Modeling high-energy light curves of the PSR B1259-63/LS 2883 binary based on 3-D SPH simulations

J. Takata^1, A.T. Okazaki^2, S. Nagataki^3, T. Naito^4, A. kawachi^5, S.-H. Lee^^3, M. Mori^6, K. Hayasaki^7, M.S. Yamaguchi^8, S.P. Owocki^9

1-Department of Physics, The University of Hong-Kong, Hong Kong
2-Faculty of Engineering, Hokkai-Gakuen University, Toyohira-ku, Sapporo 062-8605, Japan
3-Yukawa Institute for Theoretical Physics, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
4-Faculty of Management Information, Yamanashi Gakuin University, Kofu, Yamanashi 400-8575, Japan
5-Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
6-Department of Physical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga 525-8577, Japan
7-Department of Astronomy, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
8-Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
9-Bartol Research Institute, University of Delaware, Newark, DE 19716, USA

Temporal changes of X-ray to very-high-energy gamma-ray emissions from the pulsar-Be star binary PSR~B1259-63/LS~2883 are studied based on 3-D SPH simulations of pulsar wind interaction with Be-disk and wind. We focus on the periastron passage of the binary and calculate the variation of the synchrotron and inverse-Compton emissions using the simulated shock geometry and pressure distribution of the pulsar wind. The characteristic double-peaked X-ray light curve from observations is reproduced by our simulation under a dense Be disk condition (base density ~10^{-9} g~cm^{-3}). We interpret the pre- and post-periastron peaks as being due to a significant increase in the conversion efficiency from pulsar spin down power to the shock-accelerated particle energy at orbital phases when the pulsar crosses the disk before periastron passage, and when the pulsar wind creates a cavity in the disk gas after periastron passage, respectively. On the contrary, in the model TeV light curve, which also shows a double peak feature, the first peak appears around the periastron phase. The possible effects of cooling processes on the TeV light curve are briefly discussed.

Reference: Accepted for publication in ApJ.
Status: Manuscript has been accepted