Detailed Information on Publication Record
2024
X-Ray View of Little Red Dots: Do They Host Supermassive Black Holes?
ANANNA, Tonima Tasnim, Akos BOGDAN, Orsolya Eszter KOVÁCS, Priyamvada NATARAJAN, Ryan C. HICKOX et. al.Basic information
Original name
X-Ray View of Little Red Dots: Do They Host Supermassive Black Holes?
Authors
ANANNA, Tonima Tasnim, Akos BOGDAN, Orsolya Eszter KOVÁCS (348 Hungary, belonging to the institution), Priyamvada NATARAJAN and Ryan C. HICKOX
Edition
Astrophysical Journal Letters, IOP Publishing Ltd, 2024, 2041-8205
Other information
Language
English
Type of outcome
Článek v odborném periodiku
Field of Study
10308 Astronomy
Country of publisher
United Kingdom of Great Britain and Northern Ireland
Confidentiality degree
není předmětem státního či obchodního tajemství
References:
Impact factor
Impact factor: 7.900 in 2022
Organization unit
Faculty of Science
UT WoS
001260083600001
Keywords in English
Active galactic nuclei; James Webb Space Telescope; X-ray active galactic nuclei; Supermassive black holes
Tags
Tags
International impact, Reviewed
Změněno: 18/7/2024 09:43, Mgr. Marie Šípková, DiS.
Abstract
V originále
The discovery of Little Red Dots (LRDs)—a population of compact, high-redshift, dust-reddened galaxies—is one of the most surprising results from JWST. However, the nature of LRDs is still debated: does the near-infrared emission originate from accreting supermassive black holes (SMBHs), or intense star formation? In this work, we utilize ultra-deep Chandra observations and study LRDs residing behind the lensing galaxy cluster, A2744. We probe the X-ray emission from individual galaxies but find that they remain undetected and provide SMBH mass upper limits of ≲(1.5–16) × 106M⊙ assuming Eddington limited accretion. To increase the signal-to-noise ratios, we conduct a stacking analysis of the full sample with a total lensed exposure time of ≈87 Ms. We also bin the galaxies based on their stellar mass, lensing magnification, and detected broad-line Hα emission. For the LRDs exhibiting broad-line Hα emission, there is a hint of a stacked signal (∼2.6σ), corresponding to an SMBH mass of ∼3.2 × 106M⊙. Assuming unobscured, Eddington-limited accretion, this black hole (BH) mass is at least 1.5 orders of magnitude lower than that inferred from virial mass estimates using JWST spectra. Given galaxy-dominated stellar mass estimates, our results imply that LRDs do not host overmassive SMBHs and/or accrete at a few percent of their Eddington limit. However, alternative stellar mass estimates may still support that LRDs host overmassive BHs. The significant discrepancy between the JWST and Chandra data hints that the scaling relations used to infer the SMBH mass from the Hα line and virial relations may not be applicable for high-redshift LRDs.
Links
| GX21-13491X, research and development project |
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