High-redshift blazar identification for Swift J1656.3-3302
High-redshift blazar identification for Swift J1656.3-3302
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DOI：
10.1051/0004-6361:20078901
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发表时间：
2008-01
影响因子：
6.5
通讯作者：
N. Masetti;E. Mason;R. Landi;P. Giommi;L. Bassani;A. Malizia;A. Bird;A. Bazzano;A. Dean;N. Gehrels;E. Palazzi;P. Ubertini
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作者：
N. Masetti;E. Mason;R. Landi;P. Giommi;L. Bassani;A. Malizia;A. Bird;A. Bazzano;A. Dean;N. Gehrels;E. Palazzi;P. Ubertini
我们报告的高红移blazar识别的一个新的伽马射线源，斯威夫特J1656.3-3302，发现与BAT成像仪的斯威夫特卫星和IBIS仪器上的INTEGRAL卫星。后续的光学光谱学使我们能够将对应物识别为在红移处显示宽的莱曼、Si IV、He II、C IV和C III]发射线的mag源。当INTEGRAL/IBIS数据与Swift/BAT结果进行比较时，在X射线中观察到光谱演化，当源变暗时，光谱变陡。用Swift/XRT和INTEGRAL/IBIS观测到的0.7-200 keV的X射线连续谱显示了射电强（宽发射线）活动星系核（具有光子指数）的典型幂律形状，以及低于~2 keV的光谱曲率的暗示，可能是由于源局部的固有吸收（cm-2）。或者，2.7 keV附近的斜率变化（）可以同样很好地描述X射线光谱。在这个红移下，观测到的20-100 keV源的光度为~1048 erg s-1（假设各向同性发射），使斯威夫特J1656.3-3302成为最明亮的X射线耀变体之一。这个源是另一个在20 keV以上发现的遥远伽马射线响亮类星体的例子。它也是最远的对象，在以前未确认的积分源，其性质已确定后，通过光谱学。
We report on the high-redshift blazar identification of a new gamma-ray source, Swift J1656.3-3302, detected with the BAT imager onboard the Swift satellite and the IBIS instrument on the INTEGRAL satellite. Follow-up optical spectroscopy has allowed us to identify the counterpart as an mag source that shows broad Lyman-, Si IV, He II, C IV, and C III] emission lines at redshift . Spectral evolution is observed in X-rays when the INTEGRAL/IBIS data are compared to the Swift/BAT results, with the spectrum steepening when the source gets fainter. The 0.7-200 keV X-ray continuum, observed with Swift/XRT and INTEGRAL/IBIS, shows the power law shape typical of radio loud (broad emission line) active galactic nuclei (with a photon index ) and a hint of spectral curvature below ~2 keV, possibly due to intrinsic absorption ( cm-2) local to the source. Alternatively, a slope change ( ) around 2.7 keV can describe the X-ray spectrum equally well. At this redshift, the observed 20-100 keV luminosity of the source is ~1048 erg s-1 (assuming isotropic emission), making Swift J1656.3-3302 one of the most X-ray luminous blazars. This source is yet another example of a distant gamma-ray loud quasar discovered above 20 keV. It is also the farthest object, among the previously unidentified INTEGRAL sources, whose nature has been determined a posteriori through optical spectroscopy.