A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5
We use a large sample of ∼350,000 galaxies constructed by combining the UKIDSS UDS, VIDEO/CFHT-LS, UltraVISTA/COSMOS and GAMA survey regions to probe the major merging histories of massive galaxies (>1010 M⊙) at 0.005<z<3.5. We use a method adapted from that presented in Lopez-Sanjuan et al...
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Oxford University Press
2017
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| Online Access: | https://eprints.nottingham.ac.uk/43612/ |
| _version_ | 1848796728400019456 |
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| author | Mundy, Carl J. Conselice, Christopher J. Duncan, Kenneth J. Almaini, Omar Häußler, Boris Hartley, William G. |
| author_facet | Mundy, Carl J. Conselice, Christopher J. Duncan, Kenneth J. Almaini, Omar Häußler, Boris Hartley, William G. |
| author_sort | Mundy, Carl J. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | We use a large sample of ∼350,000 galaxies constructed by combining the UKIDSS UDS, VIDEO/CFHT-LS, UltraVISTA/COSMOS and GAMA survey regions to probe the major merging histories of massive galaxies (>1010 M⊙) at 0.005<z<3.5. We use a method adapted from that presented in Lopez-Sanjuan et al. (2014) using the full photometric redshift probability distributions, to measure pair fractions of flux-limited, stellar mass selected galaxy samples using close-pair statistics. The pair fraction is found to weakly evolve as ∝(1+z)0.8 with no dependence on stellar mass. We subsequently derive major merger rates for galaxies at >1010 M⊙ and at a constant number density of n>10−4 Mpc−3, and find rates a factor of 2-3 smaller than previous works, although this depends strongly on the assumed merger timescale and likelihood of a close-pair merging. Galaxies undergo approximately 0.5 major mergers at z<3.5, accruing an additional 1-4 ×1010 M⊙ in the process. Major merger accretion rate densities of ∼2×10−4 M⊙ yr−1 Mpc−3 are found for number density selected samples, indicating that direct progenitors of local massive (>1011M⊙) galaxies have experienced a steady supply of stellar mass via major mergers throughout their evolution. While pair fractions are found to agree with those predicted by the Henriques et al. (2014) semi-analytic model, the Illustris hydrodynamical simulation fails to quantitatively reproduce derived merger rates. Furthermore, we find major mergers become a comparable source of stellar mass growth compared to star-formation at z<1, but is 10-100 times smaller than the SFR density at higher redshifts. |
| first_indexed | 2025-11-14T19:52:36Z |
| format | Article |
| id | nottingham-43612 |
| institution | University of Nottingham Malaysia Campus |
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| last_indexed | 2025-11-14T19:52:36Z |
| publishDate | 2017 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-436122024-08-15T15:22:36Z https://eprints.nottingham.ac.uk/43612/ A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5 Mundy, Carl J. Conselice, Christopher J. Duncan, Kenneth J. Almaini, Omar Häußler, Boris Hartley, William G. We use a large sample of ∼350,000 galaxies constructed by combining the UKIDSS UDS, VIDEO/CFHT-LS, UltraVISTA/COSMOS and GAMA survey regions to probe the major merging histories of massive galaxies (>1010 M⊙) at 0.005<z<3.5. We use a method adapted from that presented in Lopez-Sanjuan et al. (2014) using the full photometric redshift probability distributions, to measure pair fractions of flux-limited, stellar mass selected galaxy samples using close-pair statistics. The pair fraction is found to weakly evolve as ∝(1+z)0.8 with no dependence on stellar mass. We subsequently derive major merger rates for galaxies at >1010 M⊙ and at a constant number density of n>10−4 Mpc−3, and find rates a factor of 2-3 smaller than previous works, although this depends strongly on the assumed merger timescale and likelihood of a close-pair merging. Galaxies undergo approximately 0.5 major mergers at z<3.5, accruing an additional 1-4 ×1010 M⊙ in the process. Major merger accretion rate densities of ∼2×10−4 M⊙ yr−1 Mpc−3 are found for number density selected samples, indicating that direct progenitors of local massive (>1011M⊙) galaxies have experienced a steady supply of stellar mass via major mergers throughout their evolution. While pair fractions are found to agree with those predicted by the Henriques et al. (2014) semi-analytic model, the Illustris hydrodynamical simulation fails to quantitatively reproduce derived merger rates. Furthermore, we find major mergers become a comparable source of stellar mass growth compared to star-formation at z<1, but is 10-100 times smaller than the SFR density at higher redshifts. Oxford University Press 2017-05-20 Article PeerReviewed Mundy, Carl J., Conselice, Christopher J., Duncan, Kenneth J., Almaini, Omar, Häußler, Boris and Hartley, William G. (2017) A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5. Monthly Notices of the Royal Astronomical Society . ISSN 1365-2966 (In Press) galaxies: evolution - galaxies: formation - galaxies: high-redshift |
| spellingShingle | galaxies: evolution - galaxies: formation - galaxies: high-redshift Mundy, Carl J. Conselice, Christopher J. Duncan, Kenneth J. Almaini, Omar Häußler, Boris Hartley, William G. A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5 |
| title | A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5 |
| title_full | A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5 |
| title_fullStr | A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5 |
| title_full_unstemmed | A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5 |
| title_short | A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at z < 3:5 |
| title_sort | consistent measure of the merger histories of massive galaxies using close-pair statistics i: major mergers at z < 3:5 |
| topic | galaxies: evolution - galaxies: formation - galaxies: high-redshift |
| url | https://eprints.nottingham.ac.uk/43612/ |