A massive interacting galaxy 510 million years after the Big Bang

Fuente: arXiv
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Auteurs principaux: Boyett, Kristan, Trenti, Michele, Leethochawalit, Nicha, Calabró, Antonello, Metha, Benjamin, Roberts-Borsani, Guido, Dalmasso, Nicoló, Yang, Lilan, Santini, Paola, Treu, Tommaso, Jones, Tucker, Henry, Alaina, Mason, Charlotte A., Morishita, Takahiro, Nanayakkara, Themiya, Roy, Namrata, Wang, Xin, Fontana, Adriano, Merlin, Emiliano, Castellano, Marco, Paris, Diego, Bradac, Marusa, Marchesini, Danilo, Mascia, Sara, Pentericci, Laura, Vanzella, Eros, Vulcani, Benedetta
Format: Preprint
Publié: 2023
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_version_ 1866913244957900800
author Boyett, Kristan
Trenti, Michele
Leethochawalit, Nicha
Calabró, Antonello
Metha, Benjamin
Roberts-Borsani, Guido
Dalmasso, Nicoló
Yang, Lilan
Santini, Paola
Treu, Tommaso
Jones, Tucker
Henry, Alaina
Mason, Charlotte A.
Morishita, Takahiro
Nanayakkara, Themiya
Roy, Namrata
Wang, Xin
Fontana, Adriano
Merlin, Emiliano
Castellano, Marco
Paris, Diego
Bradac, Marusa
Marchesini, Danilo
Mascia, Sara
Pentericci, Laura
Vanzella, Eros
Vulcani, Benedetta
author_facet Boyett, Kristan
Trenti, Michele
Leethochawalit, Nicha
Calabró, Antonello
Metha, Benjamin
Roberts-Borsani, Guido
Dalmasso, Nicoló
Yang, Lilan
Santini, Paola
Treu, Tommaso
Jones, Tucker
Henry, Alaina
Mason, Charlotte A.
Morishita, Takahiro
Nanayakkara, Themiya
Roy, Namrata
Wang, Xin
Fontana, Adriano
Merlin, Emiliano
Castellano, Marco
Paris, Diego
Bradac, Marusa
Marchesini, Danilo
Mascia, Sara
Pentericci, Laura
Vanzella, Eros
Vulcani, Benedetta
contents JWST observations confirm the existence of galaxies as early as 300Myr and at a higher number density than expected based on galaxy formation models and HST observations. Yet, sources confirmed spectroscopically in the first 500Myr have estimated stellar masses $<5\times10^8M_\odot$, limiting the signal to noise ratio (SNR) for investigating substructure. We present a high-resolution spectroscopic and spatially resolved study of a rare bright galaxy at $z=9.3127\pm0.0002$ with a stellar mass of $(2.5^{+0.7}_{-0.5})\times10^9M_\odot$, forming $25^{+3}_{-4}M_\odot/yr$ and with a metallicity of $\sim0.1Z_\odot$- lower than in the local universe for the stellar mass but in line with expectations of chemical enrichment in galaxies 1-2Gyr after the Big Bang. The system has a morphology typically associated to two interacting galaxies, with a two-component main clump of very young stars (age$<10$Myr) surrounded by an extended stellar population ($130\pm20$Myr old, identified by modeling the NIRSpec spectrum) and an elongated clumpy tidal tail. The spectroscopic observations identify O, Ne and H emission lines, and the Lyman break, where there is evidence of substantial Ly$α$ absorption. The [OII] doublet is resolved spectrally, enabling an estimate of the electron number density and ionization parameter of the interstellar medium and showing higher densities and ionization than in lower redshift analogs. For the first time at $z>8$, we identify evidence of absorption lines (Si, C and Fe), with low confidence individual detections but SNR$>6$ when stacked. The absorption features suggest that Ly$α$ is damped by the interstellar and circumgalactic medium. Our observations provide evidence of rapid efficient build-up of mass and metals in the immediate aftermath of the Big Bang through mergers, demonstrating that massive galaxies with several billion stars exist earlier than expected.
format Preprint
id arxiv_https___arxiv_org_abs_2303_00306
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A massive interacting galaxy 510 million years after the Big Bang
Boyett, Kristan
Trenti, Michele
Leethochawalit, Nicha
Calabró, Antonello
Metha, Benjamin
Roberts-Borsani, Guido
Dalmasso, Nicoló
Yang, Lilan
Santini, Paola
Treu, Tommaso
Jones, Tucker
Henry, Alaina
Mason, Charlotte A.
Morishita, Takahiro
Nanayakkara, Themiya
Roy, Namrata
Wang, Xin
Fontana, Adriano
Merlin, Emiliano
Castellano, Marco
Paris, Diego
Bradac, Marusa
Marchesini, Danilo
Mascia, Sara
Pentericci, Laura
Vanzella, Eros
Vulcani, Benedetta
Astrophysics of Galaxies
JWST observations confirm the existence of galaxies as early as 300Myr and at a higher number density than expected based on galaxy formation models and HST observations. Yet, sources confirmed spectroscopically in the first 500Myr have estimated stellar masses $<5\times10^8M_\odot$, limiting the signal to noise ratio (SNR) for investigating substructure. We present a high-resolution spectroscopic and spatially resolved study of a rare bright galaxy at $z=9.3127\pm0.0002$ with a stellar mass of $(2.5^{+0.7}_{-0.5})\times10^9M_\odot$, forming $25^{+3}_{-4}M_\odot/yr$ and with a metallicity of $\sim0.1Z_\odot$- lower than in the local universe for the stellar mass but in line with expectations of chemical enrichment in galaxies 1-2Gyr after the Big Bang. The system has a morphology typically associated to two interacting galaxies, with a two-component main clump of very young stars (age$<10$Myr) surrounded by an extended stellar population ($130\pm20$Myr old, identified by modeling the NIRSpec spectrum) and an elongated clumpy tidal tail. The spectroscopic observations identify O, Ne and H emission lines, and the Lyman break, where there is evidence of substantial Ly$α$ absorption. The [OII] doublet is resolved spectrally, enabling an estimate of the electron number density and ionization parameter of the interstellar medium and showing higher densities and ionization than in lower redshift analogs. For the first time at $z>8$, we identify evidence of absorption lines (Si, C and Fe), with low confidence individual detections but SNR$>6$ when stacked. The absorption features suggest that Ly$α$ is damped by the interstellar and circumgalactic medium. Our observations provide evidence of rapid efficient build-up of mass and metals in the immediate aftermath of the Big Bang through mergers, demonstrating that massive galaxies with several billion stars exist earlier than expected.
title A massive interacting galaxy 510 million years after the Big Bang
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2303.00306