TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782
TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782
复制标题
小型合并的潮汐尾巴。
DOI：
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
J. Charlton
中科院分区：
文献类型：
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作者：
K. Knierman;P. Scowen;T. Veach;C. Groppi;B. Mullan;I. Konstantopoulos;P. Knezek;J. Charlton
奇特的螺旋星系NGC 2782是发生在2.2亿年前的一次质量比为1.4：1的小型合并的结果。这种合并产生了一个分子和H i丰富，光学明亮的东部尾巴和H i丰富，光学暗淡的西部尾巴。Braine等人没有在西尾探测到CO，这表明星星的形成还没有开始。然而，深UBVR和Hα窄带图像显示了西尾最近星星形成的证据，尽管它缺乏大质量的星星星团和星团复合体。使用Herschel PACS光谱，我们发现158 μm [C ii]发射在东尾的三个最明亮的Hα源的位置，但不是在西尾的更明亮的Hα源的位置。西尾有正常的星星形成效率（SFE），但东尾有一个低的SFE。CO和[C ii]排放的缺乏表明西尾H ii区域可能具有较低的碳丰度，并且正在经历其第一颗星星的形成。西尾在形成恒星方面更有效，但缺乏大质量的星团。我们认为，在东部尾部的低SFE可能是由于它的形成作为一个飞溅区，气体加热是重要的，即使它有足够的分子和中性气体，使大规模的星星集群。西尾的气体表面密度较低，不会形成高质量的星星团，是一个潮汐形成的区域，重力压缩可能会促进星星的形成。
The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio ∼4: 1 occurring ∼200 Myr ago. This merger produced a molecular and H i-rich, optically bright eastern tail and an H i-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun. However, deep UBVR and Hα narrowband images show evidence of recent star formation in the western tail, though it lacks massive star clusters and cluster complexes. Using Herschel PACS spectroscopy, we discover 158 μm [C ii] emission at the location of the three most luminous Hα sources in the eastern tail, but not at the location of the even brighter Hα source in the western tail. The western tail is found to have a normal star formation efficiency (SFE), but the eastern tail has a low SFE. The lack of CO and [C ii] emission suggests that the western tail H ii region may have a low carbon abundance and be undergoing its first star formation. The western tail is more efficient at forming stars, but lacks massive clusters. We propose that the low SFE in the eastern tail may be due to its formation as a splash region where gas heating is important even though it has sufficient molecular and neutral gas to make massive star clusters. The western tail, which has lower gas surface density and does not form high-mass star clusters, is a tidally formed region where gravitational compression likely enhances star formation.
DOI：
10.1088/0004-6256/140/5/1194
发表时间：
2010-07
期刊：
The Astronomical Journal
影响因子：
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作者：
F. Bigiel;A. Leroy;F. Walter;L. Blitz;E. Brinks;W. D. Blok;B. M. U. Berkeley;Mpia Heidelberg;Nrao;U. Hertfordshire;U. C. Town;C. Observatories
通讯作者：
F. Bigiel;A. Leroy;F. Walter;L. Blitz;E. Brinks;W. D. Blok;B. M. U. Berkeley;Mpia Heidelberg;Nrao;U. Hertfordshire;U. C. Town;C. Observatories