On the merging cluster Abell 578 and its central radio galaxy 4C+67.13

Journal Article · Mon Jun 01 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/805/2/101· OSTI ID:22883156

Hagino, K.; Stawarz, Ł.; Simionescu, A.; Takahashi, T. ^[1]; Siemiginowska, A.; Harris, D. E. ^[2]; Cheung, C. C. ^[3]; Kozieł-Wierzbowska, D.; Szostek, A. ^[4]

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1. Institute of Space and Astronautical Science JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
2. Harvard Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States)
3. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
4. Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Kraków (Poland)

Here we analyze radio, optical, and X-ray data for the peculiar cluster Abell 578. This cluster is not fully relaxed and consists of two merging sub-systems. The brightest cluster galaxy (BCG), CGPG 0719.8+6704, is a pair of interacting ellipticals with projected separation ∼10 kpc, the brighter of which hosts the radio source 4C+67.13. The Fanaroff–Riley type-II radio morphology of 4C+67.13 is unusual for central radio galaxies in local Abell clusters. Our new optical spectroscopy revealed that both nuclei of the CGPG 0719.8+6704 pair are active, albeit at low accretion rates corresponding to the Eddington ratio ∼10{sup −4} (for the estimated black hole masses of ∼3×10{sup 8} M{sub ⊙} and ∼10{sup 9} M{sub ⊙}). The gathered X-ray (Chandra) data allowed us to confirm and to quantify robustly the previously noted elongation of the gaseous atmosphere in the dominant sub-cluster, as well as a large spatial offset (∼60 kpc projected) between the position of the BCG and the cluster center inferred from the modeling of the X-ray surface brightness distribution. Detailed analysis of the brightness profiles and temperature revealed also that the cluster gas in the vicinity of 4C+67.13 is compressed (by a factor of about ∼1.4) and heated (from ≃2.0 keV up to 2.7 keV), consistent with the presence of a weak shock (Mach number ∼1.3) driven by the expanding jet cocoon. This would then require the jet kinetic power of the order of ∼10{sup 45} erg s{sup −1}, implying either a very high efficiency of the jet production for the current accretion rate, or a highly modulated jet/accretion activity in the system.

• OSTI ID: 22883156
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 805; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BLACK HOLES
BRIGHTNESS
COMPUTERIZED SIMULATION
DISTRIBUTION
EFFICIENCY
GALAXY CLUSTERS
GALAXY NUCLEI
INTERGALACTIC SPACE
KEV RANGE 01-10
MACH NUMBER
MASS
RADIO GALAXIES
SPECTROSCOPY
STELLAR ATMOSPHERES