Kavli Affiliate: Kohei Inayoshi
| First 5 Authors: Xiaoyang Chen, Xiaoyang Chen, , ,
| Summary:
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 LRDs have been
spectroscopically identified at both Cosmic Noon and in the local universe.
Here we report the discovery of one of the lowest-z analogs of LRDs,
J204837.26-002437.2 (hereafter J2048) at z = 0.4332, 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 Msun 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 0.6, with the BH
mass and host stellar mass estimated to be 10^10.2 and 10^10.4 Msun,
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.
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