A z ~ 0.4 Galaxy Reflecting the high-redshift Little Red Dots: An Extended Starburst with an Overmassive Black Hole

Fuente: arXiv
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Autori principali: Chen, Xiaoyang, Ichikawa, Kohei, Akiyama, Masayuki, Inayoshi, Kohei, Inoue, Akio K., Onoue, Masafusa, Toba, Yoshiki, Zavala, Jorge A., Bakx, Tom J., Kawaguchi, Toshihiro, Lee, Kianhong, Matsumoto, Naoki, Vijarnwannaluk, Bovornpratch
Natura: Preprint
Pubblicazione: 2025
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author Chen, Xiaoyang
Ichikawa, Kohei
Akiyama, Masayuki
Inayoshi, Kohei
Inoue, Akio K.
Onoue, Masafusa
Toba, Yoshiki
Zavala, Jorge A.
Bakx, Tom J.
Kawaguchi, Toshihiro
Lee, Kianhong
Matsumoto, Naoki
Vijarnwannaluk, Bovornpratch
author_facet Chen, Xiaoyang
Ichikawa, Kohei
Akiyama, Masayuki
Inayoshi, Kohei
Inoue, Akio K.
Onoue, Masafusa
Toba, Yoshiki
Zavala, Jorge A.
Bakx, Tom J.
Kawaguchi, Toshihiro
Lee, Kianhong
Matsumoto, Naoki
Vijarnwannaluk, Bovornpratch
contents One of the most remarkable discoveries of JWST is a population of compact, red sources at z > 4, commonly referred to as Little Red Dots (LRDs). Spectroscopic identifications reported that most LRDs are active galactic nuclei (AGNs), which are preferentially found around z ~ 6 and could imply a key phase in the formation and growth of black holes (BHs) in the early universe. Photometric surveys at lower redshift have recently been carried out to trace their evolution across cosmic time, and a small number of LRD-like galaxies have been spectroscopically identified at both Cosmic Noon and in the local universe. Here we report the discovery of one of the lowest-z LRD-like galaxies, J204837.26-002437.2 (hereafter J2048) at z = 0.4330, using new Gemini-N/GMOS IFU observations combined with archival multi-band photometric SED data. The GMOS data reveal extended blue emission from starburst with a star formation rate of 400 solar mass per year, together with an extended, highly fast ionized outflow. This is the first spectroscopic confirmation of extended host emission and outflow in an LRD-like galaxy, providing a unique laboratory for understanding the nature of their high-redshift counterparts. Moreover, J2048 would host an extremely overmassive BH with a BH-to-stellar mass ratio of ~ 60%, with the BH mass and host stellar mass estimated to be 10^10.2 and 10^10.4 solar masses, respectively. We discuss the origin and evolutionary fate of J2048, and the implications that such low-z analogs have for interpreting the properties of high-z LRDs.
format Preprint
id arxiv_https___arxiv_org_abs_2510_02801
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A z ~ 0.4 Galaxy Reflecting the high-redshift Little Red Dots: An Extended Starburst with an Overmassive Black Hole
Chen, Xiaoyang
Ichikawa, Kohei
Akiyama, Masayuki
Inayoshi, Kohei
Inoue, Akio K.
Onoue, Masafusa
Toba, Yoshiki
Zavala, Jorge A.
Bakx, Tom J.
Kawaguchi, Toshihiro
Lee, Kianhong
Matsumoto, Naoki
Vijarnwannaluk, Bovornpratch
Astrophysics of Galaxies
One of the most remarkable discoveries of JWST is a population of compact, red sources at z > 4, commonly referred to as Little Red Dots (LRDs). Spectroscopic identifications reported that most LRDs are active galactic nuclei (AGNs), which are preferentially found around z ~ 6 and could imply a key phase in the formation and growth of black holes (BHs) in the early universe. Photometric surveys at lower redshift have recently been carried out to trace their evolution across cosmic time, and a small number of LRD-like galaxies have been spectroscopically identified at both Cosmic Noon and in the local universe. Here we report the discovery of one of the lowest-z LRD-like galaxies, J204837.26-002437.2 (hereafter J2048) at z = 0.4330, using new Gemini-N/GMOS IFU observations combined with archival multi-band photometric SED data. The GMOS data reveal extended blue emission from starburst with a star formation rate of 400 solar mass per year, together with an extended, highly fast ionized outflow. This is the first spectroscopic confirmation of extended host emission and outflow in an LRD-like galaxy, providing a unique laboratory for understanding the nature of their high-redshift counterparts. Moreover, J2048 would host an extremely overmassive BH with a BH-to-stellar mass ratio of ~ 60%, with the BH mass and host stellar mass estimated to be 10^10.2 and 10^10.4 solar masses, respectively. We discuss the origin and evolutionary fate of J2048, and the implications that such low-z analogs have for interpreting the properties of high-z LRDs.
title A z ~ 0.4 Galaxy Reflecting the high-redshift Little Red Dots: An Extended Starburst with an Overmassive Black Hole
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2510.02801