SIMBAD references

2018ApJ...855....3T - Astrophys. J., 855, 3-3 (2018/March-1)

Alternative explanations for extreme supersolar iron abundances inferred from the energy spectrum of Cygnus X-1.

TOMSICK J.A., PARKER M.L., GARCIA J.A., YAMAOKA K., BARRET D., CHIU J.-L., CLAVEL M., FABIAN A., FURST F., GANDHI P., GRINBERG V., MILLER J.M., POTTSCHMIDT K. and WALTON D.J.

Abstract (from CDS):

Here we study a 1-200 keV energy spectrum of the black hole binary Cygnus X-1 taken with NuSTAR and Suzaku. This is the first report of a NuSTAR observation of Cyg X-1 in the intermediate state, and the observation was taken during the part of the binary orbit where absorption due to the companion's stellar wind is minimal. The spectrum includes a multi-temperature thermal disk component, a cutoff power-law component, and relativistic and nonrelativistic reflection components. Our initial fits with publicly available constant density reflection models (relxill and reflionx) lead to extremely high iron abundances (>9.96 and 10.6–0.9+1.6 times solar, respectively). Although supersolar iron abundances have been reported previously for Cyg X-1, our measurements are much higher and such variability is almost certainly unphysical. Using a new version of reflionx that we modified to make the electron density a free parameter, we obtain better fits to the spectrum even with solar iron abundances. We report on how the higher density (ne=(3.98–0.25+0.12)×1020 cm–3) impacts other parameters such as the inner radius and inclination of the disk.

Abstract Copyright: © 2018. The American Astronomical Society. All rights reserved.

Journal keyword(s): accretion, accretion disks - black hole physics - stars: individual: Cygnus X-1 - X-rays: general - X-rays: stars

Simbad objects: 10

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2021.06.24-02:43:54

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