Spectral energy distributions of a large sample of BL Lacertae objects
Spectral energy distributions of a large sample of BL Lacertae objects
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DOI：
10.1051/0004-6361:20053316
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发表时间：
2005-09
影响因子：
6.5
通讯作者：
E. Nieppola;M. Tornikoski;E. Valtaoja;E. Valtaoja
中科院分区：
文献类型：
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作者：
E. Nieppola;M. Tornikoski;E. Valtaoja;E. Valtaoja
我们收集了梅察霍维射电天文台 BL Lacertae 样本中天体的大量多频数据，并以 logν - log νF - 表示形式计算了它们的光谱能量分布 (SED)。这是首次使用 300 多个物体的样本来研究 BL Lacs 的 SED。 SED 的同步加速器组件配备了抛物线函数，以确定同步加速器峰值频率 νpeak。我们检查了几个频段的光度与同步加速器峰值频率之间的依赖性，以测试耀变体序列场景，该场景表明源光度取决于同步加速器峰值的位置。我们还计算了宽带光谱指数并将它们相对于彼此和νpeak 绘制出来。与之前的研究相比，我们研究中νpeak的范围显着扩展。有 22 个对象的 logνpeak > 19。数据显示，在 5 GHz、37 GHz 和 5500 A 处，光度和νpeak 之间存在负相关性，而在 X 射线中，相关性略微呈正相关。同步加速器峰值处的光源光度与νpeak 之间不存在显着相关性。发现了几种低射电光度-低能量峰值的 BL Lacs。尽管存在大量分散，但宽带光谱指数和νpeak 之间的负相关性也很显着。因此我们发现αrx和αro都不能用来确定BL Lacs的同步加速器峰。根据我们的结果，我们得出结论，耀变序列情景是无效的。在我们的所有结果中，BL Lac 群体是连续的，没有暗示第一个 BL Lac 样本的双峰性。
We have collected a large amount of multifrequency data for the objects in the Metsahovi Radio Observatory BL Lacertae sample and computed their spectral energy distributions (SED) in the logν - log νF - representation. This is the first time the SEDs of BL Lacs have been studied with a sample of over 300 objects. The synchrotron components of the SEDs were fitted with a parabolic function to determine the synchr otron peak frequency,νpeak. We checked the dependence between luminosities at several frequency bands and synchrotron peak frequency to test the blazar sequence scenario, which states that the source luminosity depends on the location of the synchrotron peak. We also calculated broad band spectral indices and plotted them against each other andνpeak. The range ofνpeak in our study was considerably extended compared to previous studies. There were 22 objects for which logνpeak >19. The data shows that at 5 GHz, 37 GHz and 5500 A there is negative correlation between luminosity andνpeak, whereas in X-rays the correlation turns slightly positive. There is no significant correlation between source luminosi ty at syn- chrotron peak andνpeak. Several low radio luminosity-low energy peaked BL Lacs were found. The negative correlation between broad band spectral indices andνpeak is also significant, although there is substantial scatter. Therefore we find that neither αrx norαro can be used to determine the synchrotron peak of BL Lacs. On the grounds of our results we conclude that the blazar sequence scenario is not valid. In all our results the BL Lac population is continuous with no hint of the bimodality of the first BL Lac samples.