Ground-based Pa α Narrow-band Imaging of Local Luminous Infrared Galaxies. I. Star Formation Rates and Surface Densities
Ground-based Pa α Narrow-band Imaging of Local Luminous Infrared Galaxies. I. Star Formation Rates and Surface Densities
复制标题
本地发光红外星系的地基 Pa α 窄带成像 I. 恒星形成速率和表面密度。
DOI：
10.1088/0067-0049/217/1/1
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
他33人
中科院分区：
文献类型：
--
作者：
舘内謙、小西真広、本原顕太郎;他33人
发光红外星系（LIRG）被其活跃恒星形成过程中产生的大量尘埃所笼罩，很难在光波长下测量它们的活动。我们利用东京大学阿塔卡马天文台（TAO）1.0 m望远镜（miniTAO）上的阿塔卡马近红外相机对附近38个恒星形成星系（包括IRAS修订的明亮星系样本目录中列出的33个LIRG）进行了Paα窄带成像观测。根据 Paα 通量估计的恒星形成率（SFR），使用巴尔默递减法（通常为 A V∼ 4.3 星等）对尘埃消光进行校正，显示出与 IRAS 数据的辐射热红外光度在 0.27 dex 散射范围内的恒星形成率（SFR）具有良好的相关性。这表明在我们的样本中，对 Paα 通量的尘埃消光校正是足够的。我们测量了单个星系的红外光度（Σ L（IR））和恒星形成区域的恒星形成率（Σ SFR）的物理尺寸和表面密度，我们发现大多数星系在L（IR）–Σ L（IR）和SFR–Σ SFR平面上遵循一系列局部超发光或发光红外星系（U/LIRG）。我们确认，在 L (IR)= 8× 10 10 L☉ 处可以看到序列从正常星系到 U/LIRG 的转变。此外，我们发现物理尺寸存在很大的分散性，与正常星系或 ULIRG 不同。考虑到大多数U/LIRG都是合并或相互作用的星系，这种散射可能是由强烈的外部因素或合并阶段的差异引起的。
Luminous infrared galaxies (LIRGs) are enshrouded by a large amount of dust produced by their active star formation, and it is difficult to measure their activity in optical wavelengths. We have carried out Paα narrow-band imaging observations of 38 nearby star forming galaxies including 33 LIRGs listed in the IRAS Revised Bright Galaxy Sample catalog with the Atacama Near InfraRed camera on the University of Tokyo Atacama Observatory (TAO) 1.0 m telescope (miniTAO). Star formation rates (SFRs) estimated from the Paα fluxes, corrected for dust extinction using the Balmer decrement method (typically A V∼ 4.3 mag), show a good correlation with those from the bolometric infrared luminosity of the IRAS data within a scatter of 0.27 dex. This suggests that the correction of dust extinction for the Paα flux is sufficient in our sample. We measure the physical sizes and surface densities of infrared luminosities (Σ L (IR)) and the SFR (Σ SFR) of star forming regions for individual galaxies, and we find that most of the galaxies follow a sequence of local ultra-luminous or luminous infrared galaxies (U/LIRGs) on the L (IR)–Σ L (IR) and SFR–Σ SFR plane. We confirm that a transition of the sequence from normal galaxies to U/LIRGs is seen at L (IR)= 8× 10 10 L☉. Also, we find that there is a large scatter in physical size, different from normal galaxies or ULIRGs. Considering the fact that most U/LIRGs are merging or interacting galaxies, this scatter may be caused by strong external factors or differences in their merging stages.