论文标题
大量费米大麻样本的光谱变化
Optical Spectral Variations of a Large Sample of Fermi Blazars
论文作者
论文摘要
我们已经研究了大量费米大麻（40 fsrq和13 bl lac）的光谱行为，并发现了两种新的通用光谱行为。在低状态下，光谱逐渐变得更柔软（陡峭）或更难（更倾斜），但是当亮度增加时，光谱越来越慢，然后倾向于在高状态下稳定，这些稳定在高状态下，它们被简要命名为红色稳定的企业（RSWB）（RSWB）（RSWB），并且分别为稳定的稳定（BSWB）（BSWB）行为。 34个FSRQ和7个BL LACS表现出明显的RSWB行为，2个FSRQ和5 BL LACS表现出独特的BSWB行为，这意味着FSRQ比BSWB行为更偏爱RSWB，而BL LACS在两种行为中都没有明确的偏好。我们提出了一个统一的非线性公式，以定量地表征FSRQ和BL lac的光谱行为，这可以很好地适合两种行为。我们认为RSWB和BSWB的行为源于相同的机制，它们是Blazars的普遍光谱行为。经常观察到的红色时（RWB）和蓝光趋势（BWB）趋势分别被认为是RSWB和BSWB行为的近似值。很少观察到的稳定的稳定趋势（SWB）趋势也可以看作是RSWB或BSWB行为的近似值或特殊情况。我们已经开发了一个具有两个恒定谱系组件的模型，不仅可以很好地解释两种光谱行为，而且可以成功地解释FSRQ和BL lac之间的差异行为。
We have investigated the optical spectral behavior of a large sample of Fermi blazars (40 FSRQs and 13 BL Lacs), and found two new universal optical spectral behaviors. In the low state the optical spectrum gradually becomes softer (steeper) or harder (flatter) but more and more slowly when the brightness increases, and then tends to stable in the high state, which are briefly named the redder-stable-when-brighter (RSWB) and bluer-stable-when-brighter (BSWB) behaviors, respectively. 34 FSRQs and 7 BL Lacs exhibit clear RSWB behavior, and 2 FSRQs and 5 BL Lacs show distinct BSWB behavior, which mean that FSRQs favor more RSWB than BSWB behavior, while BL Lacs have no clear preference among both behaviors. We have put forward a unified nonlinear formula to quantitatively characterize the optical spectral behaviors of FSRQs and BL Lacs, which can fit both kinds of behaviors very well. We argue that the RSWB and BSWB behaviors originate from the same mechanism, and they are the universal optical spectral behaviors for blazars. The frequently observed redder-when-brighter (RWB) and bluer-when-brighter (BWB) trends can be considered to be the approximations of the behaviors of RSWB and BSWB, respectively. The rarely observed stable-when-brighter (SWB) trend can also be viewed as an approximation or a special case of the RSWB or BSWB behavior. We have developed a model with two constant-spectral-index components which can not only explain well both two kinds of optical spectral behaviors, but also successfully interpret the differential behaviors between FSRQs and BL Lacs.
