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Title: Merger signatures in the galaxy cluster A98

Abstract

We present results from Chandra and XMM-Newton observations of Abell 98 (A98), a galaxy cluster with three major components: a relatively bright subcluster to the north (A98N), a disturbed subcluster to the south (A98S), and a fainter subcluster to the far south (A98SS). We find evidence for surface brightness and temperature asymmetries in A98N consistent with a shock-heated region to the south, which could be created by an early stage merger between A98N and A98S. Deeper observations are required to confirm this result. We also find that A98S has an asymmetric core temperature structure, likely due to a separate ongoing merger. Evidence for this is also seen in optical data. A98S hosts a wide-angle tail radio source powered by a central active galactic nucleus (AGN). We find evidence for a cavity in the intracluster medium that has been evacuated by one of the radio lobes, suggesting that AGN feedback is operating in this system. Examples of cavities in non-cool core clusters are relatively rare. The three subclusters lie along a line in projection, suggesting the presence of a large-scale filament. We observe emission along the filament between A98N and A98S, and a surface brightness profile shows emission consistent with themore » overlap of the subcluster extended gas halos. We find the temperature of this region is consistent with the temperature of the gas at similar radii outside this bridge region. Lastly, we examine the cluster dynamics using optical data. We conclude A98N and A98S are likely bound to one another with a 67% probability, while A98S and A98SS are not bound at a high level of significance.« less

Authors:
;  [1]; ; ; ; ;  [2];  [3]
  1. Astronomy Department and Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States)
  2. Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  3. Department of Physics, Gettysburg College, Gettysburg, PA 17325 (United States)
Publication Date:
OSTI Identifier:
22365313
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 791; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMMETRY; BRIGHTNESS; EMISSION; FEEDBACK; GALAXY CLUSTERS; GALAXY NUCLEI; INTERACTIONS; PROBABILITY; SURFACES; X-RAY GALAXIES

Citation Formats

Paterno-Mahler, R., Blanton, E. L., Randall, S. W., Bulbul, E., Andrade-Santos, F., Jones, C., Murray, S., and Johnson, R. E., E-mail: rachelpm@bu.edu, E-mail: eblanton@bu.edu, E-mail: srandall@head.cfa.harvard.edu, E-mail: ebulbul@head.cfa.harvard.edu, E-mail: fsantos@cfa.harvard.edu, E-mail: cjones@cfa.harvard.edu, E-mail: ssm@pha.jhu.edu, E-mail: rjohnson@gettysburg.edu. Merger signatures in the galaxy cluster A98. United States: N. p., 2014. Web. doi:10.1088/0004-637X/791/2/104.
Paterno-Mahler, R., Blanton, E. L., Randall, S. W., Bulbul, E., Andrade-Santos, F., Jones, C., Murray, S., & Johnson, R. E., E-mail: rachelpm@bu.edu, E-mail: eblanton@bu.edu, E-mail: srandall@head.cfa.harvard.edu, E-mail: ebulbul@head.cfa.harvard.edu, E-mail: fsantos@cfa.harvard.edu, E-mail: cjones@cfa.harvard.edu, E-mail: ssm@pha.jhu.edu, E-mail: rjohnson@gettysburg.edu. Merger signatures in the galaxy cluster A98. United States. doi:10.1088/0004-637X/791/2/104.
Paterno-Mahler, R., Blanton, E. L., Randall, S. W., Bulbul, E., Andrade-Santos, F., Jones, C., Murray, S., and Johnson, R. E., E-mail: rachelpm@bu.edu, E-mail: eblanton@bu.edu, E-mail: srandall@head.cfa.harvard.edu, E-mail: ebulbul@head.cfa.harvard.edu, E-mail: fsantos@cfa.harvard.edu, E-mail: cjones@cfa.harvard.edu, E-mail: ssm@pha.jhu.edu, E-mail: rjohnson@gettysburg.edu. Wed . "Merger signatures in the galaxy cluster A98". United States. doi:10.1088/0004-637X/791/2/104.
@article{osti_22365313,
title = {Merger signatures in the galaxy cluster A98},
author = {Paterno-Mahler, R. and Blanton, E. L. and Randall, S. W. and Bulbul, E. and Andrade-Santos, F. and Jones, C. and Murray, S. and Johnson, R. E., E-mail: rachelpm@bu.edu, E-mail: eblanton@bu.edu, E-mail: srandall@head.cfa.harvard.edu, E-mail: ebulbul@head.cfa.harvard.edu, E-mail: fsantos@cfa.harvard.edu, E-mail: cjones@cfa.harvard.edu, E-mail: ssm@pha.jhu.edu, E-mail: rjohnson@gettysburg.edu},
abstractNote = {We present results from Chandra and XMM-Newton observations of Abell 98 (A98), a galaxy cluster with three major components: a relatively bright subcluster to the north (A98N), a disturbed subcluster to the south (A98S), and a fainter subcluster to the far south (A98SS). We find evidence for surface brightness and temperature asymmetries in A98N consistent with a shock-heated region to the south, which could be created by an early stage merger between A98N and A98S. Deeper observations are required to confirm this result. We also find that A98S has an asymmetric core temperature structure, likely due to a separate ongoing merger. Evidence for this is also seen in optical data. A98S hosts a wide-angle tail radio source powered by a central active galactic nucleus (AGN). We find evidence for a cavity in the intracluster medium that has been evacuated by one of the radio lobes, suggesting that AGN feedback is operating in this system. Examples of cavities in non-cool core clusters are relatively rare. The three subclusters lie along a line in projection, suggesting the presence of a large-scale filament. We observe emission along the filament between A98N and A98S, and a surface brightness profile shows emission consistent with the overlap of the subcluster extended gas halos. We find the temperature of this region is consistent with the temperature of the gas at similar radii outside this bridge region. Lastly, we examine the cluster dynamics using optical data. We conclude A98N and A98S are likely bound to one another with a 67% probability, while A98S and A98SS are not bound at a high level of significance.},
doi = {10.1088/0004-637X/791/2/104},
journal = {Astrophysical Journal},
number = 2,
volume = 791,
place = {United States},
year = {Wed Aug 20 00:00:00 EDT 2014},
month = {Wed Aug 20 00:00:00 EDT 2014}
}
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