A study of the accretion mechanisms of the high-mass X-ray binary IGR J00370+6122
A study of the accretion mechanisms of the high-mass X-ray binary IGR J00370+6122
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DOI：
10.1093/pasj/psab083
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发表时间：
2021-07
影响因子：
2.3
通讯作者：
N. Uchida;H. Takahashi;Y. Fukazawa;K. Makishima
中科院分区：
文献类型：
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作者：
N. Uchida;H. Takahashi;Y. Fukazawa;K. Makishima
IGR J00370+6122 是一颗高质量 X 射线双星，其中有一颗 B1 Ib 主星和一颗伴星，由于在一次性 4 ks 观测中检测到 346 s 脉动，因此被认为是中子星。为了更好地了解紧凑伴星的性质，目前的工作对该物体的 X 射线数据进行了定时和光谱研究，这些数据是使用 XMM-Newton、Swift、Suzaku、RXTE 和 INTEGRAL 拍摄的。在XMM-Newton数据中，检测到了相干674 s脉动的迹象，其之前的346 s周期可能是二次谐波。光谱在 1-10 keV 范围内表现出“越亮越硬”的趋势，在 10-80 keV 范围内呈现出没有明显截止的平坦连续谱。这些特性都与从几个低光度吸积脉冲星（特别是英仙座 X）观察到的特性相似。因此，IGR J00370+6122中的致密天体被认为是一颗光度相当低的磁化中子星。轨道周期精化为15.6649 ± 0.0014 d。沿着轨道，光度变化三个数量级，在轨道相位为 0.3 时从 ∼4 × 1033 突然下降到 ∼1 × 1032 erg s−1 （反之亦然，在 0.95 时也可能如此）。虽然这些现象不能用初级恒星风的简单霍伊尔-利特尔顿吸积来解释，但当将螺旋桨效应与~5×1013 G的强偶极子磁场结合起来时，它们可以得到解释。因此，IGR J00370+6122中的中子星与普通X射线脉冲星相比可能具有更强的磁场。
IGR J00370+6122 is a high-mass X-ray binary with a B1 Ib primary star and a companion suggested to be a neutron star because of the detection of a 346 s pulsation in a one-off 4 ks observation. To better understand the nature of the compact companion, the present work performs timing and spectral studies of the X-ray data of this object, taken with XMM-Newton, Swift, Suzaku, RXTE, and INTEGRAL. In the XMM-Newton data, a sign of coherent 674 s pulsation was detected, for which the previous 346 s period may be the second harmonic. The spectra exhibited the “harder when brighter” trend in the 1–10 keV range, and a flat continuum without clear cutoff in the 10–80 keV range. These properties are both similar to those observed from several low-luminosity accreting pulsars, including X Persei in particular. Thus, the compact object in IGR J00370+6122 is considered to be a magnetized neutron star with a rather low luminosity. The orbital period was refined to 15.6649 ± 0.0014 d. Along the orbit, the luminosity changes by three orders of magnitude, involving a sudden drop from ∼4 × 1033 to ∼1 × 1032 erg s−1 at an orbital phase of 0.3 (and probably vice verse at 0.95). Although these phenomena cannot be explained by simple Hoyle–Lyttleton accretion from the primary’s stellar winds, they can be explained when incorporating the propeller effect with a strong dipole magnetic field of ∼5 × 1013 G. Therefore, the neutron star in IGR J00370+6122 may have a stronger magnetic field compared to ordinary X-ray pulsars.