Broad-band continuum and line emission of the gamma-ray blazar PKS 0537-441
Broad-band continuum and line emission of the gamma-ray blazar PKS 0537-441
复制标题
伽马射线耀变体 PKS 0537-441 的宽带连续谱和线发射
DOI：
10.1051/0004-6361:20020881
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发表时间：
2002
影响因子：
6.5
通讯作者：
George Mason Univ.
中科院分区：
文献类型：
--
作者：
E. Pian;R. Falomo;R. Hartman;L. Maraschi;F. Tavecchio;M. Tornikoski;A. Treves;C. Urry;L. Ballo;R. Mukherjee;R. Scarpa;D. Thompson;J. E. P. Inaf;OA Trieste;;O. Padova;Nasa Gsfc;OA Brera;M. Obs.;Univ. Insubria;Como;Y. Univ.;C. Univ.;Eső;Chile.;George Mason Univ.
从射电、光学、紫外光和X射线等不同频率观测到了一颗明亮的闪耀星PKS0537-441，它通常是准同时在白鹭的不同地点出现的。1995年，人们发现该天体在所有波长都处于强烈发射状态。1998年进行的BeppoSAX观测，与其他频率的曝光不同时，使我们能够精确地表征高能blazar分量的光谱形状，我们将其归因于逆康普顿散射。不同时期的光-射线光谱能量分布表明，-射线光度对测辐射辐射输出起主导作用。这与光学和紫外线发射的存在一起表明，除了同步加速器自康普顿机制外，喷流外部(例如，在宽线区域)光子的康普顿上散射可能在高能辐射的产生中起着重要作用。通过改变等离子体的体洛伦兹因子，可以再现多波长的变化。1995年由IUE获得的光谱似乎在1700A附近被部分吸收，然而，在源的较低状态期间拍摄的HST光谱中没有检测到这一特征。场的光学成像和光谱学不支持插入吸收的存在。
PKS 0537-441, a bright-ray emitting blazar, was observed at radio, optical, UV and X-ray frequencies during various EGRET pointings, often quasi-simultaneously. In 1995 the object was found in an intense emission state at all wave- lengths. BeppoSAX observations made in 1998, non-simultaneously with exposures at other frequencies, allow us to charac- terize precisely the spectral shape of the high energy blazar component, which we attribute to inverse Compton scattering. The optical-to--ray spectral energy distributions at the dierent epochs show that the-ray luminosity dominates the bolometric output. This, together with the presence of optical and UV line emission, suggests that, besides the synchrotron self-Compton mechanism, the Compton upscattering of photons external to the jet (e.g., in the broad line region) may have a significant role in the production of high energy radiation. The multiwavelength variability can be reproduced by changes of the plasma bulk Lorentz factor. The spectrum secured by IUE in 1995 appears to be partially absorbed shortward of1700 A. However, this signature is not detected in the HST spectrum taken during a lower state of the source. The presence of intervening absorbers is not supported by optical imaging and spectroscopy of the field.