A Peculiar X-Ray Transient Source, AX J1842.8–0423, Discovered with ASCA
A Peculiar X-Ray Transient Source, AX J1842.8–0423, Discovered with ASCA
复制标题
一种特殊的 X 射线瞬态源，AX J1842.8–0423，由 ASCA 发现
DOI：
10.1093/pasj/51.1.39
复制
发表时间：
1999
影响因子：
2.3
通讯作者：
T. Kotani
中科院分区：
文献类型：
--
作者：
Y. Terada;H. Kaneda;K. Makishima;M. Ishida;K. Matsuzaki;F. Nagase;T. Kotani
1996 年 10 月，ASCA 在盾牌臂区域发现了一个新的瞬态 X 射线源 AX J1842.8-0423。该源表现出吸收校正的 2–10 keV 通量为 5.2 × 10−12erg s−1cm−2，强度变化不显着。连续光谱由光子指数 2.9 的幂律近似，被 NH∼ 5 × 1022cm−2 的氢柱吸收。光谱还显示出等效宽度极大的 Fe-K 发射线，约为 4000 eV，其质心能量为 ∼ 6.8 keV。在允许重元素丰度增加到太阳丰度的条件下，整个光谱可以通过温度约为 5.1 keV 的薄热等离子体发射模型来再现。在 1993 年 10 月的先前观测以及随后 1996 年 4 月的观测中均未检测到该源。因此，整体源行为非常奇特，但可以用从极点倾斜角度观察的涉及磁化白矮星的紧密双星来解释，其中异常强的 Fe-K 线可能是线光子共振散射的结果。
A new transient X-ray source, AX J1842.8-0423, was discovered with ASCA in 1996 October in the Scutum arm region. The source exhibited an absorption-corrected 2–10 keV flux of 5.2 × 10−12erg s−1cm−2, with insignificant intensity variability. The continuous spectrum is approximated by a power-law of photon index 2.9, absorbed by a hydrogen column of NH∼ 5 × 1022cm−2. The spectrum also exhibits the Fe-K emission line with an extremely large equivalent width of ∼ 4000 eV, of which the centroid energy is ∼ 6.8 keV. The overall spectrum can be reproduced by a thin-thermal plasma-emission model having a temperature of ∼ 5.1 keV, on the condition that the heavy-element abundance is allowed to increase tosolar abundance. The source was undetectable in a previous observation in 1993 October, as well as in a subsequent observation in 1996 April. The overall source behavior is thus quite peculiar, but may be explained in terms of a close binary involving a magnetized white dwarf viewed from pole-on inclination, where the unusually strong Fe-K line may be the result of resonant scattering of line photons.