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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2509.02672 |
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| _version_ | 1866916026534330368 |
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| author | Chaudhary, Reena Joshi, Ravi Das, Sarbeswar Fumagalli, Michele Kacprzak, Glenn G. Fossati, Matteo Péroux, Celine Ho, Luis C. |
| author_facet | Chaudhary, Reena Joshi, Ravi Das, Sarbeswar Fumagalli, Michele Kacprzak, Glenn G. Fossati, Matteo Péroux, Celine Ho, Luis C. |
| contents | We investigate the origin of intervening cool MgII absorption detected in the spectra of background quasars and the nature of associated galaxies across a broad redshift range of $0.3 \le z \le 1.6$. Using nebular [O II] $λλ$3727,3729 emission lines identified in DESI fiber spectra centered on quasar, we detect 377 galaxies at a typical detection rate of $\sim$0.45% at $z \lesssim 1$, which increases with MgII equivalent width ($W_{2796}$). A significant fraction (74%) of these galaxies are associated with strong absorbers with $W_{2796} \ge$ 2Å. These absorbers trace galaxies spanning stellar masses of $\rm 8.4 \le \log(M_{\star}/M_{\odot}) \le 11.6$ and star formation rates (SFRs) of $\rm -1.2 \le log(SFR~[M_{\odot}yr^{-1}]) \le 2.7$, located at projected galactocentric distances of 4-24 kpc. We find the average MgII absorber strength increases from 2.1Å to 2.9Å between redshifts $z \sim$ 0.4 and 1.2, indicating evolution in the cool gas content of galaxy halos. The relatively constant absorber strength with galactocentric distance implies a clumpy structure of cool gas in the circumgalactic medium (CGM). Further, we find a positive correlation between $W_{2796}$ versus $M_\star$, and SFR, suggesting that the distribution of metal-enriched cool gas in the CGM is closely tied to the properties of the host galaxies. The redshift evolution of gas-phase metallicity suggests that strong MgII absorbers trace the general population of star-forming galaxies. The velocity dispersion of the cool gas increases with halo mass, and the wide range of line of sight velocity offset (-389 to 364 $\rm km\ s^{-1}$) between the galaxy systemic velocity and absorbers highlights the dynamical nature of CGM. However, the majority of this gas remains gravitationally bound to the dark matter halos, consistent with a picture of gas recycling via galactic fountains. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_02672 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Baryonic Ecosystem IN Galaxies (BEINGMgII) -- III. Cool gas reservoirs at $0.3 \le z \le 1.6$ in the Dark Energy Survey Chaudhary, Reena Joshi, Ravi Das, Sarbeswar Fumagalli, Michele Kacprzak, Glenn G. Fossati, Matteo Péroux, Celine Ho, Luis C. Astrophysics of Galaxies We investigate the origin of intervening cool MgII absorption detected in the spectra of background quasars and the nature of associated galaxies across a broad redshift range of $0.3 \le z \le 1.6$. Using nebular [O II] $λλ$3727,3729 emission lines identified in DESI fiber spectra centered on quasar, we detect 377 galaxies at a typical detection rate of $\sim$0.45% at $z \lesssim 1$, which increases with MgII equivalent width ($W_{2796}$). A significant fraction (74%) of these galaxies are associated with strong absorbers with $W_{2796} \ge$ 2Å. These absorbers trace galaxies spanning stellar masses of $\rm 8.4 \le \log(M_{\star}/M_{\odot}) \le 11.6$ and star formation rates (SFRs) of $\rm -1.2 \le log(SFR~[M_{\odot}yr^{-1}]) \le 2.7$, located at projected galactocentric distances of 4-24 kpc. We find the average MgII absorber strength increases from 2.1Å to 2.9Å between redshifts $z \sim$ 0.4 and 1.2, indicating evolution in the cool gas content of galaxy halos. The relatively constant absorber strength with galactocentric distance implies a clumpy structure of cool gas in the circumgalactic medium (CGM). Further, we find a positive correlation between $W_{2796}$ versus $M_\star$, and SFR, suggesting that the distribution of metal-enriched cool gas in the CGM is closely tied to the properties of the host galaxies. The redshift evolution of gas-phase metallicity suggests that strong MgII absorbers trace the general population of star-forming galaxies. The velocity dispersion of the cool gas increases with halo mass, and the wide range of line of sight velocity offset (-389 to 364 $\rm km\ s^{-1}$) between the galaxy systemic velocity and absorbers highlights the dynamical nature of CGM. However, the majority of this gas remains gravitationally bound to the dark matter halos, consistent with a picture of gas recycling via galactic fountains. |
| title | Baryonic Ecosystem IN Galaxies (BEINGMgII) -- III. Cool gas reservoirs at $0.3 \le z \le 1.6$ in the Dark Energy Survey |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2509.02672 |