Hercules X-1: the positive cyclotron line energy/luminosity correlation
نویسندگان
چکیده
منابع مشابه
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...
متن کاملInversion of the decay of the cyclotron line energy in Hercules X-1
Recent observations of Her X-1 with NuSTAR and INTEGRAL in 2016 have provided evidence that the 20-year decay of the cyclotron line energy found between 1996 and 2015 has ended and that an inversion with a new increase, possibly similar to the one observed around 1990–1993, has started. We consider this a strong motivation for further observations and for enhanced efforts to significantly impro...
متن کاملContinued decay in the cyclotron line energy in Hercules X-1
The centroid energy Ecyc of the cyclotron line in the spectrum of the binary X-ray pulsar Her X-1 has been found to decrease with time on a time scale of a few tens of years – surprisingly short in astrophysical terms. This was found for the pulse phase-averaged line centroid energy using observational data from various X-ray satellites over the time period 1996 to 2012, establishing a reductio...
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متن کاملSuzaku Observations of Hercules X-1 : Measurements of the Two Cyclotron Harmonics
The accretion-powered pulsar Her X-1 was observed with Suzaku twice in its main-on state, on 2005 October 5-6 and 2006 March 29-30, for a net exposure of 30.5 ks and 34.4 ks, respectively. In the 2005 and 2006 observations, the source was detected at an average 10-30 keV intensity of 290 mCrab and 230 mCrab, respectively. The intrinsic pulse period was measured on both occasions at 1.23776 s by...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2011
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/201116863