Galaxy protocluster candidates around z ~ 2.4 radio galaxies
We study the environments of six radio galaxies at 2.2 < z < 2.6 using wide-field near-infrared images. We use colour cuts to identify galaxies in this redshift range, and find that three of the radio galaxies are surrounded by significant surface overdensities of such galaxies. The excess gal...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
2011
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| Online Access: | http://hdl.handle.net/20.500.11937/11418 |
| _version_ | 1848747800174526464 |
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| author | Hatch, N. De Breuck, C. Galametz, A. Miley, G. Overzier, R. Röttgering, H. Doherty, M. Kodama, T. Kurk, J. Seymour, Nick Venemans, B. Vernet, J. Zirm, A. |
| author_facet | Hatch, N. De Breuck, C. Galametz, A. Miley, G. Overzier, R. Röttgering, H. Doherty, M. Kodama, T. Kurk, J. Seymour, Nick Venemans, B. Vernet, J. Zirm, A. |
| author_sort | Hatch, N. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We study the environments of six radio galaxies at 2.2 < z < 2.6 using wide-field near-infrared images. We use colour cuts to identify galaxies in this redshift range, and find that three of the radio galaxies are surrounded by significant surface overdensities of such galaxies. The excess galaxies that comprise these overdensities are strongly clustered, suggesting they are physically associated. The colour distribution of the galaxies responsible for the overdensity is consistent with those of galaxies that lie within a narrow redshift range at z~ 2.4. Thus the excess galaxies are consistent with being companions of the radio galaxies. The overdensities have estimated masses in excess of 1014 M☉, and are dense enough to collapse into virialized structures by the present day; these structures may evolve into groups or clusters of galaxies. A flux-limited sample of protocluster galaxies with K < 20.6 mag is derived by statistically subtracting the foreground and background galaxies. The colour distribution of the protocluster galaxies is bimodal, consisting of a dominant blue sequence, comprising 77 ± 10 per cent of the galaxies and a poorly populated red sequence. The blue protocluster galaxies have similar colours to local star-forming irregular galaxies (U−VAB~ 0.6), suggesting that most protocluster galaxies are still forming stars at the observed epoch. The blue colours and lack of a dominant protocluster red sequence imply that these cluster galaxies form the bulk of their stars at z≲ 3. |
| first_indexed | 2025-11-14T06:54:54Z |
| format | Journal Article |
| id | curtin-20.500.11937-11418 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:54:54Z |
| publishDate | 2011 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-114182017-09-13T14:56:20Z Galaxy protocluster candidates around z ~ 2.4 radio galaxies Hatch, N. De Breuck, C. Galametz, A. Miley, G. Overzier, R. Röttgering, H. Doherty, M. Kodama, T. Kurk, J. Seymour, Nick Venemans, B. Vernet, J. Zirm, A. We study the environments of six radio galaxies at 2.2 < z < 2.6 using wide-field near-infrared images. We use colour cuts to identify galaxies in this redshift range, and find that three of the radio galaxies are surrounded by significant surface overdensities of such galaxies. The excess galaxies that comprise these overdensities are strongly clustered, suggesting they are physically associated. The colour distribution of the galaxies responsible for the overdensity is consistent with those of galaxies that lie within a narrow redshift range at z~ 2.4. Thus the excess galaxies are consistent with being companions of the radio galaxies. The overdensities have estimated masses in excess of 1014 M☉, and are dense enough to collapse into virialized structures by the present day; these structures may evolve into groups or clusters of galaxies. A flux-limited sample of protocluster galaxies with K < 20.6 mag is derived by statistically subtracting the foreground and background galaxies. The colour distribution of the protocluster galaxies is bimodal, consisting of a dominant blue sequence, comprising 77 ± 10 per cent of the galaxies and a poorly populated red sequence. The blue protocluster galaxies have similar colours to local star-forming irregular galaxies (U−VAB~ 0.6), suggesting that most protocluster galaxies are still forming stars at the observed epoch. The blue colours and lack of a dominant protocluster red sequence imply that these cluster galaxies form the bulk of their stars at z≲ 3. 2011 Journal Article http://hdl.handle.net/20.500.11937/11418 10.1111/j.1365-2966.2010.17538.x fulltext |
| spellingShingle | Hatch, N. De Breuck, C. Galametz, A. Miley, G. Overzier, R. Röttgering, H. Doherty, M. Kodama, T. Kurk, J. Seymour, Nick Venemans, B. Vernet, J. Zirm, A. Galaxy protocluster candidates around z ~ 2.4 radio galaxies |
| title | Galaxy protocluster candidates around z ~ 2.4 radio galaxies |
| title_full | Galaxy protocluster candidates around z ~ 2.4 radio galaxies |
| title_fullStr | Galaxy protocluster candidates around z ~ 2.4 radio galaxies |
| title_full_unstemmed | Galaxy protocluster candidates around z ~ 2.4 radio galaxies |
| title_short | Galaxy protocluster candidates around z ~ 2.4 radio galaxies |
| title_sort | galaxy protocluster candidates around z ~ 2.4 radio galaxies |
| url | http://hdl.handle.net/20.500.11937/11418 |