Revealing the interaction between the X-ray gas of starburst galaxy UGC 6697 and the hot intracluster medium of A1367

Abstract

We present the result from a CHANDRA observation of an X-ray luminous starburst galaxy UGC 6697, which is embedded in the northwest hot region of A1367 (5 - 6 keV). A very sharp X-ray edge (~ 13 times of surface brightness jump) at the southeast and a long tail (at least 60 kpc from the nucleus) at the northwest of the galaxy are detected, as expected if the galaxy is moving to the southeast. The X-ray edge, at the midway of the nucleus and the southeast optical disk edge, is also at the same position where the Halpha emission is truncated and a radio sharp edge is observed. The X-ray diffuse emission is also enhanced at the southeast, implying ram pressure compression. No extraplanar X-ray component is detected, probably due to the combining effects of weaker outflow activity than that in nuclear starbursts, and external confinement plus stripping. The diffuse thermal gas in UGC 6697 has a temperature of ~ 0.7 keV and a low iron abundance (~0.1 - 0.2 solar). An X-ray point source (L (0.5-10 keV) ~ 2.8 x 10^{40} ergs s^{-1}) is detected on the nucleus, but not highly absorbed. Three off-center ultraluminous X-ray sources, all with L (0.5-10 keV) > 10^{40} ergs s^{-1}, are also detected. Based on the multi-wavelength data available, we favor that the interaction between the interstellar medium (ISM) and the ICM plays a major role to trigger the starburst in UGC 6697.