星系恒星形成与尘埃遮蔽相关规律研究

研究星系尘埃遮蔽相关规律，是准确测定星系物理参量、理解星系尘埃演化和化学增丰过程的关键。我们（Qin et al. 2019）发现恒星形成星系的尘埃遮蔽IRX(=Lir/Luv)由恒星形成率、尺度、金属丰度和轴比等参量支配，遵从一个IRX普适关系。本项目申请拟开展星系尘埃遮蔽不同探针性质和尘埃遮蔽相关规律的研究，1）利用大样本近邻星系和多波段公开数据，统计分析尘埃遮蔽探针IRX、巴尔末减缩Hα/Hβ和紫外连续谱斜率β之间的差异和成因；2）空间解析非常近邻（距离8Mpc内）恒星形成星系NGC5236, NGC300, NGC628中HII区和非HII区的紫外、光学和红外等观测特征，解析研究星系内部50-200pc尺度区域尘埃遮蔽与星族参数的关联；3）结合星族能谱模型等，探究恒星-尘埃空间分布、金属丰度等参量如何影响星系整体尘埃遮蔽，理解IRX普适关系成因。

Understanding dust obscuration in star-forming galaxies (SFGs) is key to measuring galaxy observables and understanding the dust evolution and chemical enrichment in galaxies. We found that galaxy dust obscuration parameterized by IRX(=Lir/Luv) is controlled by SFR, galaxy size, metallicity and axial ratio, following a universal relation given in Qin et al. (2019). We propose to investigate different indicators of dust obscuration, and explore the physical processes determining the dust obscuration in SFGs. Our research program includes 1) to study IRX, Balmer decrement Hα/Hβ and UV continuum slope β and understand their discrepancy in probing dust obscuration; 2) spatially resolve three nearby galaxies NGC5236, NGC300, NGC628 in the UV, IR and optical, and examine the three dust obscuration indicators in relation to stellar properties; 3) explore the dependence of the average dust optical depth on the star-dust geometry, metallicity and other galaxy parameters, and understand the processes regulating the IRX universal relation.