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Physical Models for Accreting Pulsars at High LuminosityA new window for better understanding the accretion onto strongly magnetized neutron stars in X-ray binaries is opening. In these systems the accreted material follows the magnetic field lines as it approaches the neutron star, forming accretion columns above the magnetic poles. The plasma falls toward the neutron star surface at near-relativistic speeds, losing energy by emitting X-rays. The X-ray spectral continua are commonly described using phenomenological models, i.e., power laws with different types of curved cut-offs at higher energies. Here we consider high luminosity pulsars. In these systems the mass transfer rate is high enough that the accreting plasma is thought to be decelerated in a radiation-dominated radiative shock in the accretion columns. While the theory of the emission from such shocks had already been developed by 2007, a model for direct comparison with X-ray continuum spectra in xspec or isis has only recently become available. Here we analyze the broadband X-ray spectra of the accreting pulsars Centaurus X-3 and 4U1626-67 obtained withNuSTAR. We present results from traditional empirical modeling as well as successfully apply the radiation-dominated radiative shock model. We also fit the energy-dependent pulse profiles of 4U 1626-67 using a new relativistic light bending model.
Document ID
20180006096
Acquisition Source
Goddard Space Flight Center
Document Type
Presentation
Authors
Pottschmidt, Katja (Maryland Univ. Baltimore County Baltimore, MD, United States)
Hemphill, Paul B. (Massachusetts Inst. of Technology (MIT) Cambridge, MA, United States)
Wolff, Michael T. (Naval Research Lab. Washington, DC, United States)
Cheatham, Diana M. (Maryland Univ. Baltimore County (UMBC) Baltimore, MD, United States)
Iwakiri, Wataru (Institute of Physical and Chemical Research Saitama, Japan)
Gottlieb, Amy M. (Florida Univ. Gainesville, FL, United States)
Falkner, Sebastian (Friedrich-Alexander-Universität Erlangen-Nurnberg (FAU) Erlangen, Germany)
Ballhausen, Ralf (Friedrich-Alexander-Universität Erlangen-Nurnberg (FAU) Erlangen, Germany)
Fürst, Felix (European Space Astronomy Centre (ESAC) Madrid, Spain)
Kühnel, Matthias (Friedrich-Alexander-Universität Erlangen-Nurnberg (FAU) Erlangen, Germany)
Ferrigno, Carlo (INTEGRAL Science Data Center for Astrophysics Versoix, Switzerland)
Miyasaki, Hiromasa (California Institute of Technology Pasadena, CA, United States)
Becker, Peter A. (George Mason University Fairfax, VA, United States)
Wood, Kent S. (Technical Services Corporation (TSC) Arlington, VA, United States)
Wilms, Joern (Friedrich-Alexander-Universität Erlangen-Nurnberg (FAU) Erlangen, Germany)
Date Acquired
October 4, 2018
Publication Date
January 8, 2019
Subject Category
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN59939
Meeting Information
Meeting: American Astronomical Society
Location: Washington DC
Country: United States
Start Date: January 8, 2018
End Date: January 12, 2018
Sponsors: American Astronomical Society
Funding Number(s)
CONTRACT_GRANT: NNX15AV16G
CONTRACT_GRANT: N00173-14-1-G007
CONTRACT_GRANT: NNX15AV17G
CONTRACT_GRANT: 80GSFC17M0002
CONTRACT_GRANT: NNH13AV18I
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.

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