Enhancement of AGN in a protocluster at z=1.6
We investigate the prevalence of AGN in the high-redshift protocluster Cl 0218.3–0510 at z = 1.62. Using imaging from the Chandra X-ray Telescope, we find a large overdensity of AGN in the protocluster; a factor of 23±9 times the field density of AGN. Only half of this AGN overdensity is due to the...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
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Oxford University Press
2017
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| Online Access: | https://eprints.nottingham.ac.uk/43363/ |
| _version_ | 1848796671037669376 |
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| author | Krishnan, Charutha Hatch, Nina A. Almaini, Omar Kocevski, Dale Cooke, Elizabeth A. Hartley, William G. Hasinger, Guenther Maltby, David T. Muldrew, Stuart I. Simpson, Chris |
| author_facet | Krishnan, Charutha Hatch, Nina A. Almaini, Omar Kocevski, Dale Cooke, Elizabeth A. Hartley, William G. Hasinger, Guenther Maltby, David T. Muldrew, Stuart I. Simpson, Chris |
| author_sort | Krishnan, Charutha |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | We investigate the prevalence of AGN in the high-redshift protocluster Cl 0218.3–0510 at z = 1.62. Using imaging from the Chandra X-ray Telescope, we find a large overdensity of AGN in the protocluster; a factor of 23±9 times the field density of AGN. Only half of this AGN overdensity is due to the overdensity of massive galaxies in the protocluster (a factor of 11±2), as we find that 17+6−5% of massive galaxies (M∗ > 1010M⊙) in the protocluster host an X-ray luminous AGN, compared to 8±1% in the field. This corresponds to an enhancement of AGN activity in massive protocluster galaxies by a factor of 2.1±0.7 at 1.6s significance. We also find that the AGN overdensity is centrally concentrated, located within 3 arcmin and most pronounced within 1 arcmin of the centre of the protocluster. Our results confirm that there is a reversal in the local anti-correlation between galaxy density and AGN activity, so there is an enhancement of AGN in high-redshift protoclusters. We compare the properties of AGN in the protocluster to the field and find no significant differences in the distributions of their stellar mass, X-ray luminosity, or hardness ratio. We therefore suggest that triggering mechanisms are similar in both environments, and that the mechanisms simply occur more frequently in denser environments. |
| first_indexed | 2025-11-14T19:51:41Z |
| format | Article |
| id | nottingham-43363 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:51:41Z |
| publishDate | 2017 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-433632020-05-04T18:47:33Z https://eprints.nottingham.ac.uk/43363/ Enhancement of AGN in a protocluster at z=1.6 Krishnan, Charutha Hatch, Nina A. Almaini, Omar Kocevski, Dale Cooke, Elizabeth A. Hartley, William G. Hasinger, Guenther Maltby, David T. Muldrew, Stuart I. Simpson, Chris We investigate the prevalence of AGN in the high-redshift protocluster Cl 0218.3–0510 at z = 1.62. Using imaging from the Chandra X-ray Telescope, we find a large overdensity of AGN in the protocluster; a factor of 23±9 times the field density of AGN. Only half of this AGN overdensity is due to the overdensity of massive galaxies in the protocluster (a factor of 11±2), as we find that 17+6−5% of massive galaxies (M∗ > 1010M⊙) in the protocluster host an X-ray luminous AGN, compared to 8±1% in the field. This corresponds to an enhancement of AGN activity in massive protocluster galaxies by a factor of 2.1±0.7 at 1.6s significance. We also find that the AGN overdensity is centrally concentrated, located within 3 arcmin and most pronounced within 1 arcmin of the centre of the protocluster. Our results confirm that there is a reversal in the local anti-correlation between galaxy density and AGN activity, so there is an enhancement of AGN in high-redshift protoclusters. We compare the properties of AGN in the protocluster to the field and find no significant differences in the distributions of their stellar mass, X-ray luminosity, or hardness ratio. We therefore suggest that triggering mechanisms are similar in both environments, and that the mechanisms simply occur more frequently in denser environments. Oxford University Press 2017-05-29 Article PeerReviewed Krishnan, Charutha, Hatch, Nina A., Almaini, Omar, Kocevski, Dale, Cooke, Elizabeth A., Hartley, William G., Hasinger, Guenther, Maltby, David T., Muldrew, Stuart I. and Simpson, Chris (2017) Enhancement of AGN in a protocluster at z=1.6. Monthly Notices of the Royal Astronomical Society, 470 (2). pp. 2170-2178. ISSN 1365-2966 galaxies: active – galaxies: clusters: individual: Cl 0218.3−0510 https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stx1315 doi:10.1093/mnras/stx1315 doi:10.1093/mnras/stx1315 |
| spellingShingle | galaxies: active – galaxies: clusters: individual: Cl 0218.3−0510 Krishnan, Charutha Hatch, Nina A. Almaini, Omar Kocevski, Dale Cooke, Elizabeth A. Hartley, William G. Hasinger, Guenther Maltby, David T. Muldrew, Stuart I. Simpson, Chris Enhancement of AGN in a protocluster at z=1.6 |
| title | Enhancement of AGN in a protocluster at z=1.6 |
| title_full | Enhancement of AGN in a protocluster at z=1.6 |
| title_fullStr | Enhancement of AGN in a protocluster at z=1.6 |
| title_full_unstemmed | Enhancement of AGN in a protocluster at z=1.6 |
| title_short | Enhancement of AGN in a protocluster at z=1.6 |
| title_sort | enhancement of agn in a protocluster at z=1.6 |
| topic | galaxies: active – galaxies: clusters: individual: Cl 0218.3−0510 |
| url | https://eprints.nottingham.ac.uk/43363/ https://eprints.nottingham.ac.uk/43363/ https://eprints.nottingham.ac.uk/43363/ |