SPECTROSCOPIC SIGNATURES OF THE SUPERORBITAL PERIOD IN THE NEUTRON STAR BINARY LMC X-4
Name
Neilsen-2009-SPECTROSCOPIC SIGNAT.pdf
Size
318.9 KB
Format
Adobe PDF
Checksum (MD5)
5ed20553ec24670008353d322cf3c4ab
Author(s)
Neilsen, Joseph M. G.
Lee, Julia C.
Nowak, Michael A.
Dennerl, Konrad
Vrtilek, Saeqa Dil
Date Issued
May 2009
Journal
Astrophysical Journal
Publisher
Institute of Physics/American Astronomical Society
Citation
Neilsen, Joseph, Julia C. Lee, Michael A. Nowak, Konrad Dennerl, and Saeqa Dil Vrtilek. “SPECTROSCOPIC SIGNATURES OF THE SUPERORBITAL PERIOD IN THE NEUTRON STAR BINARY LMC X-4.” The Astrophysical Journal 696, no. 1 (April 15, 2009): 182–191. © 2009 American Astronomical Society.
Version
Final published version
Abstract
We present the first high-resolution X-ray study of emission line variability with superorbital phase in the neutron star binary LMC X-4. Our analysis provides new evidence from X-ray spectroscopy confirming accretion disk precession as the origin of the superorbital period. The spectra, obtained with the Chandra High-Energy Transmission Grating Spectrometer and the XMM-Newton Reflection Grating Spectrometer, contain a number of emission features, including lines from hydrogen-like and helium-like species of N, O, Ne, and Fe, a narrow O VII radiative recombination continua (RRCs), and fluorescent emission from cold Fe. We use the narrow RRC and the Heα triplets to constrain the temperature and density of the (photoionized) gas. By comparing spectra from different superorbital phases, we attempt to isolate the contributions to line emission from the accretion disk and the stellar wind. There is also evidence for highly ionized iron redshifted and blueshifted by ~25,000 km s[superscript –1]. We argue that this emission originates in the inner accretion disk and show that the emission line properties in LMC X-4 are natural consequences of accretion disk precession.
MIT Department
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/0004-637x/696/1/182
