论文标题
观察星系中恒星形成的最早阶段：三个边缘磁盘中的8微米芯
Observing the Earliest Stages of Star Formation in Galaxies: 8 micron Cores in Three Edge-on Disks
论文作者
论文摘要
为了研究星系中恒星形成的最早阶段的垂直分布，三个边缘螺旋，NGC 891，NGC 3628和IC 5052，使用Ansharp Mask Mask技术检查了Spitzer Space望远镜红外阵列（IRAC）的Spitzer Space望远镜红外阵列（IRAC）；分别区分了173、267和60个核心。颜色色的分布表明，PAH和年轻恒星的高光谱发射的混合物。平均V波段灭绝是〜20 mag，同样分配在前景和核心之间。假设年龄为1 MYR，将团块的IRAC幅度转换为恒星质量，大约等于每个星系中总核心质量与恒星形成率的比率。灭绝和恒星质量表明，固有的核心直径约为18 pc，达到5％的星形形成效率。对于NGC 891的8微米核心的磁盘的半厚度为105 pc，对于IC 5052，磁盘为105 PC，随着半径的变化量为〜2。对于正在相互作用的NGC 3628，半厚度为438 PC，但是即使有这种相互作用，8微米磁盘也非常平坦，表明垂直稳定性。在核心位置可以看到小规模的结构，例如带状疱疹或螺旋。在8个微米核心中，很少有光学对应物。
To study the vertical distribution of the earliest stages of star formation in galaxies, three edge-on spirals, NGC 891, NGC 3628, and IC 5052 observed by the Spitzer Space Telescope InfraRed Array Camera (IRAC) were examined for compact 8 micron cores using an unsharp mask technique; 173, 267, and 60 cores were distinguished, respectively. Color-color distributions suggest a mixture of PAHs and highly-extincted photospheric emission from young stars. The average V-band extinction is ~20 mag, equally divided between foreground and core. IRAC magnitudes for the clumps are converted to stellar masses assuming an age of 1 Myr, which is about equal to the ratio of the total core mass to the star formation rate in each galaxy. The extinction and stellar mass suggest an intrinsic core diameter of ~18 pc for 5% star formation efficiency. The half-thickness of the disk of 8 micron cores is 105 pc for NGC 891 and 74 pc for IC 5052, varying with radius by a factor of ~2. For NGC 3628, which is interacting, the half-thickness is 438 pc, but even with this interaction, the 8 micron disk is remarkably flat, suggesting vertical stability. Small scale structures like shingles or spirals are seen in the core positions. Very few of the 8 micron cores have optical counterparts.
