X-ray emission from RX J1720.1+2638 and Abell 267: a comparison between
  a fossil and a non-fossil system
  We present the XMM-Newton X-ray analysis of RXJ1720.1+2638 and Abell267, a
non-fossil and a fossil system, respectively. The whole spectrum of both
objects can be explained by thermal emission. The luminosities found for
RXJ1720.1+2638 and Abell267 in the 2-10 keV band are
6.20^{+0.04}_{-0.02}\times10^{44} and 3.90^{+0.10}_{-0.11}\times10^{44} cgs,
respectively. The radial profiles show a cool core nature for the non-fossil
system RXJ1720.1+2638, while Abell267 shows a constant behaviour of temperature
with radius. Metallicity profiles have also been produced, but no evidence of
any gradient was detected due to the large uncertainties in the determination
of this parameter. Finally, density and mass profiles were also produced
allowing to derive M_500 for RXJ1720.1+2638 and Abell267. The masses obtained
are high, in the range of (5-7)10^{14}\,M_{\odot}. The X-ray properties
obtained for both systems are not always in good agreement with what is
expected: cool cores are expected for fossil systems, as Abell267, considering
them as and relaxed systems. However, the decrement of the temperature in
Abell267 could start at lower radii. Also the presence of a recent merger in
Abell267, already suggested in the literature, could have increased the central
temperature. The non-fossil system RXJ1720.1+2638 actually exhibits a cool core
profile, but also evidence of a recent merger has been reported.
