Suzaku observations of the merging cluster abell 85: Temperature map and impact direction

Nobuhiro Tanaka, Akihiro Furuzawa, Shigeru J. Miyoshi, Takayuki Tamura, Tadafumi Takata

Research output: Contribution to journalArticle

9 Citations (Scopus)

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 languageEnglish
Pages (from-to)743-754
Number of pages12
JournalPublications of the Astronomical Society of Japan
Volume62
Issue number3
DOIs
Publication statusPublished - 01-01-2010

Fingerprint

hardness
heating
hot spot
deceleration
Mach number
line of sight
x rays
kinetic energy
temperature
shock
estimates
energy

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Tanaka, Nobuhiro ; Furuzawa, Akihiro ; Miyoshi, Shigeru J. ; Tamura, Takayuki ; Takata, Tadafumi. / Suzaku observations of the merging cluster abell 85 : Temperature map and impact direction. In: Publications of the Astronomical Society of Japan. 2010 ; Vol. 62, No. 3. pp. 743-754.
@article{d182ab607c38484ba97ae4629ae916d7,
title = "Suzaku observations of the merging cluster abell 85: Temperature map and impact direction",
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.",
author = "Nobuhiro Tanaka and Akihiro Furuzawa and Miyoshi, {Shigeru J.} and Takayuki Tamura and Tadafumi Takata",
year = "2010",
month = "1",
day = "1",
doi = "10.1093/pasj/62.3.743",
language = "English",
volume = "62",
pages = "743--754",
journal = "Publication of the Astronomical Society of Japan",
issn = "0004-6264",
publisher = "Astronomical Society of Japan",
number = "3",

}

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 journalArticle

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.

UR - http://www.scopus.com/inward/record.url?scp=77954779706&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77954779706&partnerID=8YFLogxK

U2 - 10.1093/pasj/62.3.743

DO - 10.1093/pasj/62.3.743

M3 - Article

AN - SCOPUS:77954779706

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 -