GIANT MOLECULAR CLOUD EVOLUTIONS IN THE NEARBY SPIRAL GALAXY M33
GIANT MOLECULAR CLOUD EVOLUTIONS IN THE NEARBY SPIRAL GALAXY M33
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DOI：
10.1088/0004-637x/761/1/37
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发表时间：
2012-10
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通讯作者：
R. Miura;K. Kohno;T. Tosaki;D. Espada;N. Hwang;N. Kuno;S. Okumura;A. Hirota;K. Muraoka;S. Onodera;T. Minamidani;S. Komugi;K. Nakanishi;T. Sawada;H. Kaneko;R. Kawabe
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作者：
R. Miura;K. Kohno;T. Tosaki;D. Espada;N. Hwang;N. Kuno;S. Okumura;A. Hirota;K. Muraoka;S. Onodera;T. Minamidani;S. Komugi;K. Nakanishi;T. Sawada;H. Kaneko;R. Kawabe
利用ASTE 10 m望远镜100 pc空间分辨率的宽视场高灵敏度CO（J = 3-2）观测资料，编制了M33的巨分子云（GMC）星表，共包含71个GMC。利用光学数据，我们从表面恒星密度的过剩中识别出75个年轻恒星群，并通过与恒星演化模型的比较估计了它们的年龄。通过对GMC、YSG和H ii区的空间比较，我们可以将GMC分为四类：A型，没有大质量星星形成的迹象; B型，只与H ii区有关; C型，既有H ii区，又有105 M，估计为2000 - 4000万年。此外，我们发现，致密气体分数跟踪的CO（J = 3-2）/CO（J = 1-0）的比例增加周围SF区域。这证实了一种情况，即致密气体优先在先前生成的恒星周围形成，并将成为下一代恒星的燃料。以这种方式，大量的SF逐渐在GMC中传播，直到气体耗尽。
We present a giant molecular cloud (GMC) catalog of M33, containing 71 GMCs in total, based on wide-field and high-sensitivity CO(J = 3–2) observations with a spatial resolution of 100 pc using the ASTE 10 m telescope. Employing archival optical data, we identify 75 young stellar groups (YSGs) from the excess of the surface stellar density, and estimate their ages by comparing with stellar evolution models. A spatial comparison among the GMCs, YSGs, and H ii regions enable us to classify GMCs into four categories: Type A, showing no sign of massive star formation (SF); Type B, being associated only with H ii regions; Type C, with both H ii regions and 105 M☉ is estimated to be 20–40 Myr. In addition, we find that the dense gas fraction as traced by the CO(J = 3–2)/CO(J = 1–0) ratio is enhanced around SF regions. This confirms a scenario where dense gas is preferentially formed around previously generated stars, and will be the fuel for the next stellar generation. In this way, massive SF gradually propagates in a GMC until gas is exhausted.