BROAD IRON LINES IN NEUTRONS STARS: DYNAMICAL BROADENING OR WIND SCATTERING?
Broad iron emission lines are observed in many accreting systems from black holes in active galactic nuclei and X-ray binaries to neutron star low-mass X-ray binaries. The origin of the line broadening is often interpreted as due to dynamical broadening and relativistic effects. However, alternative interpretations have been proposed, included broadening due to Compton scattering in a wind or accretion disk atmosphere. Here we explore the observational signatures expected from broadening in a wind, in particular that the iron line width should increase with an increase in the column density of the absorber (due to an increase in the number of scatterings). We study the data from three neutron star low-mass X-ray binaries where both a broad iron emission line and absorption lines are seen simultaneously, and show that there is no significant correlation between line width and column density. This favors an inner disk origin for the line broadening rather than scattering in a wind.
- Department of Physics and Astronomy, Wayne State University, 666 W. Hancock Street, Detroit, MI 48201 (United States)
- Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States)
- Publication Date:
- OSTI Identifier:
- Resource Type:
- Journal Article
- Resource Relation:
- Journal Name: Astrophysical Journal; Journal Volume: 777; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
- Country of Publication:
- United States
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BINARY STARS; BLACK HOLES; COMPTON EFFECT; CORRELATIONS; COSMIC X-RAY SOURCES; DENSITY; GALAXY NUCLEI; IRON; LINE BROADENING; LINE WIDTHS; NEUTRON STARS; RELATIVISTIC RANGE; STELLAR WINDS