Pulse Profiles and Cyclotron Line Energy Dependence on X-ray Pulsars Luminosity
نویسندگان
چکیده
We present the results of broad band (3-100 keV) observations of several X-ray pulsars with the INTEGRAL and RXTE observatories. We concentrate on the luminosity and energy dependence of the pulse profile and the variations of the cyclotron line energy. In V0332+53 the line energy changes nearly linearly with the source luminosity, while in 4U0115+63 its behavior is more complicated. Strong variations of the pulse profile with the energy and source intensity were found for both of pulsars; in V0332+53 the changes of the pulse profile near the cyclotron line are especially drastic. The preliminary results obtained for Her X-1 and GX 301-2 in a high intensity state show the absence of significant pulse profile changes with the energy. Results and possible emission mechanisms are briefly discussed in terms of theoretical models of accreting pulsars.
منابع مشابه
V 0332 + 53 in the outburst of 2004 – 2005 : luminosity dependence of the cyclotron line and pulse profile
We present results of observations of the transient X-ray pulsar V0332+53 performed during a very powerful outburst in Dec, 2004 – Feb, 2005 with the INTEGRAL and RXTE observatories in a wide (3 − 100 keV) energy band. A cyclotron resonance scattering line at an energy of ∼ 26 keV has been detected in the source spectrum together with its two higher harmonics at ∼ 50 and ∼ 73 keV, respectively....
متن کاملTiming Characteristics of the Hard X-ray Emission from Bright X-ray Pulsars Based on INTEGRAL Data
We review the results of a timing analysis of the observations for ten bright X-ray pulsars (with fluxes > 100 mCrab in the 20-100 keV energy band) that fell within the INTEGRAL field of view from 2003 to 2007. The dependence of the pulse profile on the energy and intrinsic source luminosity has been investigated; particular attention has been paid to searching for changes in the pulse profile ...
متن کاملX-ray pulsars through the eyes of INTEGRAL
Recent results of the spectral and timing analysis of X-ray pulsars in hard X-rays with the INTEGRAL observatory are reviewed. The evolution of the cyclotron line energy with the source luminosity was studied in detail for the first time for several sources. It was shown that for V0332+53 this dependence is linear, but for 4U0115+63 and A0535+262 it is more complicated. There are some evidences...
متن کاملSpectral formation in accreting X-ray pulsars: bimodal variation of the cyclotron energy with luminosity
Context. Accretion-powered X-ray pulsars exhibit significant variability of the cyclotron resonance scattering feature (CRSF) centroid energy on pulse-to-pulse timescales, and also on much longer timescales. Two types of spectral variability are observed. For sources in group 1, the CRSF energy is negatively correlated with the variable source luminosity, and for sources in group 2, the opposit...
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 کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2006