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hard x ray observations of vela x-1 and a0535+26 with hexe: discovery of cyclotron linesThe X ray pulsars Vela X-1 (4U 0900-40) and A0535+26) were observed with the High Energy X ray Experiment (HEXE) onboard the Mir space station at energies above 20 keV. The pulse profiles of Vela X-1 (P = 283.22 s for JD 244 7486) and A0535+26 (P = 103.27 s for JD 244 7626) were measured up to at least 100 keV. The time averaged pulse profiles of the two sources both show a clear double peak structure with an asymmetric main pulse and a more symmetric secondary pulse. The spectrum of the main pulse is significantly harder than that of the secondary. Pulse phase resolved spectra show absorption features at 54 keV and possibly 27 keV for Vela X-1 and around 100 keV for A0535+26. If these features are interpreted as second and first harmonic (fundamental) cyclotron absorption lines, lower limits are derived of 2.6 x 10(exp 12) and 4.3 x 10(exp 12) Gauss for the magnetic fields of the neutron stars in Vela X-1 and A0535+26, respectively.
Document ID
19920012657
Document Type
Conference Paper
Authors
Kendziorra, E.
(Tuebingen Univ. (Germany F.R.)., United States)
Mony, B.
(Tuebingen Univ. (Germany F.R.)., United States)
Kretschmar, P.
(Tuebingen Univ. (Germany F.R.)., United States)
Maisack, M.
(George Mason Univ. Fairfax, VA., United States)
Staubert, R.
(Tuebingen Univ. (Germany F.R.)., United States)
Doebereiner, S.
(Max-Planck-Gesellschaft Garching (Germany, F.R.)., United States)
Englhauser, J.
(Max-Planck-Gesellschaft Garching (Germany, F.R.)., United States)
Pietsch, W.
(Max-Planck-Gesellschaft Garching (Germany, F.R.)., United States)
Reppin, C.
(Max-Planck-Gesellschaft Garching (Germany, F.R.)., United States)
Truemper, J.
(Max-Planck-Inst. fuer Extraterrestrische Physik, Garching, Germany F.R. , United States)
Date Acquired
September 6, 2013
Publication Date
February 1, 1992
Publication Information
Publication: NASA. Goddard Space Flight Center, The Compton Observatory Science Workshop
Subject Category
SPACE RADIATION
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.