The NuSTAR X-ray Spectrum of Hercules X-1: A Radiation-Dominated Radiative Shock

Simple item page
dc.contributor.authorWolff, Michael T.
dc.contributor.authorBecker, Peter A.
dc.contributor.authorGottlieb, Amy M.
dc.contributor.authorFürst, Felix
dc.contributor.authorHemphill, Paul B.
dc.contributor.authorMarcu-Cheatham, Diana M.
dc.contributor.authorPottschmidt, Katja
dc.contributor.authorSchwarm, Fritz-Walter
dc.contributor.authorWilms, Jörn
dc.contributor.authorWood, Kent S.
dc.date.accessioned2023-08-31T16:55:47Z
dc.date.available2023-08-31T16:55:47Z
dc.date.issued2016-11-08
dc.description.abstractWe report on new spectral modeling of the accreting X-ray pulsar Hercules X-1. Our radiation-dominated radiative shock model is an implementation of the analytic work of Becker & Wolff on Comptonized accretion flows onto magnetic neutron stars. We obtain a good fit to the spin-phase-averaged 4–78 keV X-ray spectrum observed by the Nuclear Spectroscopic Telescope Array during a main-on phase of the Her X-1 35 day accretion disk precession period. This model allows us to estimate the accretion rate, the Comptonizing temperature of the radiating plasma, the radius of the magnetic polar cap, and the average scattering opacity parameters in the accretion column. This is in contrast to previous phenomenological models that characterized the shape of the X-ray spectrum, but could not determine the physical parameters of the accretion flow. We describe the spectral fitting details and discuss the interpretation of the accretion flow physical parameters.en_US
dc.description.sponsorshipThe authors thank Dr. Carlo Ferrigno and Dr. Kenneth Wolfram for valuable help in formulating the numerical implementation of many of the analytical expressions. We thank Dr. Richard Rothschild for a number of stimulating discussions. We also thank an anonymous referee for a number of insightful comments that helped improve the manuscript. This research was supported by the National Aeronautics and Space Administration Astrophysical Data Analysis Program under Grant 12-ADAP12-0118. MTW and KSW are also supported by the Chief of Naval Research. JW and F-WS are grateful for support by the Deutsche Forschungsgemeinschaft. This work made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. This research has also made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA).en_US
dc.description.urihttps://iopscience.iop.org/article/10.3847/0004-637X/831/2/194en_US
dc.format.extent10 pagesen_US
dc.genrejournal articlesen_US
dc.identifierdoi:10.13016/m2bjnl-tfgz
dc.identifier.citationWolff, Michael T., Peter A. Becker, Amy M. Gottlieb, Felix Fürst, Paul B. Hemphill, Diana M. Marcu-Cheatham, Katja Pottschmidt, Fritz-Walter Schwarm, Jörn Wilms, and Kent S. Wood. “The NuSTAR X-Ray Spectrum of Hercules X-1: A Radiation-Dominated Radiative Shock.” The Astrophysical Journal 831, no. 2 (November 2016): 194. https://doi.org/10.3847/0004-637X/831/2/194.en_US
dc.identifier.urihttps://doi.org/10.3847/0004-637X/831/2/194
dc.identifier.urihttp://hdl.handle.net/11603/29492
dc.language.isoen_USen_US
dc.publisherIOP Publishingen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Center for Space Sciences and Technology
dc.relation.ispartofUMBC Physics Department
dc.relation.ispartofUMBC Faculty Collection
dc.relation.ispartofUMBC Student Collection
dc.rightsThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.en_US
dc.rightsPublic Domain Mark 1.0*
dc.rights.urihttp://creativecommons.org/publicdomain/mark/1.0/*
dc.titleThe NuSTAR X-ray Spectrum of Hercules X-1: A Radiation-Dominated Radiative Shocken_US
dc.typeTexten_US
dcterms.creatorhttps://orcid.org/0000-0002-4656-6881en_US

Files

Collections

UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)
UMBC Faculty Collection
UMBC Physics Department
UMBC Student Collection