The 2005 Outburst of the Halo Black Hole X-Ray Transient XTE J1118+480
The 2005 Outburst of the Halo Black Hole X-Ray Transient XTE J1118+480
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2005 年光环黑洞爆发 X 射线瞬态 XTE J1118 480
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
U. Virginia
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作者：
C. Zurita;M. Torres;D.Steeghs;P. Rodríguez;T. Muñoz;J. Casares;T. Shahbaz;I. G. Martínez;P. Zhao;M. Garcia;A. Piccioni;C. Bartolini;A. Guarnieri;J. Bloom;C. Blake;E. Falco;A.Szentgyorgyi;M. I. D. A. D. Canarias;H. C. F. Astrophysics;D. Astrof́isica;U. L. Laguna;D. Astronomia;U. Bologna;A. Department;U. O. C. Berkeley;D. Astronomy;U. Virginia
我们提出了2005年爆发的晕黑洞X射线瞬态XTE J1118+480的光学和红外监测。我们在R波段测量到的总爆发幅度为~5.7 ± 0.1等，在红外J、H和Ks波段测量到的总爆发幅度为~5等。RXTE ASM数据的硬度比HR 2（5-12 keV：3-5 keV）在爆发峰值时为1.53 ± 0.02，表明为硬光谱。光变曲线的形状和LX（1-10 keV）/Lopt的比值都类似于在GRO J 0422 +32和XTE J1859+226中观察到的迷你爆发。在早期的下降，我们发现一个0.02等振幅变化符合一个超级驼峰调制，就像在2000年的爆发观察。类似地，XTE J1118+480在稳定到接近静止的水平时，显示出一个双峰椭圆调制，被一个超级峰波扭曲，这表明该盘在爆发后扩展到3：1的共振半径，并一直保持到早期静止。在爆发开始后约3个月，系统在R = 19.02 ± 0.03处达到平静。光学上升最多比X射线上升早4天。爆发过程中不同时刻的光谱能量分布（SED）均为Fν να向蓝方向增加的准幂律分布。在爆发的峰值，我们得出α = 0.49 ± 0.04的光学数据单独和α = 0.1 ± 0.1时，单独的红外拟合。光学和红外SED之间的这种差异表明，红外由不同的成分（射流？）主导，而光学图像大概显示了圆盘的演化。
We present optical and infrared monitoring of the 2005 outburst of the halo black hole X-ray transient XTE J1118+480. We measured a total outburst amplitude of ~5.7 ± 0.1 mag in the R band and ~5 mag in the infrared J, H, and Ks bands. The hardness ratio HR2 (5-12 keV : 3-5 keV) from the RXTE ASM data is 1.53 ± 0.02 at the peak of the outburst, indicating a hard spectrum. Both the shape of the light curve and the ratio LX(1-10 keV)/Lopt resemble the minioutbursts observed in GRO J0422+32 and XTE J1859+226. During early decline, we find a 0.02 mag amplitude variation consistent with a superhump modulation, like the one observed during the 2000 outburst. Similarly, XTE J1118+480 displayed a double-humped ellipsoidal modulation distorted by a superhump wave when settled into a near-quiescence level, suggesting that the disk expanded to the 3 : 1 resonance radius after outburst, where it remained until early quiescence. The system reached quiescence at R = 19.02 ± 0.03, about 3 months after the onset of the outburst. The optical rise preceded the X-ray rise by at most 4 days. The spectral energy distributions (SEDs) at the different epochs during outburst are all quasi-power laws with Fν ∝ να increasing toward the blue. At the peak of the outburst, we derived α = 0.49 ± 0.04 for the optical data alone and α = 0.1 ± 0.1 when fitting solely the infrared. This difference between the optical and the infrared SEDs suggests that the infrared is dominated by a different component (a jet?), whereas the optical is presumably showing the disk evolution.