论文标题
排放和吸收线之间的速度偏移可能是双核系统的有效指标
Velocity offset between emission and absorption lines might be an effective indicator of dual core system
论文作者
论文摘要
本文提出了SDSS中的双核系统的发射和吸收线之间的显着速度偏移〜J155708.82+273518.74（= SDSS〜J1557）。 SDSS 〜J1557的光度图表显示了两个由Galfit确定的$ \ sim $ 2.2 Arcseconds（4.9 kpc）的明确核心。根据636个理论SSP模板的普遍接受的PPXF代码的应用，可以很好地确定主机星系贡献。然后，在宿主星光减去后，可以很好地测量SDSS 〜J1557的发射线特征。发现相对于吸收线的排放线的速度抵消了$ 458 \ pm 13 $ km/s。根据Baldwin-Phillips-Terlevich（BPT）图，SDSS J1557是复合星系。此外，SDSS J1557可以很好地适合$ m _ {\ rm bh} -tement _ {\ ast} $凸起的关系，而星系合并不会改变此关系。已经讨论了两个合理的模型（例如，AGN驱动的流出与双核心系统）来解释此速度偏移。 AGN驱动的流出模型无法解释SDSS 〜J1557中各种发射线的发射线的系统红移和类似的速度偏移。排放和吸收线之间的显着速度偏移可能是双核系统的有效指标。
This paper presents a detection of significant velocity offset between emission and absorption lines for a dual core system in SDSS~J155708.82+273518.74 (= SDSS~J1557). The photometric image of SDSS~J1557 exhibits clear two cores with a projected separation of $\sim$2.2 arcseconds (4.9 kpc) determined by GALFIT. Based on the applications of the commonly accepted pPXF code with 636 theoretical SSP templates, the host galaxy contribution can be well determined. Then, the emission line features of SDSS~J1557 can be well measured after subtraction of host starlight. It is found that the velocity offset of emission lines with respect to absorption lines reaches $458 \pm 13$ km/s. According to the Baldwin-Phillips-Terlevich (BPT) diagram, SDSS J1557 is a composite galaxy. In addition, SDSS J1557 can well fit the $M_{\rm BH}-σ_{\ast}$ relation of bulges and the galaxy merger would not change this relation. Two reasonable models (say, AGN-driven outflow vs. dual core system) have been discussed to explain this velocity offset. The model of AGN-driven outflow fails to interpret the systematic redshift of emission lines and similar velocity offsets for various emission lines in SDSS~J1557. A significant velocity offset between emission and absorption lines might be an effective indicator of dual core system.
