4U 0115+63 from RXTE and INTEGRAL data: Pulse profile and cyclotron line energy
4U 0115+63 from RXTE and INTEGRAL data: Pulse profile and cyclotron line energy
复制标题
DOI：
10.1134/s1063773707060023
复制
发表时间：
2007-04
期刊：
影响因子：
--
通讯作者：
S. Tsygankov;A. Lutovinov;E. Churazov;R. S. R. Institute-R.-S.-R.-Institute-102350741;Moscow;Russia Mpi for Astrophysik;Garching;Germany
中科院分区：
文献类型：
--
作者：
S. Tsygankov;A. Lutovinov;E. Churazov;R. S. R. Institute-R.-S.-R.-Institute-102350741;Moscow;Russia Mpi for Astrophysik;Garching;Germany
利用RXTE和INTEGRAL天文台对4U 0115+63在宽X射线（3-100 keV）能区的观测资料，分析了其在1999年和2004年的强烈爆发过程。回旋共振吸收线的基谐波在最大X射线通量附近的能量（亮度范围5 × 1037-2 × 1038 erg s−1）为1.11 keV。当脉冲星的光度福尔斯低于1037 erg s−1时，基波的能量急剧地向高能移动，最高可达1036 keV。在偶极磁场配置的假设下，回旋谐波能量的这种变化对应于发射区高度减少1.2km，而其他光谱参数，特别是截止能量，基本上保持不变。在光度为<$7 × 1037 erg s−1时，在光谱中记录到四个几乎等距的回旋线谐波。这表明，要么发射起源的区域是紧凑的，要么从吸积柱的不同（高度）段的出射光谱是均匀的。我们已经发现了显着的脉冲轮廓的变化与能量，光度和时间。特别是，我们表明，从脉冲到脉冲的轮廓变化不会减少到一个简单的调制的吸积率指定的外部条件。
We analyze the observations of the transient X-ray pulsar 4U 0115+63 with the RXTE and INTEGRAL observatories in a wide X-ray (3–100 keV) energy band during its intense outbursts in 1999 and 2004. The energy of the fundamental harmonic of the cyclotron resonance absorption line near the maximum of the X-ray flux from the source (luminosity range 5 × 1037–2 × 1038erg s−1) is ∼11 keV. When the pulsar luminosity falls below ∼5 × 1037erg s−1, the energy of the fundamental harmonic is displaced sharply toward the high energies, up to ∼16 keV. Under the assumption of a dipole magnetic field configuration, this change in cyclotron harmonic energy corresponds to a decrease in the height of the emitting region by ∼2 km, while other spectral parameters, in particular, the cutoff energy, remain essentially constant. At a luminosity ∼7 × 1037erg s−1, four almost equidistant cyclotron line harmonics are recorded in the spectrum. This suggests that either the region where the emission originates is compact or the emergent spectrum from different (in height) segments of the accretion column is uniform. We have found significant pulse profile variations with energy, luminosity, and time. In particular, we show that the profile variations from pulse to pulse are not reduced to a simple modulation of the accretion rate specified by external conditions.