The role of mergers and rejuvenation in the buildup of the quiescent population at cosmic noon
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| Autores principales: | , , , , , , , , |
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| Formato: | Preprint |
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2025
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| author | Harrold, Jimi Evan Almaini, Omar Pearce, Frazer R. Yates, Robert M. Maltby, Dave Rowlands, Kate Wild, Vivienne Skarbinski, Maya de Lisle, Thomas |
| author_facet | Harrold, Jimi Evan Almaini, Omar Pearce, Frazer R. Yates, Robert M. Maltby, Dave Rowlands, Kate Wild, Vivienne Skarbinski, Maya de Lisle, Thomas |
| contents | We investigate the quenching of galaxies using a mock observational lightcone generated from the Semi-Analytic Model (SAM) L-Galaxies, closely matched to observations from the UKIDSS Ultra Deep Survey (UDS). The sample is used to study merging, rejuvenation, and visibility times for star-forming, quiescent, and post-starburst (PSB) galaxies, to assess the impact on the build-up of the passive galaxy mass functions.
We find, for example, that a typical PSB ($M_\ast\sim10^{10}$\,M$_\odot$) at $z\approx1$ has a 15 per cent likelihood of merging and around a 25 per cent likelihood of rejuvenating within 1 Gyr of being identified. Applying these rates and timescales to the observational data, we estimate the fraction of quiescent galaxies that passed through a PSB phase. We find that $18 - 28$ per cent of the build-up in the massive end ($M_\ast>10^{10}$\,M$\,_\odot$) of the passive mass function at $1<z<2$ can be explained by PSBs, with the contribution declining to $\sim5$ per cent by $z \simeq 0.5$. Accounting for mergers and rejuvenation reduces the inferred PSB contribution by approximately a factor of two. At lower stellar masses ($M_\ast < 10^{10}$\,M$_\odot$), rapid quenching through a PSB phase explains a significantly larger fraction of the growth in the passive mass function. With a visibility time of $\sim$ 0.75 Gyr, we find that around $60-80$ per cent of low-mass passive galaxies underwent a PSB phase. Our findings provide further evidence that low- and high-mass galaxies follow different quenching pathways. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_14599 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The role of mergers and rejuvenation in the buildup of the quiescent population at cosmic noon Harrold, Jimi Evan Almaini, Omar Pearce, Frazer R. Yates, Robert M. Maltby, Dave Rowlands, Kate Wild, Vivienne Skarbinski, Maya de Lisle, Thomas Astrophysics of Galaxies We investigate the quenching of galaxies using a mock observational lightcone generated from the Semi-Analytic Model (SAM) L-Galaxies, closely matched to observations from the UKIDSS Ultra Deep Survey (UDS). The sample is used to study merging, rejuvenation, and visibility times for star-forming, quiescent, and post-starburst (PSB) galaxies, to assess the impact on the build-up of the passive galaxy mass functions. We find, for example, that a typical PSB ($M_\ast\sim10^{10}$\,M$_\odot$) at $z\approx1$ has a 15 per cent likelihood of merging and around a 25 per cent likelihood of rejuvenating within 1 Gyr of being identified. Applying these rates and timescales to the observational data, we estimate the fraction of quiescent galaxies that passed through a PSB phase. We find that $18 - 28$ per cent of the build-up in the massive end ($M_\ast>10^{10}$\,M$\,_\odot$) of the passive mass function at $1<z<2$ can be explained by PSBs, with the contribution declining to $\sim5$ per cent by $z \simeq 0.5$. Accounting for mergers and rejuvenation reduces the inferred PSB contribution by approximately a factor of two. At lower stellar masses ($M_\ast < 10^{10}$\,M$_\odot$), rapid quenching through a PSB phase explains a significantly larger fraction of the growth in the passive mass function. With a visibility time of $\sim$ 0.75 Gyr, we find that around $60-80$ per cent of low-mass passive galaxies underwent a PSB phase. Our findings provide further evidence that low- and high-mass galaxies follow different quenching pathways. |
| title | The role of mergers and rejuvenation in the buildup of the quiescent population at cosmic noon |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2512.14599 |