The headlight cloud in NGC 628: An extreme giant molecular cloud in a typical galaxy disk
The headlight cloud in NGC 628: An extreme giant molecular cloud in a typical galaxy disk
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NGC 628 中的头灯云：典型星系盘中的极端巨型分子云
DOI：
10.1051/0004-6361/201936060
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发表时间：
2019
影响因子：
6.5
通讯作者：
D. Utomo
中科院分区：
文献类型：
--
作者：
C. Herrera;J. Pety;A. Hughes;S. Meidt;K. Kreckel;M. Querejeta;T. Saito;P. Lang;M. Jiménez;I. Pessa;D. Cormier;A. Usero;K. Śliwa;C. Faesi;G. Blanc;F. Bigiel;M. Chevance;D. Dale;K. Grasha;S. Glover;A. Hygate;J. Kruijssen;A. Leroy;E. Rosolowsky;E. Schinnerer;A. Schruba;Jiayi Sun;D. Utomo
云尺度的分子气体观测揭示了巨大分子云的性质与星系环境中星星形成之间的联系。星系盘中的云群被认为是正常星星形成过程的代表，而星系中心往往含有更密集的气体，表现出更极端的星星形成。然而，在高分辨率下，在正常的磁盘环境中也可以观察到具有特殊气体性质和星星形成活动的分子云。本文研究了邻近旋涡星系NGC 628盘中最亮的CO（2-1）辐射云，目的是在NGC 628星系环境中研究与极亮H II区空间一致的分子和电离气体的性质。我们研究反馈和大尺度过程如何影响分子气体在这一region.Methods的性质。高分辨率的阿尔马观测CO（2-1）和CO（1−0）的排放被用来表征的质量和动力学状态的“头灯”分子云。将该云的特征与NGC 628分子云的典型特征进行比较。一个简单的大速度梯度（LVG）分析结合了额外的阿尔马观测13 CO（1−0），HCO+（1−0）和HCN（1−0）发射被用来约束束稀释的分子气体的密度和温度。我们使用Starburst 99分析了MUSE光谱，以表征与H II区相关的年轻恒星群。结果：异常明亮的前灯云质量很大（1 − 2 × 107 M <$），根据LVG模型，光束稀释密度为nH 2 = 5 × 104 cm − 3。 它有一个低维里参数，这表明与此云的CO排放可能是overlightning由于加热的H II区。一个质量为3× 105 M的年轻（2-400万年）恒星群与之相关。结论：我们认为前灯云目前正在被年轻大质量恒星的反馈所破坏。 由于云的质量很大，其演化的这个阶段足够长，以便观察反馈对气体激发的影响。车头灯云的高质量可能与其在螺旋共同旋转半径处的位置有关，与盘的其他区域相比，气体经历了减少的星系切变，并接受了可促进云质量增长的持续气体流入。
Context.Cloud-scale surveys of molecular gas reveal the link between giant molecular cloud properties and star formation across a range of galactic environments. Cloud populations in galaxy disks are considered to be representative of the normal star formation process, while galaxy centers tend to harbor denser gas that exhibits more extreme star formation. At high resolution, however, molecular clouds with exceptional gas properties and star formation activity may also be observed in normal disk environments. In this paper we study the brightest cloud traced in CO(2–1) emission in the disk of nearby spiral galaxy NGC 628.Aims.We characterize the properties of the molecular and ionized gas that is spatially coincident with an extremely bright H IIregion in the context of the NGC 628 galactic environment. We investigate how feedback and large-scale processes influence the properties of the molecular gas in this region.Methods.High-resolution ALMA observations of CO(2–1) and CO(1−0) emission were used to characterize the mass and dynamical state of the “headlight” molecular cloud. The characteristics of this cloud are compared to the typical properties of molecular clouds in NGC 628. A simple large velocity gradient (LVG) analysis incorporating additional ALMA observations of13CO(1−0), HCO+(1−0), and HCN(1−0) emission was used to constrain the beam-diluted density and temperature of the molecular gas. We analyzed the MUSE spectrum using Starburst99 to characterize the young stellar population associated with the H IIregion.Results.The unusually bright headlight cloud is massive (1 − 2 × 107 M⊙), with a beam-diluted density ofnH2 = 5 × 104cm−3based on LVG modeling. It has a low virial parameter, suggesting that the CO emission associated with this cloud may be overluminous due to heating by the H IIregion. A young (2 − 4 Myr) stellar population with mass 3 × 105 M⊙is associated.Conclusions.We argue that the headlight cloud is currently being destroyed by feedback from young massive stars. Due to the large mass of the cloud, this phase of the its evolution is long enough for the impact of feedback on the excitation of the gas to be observed. The high mass of the headlight cloud may be related to its location at a spiral co-rotation radius, where gas experiences reduced galactic shear compared to other regions of the disk and receives a sustained inflow of gas that can promote the mass growth of the cloud.
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通过测量图案速度的径向变化来揭示螺旋结构的起源
DOI：
10.1088/0004-637x/702/1/277
发表时间：
2009
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Meidt S
通讯作者：
Meidt S
模拟大质量恒星的紫外线辐射反馈。
DOI：
10.3847/1538-4357/aabe27
发表时间：
2018
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Kim, Jeong-Gyu;Kim, Woong-Tae;Ostriker, Eve C.
通讯作者：
Ostriker, Eve C.
NGC 628 盘-晕界面中的磁结构解析
影响因子：
6.5
作者：
Mulcahy
通讯作者：
Mulcahy
DOI：
10.3847/1538-4365/ab3925
发表时间：
2019-09
期刊：
The Astrophysical Journal Supplement Series
影响因子：
--
作者：
A. Leroy;K. Sandstrom;D. Lang;A. Lewis;S. Salim;E. Behrens;J. Chastenet;I. Chiang 江;M. Gallag
通讯作者：
A. Leroy;K. Sandstrom;D. Lang;A. Lewis;S. Salim;E. Behrens;J. Chastenet;I. Chiang 江;M. Gallag
NGC 628 恒星形成效率的 50 片比例视图
DOI：
10.3847/2041-8213/aad77d
发表时间：
2018
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Kreckel, K.;Faesi, C.;Kruijssen, J. M.;Schruba, A.;Groves, B.;Leroy, A. K.;Bigiel, F.;Blanc, G. A.;Chevance, M.;Herrera, C.
通讯作者：
Herrera, C.