Cyclotron line strength variations in gamma-ray burst GB870303 - Possible evidence of neutron star rotationAn exhaustive search of the Ginga data on gamma-ray burst GB870303 reveals two separate time intervals during which statistically significant line features are evident. One interval shows a single prominent line feature at about 20 keV; a second, shows two line features at about 20 and 40 keV. From model fits to the data, we find that both sets of lines are well-described by cyclotron resonant scattering in a magnetic field B about 1.8 x 10 exp 12 G, and that the differences in the line strengths between the two intervals are significant. The variations are qualitatively similar to those produced by a change in the viewing angle theta relative to the magnetic field. We conjecture that the change in theta is due to rotation of the neutron star, and derive limits P = 45-180 sec on the rotation period P.
Document ID
19930036254
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Graziani, Carlo (Los Alamos National Lab., NM; Chicago Univ. IL, United States)
Fenimore, Edward E. (Los Alamos National Lab. NM, United States)
Murakami, Toshio (Inst. of Space and Astronautical Science Sagamihara, Japan)
Yoshida, Atsumasa (Inst. of Physical and Chemical Research Saitama, Japan)
Lamb, D. Q. (NASA Headquarters Washington, DC United States)
Wang, John C. L. (NASA Headquarters Washington, DC United States)
Loredo, Thomas J. (Chicago Univ. IL, United States)