论文标题
通过Swift观察确认灰尘散射在Maxi J1421-613周围的回声
Confirmation of dust scattering echo around MAXI J1421-613 by Swift observation
论文作者
论文摘要
Maxi J1421-613是2014年1月9日由All-Sky X射线图像（Maxi）的Monitor发现的X射线Burster，被认为是低质量X射线二进制文件。先前的研究分析了苏扎库在2014年1月31日至2月3日获得的后续观察数据，报告说，在瞬态源周围发现了〜3'-9'半径的环形发射。环形发射的最合理的起源是Maxi J1421-613爆发时尘埃散射回声。在本文中，我们通过分析通过光子计数模式于2014年1月18日进行的快速后续观察数据来确认环形发射。在径向轮廓中，我们发现〜2'.5-4'.5的环形发射。它的频谱通过吸收的功率定律很好地解释了，并且光子指数高于Delta Gamma〜2的Maxi J1421-613本身。 Swift观察到的环形发射的通量和半径是通过尘埃散射与苏扎库观察到的环形发射的相同爆发的粉尘散射来解释的。假设引起Swift发现的环形发射的尘埃层位于与Maxi J1421-613前面的CO云相同的位置，则估计与瞬态源的距离为〜3 kpc，这与先前对苏查库的研究所估计的值一致。
MAXI J1421-613 is an X-ray burster discovered by Monitor of All-sky X-ray Image (MAXI) on 9 January 2014 and is considered to be a low-mass X-ray binary. A previous study analyzing follow-up observation data obtained by Suzaku on 31 January to 3 February 2014 reported that an annular emission of ~3'-9' radius was found around the transient source. The most plausible origin of the annular emission is a dust scattering echo by the outburst of MAXI J1421-613. In this paper, we confirm the annular emission by analyzing the data of the Swift follow-up observation which was conducted by the photon counting mode on 18 January 2014. In a radial profile, we found an annular emission at ~2'.5-4'.5. Its spectrum was well explained by an absorbed power law, and the photon index was higher than that of MAXI J1421-613 itself by delta Gamma~2. The flux and radius of the annular emission observed by Swift are explained by dust scattering of the same outburst as is responsible for the annular emission observed by Suzaku. Assuming that the dust layer causing the annular emission found by Swift is located at the same position as the CO cloud in front of MAXI J1421-613, the distance to the transient source was estimated to be ~3 kpc, which is consistent with the value estimated by the previous study of Suzaku.
