A Herschel study of YSO evolutionary stages and formation timelines in two fields of the Hi-GAL survey
A Herschel study of YSO evolutionary stages and formation timelines in two fields of the Hi-GAL survey
复制标题
Hi-GAL 巡天两个领域中 YSO 演化阶段和形成时间线的赫歇尔研究
DOI：
10.1051/0004-6361/201014651
复制
发表时间：
2010
影响因子：
6.5
通讯作者：
Elia D
中科院分区：
文献类型：
--
作者：
Elia D
本文首次研究了Herschelin在银河系红外线巡天（Hi-GAL）科学论证阶段观测到的两个2° × 2°银道面场（中心分别为[，B] = [30°，0°]和[，B] =[59°，0°]）上发现的恒星形成致密尘埃凝聚。基于位置关联和光谱能量分布（SED）一致性的简单标准，将为五个Hi-GAL波段（70、160、250、350和500μm）中的两个场提取的紧凑源目录合并为最终目录，该目录仅包含与至少三个相邻赫歇尔带中的对应物的相干SED。这些最终的源列表包含528个= 30°字段的条目和444个= 59°字段的条目。在24μm和1.1 mm处使用辅助数据扩大了SED覆盖范围。 SED建模的子集318和101源（在两个领域，分别）的距离是已知的进行使用结构化的星星/磁盘/信封辐射传输模型和一个简单的等温灰体。全球参数，如质量，光度，温度和尘埃的性质进行了估计。Lbol/Menvratio跨越四个数量级，从与前原恒星相兼容的值到嵌入的大质量零年龄主序星。在= 59°场中的源具有平均较低的L/M，可能概述了相对于= 30°场中的源的总体较早的演化阶段。许多这些核心正在积极形成高质量的恒星，虽然估计的核心表面密度似乎是一个数量级低于1克厘米-2的临界阈值的高质量星星形成。
We present a first study of the star-forming compact dust condensations revealed byHerschelin the two 2° × 2° Galactic Plane fields centered at [,b] = [30°, 0°] and [,b] =[59°, 0°] , respectively, and observed during the science demonstration phase for theHerschelInfrared GALactic plane survey (Hi-GAL) key-project. Compact source catalogs extracted for the two fields in the five Hi-GAL bands (70, 160, 250, 350 and 500μm) were merged based on simple criteria of positional association and spectral energy distribution (SED) consistency into a final catalog which contains only coherent SEDs with counterparts in at least three adjacentHerschelbands. These final source lists contain 528 entries for the = 30° field, and 444 entries for the = 59° field. The SED coverage has been augmented with ancillary data at 24μm and 1.1 mm. SED modeling for the subset of 318 and 101 sources (in the two fields, respectively) for which the distance is known was carried out using both a structured star/disk/envelope radiative transfer model and a simple isothermal grey-body. Global parameters like mass, luminosity, temperature and dust properties have been estimated. TheLbol/Menvratio spans four orders of magnitudes from values compatible with the pre-protostellar phase to embedded massive zero-age main sequence stars. Sources in the = 59° field have on average lowerL/M, possibly outlining an overall earlier evolutionary stage with respect to the sources in the = 30° field. Many of these cores are actively forming high-mass stars, although the estimated core surface densities appear to be an order of magnitude below the 1 g cm-2critical threshold for high-mass star formation.