VLBI Detections of Parsec-Scale Nonthermal Jets in Radio-Loud Broad Absorption Line Quasars
VLBI Detections of Parsec-Scale Nonthermal Jets in Radio-Loud Broad Absorption Line Quasars
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DOI：
10.1093/pasj/61.6.1389
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发表时间：
2009-10
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通讯作者：
A. Doi;N. Kawaguchi;Y. Kono;T. Oyama;K. Fujisawa;H. Takaba;H. Sudou;K. Wakamatsu;Aya Yamauchi;Y. Murata;N. Mochizuki;K. Wajima;T. Omodaká;T. Nagayama;N. Nakai;K. Sorai;E. Kawai;M. Sekido;Y. Koyama;the Vlbi group at Gsi;S. Asano;H. Uose
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文献类型：
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作者：
A. Doi;N. Kawaguchi;Y. Kono;T. Oyama;K. Fujisawa;H. Takaba;H. Sudou;K. Wakamatsu;Aya Yamauchi;Y. Murata;N. Mochizuki;K. Wajima;T. Omodaká;T. Nagayama;N. Nakai;K. Sorai;E. Kawai;M. Sekido;Y. Koyama;the Vlbi group at Gsi;S. Asano;H. Uose
我们使用甚长基线干涉测量(VLBI)技术，在8.4 GHz对22个射电响亮宽吸收线(BAL)类星体进行了射电探测观测，这些类星体是从斯隆数字巡天(SDSS)第三次数据发布中挑选出来的。我们使用的VLBI仪器是由VLBI探测项目的光连接阵列(OCTAVE)开发的，该阵列是日本VLBI网络(JVN)的一个子阵列。我们的目标是通过随后详细的VLBI成像研究，选择具有非热喷流的BAL类星体来测量它们的方位角和年龄，以评估BAL类星体是否被近旁观察以及BAL类星体是否处于类星体种群的短暂进化阶段这两个有争议的问题。我们使用倍频程基线探测到了22个源中的20个，这意味着亮度温度超过10^5K，推测它们来自非热喷流。因此，BAL外流和非热喷流可以在这些中央发动机中同时产生。我们还发现了四个倒谱源，它们被解释为多普勒波束的、极点观察的相对论喷流源或年轻射电源：单边几何不能描述所有的BAL类星体。我们讨论了倍频程观测对BAL类星体取向和演化阶段研究的意义。
We conducted radio detection observations at 8.4 GHz for 22 radio-loud broad absorption line (BAL) quasars, selected from the Sloan Digital Sky Survey (SDSS) Third Data Release, by a very-long-baseline interferometry (VLBI) technique. The VLBI instrument we used was developed by the Optically ConnecTed Array for VLBI Exploration project (OCTAVE), which is operated as a subarray of the Japanese VLBI Network (JVN). We aimed at selecting BAL quasars with nonthermal jets suitable for measuring their orientation angles and ages by subsequent detailed VLBI imaging studies to evaluate two controversial issues of whether BAL quasars are viewed nearly edge-on, and of whether BAL quasars are in a short-lived evolutionary phase of quasar population. We detected 20 out of 22 sources using the OCTAVE baselines, implying brightness temperatures greater than 10^5 K, which presumably come from nonthermal jets. Hence, BAL outflows and nonthermal jets can be generated simultaneously in these central engines. We also found four inverted-spectrum sources, which are interpreted as Doppler-beamed, pole-on-viewed relativistic jet sources or young radio sources: single edge-on geometry cannot describe all BAL quasars. We discuss the implications of the OCTAVE observations for investigations for the orientation and evolutionary stage of BAL quasars.