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 similar to 1 keV, an electron temperature of similar to 3 keV and an optical depth tau similar to 8. Assuming spherical geometry, the radius of the seed-photons emitting region is similar to 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.
LAVAGETTO G, DI SALVO T, FALANGA M, IARIA R, ROBBA N R, BURDERI L, et al. (2006). The broad-band spectrum of Cyg X-2 with INTEGRAL. ASTRONOMY & ASTROPHYSICS, 445, 1089-1092 [10.1051/0004-6361:20053189].
The broad-band spectrum of Cyg X-2 with INTEGRAL
LAVAGETTO, Giuseppe;DI SALVO, Tiziana;IARIA, Rosario;ROBBA, Natale;
2006-01-01
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 similar to 1 keV, an electron temperature of similar to 3 keV and an optical depth tau similar to 8. Assuming spherical geometry, the radius of the seed-photons emitting region is similar to 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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