Reverberation lags viewed in hard X-rays from an accreting stellar-mass black hole.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41702894.
- Also identified by DOI 10.1038/s41467-026-69604-9 and PMC identifier 13021959.
- Licence recorded as CC BY-NC-ND.
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Abstract
The X-ray-emitting corona near a black hole (BH) is too small to be directly imaged, but the rapid variability is used to infer the geometry by measuring time lags caused by coronal X-rays reflecting off the disk, known as reverberation lags. Though reverberation lags have previously been detected for some supermassive BHs in active galactic nuclei (AGNs), detecting them from stellar-mass BHs poses much greater challenges due to their size being over a million times smaller. Previous measurements of reverberation lags for stellar-mass BHs were limited to energies below 10 keV. Here, we report the detection of the Compton hump reverberation, peaking at about 30 keV, from an X-ray binary. The accompanying detection of an iron line feature at about 6.4 keV confirms the X-ray reverberation scenario and provides strong evidence that accretion flows in AGNs and X-ray binaries are governed by an ubiquitous process.