论文标题
低Z星系中局部LIRG的紧凑分子气体排放
Compact molecular gas emission in local LIRGs among low- and high-z galaxies
论文作者
论文摘要
我们介绍了24个本地（Z $ <$ 0.02）发光红外星系（LIRGS）的代表性样本的新CO（2-1），该样本是从Alma获得的高空间分辨率（$ <$ <$ 100）。我们使用增长曲线方法得出CO（2-1）和1.3 mM连续体排放的有效半径。 LIRGS显示出极度紧凑的冷分子气体分布（中位r $ _ {CO} $ \ sim $ 0.7 kpc），这是一个比电离气体小2的因子，比出色的尺寸小3.5倍。 LIRGS的分子大小与早期型星系（R $ _ {CO} \ SIM $ 1 kpc）的分子大小相似，比相似恒星质量的局部螺旋型高约6倍。与这些本地LIRGs相比，只有低Z ulirgs中的CO排放更紧凑。与High-Z（1 $ <$ <$ Z $ <$ 6）的系统相比，恒星尺寸和大量本地LIRG类似于High-Z MS MS MS MS-MS-MS形成星系（SFG）（SFG）（SFG）和2-3个低于2-3个低于Submmmmmmmmmmmm的Galaxies（Smg）。 High-Z MS SFG和SMG的分子尺寸大于$ \ sim $ 3和$ \ sim $ 8的分子大小。这些结果表明，尽管低Z LIRGS和High-Z MS-SFG具有相似的恒星质量和大小，但当前恒星形成的区域（由电离气体追踪）和潜在的星形成（通过分子气体追踪）在LIRGS中较小，并约束至中央KPC区域。高Z星系代表着更广泛的人口，但其星形区域更扩展，甚至涵盖了宿主星系的整体规模。高Z星系比低Z LIRG具有更大的气体分数，因此，恒星的形成可以通过相互作用和延伸磁盘或细丝中的相互作用和合并引起，具有足够大的分子气体表面密度，涉及与LIRGS中央KPC中鉴定的物理机制相似的物理机制。
We present new CO(2-1) observations of a representative sample of 24 local (z$<$0.02) luminous infrared galaxies (LIRGs) obtained at high spatial resolution ($<$100 pc) from ALMA. We derive the effective radii of the CO(2-1) and the 1.3 mm continuum emissions using the curve-of-growth method. LIRGs show an extremely compact cold molecular gas distribution (median R$_{CO}$ $\sim$0.7 kpc), which is a factor 2 smaller than the ionized gas, and 3.5 times smaller than the stellar size. The molecular size of LIRGs is similar to that of early-type galaxies (R$_{CO}\sim$1 kpc) and about a factor of 6 more compact than local Spirals of similar stellar mass. Only the CO emission in low-z ULIRGs is more compact than these local LIRGs by a factor of 2. Compared to high-z (1$<$z$<$6) systems, the stellar sizes and masses of local LIRGs are similar to those of high-z MS star-forming galaxies (SFG) and about a factor of 2-3 lower than sub-mm galaxies (SMG). The molecular sizes of high-z MS SFGs and SMGs are larger than those derived for LIRGs by a factor of $\sim$3 and $\sim$8, respectively. These results indicate that while low-z LIRGs and high-z MS-SFGs have similar stellar masses and sizes, the regions of current star formation (traced by the ionized gas) and of potential star-formation (traced by the molecular gas) are substantially smaller in LIRGs, and constrained to the central kpc region. High-z galaxies represent a wider population but their star-forming regions are more extended, even covering the overall size of the host galaxy. High-z galaxies have larger fractions of gas than low-z LIRGs, and therefore the formation of stars could be induced by interactions and mergers in extended disks or filaments with large enough molecular gas surface density involving physical mechanisms similar to those identified in the central kpc of LIRGs.
