Multiple Cyclotron Lines in the Spectrum of 4U 0115+63
W.A. Heindl, W. Coburn, D.E. Gruber, M.R. Pelling, R.E. Rothschild
J. Wilms, K. Pottschmidt, R. Staubert
We have discovered a third harmonic cyclotron resonance scattering
feature (CRSF) in Rossi X-ray Timing Explorer (RXTE)
observations of the recent outburst of 4U 0115+63. This is the first
time that more than two harmonics have been observed in a single
accreting X-ray pulsar. The CRSFs are apparently not harmonically
spaced; however, this may be due to fitting the complex shape of the
fundamental with a simple absorption profile. We report on spectral
changes through the pulse phase, including the posssible presence of a
4th cyclotron line, as well as the detection of a strong 2 mHz QPO
seen at periastron passage.
File translated from TEX by TTH, version 2.32.
On 16 Jul 1999, 09:19.