A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments
We present results from a narrow-band survey of the field around the high-redshift radio galaxy MRC 2104−242. We have selected Hα emitters in a 7 arcmin2 field and compared the measured number density with that of a field sample at similar redshift. We find that MRC 2104−242 lies in an overdensity o...
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| Format: | Article |
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Oxford University Press
2014
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| Online Access: | https://eprints.nottingham.ac.uk/37219/ |
| _version_ | 1848795416307433472 |
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| author | Cooke, E.A. Hatch, Nina A. Muldrew, S.I. Rigby, E.E. Kurk, J.D. |
| author_facet | Cooke, E.A. Hatch, Nina A. Muldrew, S.I. Rigby, E.E. Kurk, J.D. |
| author_sort | Cooke, E.A. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | We present results from a narrow-band survey of the field around the high-redshift radio galaxy MRC 2104−242. We have selected Hα emitters in a 7 arcmin2 field and compared the measured number density with that of a field sample at similar redshift. We find that MRC 2104−242 lies in an overdensity of galaxies that is 8.0 ± 0.8 times the average density of a blank field, suggesting it resides in a large-scale structure that may eventually collapse to form a massive cluster. We find that there is more dust obscured star formation in the protocluster galaxies than in similarly selected control field galaxies and there is tentative evidence of a higher fraction of starbursting galaxies in the denser environment. However, on average we do not find a difference between the star formation rate (SFR)–mass relations of the protocluster and field galaxies and so conclude that the SFR of these galaxies at z ∼ 2.5 is governed predominantly by galaxy mass and not the host environment. We also find that the stellar mass distribution of the protocluster galaxies is skewed towards higher masses and there is a significant lack of galaxies at M < 1010M_ within our small field of view. Based on the level of overdensity we expect to find ∼22 star-forming galaxies below 1010M_ in the protocluster and do not detect any. This lack of low-mass galaxies affects the level of overdensity which we detect. If we only consider high-mass (M > 1010.5M_) galaxies, the density of the protocluster field increases to ∼55 times the control field density. |
| first_indexed | 2025-11-14T19:31:44Z |
| format | Article |
| id | nottingham-37219 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:31:44Z |
| publishDate | 2014 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-372192020-05-04T16:46:31Z https://eprints.nottingham.ac.uk/37219/ A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments Cooke, E.A. Hatch, Nina A. Muldrew, S.I. Rigby, E.E. Kurk, J.D. We present results from a narrow-band survey of the field around the high-redshift radio galaxy MRC 2104−242. We have selected Hα emitters in a 7 arcmin2 field and compared the measured number density with that of a field sample at similar redshift. We find that MRC 2104−242 lies in an overdensity of galaxies that is 8.0 ± 0.8 times the average density of a blank field, suggesting it resides in a large-scale structure that may eventually collapse to form a massive cluster. We find that there is more dust obscured star formation in the protocluster galaxies than in similarly selected control field galaxies and there is tentative evidence of a higher fraction of starbursting galaxies in the denser environment. However, on average we do not find a difference between the star formation rate (SFR)–mass relations of the protocluster and field galaxies and so conclude that the SFR of these galaxies at z ∼ 2.5 is governed predominantly by galaxy mass and not the host environment. We also find that the stellar mass distribution of the protocluster galaxies is skewed towards higher masses and there is a significant lack of galaxies at M < 1010M_ within our small field of view. Based on the level of overdensity we expect to find ∼22 star-forming galaxies below 1010M_ in the protocluster and do not detect any. This lack of low-mass galaxies affects the level of overdensity which we detect. If we only consider high-mass (M > 1010.5M_) galaxies, the density of the protocluster field increases to ∼55 times the control field density. Oxford University Press 2014-04-17 Article PeerReviewed Cooke, E.A., Hatch, Nina A., Muldrew, S.I., Rigby, E.E. and Kurk, J.D. (2014) A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments. Monthly Notices of the Royal Astronomical Society, 440 (4). pp. 3262-3274. ISSN 1365-2966 Cluster galaxies MRC 2104-242 High-redshift galaxies http://dx.doi.org/10.1093/mnras/stu522 doi:10.1093/mnras/stu522 doi:10.1093/mnras/stu522 |
| spellingShingle | Cluster galaxies MRC 2104-242 High-redshift galaxies Cooke, E.A. Hatch, Nina A. Muldrew, S.I. Rigby, E.E. Kurk, J.D. A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments |
| title | A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments |
| title_full | A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments |
| title_fullStr | A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments |
| title_full_unstemmed | A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments |
| title_short | A z = 2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments |
| title_sort | z = 2.5 protocluster associated with the radio galaxy mrc 2104-242: star formation and differing mass functions in dense environments |
| topic | Cluster galaxies MRC 2104-242 High-redshift galaxies |
| url | https://eprints.nottingham.ac.uk/37219/ https://eprints.nottingham.ac.uk/37219/ https://eprints.nottingham.ac.uk/37219/ |