A XRISM View of Relativistic Reflection in Cygnus X-1

Fuente: arXiv
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Main Authors: Draghis, Paul A., Miller, Jon M., Kara, Erin, Costantini, Elisa, Adegoke, Oluwashina, Garcia, Javier A.
Format: Preprint
Published: 2025
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_version_ 1866918213484281856
author Draghis, Paul A.
Miller, Jon M.
Kara, Erin
Costantini, Elisa
Adegoke, Oluwashina
Garcia, Javier A.
author_facet Draghis, Paul A.
Miller, Jon M.
Kara, Erin
Costantini, Elisa
Adegoke, Oluwashina
Garcia, Javier A.
contents We present the first high-resolution XRISM/Resolve view of the relativistically broadened Fe K line in Cygnus X-1. The data clearly separate the relativistic broad line from the underlying continuum and from narrow emission and absorption features in the Fe band. The unprecedented spectral resolution in the Fe K band clearly demonstrates that the flux excess can be attributed to a single, broad feature, as opposed to a superposition of previously unresolved narrow features. This broad feature can be best interpreted as emission consistent with an origin near the innermost stable circular orbit around a rapidly rotating black hole. By modeling the shape of the broad line, we find a black hole spin of $a\simeq0.98$ and an inclination of the inner accretion disk of $θ\simeq63^\circ$. The spin is consistent with prior reflection studies, reaffirming the robustness of past spin measurements using the relativistic reflection method. The measured inclination provides reinforcing evidence of a disk-orbit misalignment in Cygnus X-1. These results highlight the unique abilities of XRISM in separating overlapping spectral features and providing constraints on the geometry of accretion in X-ray binaries.
format Preprint
id arxiv_https___arxiv_org_abs_2511_17338
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A XRISM View of Relativistic Reflection in Cygnus X-1
Draghis, Paul A.
Miller, Jon M.
Kara, Erin
Costantini, Elisa
Adegoke, Oluwashina
Garcia, Javier A.
High Energy Astrophysical Phenomena
We present the first high-resolution XRISM/Resolve view of the relativistically broadened Fe K line in Cygnus X-1. The data clearly separate the relativistic broad line from the underlying continuum and from narrow emission and absorption features in the Fe band. The unprecedented spectral resolution in the Fe K band clearly demonstrates that the flux excess can be attributed to a single, broad feature, as opposed to a superposition of previously unresolved narrow features. This broad feature can be best interpreted as emission consistent with an origin near the innermost stable circular orbit around a rapidly rotating black hole. By modeling the shape of the broad line, we find a black hole spin of $a\simeq0.98$ and an inclination of the inner accretion disk of $θ\simeq63^\circ$. The spin is consistent with prior reflection studies, reaffirming the robustness of past spin measurements using the relativistic reflection method. The measured inclination provides reinforcing evidence of a disk-orbit misalignment in Cygnus X-1. These results highlight the unique abilities of XRISM in separating overlapping spectral features and providing constraints on the geometry of accretion in X-ray binaries.
title A XRISM View of Relativistic Reflection in Cygnus X-1
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2511.17338