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The broad-band spectrum of Cyg X-2 with INTEGRAL

G. Lavagetto·T. Di Salvo·M. Falanga·R. Iaria·N. R. Robba·L. Burderi·W. H. G. Lewin·M. Mendez·L. Stella·M. van der Klis
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Abstract

We study the broad band (3-100 keV) spectrum of Cygnus X-2 with INTEGRAL. We find that the spectrum is well fitted by a Comptonized component with a seed-photons temperature of ~1 keV, an electron temperature of ~3 keV and an optical depth tau ~ 8. Assuming spherical geometry, the radius of the seed-photons emitting region is ~17 km. The source shows no hard X-ray emission; it was detected only at a 3 sigma level above 40 keV. We also analyzed public ISGRI data of Cyg X--2 to investigate the presence of a hard X-ray component. We report the possible presence of hard X-ray emission in one data set.

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G. Lavagetto, T. Di Salvo, M. Falanga, R. Iaria, N. R. Robba, L. Burderi, W. H. G. Lewin, M. Mendez, L. Stella, M. van der Klis. 2005-10-12. The broad-band spectrum of Cyg X-2 with INTEGRAL. https://doi.org/10.1051/0004-6361%3A20053189

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