X-ray Polarimetry Reveals Rapidly Spinning Black Hole in GRS 1739--278
Analysis
This paper is significant because it uses X-ray polarimetry, combined with broadband spectroscopy, to directly probe the geometry and relativistic effects in the accretion disk of a stellar-mass black hole. The study provides strong evidence for a rapidly spinning black hole in GRS 1739--278, offering valuable insights into the behavior of matter under extreme gravitational conditions. The use of simultaneous observations from IXPE and NuSTAR allows for a comprehensive analysis, enhancing the reliability of the findings.
Key Takeaways
- •X-ray polarimetry, combined with broadband spectroscopy, is a powerful tool for studying black hole accretion disks.
- •The study provides evidence for a rapidly spinning black hole in GRS 1739--278.
- •The observed polarization properties are dominated by reflected returning radiation.
- •The black hole spin is estimated to be extremely high (a ≈ 0.994).
“The best-fitting results indicate that high-spin configurations enhance the contribution of reflected returning radiation, which dominates the observed polarization properties. From the \texttt{kynbbrr} modeling, we infer an extreme black hole spin of a = 0.994+0.004-0.003 and a system inclination of i = 54°+8°-4°.”