Compact Starburst Galaxies with Fast Outflows: Central Escape Velocities and Stellar Mass Surface Densities from Multiband Hubble Space Telescope Imaging
Compact Starburst Galaxies with Fast Outflows: Central Escape Velocities and Stellar Mass Surface Densities from Multiband Hubble Space Telescope Imaging
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DOI：
10.3847/1538-4357/abe935
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发表时间：
2021-02
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通讯作者：
A. Diamond-Stanic;J. Moustakas;P. Sell;C. Tremonti;A. Coil;Julie D. Davis;J. Geach;Sophia C. W. Gottlieb;R. Hickox;A. Kepley;Charles Lipscomb;Joshua Rines;G. Rudnick;C. Thompson;K. Valdez;C. Bradna;Jordan Camarillo;Eve Cinquino;Senyo Ohene;S. Perrotta;Grayson C. Petter;D. Rupke;C. Umeh;Kelly E. Whalen
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作者：
A. Diamond-Stanic;J. Moustakas;P. Sell;C. Tremonti;A. Coil;Julie D. Davis;J. Geach;Sophia C. W. Gottlieb;R. Hickox;A. Kepley;Charles Lipscomb;Joshua Rines;G. Rudnick;C. Thompson;K. Valdez;C. Bradna;Jordan Camarillo;Eve Cinquino;Senyo Ohene;S. Perrotta;Grayson C. Petter;D. Rupke;C. Umeh;Kelly E. Whalen
我们展示了多波段哈勃太空望远镜成像，该成像跨越静止框架近紫外到近红外波长（–1.1 μm），对 z = 0.4–0.8 处的 12 个致密星暴星系进行成像。这些巨大的星系 ( ) 正在驱动非常快的外流 ( –3000 km s−1)，它们的光剖面主要由极其紧凑的星暴组成部分（半光半径 ~ 100 pc）组成。我们的目标是通过测量中央千秒差距内的物理条件来限制负责启动这些快速流出的物理机制。根据我们的恒星种群分析，中心成分通常占恒星总质量的约 25%，并且中心逃逸速度 km s−1 比观测到的流出速度小两倍。这需要物理机制能够将气体加速到显着超过中心逃逸速度的速度，并且很明显，这些快速流出物能够进入环绕银河系的介质，甚至可能超出银河系介质。我们发现中心恒星密度 kpc−2 与爱丁顿极限的理论估计相当，并且我们估计中心千秒差距内的表面密度与 处致密大质量星系的表面密度相当。相对于 处的“红金块”和“蓝金块”，我们发现给定恒星质量下的 re 值明显更小，我们将其归因于样本中年轻恒星成分的主导地位以及相对于 处的静止框架光学观测的更好的物理分辨率。我们与涉及重大合并和剧烈盘不稳定的理论场景进行比较，并推测我们的星系是具有突出恒星尖点的局部宇宙中幂律椭圆的祖先。
We present multiband Hubble Space Telescope imaging that spans rest-frame near-ultraviolet through near-infrared wavelengths ( –1.1 μm) for 12 compact starburst galaxies at z = 0.4–0.8. These massive galaxies ( ) are driving very fast outflows ( –3000 km s−1), and their light profiles are dominated by an extremely compact starburst component (half-light radius ∼ 100 pc). Our goal is to constrain the physical mechanisms responsible for launching these fast outflows by measuring the physical conditions within the central kiloparsec. Based on our stellar population analysis, the central component typically contributes ≈25% of the total stellar mass, and the central escape velocities km s−1 are a factor of two smaller than the observed outflow velocities. This Requires physical mechanisms that can accelerate gas to speeds significantly beyond the central escape velocities, and it makes clear that these fast outflows are capable of traveling into the circumgalactic medium, and potentially beyond. We find central stellar densities kpc−2 comparable to theoretical estimates of the Eddington limit, and we estimate surface densities within the central kiloparsec comparable to those of compact massive galaxies at . Relative to “red nuggets” and “blue nuggets” at , we find significantly smaller r e values at a given stellar mass, which we attribute to the dominance of a young stellar component in our sample and the better physical resolution for rest-frame optical observations at versus . We compare to theoretical scenarios involving major mergers and violent disk instability, and we speculate that our galaxies are progenitors of power-law ellipticals in the local universe with prominent stellar cusps.