2025-08-06 愛媛大学
ブラックホールX線連星の想像図（クレジット：JAXA）
＜関連情報＞
- https://www.ehime-u.ac.jp/data_relese/pr_20250806_sce/
- https://www.ehime-u.ac.jp/wp-content/uploads/2025/08/pr_20250806_sce.pdf
- https://iopscience.iop.org/article/10.3847/2041-8213/ade25c
恒星質量ブラックホール4U 1630-472の爆発的増光期におけるXRISMによる分光観測 XRISM Spectroscopy of the Stellar-mass Black Hole 4U 1630-472 in Outburst
Jon M. Miller, Misaki Mizumoto, Megumi Shidatsu, Ralf Ballhausen, Ehud Behar, María Díaz Trigo, Chris Done, Tadayasu Dotani, Javier A. García, Timothy Kallman,…
The Astrophysical Journal Letters Published: 2025 July 17
DOI:10.3847/2041-8213/ade25c
Abstract
We report on XRISM/Resolve spectroscopy of the recurrent transient and well-known black hole candidate 4U 1630−472 during its 2024 outburst. The source was captured at the end of a disk-dominated high/soft state at an Eddington fraction of λEdd ∼ 0.05 (10 M⊙/MBH). A variable absorption spectrum with unprecedented complexity is revealed with the Resolve calorimeter. This marks one of the lowest Eddington fractions at which highly ionized absorption has been detected in an X-ray binary. The strongest lines are fully resolved, with He-like Fe XXV separated into resonance and intercombination components and H-like Fe XXVI seen as a spin–orbit doublet. The depth of some absorption lines varied by almost an order of magnitude, far more than expected based on a 10% variation in apparent X-ray flux and ionization parameter. The velocity of some absorption components also changed significantly. Jointly modeling two flux segments with a consistent model including four photoionization zones, the spectrum can be described in terms of highly ionized but likely failed winds that sometimes show redshifts, variable obscuration that may signal asymmetric structures in the middle and outer accretion disk, and a tentative very fast outflow (v = 0.026–0.033c). We discuss the impact of these findings on our understanding of accretion and winds in stellar-mass black holes and potential consequences for future studies.
