论文标题
在NGC 253的Starburst心脏中揭示运动学结构
Unveiling Kinematic Structure in the Starburst Heart of NGC 253
论文作者
论文摘要
我们研究了NGC 253的核星爆的电离气体的运动学，并观察到Brackett $α$重组线为4.05 $μ$ m。目的是区分由恒星形成反馈驱动的运动与中央质量结构引起的重力运动的动作。在Keck II上使用NIRSPEC，我们通过$ 0''获得了30个光谱。5$ slit跨过中央$ \ sim $ \ sim $ 5 $ 5 $''\ times 25''$（85 $ \ times $ 425 $ 425 PC）地区，以生产光谱cube。 BR $α$排放分解为四个核源：红外核心（IRC）的S1，在非热源TH2附近的无线电核心的N1，而东北的Fainter Sources N2和N3则是fainter。该行配置文件的特征在于主要组件，其$ΔV_ {\ MathRm {primary}} $ \ sim $ 90-130 km s $ s $^{ - 1} $（fwhm）在带有$ΔV_{\ nive的blue}机翼上西方红移狭窄的组件。从我们的立方体生成的速度场揭示了几种不同的模式。 +10 km s $^{ - 1} $ arcsec $^{ - 1} $的平均NE-SW速度梯度沿主要轴沿核磁盘的实体旋转曲线追踪。在无线电核心上，等距轮廓变为S形，表明存在总范围$ \ sim $ 5 $''$（90 PC）的次级核棒。酒吧的对称性将银河系中心放置在银河系的无线电峰值TH2附近，而不是IRC，使其成为SMBH最有可能的位置。 IRC东南侧的Blueshifted气体形成了第三个运动学子结构。此功能为$ \ sim $ 100-250 km s $^{ - 1} $ starburst驱动的流出可能负责为NGC 253的KPC尺度银河风提供动力的证据。
We investigate the kinematics of ionized gas within the nuclear starburst of NGC 253 with observations of the Brackett $α$ recombination line at 4.05 $μ$m. The goal is to distinguish motions driven by star-formation feedback from gravitational motions induced by the central mass structure. Using NIRSPEC on Keck II, we obtained 30 spectra through a $0''.5$ slit stepped across the central $\sim$5$''\times 25''$ (85 $\times$ 425 pc) region to produce a spectral cube. The Br$α$ emission resolves into four nuclear sources: S1 at the infrared core (IRC), N1 at the radio core near nonthermal source TH2, and the fainter sources N2 and N3 in the northeast. The line profile is characterized by a primary component with $Δv_{\mathrm{primary}}$$\sim$90-130 km s$^{-1}$ (FWHM) on top of a broad {blue} wing with $Δv_{\mathrm{broad}}$$\sim$300-350 km s$^{-1}$, and an additional redshifted narrow component in the west. The velocity field generated from our cube reveals several distinct patterns. A mean NE-SW velocity gradient of +10 km s$^{-1}$ arcsec$^{-1}$ along the major axis traces the solid-body rotation curve of the nuclear disk. At the radio core, isovelocity contours become S-shaped, indicating the presence of secondary nuclear bar of total extent $\sim$5$''$ (90 pc). The symmetry of the bar places the galactic center near the radio peak TH2 of the galaxy rather than the IRC, and makes this the most likely location of a SMBH. A third kinematic substructure is formed by blueshifted gas on the southeast side of the IRC. This feature provides evidence for a $\sim$100-250 km s$^{-1}$ starburst-driven outflow potentially responsible for powering the kpc-scale galactic wind of NGC 253.
