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Discovery of a Powerful >1061 erg AGN Outburst in the Distant Galaxy Cluster SPT-CLJ0528-5300

Calzadilla, Michael S.; McDonald, Michael; Bayliss, Matthew; Benson, Bradford A.; Bleem, Lindsey E.; Brodwin, Mark; Edge, Alastair C.; Floyd, Benjamin; Gupta, Nikhel; Hlavacek-Larrondo, Julie; McNamara, Brian R.; Reichardt, Christian L.

Discovery of a Powerful >1061 erg AGN Outburst in the Distant Galaxy Cluster SPT-CLJ0528-5300 Thumbnail


Michael S. Calzadilla

Michael McDonald

Matthew Bayliss

Bradford A. Benson

Lindsey E. Bleem

Mark Brodwin

Benjamin Floyd

Nikhel Gupta

Julie Hlavacek-Larrondo

Brian R. McNamara

Christian L. Reichardt


We present ~103 ks of Chandra observations of the galaxy cluster SPT-CLJ0528-5300 (SPT0528, z = 0.768). This cluster harbors the most radio-loud (L 1.4GHz = 1.01 × 1033 erg s−1 Hz−1) central active galactic nucleus (AGN) of any cluster in the South Pole Telescope (SPT) Sunyaev–Zeldovich survey with available X-ray data. We find evidence of AGN-inflated cavities in the X-ray emission, which are consistent with the orientation of the jet direction revealed by Australia Telescope Compact Array radio data. The combined probability that two such depressions—each at ~1.4–1.8σ significance, oriented ~180° apart and aligned with the jet axis—would occur by chance is 0.1%. At gsim1061 erg, the outburst in SPT0528 is among the most energetic known in the universe, and certainly the most powerful known at z > 0.25. This work demonstrates that such powerful outbursts can be detected even in shallow X-ray exposures out to relatively high redshifts (z ~ 0.8), providing an avenue for studying the evolution of extreme AGN feedback. The ratio of the cavity power (${P}_{\mathrm{cav}}=(9.4\pm 5.8)\times {10}^{45}$ erg s−1) to the cooling luminosity (L cool = (1.5 ± 0.5) × 1044 erg s−1) for SPT0528 is among the highest measured to date. If, in the future, additional systems are discovered at similar redshifts with equally high P cav/L cool ratios, it would imply that the feedback/cooling cycle was not as gentle at high redshifts as in the low-redshift universe.


Calzadilla, M. S., McDonald, M., Bayliss, M., Benson, B. A., Bleem, L. E., Brodwin, M., …Reichardt, C. L. (2019). Discovery of a Powerful >1061 erg AGN Outburst in the Distant Galaxy Cluster SPT-CLJ0528-5300. Astrophysical Journal Letters, 887(1), Article L17.

Journal Article Type Article
Acceptance Date Nov 23, 2019
Online Publication Date Dec 10, 2019
Publication Date Dec 10, 2019
Deposit Date Jan 22, 2020
Publicly Available Date Jan 22, 2020
Journal Astrophysical Journal
Print ISSN 2041-8205
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 887
Issue 1
Article Number L17


Published Journal Article (1.5 Mb)

Copyright Statement
© 2019. The American Astronomical Society. All rights reserved.

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