Evidence of Wind Signatures in the Gas Velocity Profiles of Red Geysers
Evidence of Wind Signatures in the Gas Velocity Profiles of Red Geysers
复制标题
DOI：
10.3847/1538-4357/abf1e6
复制
发表时间：
2021-03
期刊：
影响因子：
--
通讯作者：
N. Roy;K. Bundy;R. Nevin;F. Belfiore;R. Yan;S. Campbell;R. Riffel;R. Riffel;M. Bershady;K. Westfall;N. Drory;Kai Zhang
中科院分区：
文献类型：
--
作者：
N. Roy;K. Bundy;R. Nevin;F. Belfiore;R. Yan;S. Campbell;R. Riffel;R. Riffel;M. Bershady;K. Westfall;N. Drory;Kai Zhang
斯隆数字巡天IV在阿帕奇点天文台（MaNGA）的测绘附近星系的空间分辨光谱显示了一类静止的，相对常见的早期类型星系，称为“红色间歇泉”，可能拥有大规模的活动星系核驱动的风。考虑到它们在后期维持低水平星星形成方面的潜在重要性，证实风是红色间歇泉现象的原因的额外证据至关重要。在这项工作中，我们提出了后续的观察与Echellette光谱仪和成像仪（ESI）在凯克望远镜的两个红色间歇泉（z < 0.1）使用多个长缝位置采样每个星系的不同区域。我们的光谱分辨率（R）为8000的ESI数据比MaNGA的分辨率提高了4倍，使我们能够以σ = 16 km s−1的仪器分辨率解析沿着假定风锥的电离气体速度剖面。Hα和[N ii] λ6584的谱线轮廓显示出系统性地依赖于位置的不对称形状：在星系红移一侧延伸的蓝翼和在相反一侧的红翼。我们构建了一个简单的风模型，并表明我们的结果是一致的几何投影通过一个流出的锥形风朝向视线的角度。另一种假设，分配的不对称图案的旋转，电离气体盘的“光束拖尾”不匹配线不对称配置文件的工作。虽然我们的研究只有两个来源，但它进一步支持了红色间歇泉是星系级风的结果的观点。
Spatially resolved spectroscopy from the Sloan Digital Sky Survey IV Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey has revealed a class of quiescent, relatively common early-type galaxies termed “red geysers” that possibly host large-scale active galactic nuclei–driven winds. Given their potential importance in maintaining a low level of star formation at late times, additional evidence confirming that winds are responsible for the red geyser phenomenon is critical. In this work, we present follow-up observations with the Echellette Spectrograph and Imager (ESI) at the Keck telescope of two red geysers (z < 0.1) using multiple long slit positions to sample different regions of each galaxy. Our ESI data with a spectral resolution (R) ∼ 8000 improve upon MaNGA’s resolution by a factor of 4, allowing us to resolve the ionized gas velocity profiles along the putative wind cone with an instrumental resolution of σ = 16 km s−1. The line profiles of Hα and [N ii] λ6584 show asymmetric shapes that depend systematically on location: extended blue wings on the redshifted side of the galaxy and red wings on the opposite side. We construct a simple wind model and show that our results are consistent with geometric projections through an outflowing conical wind oriented at an angle toward the line of sight. An alternative hypothesis that assigns the asymmetric pattern to “beam smearing” of a rotating, ionized gas disk does a poor job matching the line asymmetry profiles. While our study features just two sources, it lends further support to the notion that red geysers are the result of galaxy-scale winds.