Obtaining Galaxy Masses Using Stellar Absorption and [O II] Emission-Line Diagnostics in Late-Type Galaxies
Obtaining Galaxy Masses Using Stellar Absorption and [O II] Emission-Line Diagnostics in Late-Type Galaxies
复制标题
使用晚型星系中的恒星吸收和 [O II] 发射线诊断来获取星系质量
DOI：
10.1086/301301
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
K. Gebhardt
中科院分区：
文献类型：
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作者：
H. Kobulnicky;K. Gebhardt
恒星巴尔默线和 Ca H 和 K 线的 [O II] λ3727 发射线和吸收特征是 z ∼ 1 星系中最容易获得的运动学诊断。我们利用这些光谱特征研究了 22 个局部晚型星系的运动学，并将结果与 21 cm 中性氢光谱进行比较，以评估每种诊断对于测量星系质量的实用性。为了模拟高红移数据（通常只能获得一维速度剖面），我们研究了空间积分以及空间分辨光谱。尽管所研究的星系涵盖了广泛的形态类型、倾角和恒星形成率，但我们发现气体和恒星运动示踪剂产生了可比的运动线宽度和系统速度。 [O II] 和 H I 线宽相关性最强，显示出~20 km s-1 的固有色散，或者对于运动学宽度为 200 km s-1 的典型星系来说~10%。在一些极端情况下，[O II] 线宽低估了中性氢宽度 50%。可靠的速度宽度也可以从恒星巴尔默和 Ca H 和 K 吸收线获得，甚至对于一些具有强发射线的晚期类型星系也是如此。恒星吸收和 H I 线宽之间的本征色散≤10%。我们提供了利用这些强恒星吸收和 [O II] 发射特征来测量遥远宇宙中星系的运动学和质量的方法。
The [O II] λ3727 emission lines and absorption features from stellar Balmer and Ca H and K lines are the most accessible kinematic diagnostics in galaxies at z ∼ 1. We investigate the kinematics of 22 local late-type galaxies using these spectral features, and we compare the results with 21 cm neutral hydrogen spectra in order to assess the utility of each diagnostic for measuring galaxy masses. In order to simulate data at high redshift, where only one-dimensional velocity profiles are normally available, we study spatially integrated, as well as spatially resolved, spectra. Although the studied galaxies span a wide range of morphological types, inclinations, and star formation rates, we find that the gaseous and stellar kinematic tracers yield comparable kinematic line widths and systemic velocities. The [O II] and H I line widths correlate most strongly, showing an intrinsic dispersion of ∼20 km s-1, or ∼10% for a typical galaxy with a kinematic width of 200 km s-1. In a few extreme cases, the [O II] line widths underestimate the neutral hydrogen width by 50%. Reliable velocity widths can also be obtained from the stellar Balmer and Ca H and K absorption lines, even for some of the very late type galaxies that have strong emission lines. The intrinsic dispersion is ≤10% between the stellar absorption and H I line widths. We provide a prescription for using these strong stellar absorption and [O II] emission features to measure the kinematics, and thus masses, of galaxies in the distant universe.