The X-ray View of Abell 3120
  Identification of Abell 3120 as a galaxy cluster has recently been questioned
with alternative suggestions including: a fossil remnant of a group merger,
non-thermal emission from a radio galaxy, and projected emission from of a
filamentary string of galaxies. We report on our analysis of the Chandra
observation and evaluate these hypotheses based on our results. Abell 3120
shows X-ray emission extending 158 kpc, well beyond the central galaxy. The
spatial distribution of X-rays in the core more closely follows the radio
emission showing a jet-like structure extending to the north that is misaligned
with the stellar light distribution of the central galaxy. At larger radii the
X-ray emission is aligned with the SE-NW running axis of the galaxy
distribution in the cluster core. Modeling the X-ray spectrum excludes purely
non-thermal emission. The emission weighted temperature is 1.93 - 2.19 keV and
the 0.3 - 10 keV luminosity is 1.23$\times10^{43}$ ergs s$^{-1}$. Abell 3120
appears to be a poor cluster with Virgo and MKW 4 as peers. The best fitting
model consists of a thermal component and a second component that may be either
thermal or non-thermal, with luminosity 25% of the total X-ray luminosity.
While, a more detailed spatial-spectral search failed to detect a central AGN,
there is some evidence for an extended hard X-ray component. Cooler gas, 1.28 -
1.80 was detected in the central 20 kpc. The second thermal component
marginally requires a higher redshift, >0.12, which may be due to a second
cluster in the rich surrounding environment consisting of nearly a thousand
catalogued galaxies.
