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| Main Authors: | , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2507.11804 |
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| _version_ | 1866918093878460416 |
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| author | Rubet, Mariana Menéndez-Delmestre, Karín Gonçalves, Thiago Signorini Almeida-Fernandes, Felipe Santana-Silva, Luidhy Capak, Peter L. Sheth, Kartik |
| author_facet | Rubet, Mariana Menéndez-Delmestre, Karín Gonçalves, Thiago Signorini Almeida-Fernandes, Felipe Santana-Silva, Luidhy Capak, Peter L. Sheth, Kartik |
| contents | We report the discovery of a large-scale structure containing multiple overdensities at $z= 4.54 \pm 0.03$ in the COSMOS field, with the most prominent one likely infalling towards the recently identified Taralay protocluster. We use combined wide-band and narrow-band optical photometry to identify Ly$α$ emitters (LAEs) within a 21 cMpc radius from the submm source J1000+0234, at $z= 4.54$, to identify typical star-forming galaxies that may trace an underlying structure. Our approach selects line emitters as narrow-band excess objects and we use the COSMOS2020 photometric redshift catalog to eliminate potential low-redshift interlopers whose line emission (e.g. [OIII] at $z\sim 0.3$) might be responsible for the observed excess in the narrow band. In comparison with the LAE density in the field, our results point to a mean LAE number overdensity of $\barδ= 3$ spanning a region of $27 \times 20 \times 36$ cMpc$^3$, probably evolving into a moderate-mass cluster ($3 - 10 \times 10^{14} \, M_\odot$) at $z\sim 0$. This work supports the idea that submm sources, although offset from the major overdensity peaks, serve as traces of moderately massive, potentially infalling structures. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_11804 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Identifying a protocluster formation at z $\sim$ 4.5 in the COSMOS field: an extension of Taralay protocluster, traced by Ly-alpha emitters surrounding a submm galaxy Rubet, Mariana Menéndez-Delmestre, Karín Gonçalves, Thiago Signorini Almeida-Fernandes, Felipe Santana-Silva, Luidhy Capak, Peter L. Sheth, Kartik Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics We report the discovery of a large-scale structure containing multiple overdensities at $z= 4.54 \pm 0.03$ in the COSMOS field, with the most prominent one likely infalling towards the recently identified Taralay protocluster. We use combined wide-band and narrow-band optical photometry to identify Ly$α$ emitters (LAEs) within a 21 cMpc radius from the submm source J1000+0234, at $z= 4.54$, to identify typical star-forming galaxies that may trace an underlying structure. Our approach selects line emitters as narrow-band excess objects and we use the COSMOS2020 photometric redshift catalog to eliminate potential low-redshift interlopers whose line emission (e.g. [OIII] at $z\sim 0.3$) might be responsible for the observed excess in the narrow band. In comparison with the LAE density in the field, our results point to a mean LAE number overdensity of $\barδ= 3$ spanning a region of $27 \times 20 \times 36$ cMpc$^3$, probably evolving into a moderate-mass cluster ($3 - 10 \times 10^{14} \, M_\odot$) at $z\sim 0$. This work supports the idea that submm sources, although offset from the major overdensity peaks, serve as traces of moderately massive, potentially infalling structures. |
| title | Identifying a protocluster formation at z $\sim$ 4.5 in the COSMOS field: an extension of Taralay protocluster, traced by Ly-alpha emitters surrounding a submm galaxy |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2507.11804 |