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arXiv 1111.3295astro-ph.GA
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ISOGAL II观测到的银河系内球最近的恒星形成--中央分子区

Recent star formation in the inner Galactic Bulge seen by ISOGAL II -- The Central Molecular Zone

K. Immer, F. Schuller, A. Omont, K. M. Menten

摘要:

本文用斯皮策红外光谱仪对68个未知性质的ISOGAL源进行了5- 38 $μ$ m光谱观测。根据其光谱的特征和斜率,我们将其分类为年轻或晚型演化天体。选择这些源以测试基于ISOGAL [7]-[15]颜色和空间范围参数$σ_{\rm 15}$的选择标准。我们修改了这些标准,直到它们可靠地区分年轻和晚期类型的进化物体,然后将它们应用于中央分子区(CMZ)的所有ISOGAL来源,从而选择了485个被认为是年轻的来源。此外,我们将656个中途空间实验(MSX)源添加到CMZ样本中,这些源满足$F_{\rm E}/F_{\rm D} > 2$,其中$F{\rm D}$和$F_{\rm E}$是D(15 $μ$ m)和E(21 $μ$ m)波段的通量密度。在获得$\frac{L_{\rm bol}}{F_{\rm 15}}$转换因子后,我们计算了CMZ样品的热光度$L_{\rm bol}$值,并随后计算了源的质量。应用Kroupa初始质量函数,我们得出了在过去100万年内形成的年轻天体的总质量,从而得出CMZ的平均恒星形成率为每年0.08太阳质量。

英文摘要:

We present 5--38 $μ$m spectroscopic observations of a sample of 68 ISOGAL sources with unknown natures, taken with the Spitzer Infrared Spectrograph. Based on the characteristics and the slope of their spectra we classified the sources as young or late-type evolved objects. These sources were selected to test selection criteria based on the ISOGAL [7]--[15] color and the spatial extent parameter $σ_{\rm 15}$. We revised these criteria until they reliably distinguished between young and late-type evolved objects and then applied them to all ISOGAL sources in the central molecular zone (CMZ), resulting in the selection of 485 sources believed to be young. Furthermore, we added 656 Midcourse Space Experiment (MSX) sources to the CMZ sample that fulfilled $F_{\rm E}/F_{\rm D} > 2$ with $F{\rm D}$ and $F_{\rm E}$ being the flux densities in the D (15 $μ$m) and E (21 $μ$m) bands. After obtaining $\frac{L_{\rm bol}}{F_{\rm 15}}$ conversion factors, we calculated the bolometric luminosity, $L_{\rm bol}$, values for the CMZ sample and subsequently the masses of the sources. Applying a Kroupa initial mass function, we derived the total mass in young objects that has been formed over the last 1 Myr, resulting in an average star formation rate of 0.08 solar masses per year for the CMZ.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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