A z ≃ 0.4 Galaxy Reflecting the High-redshift Little Red Dots: An Extended Starburst with an Overmassive Black Hole
Journal article, 2026
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, which are preferentially found around z similar to 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 integral field unit observations combined with archival multiband photometric spectral energy distribution data. The GMOS data reveal extended blue emission from starburst with a star formation rate of 400 M-circle dot yr(-1), 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 similar or equal to 60%, with the BH mass and host stellar mass estimated to be 10(10.2) and 10(10.4)M(circle dot), 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.
Author
Xiaoyang Chen
Tohoku University
Waseda University
Kohei Ichikawa
Tohoku University
Masayuki Akiyama
Tohoku University
Kohei Inayoshi
Beijing University of Technology
Akio K. Inoue
Waseda University
Masafusa Onoue
University of Tokyo
Waseda University
Yoshiki Toba
Academia Sinica
Ehime University
Ritsumeikan University
Jorge Zavala
University of Massachusetts
Tom Bakx
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Toshihiro Kawaguchi
University of Toyama
Kianhong Lee
Tohoku University
Nagoya University
National Astronomical Observatory of Japan
Naoki Matsumoto
Tohoku University
Bovornpratch Vijarnwannaluk
Tohoku University
Academia Sinica
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 999 1 30Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.3847/1538-4357/ae3683