obtain a complete temperature map as well as a total group mass profile. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]