The complex X-ray morphology of NGC 7618: A major group-group merger in the local Universe?

Details The complex X-ray morphology of NGC 7618: A major group-group merger in the local Universe? The complex X-ray morphology of NGC 7618: A major group-group merger in the local Universe?

2006-01-17

arxiv.org/abs/astro-ph/0601378v1

Astrophys.J. 640 (2006) 762-767

Astronomy and Astrophysics

Astrophysics

20 pages, 6 figures, 2 tables - accepted for publication in the Astrophysical Journal

Scientific paper

10.1086/500123

We present results from a short {\em Chandra}/ACIS-S observation of NGC 7618, the dominant central galaxy of a nearby ($z$=0.017309, d=74.1 Mpc) group. We detect a sharp surface brightness discontinuity 14.4 kpc N of the nucleus subtending an angle of 130$^\circ$ with an X-ray tail extending $\sim$ 70 kpc in the opposite direction. The temperature of the gas inside and outside the discontinuity is 0.79$\pm$0.03 and 0.81$\pm$0.07 keV, respectively. There is marginal evidence for a discontinuous change in the elemental abundance ($Z_{inner}$=0.65$\pm$0.25,$Z_{outer}$=0.17$\pm$0.21 at 90% confidence), suggesting that this may be an `abundance' front. Fitting a two-temperature model to the ASCA/GIS spectrum of the NGC 7618/UGC 12491 pair shows the presence of a second, much hotter ($T$=$\sim$2.3 keV) component. We consider several scenarios for the origin of the edge and the tail including a radio lobe/IGM interaction, non-hydrostatic `sloshing', equal-mass merger and collision, and ram-pressure stripping. In the last case, we consider the possibility that NGC 7618 is falling into UGC 12491, or that both groups are falling into a gas poor cluster potential. There are significant problems with the first two models, however, and we conclude that the discontinuity and tail are most likely the result of ram pressure stripping of the NGC 7618 group as it falls into a larger dark matter potential.

Affiliated with

Also associated with

No associations

Rating

The complex X-ray morphology of NGC 7618: A major group-group merger in the local Universe? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The complex X-ray morphology of NGC 7618: A major group-group merger in the local Universe?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The complex X-ray morphology of NGC 7618: A major group-group merger in the local Universe? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-593836