Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45
The baryon cycle is crucial for understanding galaxy formation, as gas inflows and outflows vary throughout a galaxy’s lifetime and affect its star formation rate. Despite the necessity of accretion for galaxy growth at high redshifts, direct observations of inflowing gas have proven elusive, especi...
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/ad93d0 |
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| author | Erin Coleman Keerthi Vasan G.C. Yuguang Chen Tucker Jones Sunny Rhoades Richard Ellis Dan Stark Nicha Leethochawalit Ryan Sanders Kris Mortensen Karl Glazebrook Glenn G. Kacprzak |
| author_facet | Erin Coleman Keerthi Vasan G.C. Yuguang Chen Tucker Jones Sunny Rhoades Richard Ellis Dan Stark Nicha Leethochawalit Ryan Sanders Kris Mortensen Karl Glazebrook Glenn G. Kacprzak |
| author_sort | Erin Coleman |
| collection | DOAJ |
| description | The baryon cycle is crucial for understanding galaxy formation, as gas inflows and outflows vary throughout a galaxy’s lifetime and affect its star formation rate. Despite the necessity of accretion for galaxy growth at high redshifts, direct observations of inflowing gas have proven elusive, especially at z ≳ 2. We present a spectroscopic analysis of a galaxy at redshift z = 2.45, which exhibits signs of inflow in several ultraviolet interstellar absorption lines, with no clear outflow signatures. The absorption lines are redshifted by ∼250 km s ^−1 with respect to the systemic redshift, and C iv shows a prominent inverse P-Cygni profile. Simple stellar population models suggest that this galaxy has a low metallicity (∼5% solar), with a very young starburst of age ∼4 Myr dominating the ultraviolet luminosity. The gas inflow velocity and nebular velocity dispersion suggest an approximate halo mass of order ∼10 ^11 M _⊙ , a regime in which simulations predict that bursty star formation is common at this redshift. We conclude that this system is likely in the beginning of a cycle of bursty star formation, where inflow and star formation rates are high, but where supernovae and other feedback processes have not yet launched strong outflows. In this scenario, we expect the inflow-dominated phase to be observable (e.g., with net redshifted interstellar medium absorption) for only a short timescale after a starburst onset. This result represents a promising avenue for probing the full baryon cycle, including inflows, during the formative phases of low-mass galaxies at high redshifts. |
| format | Article |
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| institution | OA Journals |
| issn | 2041-8205 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-840fb8e83fd74c24894a49c35cfa421c2025-08-20T02:09:05ZengIOP PublishingThe Astrophysical Journal Letters2041-82052024-01-019771L2310.3847/2041-8213/ad93d0Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45Erin Coleman0https://orcid.org/0009-0008-3927-4638Keerthi Vasan G.C.1https://orcid.org/0000-0002-2645-679XYuguang Chen2https://orcid.org/0000-0003-4520-5395Tucker Jones3https://orcid.org/0000-0001-5860-3419Sunny Rhoades4https://orcid.org/0009-0007-0184-8176Richard Ellis5https://orcid.org/0000-0001-7782-7071Dan Stark6Nicha Leethochawalit7https://orcid.org/0000-0003-4570-3159Ryan Sanders8https://orcid.org/0000-0003-4792-9119Kris Mortensen9https://orcid.org/0000-0001-9676-5005Karl Glazebrook10https://orcid.org/0000-0002-3254-9044Glenn G. Kacprzak11https://orcid.org/0000-0003-1362-9302Department of Physics, Gustavus Adolphus College , 800 W College Avenue, Saint Peter, MN 56082, USA ; coleman@gustavus.eduDepartment of Physics and Astronomy, University of California Davis , 1 Shields Avenue, Davis, CA 95616, USA; The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101, USADepartment of Physics and Astronomy, University of California Davis , 1 Shields Avenue, Davis, CA 95616, USADepartment of Physics and Astronomy, University of California Davis , 1 Shields Avenue, Davis, CA 95616, USADepartment of Physics and Astronomy, University of California Davis , 1 Shields Avenue, Davis, CA 95616, USADepartment of Physics & Astronomy, University College London , Gower Street, London WC1E 6BT, UKSteward Observatory, University of Arizona , 933 N Cherry Avenue, Tucson, AZ 85721, USANational Astronomical Research Institute of Thailand (NARIT) , Mae Rim, Chiang Mai, 50180, ThailandDepartment of Physics and Astronomy, University of Kentucky , 505 Rose Street, Lexington, KY 40506, USADepartment of Physics and Astronomy, University of California Davis , 1 Shields Avenue, Davis, CA 95616, USACentre for Astrophysics and Supercomputing, Swinburne University of Technology , Hawthorn, Victoria 3122, Australia; ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) , AustraliaCentre for Astrophysics and Supercomputing, Swinburne University of Technology , Hawthorn, Victoria 3122, Australia; ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) , AustraliaThe baryon cycle is crucial for understanding galaxy formation, as gas inflows and outflows vary throughout a galaxy’s lifetime and affect its star formation rate. Despite the necessity of accretion for galaxy growth at high redshifts, direct observations of inflowing gas have proven elusive, especially at z ≳ 2. We present a spectroscopic analysis of a galaxy at redshift z = 2.45, which exhibits signs of inflow in several ultraviolet interstellar absorption lines, with no clear outflow signatures. The absorption lines are redshifted by ∼250 km s ^−1 with respect to the systemic redshift, and C iv shows a prominent inverse P-Cygni profile. Simple stellar population models suggest that this galaxy has a low metallicity (∼5% solar), with a very young starburst of age ∼4 Myr dominating the ultraviolet luminosity. The gas inflow velocity and nebular velocity dispersion suggest an approximate halo mass of order ∼10 ^11 M _⊙ , a regime in which simulations predict that bursty star formation is common at this redshift. We conclude that this system is likely in the beginning of a cycle of bursty star formation, where inflow and star formation rates are high, but where supernovae and other feedback processes have not yet launched strong outflows. In this scenario, we expect the inflow-dominated phase to be observable (e.g., with net redshifted interstellar medium absorption) for only a short timescale after a starburst onset. This result represents a promising avenue for probing the full baryon cycle, including inflows, during the formative phases of low-mass galaxies at high redshifts.https://doi.org/10.3847/2041-8213/ad93d0Galaxy formationGalaxy evolutionHigh-redshift galaxiesCircumgalactic mediumInterstellar absorption |
| spellingShingle | Erin Coleman Keerthi Vasan G.C. Yuguang Chen Tucker Jones Sunny Rhoades Richard Ellis Dan Stark Nicha Leethochawalit Ryan Sanders Kris Mortensen Karl Glazebrook Glenn G. Kacprzak Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45 The Astrophysical Journal Letters Galaxy formation Galaxy evolution High-redshift galaxies Circumgalactic medium Interstellar absorption |
| title | Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45 |
| title_full | Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45 |
| title_fullStr | Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45 |
| title_full_unstemmed | Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45 |
| title_short | Detection of Gas Inflow during the Onset of a Starburst in a Low-mass Galaxy at z = 2.45 |
| title_sort | detection of gas inflow during the onset of a starburst in a low mass galaxy at z 2 45 |
| topic | Galaxy formation Galaxy evolution High-redshift galaxies Circumgalactic medium Interstellar absorption |
| url | https://doi.org/10.3847/2041-8213/ad93d0 |
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