Evidence for Non-Hydrostatic Gas Motions in the Hot ISM of Centaurus A

Details Evidence for Non-Hydrostatic Gas Motions in the Hot ISM of Centaurus A Evidence for Non-Hydrostatic Gas Motions in the Hot ISM of Centaurus A

2008-03-25

arxiv.org/abs/0803.3595v1

Astronomy and Astrophysics

Astrophysics

14 pages, 3 figures, 1 table - accepted for publication in the Astrophysical Journal Letters

Scientific paper

10.1086/588023

We present preliminary results from a deep (600 ks) {\em Chandra} observation of the hot interstellar medium of the nearby early-type galaxy Centaurus A (Cen A). We find a surface brightness discontinuity in the gas $\sim$3.5 kpc from the nucleus spanning a 120$^\circ$ arc. The temperature of the gas is 0.60$\pm$0.05 and 0.68$\pm$0.10 keV, interior and exterior to the discontinuity, respectively. The elemental abundance is poorly constrained by the spectral fits, but if the abundance is constant across the discontinuity, there is a factor of 2.3$\pm$0.4 pressure jump across the discontinuity. This would imply that the gas is moving at 470$\pm$100 km s$^{-1}$, or Mach 1.0$\pm$0.2 (1.2$\pm$0.2) relative to the sound speed of the gas external (internal) to the discontinuity. Alternatively, pressure balance could be maintained if there is a large (factor of $\sim$7) discontinuity in the elemental abundance. We suggest that the observed discontinuity is the result of non-hydrostatic motion of the gas core (i.e. sloshing) due to the recent merger. In this situation, both gas motions and abundance gradients are important in the visibility of the discontinuity. Cen A is in the late stages of merging with a small late-type galaxy, and a large discontinuity in density and abundance across a short distance demonstrates that the gas of the two galaxies remains poorly mixed even several hundred million years after the merger. The pressure discontinuity may have had a profound influence on the temporal evolution of the kpc-scale jet. The jet could have decollimated crossing the discontinuity and thereby forming the northeast radio lobe.

Affiliated with

Also associated with

No associations

Rating

Evidence for Non-Hydrostatic Gas Motions in the Hot ISM of Centaurus A 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 Evidence for Non-Hydrostatic Gas Motions in the Hot ISM of Centaurus A, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evidence for Non-Hydrostatic Gas Motions in the Hot ISM of Centaurus A will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-349374