A catalogue of dense cores and young stellar objects in the Lupus complex based on Herschel Gould Belt Survey observations
A catalogue of dense cores and young stellar objects in the Lupus complex based on Herschel Gould Belt Survey observations
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DOI：
10.1051/0004-6361/201833364
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发表时间：
2018-09
影响因子：
6.5
通讯作者：
M. Benedettini;S. Pezzuto;E. Schisano;P. André;V. Könyves;A. Menshchikov;B. Ladjelate;J. D. Francesco;D. Elia;D. Arzoumanian;F. Louvet;P. Palmeirim;K. Rygl;N. Schneider;L. Spinoglio;D. Ward-Thompson
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作者：
M. Benedettini;S. Pezzuto;E. Schisano;P. André;V. Könyves;A. Menshchikov;B. Ladjelate;J. D. Francesco;D. Elia;D. Arzoumanian;F. Louvet;P. Palmeirim;K. Rygl;N. Schneider;L. Spinoglio;D. Ward-Thompson
上下文分子云的扩散介质如何凝聚成致密的核心，以及这些核心中有多少将演变成原恒星，这仍然是星星形成过程中一个知之甚少的步骤。由于赫歇尔空间天文台对恒星形成区进行了广泛的成像，这一领域正在取得很大进展。目标。赫歇尔古尔德带巡天关键项目绘制了附近大部分恒星形成分子云的五个远红外波段，目的是编制星前核心和年轻嵌入原恒星的完整普查。从星前核的完整样本出发，我们的目标是定义核质量函数，并研究它与恒星初始质量函数的关系。年轻的恒星物体（YSO）与残余拱星信封也被检测到。方法.在本文中，我们提出了目录的致密的核心和YSO/原恒星提取的赫歇尔地图的狼疮I，III和IV分子云。通过拟合被探测物体的光谱能量分布，得到被探测物体的物理特性。结果总共有532个致密的核心，其中103个可能是星前的性质，和38个YSO/原恒星已被发现在三个云。几乎所有的星前核都与细丝有关，而只有大约三分之一的未结合核和YSO/原恒星。甚至在平均热亚临界和背景柱密度低于迄今为止在其他恒星形成区域测量的背景柱密度的灯丝中也发现了星前核心候选者。星前核心的核心质量函数在0.2和0.3 M之间达到峰值，并且与在其他区域发现的对数正态形状相兼容。赫歇尔的数据揭示了几个以前未被发现的原恒星和新的0类和II类过渡盘的候选者。我们使用两个独立的指标来估计YSO/原恒星的演化状态：α指数和从近红外到远红外波长的光谱能量分布拟合。对于70%的对象，两种方法得出的演化阶段是一致的。结论.根据星前凝聚和扩散介质，狼疮被证实是一个非常低质量的恒星形成区。值得注意的是，在狼星云中，我们发现了与低柱密度星际介质相关的星星形成活动，在其他（更大质量的）恒星形成区域通常是静止的。
Context. How the diffuse medium of molecular clouds condenses in dense cores and how many of these cores will evolve in protostars is still a poorly understood step of the star formation process. Much progress is being made in this field, thanks to the extensive imaging of star-forming regions carried out with the Herschel Space Observatory. Aims. The Herschel Gould Belt Survey key project mapped the bulk of nearby star-forming molecular clouds in five far-infrared bands with the aim of compiling complete census of prestellar cores and young, embedded protostars. From the complete sample of prestellar cores, we aim at defining the core mass function and studying its relationship with the stellar initial mass function. Young stellar objects (YSOs) with a residual circumstellar envelope are also detected. Methods. In this paper, we present the catalogue of the dense cores and YSOs/protostars extracted from the Herschel maps of the Lupus I, III, and IV molecular clouds. The physical properties of the detected objects were derived by fitting their spectral energy distributions. Results. A total of 532 dense cores, out of which 103 are presumably prestellar in nature, and 38 YSOs/protostars have been detected in the three clouds. Almost all the prestellar cores are associated with filaments against only about one third of the unbound cores and YSOs/protostars. Prestellar core candidates are found even in filaments that are on average thermally subcritical and over a background column density lower than that measured in other star-forming regions so far. The core mass function of the prestellar cores peaks between 0.2 and 0.3 M⊙, and it is compatible with the log-normal shape found in other regions. Herschel data reveal several, previously undetected, protostars and new candidates of Class 0 and Class II with transitional disks. We estimate the evolutionary status of the YSOs/protostars using two independent indicators: the α index and the fitting of the spectral energy distribution from near- to far-infrared wavelengths. For 70% of the objects, the evolutionary stages derived with the two methods are in agreement. Conclusions. Lupus is confirmed to be a very low-mass star-forming region, in terms of both the prestellar condensations and the diffuse medium. Noticeably, in the Lupus clouds we have found star formation activity associated with interstellar medium at low column density, usually quiescent in other (more massive) star-forming regions.