论文标题
在高合金峰峰值的parsec尺度摇摆射流峰值1553+113
A parsec-scale wobbling jet in the high-synchrotron peaked blazar PG 1553+113
论文作者
论文摘要
Pg 1553+113是第一个在其伽马射线光曲线中显示大约两年的准周期模式的大型。这种准周期性可能具有几何起源，可能与射流的进攻性有关，或者可能与源头固有，并且与脉动积聚流动不稳定性有关。通过在15、24和43 GHz处的一个非常长的基线阵列（VLBA）监测，我们在2015 - 2017年期间研究了整个伽马射线活性周期中的源PC尺度属性。与伽马射线发射中定义明确的周期性相反，在无线电频率下，无法识别明确的周期性模式。通过总强度脊线限制的射流位置角在40-60度范围内的不同观察时期内变化。我们还研究了源极化特性的时间演变，包括旋转度量。发现亮度温度随着频率的增加而降低，内在值〜1.5 x 10^10 k，估计的多普勒因子为〜1.4。
PG 1553+113 is the first blazar showing an approximately two-year quasi-periodic pattern in its gamma-ray light curve. Such quasi-periodicity might have a geometrical origin, possibly related to the precessing nature of the jet, or could be intrinsic to the source and related to pulsational accretion flow instabilities. By means of a ~2yr very long baseline array (VLBA) monitoring at 15, 24, and 43 GHz we investigate the source pc-scale properties during an entire cycle of gamma-ray activity in the period 2015-2017. In contrast to the well-defined periodicity in the gamma-ray emission, at radio frequencies no clear periodic pattern can be recognized. The jet position angle, constrained by means of the total intensity ridge line, varies across the different observing epochs in the range 40-60 deg. We also investigate the time evolution of the source polarization properties, including the rotation measure. The brightness temperature is found to decrease as the frequency increases with an intrinsic value of ~1.5 x 10^10 K and the estimated Doppler factor is ~1.4.
