Optical spectral characterization of the gamma-ray blazars S4 0954+65, TXS 1515−273, and RX J0812.0+0237
Optical spectral characterization of the gamma-ray blazars S4 0954+65, TXS 1515−273, and RX J0812.0+0237
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DOI：
10.1093/mnras/stab1274
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发表时间：
2020-10
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影响因子：
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通讯作者：
J. Gonz'alez;J. Acosta-Pulido;W. Boschin;R. Clavero;J. Otero-Santos;J. Carballo-Bello;L. Domínguez-Palmero
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文献类型：
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作者：
J. Gonz'alez;J. Acosta-Pulido;W. Boschin;R. Clavero;J. Otero-Santos;J. Carballo-Bello;L. Domínguez-Palmero
由于缺乏关于其红移和低能光子场的信息，对伽马射线耀变体的研究通常受到阻碍。这一信息对于理解河外背景光和/或本征吸收和发射过程对伽马射线吸收的影响至关重要。所有这些信息对确定相对论性喷流中发射区域的位置也有影响。本文对3颗伽玛射线耀变体S4 0954+65、TXS 1515-273和RX J0812.0+0237进行了新的光谱表征。3个目标的红移测定和分类均成功，均属于BL Lac型。对于S4 0954+65 (z=$0.3694\pm0.0011$)，根据观测到的光发射线对其盘、宽线区域和环面光度进行了估计。这项研究的结果与S4 0954+65作为过渡耀变体的性质是一致的。在TXS 1515-273 （$z=0.1281\pm 0.0004$）的情况下，虽然它的光谱主要是由喷流的连续辐射主导，但应用pPXF技术，恒星种群与古老的金属种群兼容。RX J0812.0+0237 （$z=0.1721\pm 0.0002$）也是如此。此外，这项工作证实了RX J0812.0+0237的光谱与一个极端耀变体分类是兼容的。
The study of gamma-ray blazars is usually hindered due to the lack of information on their redshifts and on their low energy photon fields. This information is key to understand the effect on the gamma-ray absorption due to either extragalactic background light and/or intrinsic absorption and emission processes. All this information has also an impact on the determination of the location of the emitting region within the relativistic jets. In this work a new optical spectroscopic characterization is presented for three gamma-ray blazars: S4 0954+65, TXS 1515-273 and RX J0812.0+0237. For all the three targets the redshift determination was successful as well as their classification, belonging all of them to the BL Lac type. For S4 0954+65 (z=$0.3694\pm0.0011$) an estimation on the disk, broad line region and torus luminosities was performed based on the observed optical emission lines. The results from this study are compatible with the nature of S4 0954+65 as a transitional blazar. In the case of TXS 1515-273 ($z=0.1281\pm 0.0004$), although its optical spectrum is dominated by the continuum emission from the jet, applying the pPXF technique, the stellar population is compatible with an old and metallic population. It is also the case of RX J0812.0+0237 ($z=0.1721\pm 0.0002$). Moreover, this work confirms that the optical spectrum from RX J0812.0+0237 is compatible with an extreme blazar classification.