H-alpha Emission Variability in the gamma-ray Binary LS I +61 303

Bibliographic Details
Title: H-alpha Emission Variability in the gamma-ray Binary LS I +61 303
Authors: McSwain, M. Virginia, Grundstrom, Erika D., Gies, Douglas R., Ray, Paul S.
Source: Astrophys.J.724:379-385,2010
Publication Year: 2010
Collection: Astrophysics
Subject Terms: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
More Details: LS I +61 303 is an exceptionally rare example of a high mass X-ray binary (HMXB) that also exhibits MeV-TeV emission, making it one of only a handful of "gamma-ray binaries". Here we present H-alpha spectra that show strong variability during the 26.5 day orbital period and over decadal time scales. We detect evidence of a spiral density wave in the Be circumstellar disk over part of the orbit. The H-alpha line profile also exhibits a dramatic emission burst shortly before apastron, observed as a redshifted shoulder in the line profile, as the compact source moves almost directly away from the observer. We investigate several possible origins for this red shoulder, including an accretion disk, mass transfer stream, and a compact pulsar wind nebula that forms via a shock between the Be star's wind and the relativistic pulsar wind.
Comment: Accepted to ApJ
Document Type: Working Paper
DOI: 10.1088/0004-637X/724/1/379
Access URL: http://arxiv.org/abs/1009.2173
Accession Number: edsarx.1009.2173
Database: arXiv
More Details
DOI:10.1088/0004-637X/724/1/379