Simulating High-redshift Galaxies: Enhancing UV Luminosity with Star Formation Efficiency and a Top-heavy IMF
Recent findings from photometric and spectroscopic JWST surveys have identified examples of high-redshift galaxies at z ≳ 10. These high- z galaxies appear to form much earlier and exhibit greater UV luminosity than predicted by theoretical work. In this study, our goal is to reproduce the brightne...
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2025-01-01
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| author | Tae Bong Jeong Myoungwon Jeon Hyunmi Song Volker Bromm |
| author_facet | Tae Bong Jeong Myoungwon Jeon Hyunmi Song Volker Bromm |
| author_sort | Tae Bong Jeong |
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| description | Recent findings from photometric and spectroscopic JWST surveys have identified examples of high-redshift galaxies at z ≳ 10. These high- z galaxies appear to form much earlier and exhibit greater UV luminosity than predicted by theoretical work. In this study, our goal is to reproduce the brightness of these sources by simulating high-redshift galaxies with virial masses M _vir = 10 ^9 –10 ^10 M _⊙ at z > 10. To achieve this, we conduct cosmological hydrodynamic zoom-in simulations, modifying baryonic subgrid physics, and post-process our simulation results to confirm the observability of our simulated galaxies. Specifically, we enhanced star formation activity in high-redshift galaxies by either increasing the star formation efficiency up to 100% or adopting a top-heavy initial mass function (IMF). Our simulation results indicate that both increasing star formation efficiency and adopting a top-heavy IMF play crucial roles in boosting the UV luminosity of high-redshift galaxies, potentially exceeding the limiting magnitude of JWST surveys in earlier epochs. In particular, the episodic starburst resulting from enhanced star formation efficiency may explain the high-redshift galaxies observed by JWST, as it evacuates dust from star-forming regions, making the galaxies more observable. We demonstrate this correlation between star formation activity and dust mass evolution within the simulated galaxies. Also, adopting a top-heavy IMF could enhance observability due to an overabundance of massive stars, although it may also facilitate rapid metal enrichment. Using our simulation results, we derive several observables such as effective radius, UV slope, and emission-line rates, which could serve as valuable theoretical estimates for comparison with existing spectroscopic results and forthcoming data from the JWST NIRSpec and MIRI instruments. |
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| institution | Kabale University |
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| language | English |
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| series | The Astrophysical Journal |
| spelling | doaj-art-4d933cd2b58f4aecbd89e492814169ff2025-01-30T12:40:26ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198011010.3847/1538-4357/ada27dSimulating High-redshift Galaxies: Enhancing UV Luminosity with Star Formation Efficiency and a Top-heavy IMFTae Bong Jeong0https://orcid.org/0009-0000-8108-6456Myoungwon Jeon1https://orcid.org/0000-0001-6529-9777Hyunmi Song2https://orcid.org/0000-0002-4362-4070Volker Bromm3https://orcid.org/0000-0003-0212-2979School of Space Research, Kyung Hee University , 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Republic of Korea ; myjeon@khu.ac.krSchool of Space Research, Kyung Hee University , 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Republic of Korea ; myjeon@khu.ac.kr; Department of Astronomy & Space Science, Kyung Hee University , 1732 Deogyeong-daero, Yongin-si, Gyeonggi-do 17104, Republic of KoreaDepartment of Astronomy & Space Science, Chungnam National University , 99 Daehak-ro, Yoosung-gu, Daejeon 34134, Republic of KoreaDepartment of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA; Weinberg Institute for Theoretical Physics, University of Texas at Austin , Austin, TX 78712, USARecent findings from photometric and spectroscopic JWST surveys have identified examples of high-redshift galaxies at z ≳ 10. These high- z galaxies appear to form much earlier and exhibit greater UV luminosity than predicted by theoretical work. In this study, our goal is to reproduce the brightness of these sources by simulating high-redshift galaxies with virial masses M _vir = 10 ^9 –10 ^10 M _⊙ at z > 10. To achieve this, we conduct cosmological hydrodynamic zoom-in simulations, modifying baryonic subgrid physics, and post-process our simulation results to confirm the observability of our simulated galaxies. Specifically, we enhanced star formation activity in high-redshift galaxies by either increasing the star formation efficiency up to 100% or adopting a top-heavy initial mass function (IMF). Our simulation results indicate that both increasing star formation efficiency and adopting a top-heavy IMF play crucial roles in boosting the UV luminosity of high-redshift galaxies, potentially exceeding the limiting magnitude of JWST surveys in earlier epochs. In particular, the episodic starburst resulting from enhanced star formation efficiency may explain the high-redshift galaxies observed by JWST, as it evacuates dust from star-forming regions, making the galaxies more observable. We demonstrate this correlation between star formation activity and dust mass evolution within the simulated galaxies. Also, adopting a top-heavy IMF could enhance observability due to an overabundance of massive stars, although it may also facilitate rapid metal enrichment. Using our simulation results, we derive several observables such as effective radius, UV slope, and emission-line rates, which could serve as valuable theoretical estimates for comparison with existing spectroscopic results and forthcoming data from the JWST NIRSpec and MIRI instruments.https://doi.org/10.3847/1538-4357/ada27dJames Webb Space Telescope |
| spellingShingle | Tae Bong Jeong Myoungwon Jeon Hyunmi Song Volker Bromm Simulating High-redshift Galaxies: Enhancing UV Luminosity with Star Formation Efficiency and a Top-heavy IMF The Astrophysical Journal James Webb Space Telescope |
| title | Simulating High-redshift Galaxies: Enhancing UV Luminosity with Star Formation Efficiency and a Top-heavy IMF |
| title_full | Simulating High-redshift Galaxies: Enhancing UV Luminosity with Star Formation Efficiency and a Top-heavy IMF |
| title_fullStr | Simulating High-redshift Galaxies: Enhancing UV Luminosity with Star Formation Efficiency and a Top-heavy IMF |
| title_full_unstemmed | Simulating High-redshift Galaxies: Enhancing UV Luminosity with Star Formation Efficiency and a Top-heavy IMF |
| title_short | Simulating High-redshift Galaxies: Enhancing UV Luminosity with Star Formation Efficiency and a Top-heavy IMF |
| title_sort | simulating high redshift galaxies enhancing uv luminosity with star formation efficiency and a top heavy imf |
| topic | James Webb Space Telescope |
| url | https://doi.org/10.3847/1538-4357/ada27d |
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