Abstract
To investigate the present situation of the merging in the southern outer region of Abell 85, we carried out long time (∼ lOOks) observations with Suzaku, and produced an X-ray hardness ratio map. We found a high hardness ratio peak on the east side of a subcluster located south of the cluster; an X-ray spectrum of the region including this peak indicates a high temperature of ∼ 8.5 keV. This hot spot has not been reported so far. We consider that this hot spot is a postshock region produced by the infall of the subcluster from the southwest. By using the Rankine- Hugoniot jump conditions for shocks, the Mach number and the infall velocity of the subcluster were obtained as 1.5 ±0.2 and 1950-280 +290km s-1, respectively, in the case of merging with the subcluster from the southwest direction. By using the difference in redshift between A 85 and the subcluster obtained from optical observations, the angle between the line of sight and the direction of the motion of the subcluster is estimated to be 75°+7°-8°,. We estimate the kinetic energy of the subcluster and the energy used for the intracluster medium (ICM) heating to be ∼ 1063 and ≲8 × l060erg, respectively. This shows that the deceleration of the subcluster by the ICM heating has been negligibly small.
| Original language | English |
|---|---|
| Pages (from-to) | 743-754 |
| Number of pages | 12 |
| Journal | Publications of the Astronomical Society of Japan |
| Volume | 62 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 01-01-2010 |
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All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
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Suzaku observations of the merging cluster abell 85 : Temperature map and impact direction. / Tanaka, Nobuhiro; Furuzawa, Akihiro; Miyoshi, Shigeru J.; Tamura, Takayuki; Takata, Tadafumi.
In: Publications of the Astronomical Society of Japan, Vol. 62, No. 3, 01.01.2010, p. 743-754.Research output: Contribution to journal › Article
TY - JOUR
T1 - Suzaku observations of the merging cluster abell 85
T2 - Temperature map and impact direction
AU - Tanaka, Nobuhiro
AU - Furuzawa, Akihiro
AU - Miyoshi, Shigeru J.
AU - Tamura, Takayuki
AU - Takata, Tadafumi
PY - 2010/1/1
Y1 - 2010/1/1
N2 - To investigate the present situation of the merging in the southern outer region of Abell 85, we carried out long time (∼ lOOks) observations with Suzaku, and produced an X-ray hardness ratio map. We found a high hardness ratio peak on the east side of a subcluster located south of the cluster; an X-ray spectrum of the region including this peak indicates a high temperature of ∼ 8.5 keV. This hot spot has not been reported so far. We consider that this hot spot is a postshock region produced by the infall of the subcluster from the southwest. By using the Rankine- Hugoniot jump conditions for shocks, the Mach number and the infall velocity of the subcluster were obtained as 1.5 ±0.2 and 1950-280 +290km s-1, respectively, in the case of merging with the subcluster from the southwest direction. By using the difference in redshift between A 85 and the subcluster obtained from optical observations, the angle between the line of sight and the direction of the motion of the subcluster is estimated to be 75°+7°-8°,. We estimate the kinetic energy of the subcluster and the energy used for the intracluster medium (ICM) heating to be ∼ 1063 and ≲8 × l060erg, respectively. This shows that the deceleration of the subcluster by the ICM heating has been negligibly small.
AB - To investigate the present situation of the merging in the southern outer region of Abell 85, we carried out long time (∼ lOOks) observations with Suzaku, and produced an X-ray hardness ratio map. We found a high hardness ratio peak on the east side of a subcluster located south of the cluster; an X-ray spectrum of the region including this peak indicates a high temperature of ∼ 8.5 keV. This hot spot has not been reported so far. We consider that this hot spot is a postshock region produced by the infall of the subcluster from the southwest. By using the Rankine- Hugoniot jump conditions for shocks, the Mach number and the infall velocity of the subcluster were obtained as 1.5 ±0.2 and 1950-280 +290km s-1, respectively, in the case of merging with the subcluster from the southwest direction. By using the difference in redshift between A 85 and the subcluster obtained from optical observations, the angle between the line of sight and the direction of the motion of the subcluster is estimated to be 75°+7°-8°,. We estimate the kinetic energy of the subcluster and the energy used for the intracluster medium (ICM) heating to be ∼ 1063 and ≲8 × l060erg, respectively. This shows that the deceleration of the subcluster by the ICM heating has been negligibly small.
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U2 - 10.1093/pasj/62.3.743
DO - 10.1093/pasj/62.3.743
M3 - Article
VL - 62
SP - 743
EP - 754
JO - Publication of the Astronomical Society of Japan
JF - Publication of the Astronomical Society of Japan
SN - 0004-6264
IS - 3
ER -