منابع مشابه
On the cyclotron line in Cepheus X-4
Context. Accreting X-ray pulsars provide us with laboratories for the study of extreme gravitational and magnetic fields, hence accurate descriptions of their observational properties contribute to our understanding of this group of objects. Aims. We aim to detect a cyclotron resonance scattering feature in the Be/X-ray binary Cep X-4 and to investigate pulse profile and spectral changes throug...
متن کاملLuminosity-dependent changes of the cyclotron line energy and spectral hardness in Cep X-4
Context. X-ray spectra of accreting pulsars are generally observed to vary with their X-ray luminosity. In particular, the hardness of the X-ray continuum is found to depend on luminosity. In a few sources, the correlation between the energy of the cyclotron resonance scattering feature (CRSF) and the luminosity is clear. Different types (signs) of the correlation are believed to reflect differ...
متن کاملThe identification of the transient X - ray pulsar Cepheus X - 4 with a Be / X - ray binary ?
We present long slit spectral (375-725 nm) observations of the proposed identification of the transient 66s Xray pulsar Cep X-4=GS2138+56. Spectra show features typical of Be/X-ray binaries. Superimposed on a weak emission from the IC 1396 nebula, strong Hα (4.5 nm EW) and Hβ (0.3 nm EW) lines are seen in emission with the other Balmer lines in absorption. Significant interstellar absorption fe...
متن کاملthe impact of e-readiness on ec success in public sector in iran the impact of e-readiness on ec success in public sector in iran
acknowledge the importance of e-commerce to their countries and to survival of their businesses and in creating and encouraging an atmosphere for the wide adoption and success of e-commerce in the long term. the investment for implementing e-commerce in the public sector is one of the areas which is focused in government‘s action plan for cross-disciplinary it development and e-readiness in go...
Long-term change in the cyclotron line energy in Hercules X-1
Aims. We investigate the long-term evolution of the cyclotron resonance scattering feature (CRSF) in the spectrum of the binary X-ray pulsar Her X-1 and present evidence of a true long-term decrease in the centroid energy Ecyc of the cyclotron line in the pulse phase averaged spectra from 1996 to 2012. Methods. Our results are based on repeated observations of Her X-1 by those X-ray observatori...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2007
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20077238