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| Autori principali: | , , , , , , , , , , , , , , , |
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| Natura: | Preprint |
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2024
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| Accesso online: | https://arxiv.org/abs/2403.02399 |
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| _version_ | 1866913953455538176 |
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| author | Wang, Tao Sun, Hanwen Zhou, Luwenjia Xu, Ke Cheng, Cheng Li, Zhaozhou Chen, Yangyao Mo, H. J. Dekel, Avishai Yang, Tiacheng Wang, Yijun Zheng, Xianzhong Cai, Zheng Elbaz, David Dai, Y. -S. Huang, J. -S. |
| author_facet | Wang, Tao Sun, Hanwen Zhou, Luwenjia Xu, Ke Cheng, Cheng Li, Zhaozhou Chen, Yangyao Mo, H. J. Dekel, Avishai Yang, Tiacheng Wang, Yijun Zheng, Xianzhong Cai, Zheng Elbaz, David Dai, Y. -S. Huang, J. -S. |
| contents | Early JWST studies reporting an unexpected abundance of massive galaxies at $z \sim 5$--$8$ challenge galaxy formation models in the $Λ$CDM framework. Previous stellar mass ($M_\star$) estimates suffered from large uncertainties due to the lack of rest-frame near-infrared data. Using deep JWST/NIRCam and MIRI photometry from PRIMER, we systematically analyze massive galaxies at $z \sim 3$--$8$, leveraging rest-frame $\gtrsim 1\,μ$m constraints. We find MIRI is critical for robust $M_\star$ measurements for massive galaxies at $z > 5$: excluding MIRI overestimates $M_\star$ by $\sim 0.4$ dex on average for $M_\star > 10^{10}\,M_\odot$ galaxies, with no significant effects at lower masses. This reduces number densities of $M_\star > 10^{10}\,M_\odot$ ($10^{10.3}\,M_\odot$) galaxies by $\sim 36\%$ ($55\%$). MIRI inclusion also reduces ``Little Red Dot'' (LRD) contamination in massive galaxy samples, lowering the LRD fraction from $\sim 32\%$ to $\sim 13\%$ at $M_\star > 10^{10.3}\,M_\odot$. Assuming pure stellar origins, LRDs exhibit $M_\star \sim 10^{9\text{--}10.5}\,M_\odot$ with MIRI constraints, rarely exceeding $10^{10.5}\,M_\odot$. Within standard $Λ$CDM, our results indicate a moderate increase in the baryon-to-star conversion efficiency ($ε$) toward higher redshifts and masses at $z > 3$. For the most massive $z \sim 8$ galaxies, $ε\sim 0.3$, compared to $ε\lesssim 0.2$ for typical galaxies at $z < 3$. This result is consistent with models where high gas densities and short free-fall times suppress stellar feedback in massive high-$z$ halos. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_02399 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | JWST/MIRI reveals the true number density of massive galaxies in the early Universe Wang, Tao Sun, Hanwen Zhou, Luwenjia Xu, Ke Cheng, Cheng Li, Zhaozhou Chen, Yangyao Mo, H. J. Dekel, Avishai Yang, Tiacheng Wang, Yijun Zheng, Xianzhong Cai, Zheng Elbaz, David Dai, Y. -S. Huang, J. -S. Astrophysics of Galaxies Early JWST studies reporting an unexpected abundance of massive galaxies at $z \sim 5$--$8$ challenge galaxy formation models in the $Λ$CDM framework. Previous stellar mass ($M_\star$) estimates suffered from large uncertainties due to the lack of rest-frame near-infrared data. Using deep JWST/NIRCam and MIRI photometry from PRIMER, we systematically analyze massive galaxies at $z \sim 3$--$8$, leveraging rest-frame $\gtrsim 1\,μ$m constraints. We find MIRI is critical for robust $M_\star$ measurements for massive galaxies at $z > 5$: excluding MIRI overestimates $M_\star$ by $\sim 0.4$ dex on average for $M_\star > 10^{10}\,M_\odot$ galaxies, with no significant effects at lower masses. This reduces number densities of $M_\star > 10^{10}\,M_\odot$ ($10^{10.3}\,M_\odot$) galaxies by $\sim 36\%$ ($55\%$). MIRI inclusion also reduces ``Little Red Dot'' (LRD) contamination in massive galaxy samples, lowering the LRD fraction from $\sim 32\%$ to $\sim 13\%$ at $M_\star > 10^{10.3}\,M_\odot$. Assuming pure stellar origins, LRDs exhibit $M_\star \sim 10^{9\text{--}10.5}\,M_\odot$ with MIRI constraints, rarely exceeding $10^{10.5}\,M_\odot$. Within standard $Λ$CDM, our results indicate a moderate increase in the baryon-to-star conversion efficiency ($ε$) toward higher redshifts and masses at $z > 3$. For the most massive $z \sim 8$ galaxies, $ε\sim 0.3$, compared to $ε\lesssim 0.2$ for typical galaxies at $z < 3$. This result is consistent with models where high gas densities and short free-fall times suppress stellar feedback in massive high-$z$ halos. |
| title | JWST/MIRI reveals the true number density of massive galaxies in the early Universe |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2403.02399 |