77 research outputs found
Systematic X-ray Analysis of Radio Relic Clusters with SUZAKU
We perform a systematic X-ray analysis of six giant radio relics in four
clusters of galaxies using the Suzaku satellite. The sample includes CIZA
2242.8-5301, Zwcl 2341.1-0000, the South-East part of Abell 3667 and previously
published results of the North-West part of Abell 3667 and Abell 3376.
Especially we first observed the narrow (50 kpc) relic of CIZA 2242.8-5301 by
Suzaku satellite, which enable us to reduce the projection effect. We report
X-ray detections of shocks at the position of the relics in CIZA2242.8-5301 and
Abell 3667 SE. At the position of the two relics in ZWCL2341.1-0000, we do not
detect shocks. From the spectroscopic temperature profiles across the relic, we
find that the temperature profiles exhibit significant jumps across the relics
for CIZA 2242.8-5301, Abell 3376, Abell 3667NW, and Abell 3667SE. We estimated
the Mach number from the X-ray temperature or pressure profile using the
Rankine-Hugoniot jump condition and compared it with the Mach number derived
from the radio spectral index. The resulting Mach numbers (M=1.5-3) are almost
consistent with each other, while the Mach number of CIZA2242 derived from the
X-ray data tends to be lower than that of the radio observation. These results
indicate that the giant radio relics in merging clusters are related to the
shock structure, as suggested by previous studies of individual clusters.Comment: Accepted for publication in PAS
Suzaku and Chandra observations of the galaxy cluster RXC J1053.7+5453 with a radio relic
We present the results of Suzaku and Chandra observations of the galaxy
cluster RXC J1053.7+5453 (), which contains a radio relic. The radio
relic is located at the distance of kpc from the X-ray peak toward
the west. We measured the temperature of this cluster for the first time. The
resultant temperature in the center is keV, which is lower than the
value expected from the X-ray luminosity - temperature and the velocity
dispersion - temperature relation. Though we did not find a significant
temperature jump at the outer edge of the relic, our results suggest that the
temperature decreases outward across the relic. Assuming the existence of the
shock at the relic, its Mach number becomes . A possible spatial
variation of Mach number along the relic is suggested. Additionally, a sharp
surface brightness edge is found at the distance of kpc from the
X-ray peak toward the west in the Chandra image. We performed X-ray spectral
and surface brightness analyses around the edge with Suzaku and Chandra data,
respectively. The obtained surface brightness and temperature profiles suggest
that this edge is not a shock but likely a cold front. Alternatively, it cannot
be ruled out that thermal pressure is really discontinuous across the edge. In
this case, if the pressure across the surface brightness edge is in
equilibrium, other forms of pressure sources, such as cosmic-rays, are
necessary. We searched for the non-thermal inverse Compton component in the
relic region. Assuming the photon index , the resultant upper
limit of the flux is for
area in the 0.3-10 keV band, which
implies that the lower limit of magnetic field strength becomes $ 0.7 {\rm \
\mu G}$.Comment: 13page, 8 figures, accepted for publication in PASJ. arXiv admin
note: text overlap with arXiv:1508.0584
- …