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arXiv 2510.04429astro-ph.GA
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VVV巡天中的高能伽马射线源——III. 低银纬活动星系核(AGN)的光谱证认

High energy gamma-ray sources in the VVV survey - III. Spectroscopic confirmation of an AGN at low Galactic latitudes

Eduardo O. Schmidt, Laura D. Baravalle, Ana Pichel, Damián Mast, María Victoria Alonso, Jorge Díaz Tello, Luciano H. García, Valentin D. Ivanov, Dante Minniti, … 展开作者

Eduardo O. Schmidt, Laura D. Baravalle, Ana Pichel, Damián Mast, María Victoria Alonso, Jorge Díaz Tello, Luciano H. García, Valentin D. Ivanov, Dante Minniti, Nicola Masetti, Laura G. Donoso, Rodrigo Zelada Bacigalupo

AI总结:

本研究利用Gemini South的Flamingos-2近红外光谱,证认低银纬未关联伽马射线源候选体VVV-J181258.71-314346.7为红移z=0.206的1型AGN,证明近红外巡天可穿透隐带,助力搜寻银河系后方隐匿的AGN。

摘要:

我们旨在通过光谱学证认VVV-J181258.71-314346.7的本质,该天体是未关联伽马射线源4FGLJ1812.8-3144的候选对应体。该天体是根据其近红外测光特性和中等光变选出的,属于识别银河系核球和盘后方活动星系核(AGN)更广泛研究工作的一部分。我们使用位于Gemini South的Flamingos-2仪器获取了近红外光谱,覆盖1.1–1.8 μm范围,光谱分辨率为R~1200。我们应用了标准数据缩减流程,包括大气校正和波长定标。分析重点在于发射线的识别,以及使用互相关技术和光谱模板拟合估计红移。尽管信噪比相对较低,光谱仍显示出Paβ和Fe II发射线的存在。测得的红移为z=0.206±0.001,这证实了该源的河外性质。线比、半高全宽等光谱特征与通常在1型AGN(尤其是赛弗特1星系)中观测到的特征一致。本研究证明了近红外光谱学能够揭示被高消光、高密度星场遮挡的AGN。对低银纬(b~-6.5°)AGN的证认表明,类似VVV的近红外巡天能够成功穿透隐带。将这一方法拓展到更多候选体,对于完善隐藏在银河系后方的AGN统计、以及约束这些复杂区域中未关联伽马射线源的族群至关重要。

英文摘要:

We aim to spectroscopically confirm the nature of VVV-J181258.71-314346.7, a candidate counterpart to the unassociated gamma-ray source 4FGLJ1812.8-3144. This object was selected based on its near-infrared photometric properties and moderate variability, as part of a broader effort to identify active galactic nuclei (AGN) behind the Galactic bulge and disc. We obtained near-infrared spectra using the Flamingos-2 instrument at Gemini South, covering the $1.1 $--$ 1.8~μ$m range with a spectral resolution of $R \sim 1200$. Standard data reduction procedures were applied, including telluric correction and wavelength calibration. The analysis focused on the identification of emission lines and the estimation of the redshift using cross-correlation techniques and spectral template fitting. Despite a relatively low signal-to-noise ratio, the spectrum reveals the presence of Pa$β$ and Fe\,\textsc{ii} emission lines. The measured redshift is $z = 0.206 \pm 0.001$, which confirms the extragalactic nature of the source. The spectral features such as line ratios and full width at half maximum are consistent with those typically observed in type-1 AGNs, particularly Seyfert 1 galaxies. This study demonstrates the ability of near-infrared spectroscopy to reveal AGNs that are obscured by highly extincted and crowded galactic fields. The confirmation of an AGN at low Galactic latitude ($b\sim -6.5$°) shows that near-IR surveys like VVV can successfully penetrate the zone of avoidance. Extending this approach to additional candidates is crucial for improving the census of AGNs hidden behind the Milky Way, as well as for constraining the population of unassociated gamma-ray sources in these troublesome regions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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