成長著しいブラックホールをチャンドラ宇宙望遠鏡が発見（NASA’s Chandra Finds Black Hole With Tremendous Growth）

2025-09-18 NASA

An artist’s concept of a supermassive black hole, a surrounding disk of material falling towards the black hole and a jet containing particles moving away at close to the speed of light. This black hole represents a recently-discovered quasar powered by a black hole. New Chandra observations indicate that the black hole is growing at a rate that exceeds the usual limit for black holes, called the Eddington Limit. Credit: NASA/CXC/SAO/M. Weiss
X-ray: NASA/CXC/INAF-Brera/L. Ighina et al.; Illustration: NASA/CXC/SAO/M. Weiss; Image Processing: NASA/CXC/SAO/N. Wolk

＜関連情報＞

• https://www.nasa.gov/missions/chandra/nasas-chandra-finds-black-hole-with-tremendous-growth/
• https://iopscience.iop.org/article/10.3847/2041-8213/aded0a

赤方偏移z=6.13の電波輝度クエーサーにおける超エディントン吸積の可能性に関するX線調査 X-Ray Investigation of Possible Super-Eddington Accretion in a Radio-loud Quasar at z = 6.13

Luca Ighina, Alessandro Caccianiga, Thomas Connor, Alberto Moretti, Fabio Pacucci, Cormac Reynolds, José Afonso, Bruno Arsioli, Silvia Belladitta, Jess W. Broderick,…
The Astrophysical Journal Letters  Published: 2025 September 8
DOI:10.3847/2041-8213/aded0a

Abstract

We present radio and X-ray observations of the recently discovered z = 6.13 radio-powerful quasar RACS J032021.44−352104.1 using the upgraded Giant Metrewave Radio Telescope, the Australia Telescope Compact Array, the Australian Large Baseline Array, and Chandra. The observed radio properties are in line with what is typically observed in high-z radio quasars (α_r = 0.72 ± 0.02 and L_{1.4 GHz} = 5.8 ± 0.9 × 10²⁶ W Hz⁻¹). Despite the relatively low X-ray flux observed, F_{0.5−7.0 keV} = 2.3 ± 0.5 × 10⁻¹⁴ erg s⁻¹ cm⁻², the intrinsic luminosity in the 2–10 keV rest frame is markedly high,L_2-10keV= 1.8 ^+1.1_-0.7× 10⁴⁶ erg s⁻¹, making RACS J032021.44−352104.1 one of the most luminous quasars currently known at z > 5.5. The high X-ray luminosity is largely driven by an extrapolation to energies below the observable X-ray window with Chandra and the slope derived in the 0.5–7 keV band (or 3.5–50 keV in the rest frame; Γ_X = 3.3 ± 0.4). By analyzing the overall spectral energy distribution of the quasar, we found that the remarkably soft X-ray emission (1) cannot be produced by relativistic jets, even when relativistic boosting is considered, and (2) is consistent with expectations for a super-Eddington accreting supermassive black hole. If such a high accretion rate was confirmed, this source would be a unique laboratory to study high accretion in the early Universe and could help resolve some challenges inherent in early black hole growth paradigms.