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arXiv 2102.11287astro-ph.GA
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具有快速外流的紧凑型星暴星系:来自多波段哈勃空间望远镜成像的中心逃逸速度和恒星质量表面密度

Compact Starburst Galaxies with Fast Outflows: Central Escape Velocities and Stellar Mass Surface Densities from Multi-band Hubble Space Telescope Imaging

Aleksandar M. Diamond-Stanic, John Moustakas, Paul H. Sell, Christy A. Tremonti, Alison L. Coil, Julie D. Davis, James E. Geach, Sophia C. W. Gottlieb, Ryan C. … 展开作者

Aleksandar M. Diamond-Stanic, John Moustakas, Paul H. Sell, Christy A. Tremonti, Alison L. Coil, Julie D. Davis, James E. Geach, Sophia C. W. Gottlieb, Ryan C. Hickox, Amanda Kepley, Charles Lipscomb, Joshua Rines, Gregory H. Rudnick, Cristopher Thompson, Kingdell Valdez, Christian Bradna, Jordan Camarillo, Eve Cinquino, Senyo Ohene Serena Perrotta, Grayson C. Petter, David S. N. Rupke, Chidubem Umeh, Kelly E. Whalen

摘要:

我们提出了多波段哈勃太空望远镜成像,跨越静止帧近紫外线到近红外波长(0.3-1.1 $μ$ m)的12个紧凑的星暴星系在z=0.4-0.8。这些大质量星系(M_stellar ~ 10^11 M_Sun)驱动着非常快的外流($v_{max}$ =1000-3000 km/s),它们的光剖面由极其紧凑的星暴组成(半光半径~ 100 pc)。我们的目标是通过测量中心千秒差距内的物理条件来限制负责发射这些快速外流的物理机制。根据我们的恒星人口分析,中央组件通常贡献$\approx$ 25%的总恒星质量和中央逃逸速度$v_{esc,central}\approx900$公里/秒是一个因素的两倍小于观测到的外流速度。这需要物理机制来将气体加速到大大超过中心逃逸速度的速度,并且它清楚地表明这些快速流出能够进入环银河系介质,甚至可能超出。我们发现中央恒星密度的爱丁顿极限的理论估计相媲美,我们估计$Σ_1$的表面密度在中央千秒差距相当于那些紧凑的大质量星系在$0.5<z<3.0$。相对于“红金块”和“蓝金块”在$z\sim2$,我们发现显着较小的$r_e$值在一个给定的恒星质量,我们归因于一个年轻的恒星成分在我们的样本中占主导地位,并在$z\sim0.6$与$z\sim2$更好的物理分辨率的休息帧光学观测。我们比较涉及重大合并和暴力光盘不稳定的理论方案,我们推测,我们的星系是祖先的幂律椭圆在本地宇宙与突出的恒星尖。

英文摘要:

We present multi-band Hubble Space Telescope imaging that spans rest-frame near-ultraviolet through near-infrared wavelengths (0.3-1.1 $μ$m) for 12 compact starburst galaxies at z=0.4-0.8. These massive galaxies (M_stellar ~ 10^11 M_Sun) are driving very fast outflows ($v_{max}$=1000-3000 km/s), 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 $\approx$25% of the total stellar mass and the central escape velocities $v_{esc,central}\approx900$ km/s 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 comparable to theoretical estimates of the Eddington limit, and we estimate $Σ_1$ surface densities within the central kpc comparable to those of compact massive galaxies at $0.5<z<3.0$. Relative to "red nuggets" and "blue nuggets" at $z\sim2$, 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 $z\sim0.6$ versus $z\sim2$. We compare to theoretical scenarios involving major mergers and violent disc instability, and we speculate that our galaxies are progenitors of power-law ellipticals in the local universe with prominent stellar cusps.

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