论文标题
SDSS-IV漫画中的狼射线星系。 I.目录结构和样品特性
Wolf-Rayet galaxies in SDSS-IV MaNGA. I. Catalog construction and sample properties
论文作者
论文摘要
Wolf-Rayet (WR) galaxies are a rare population of galaxies that host living high-mass stars during their WR phase (i.e. WR stars) and are thus expected to provide interesting constraints on the stellar Initial Mass Function, massive star formation, stellar evolution models, etc. Spatially resolved spectroscopy should in principle provide a more efficient way of identifying WR galaxies than single-fiber surveys of galactic centers such as SDSS-I & II，因为WR恒星应该在圆盘中更优先找到。使用正在进行的SDSS-IV漫画调查中的IFU数据，我们对WR星系进行了彻底的搜索。我们首先识别每个数据库中的H II区域，并对堆叠的光谱进行全光谱拟合。然后，我们可以直观地检查每个H II区域的残留频谱，并确定在4600-4750 A中呈现出明显的“蓝色凹凸”的WR区域。所得的WR目录包括267个WR区域〜500pc（Radius）尺寸，分布在90个星系中，来自当前的Manga（Manga Product Punaune 7）的90个星系。我们发现，WR区域仅在星系中发现，这些星系显示出最蓝色的颜色和最高的恒星形成率。大多数WR星系具有晚期形态，图像中显示出相对较大的不对称性，这意味着WR区域在相互作用/合并星系中更加优先找到。我们估计WR星系的出色质量功能和质量依赖性检测率。 WR星系的检测率通常约为2％，对恒星质量的依赖性较弱。该检测率比以前使用SDSS单光纤数据的研究高40倍，比基于CALICA的WR目录低2倍。我们与SDSS和CALICA研究进行了比较，并得出结论，可以用三个因素来解释不同的检测率：空间覆盖率，光谱信号 - 噪声比和父样本的红移范围。
Wolf-Rayet (WR) galaxies are a rare population of galaxies that host living high-mass stars during their WR phase (i.e. WR stars) and are thus expected to provide interesting constraints on the stellar Initial Mass Function, massive star formation, stellar evolution models, etc. Spatially resolved spectroscopy should in principle provide a more efficient way of identifying WR galaxies than single-fiber surveys of galactic centers such as SDSS-I & II, as WR stars should be more preferentially found in discs. Using IFU data from the ongoing SDSS-IV MaNGA survey, we have performed a thorough search for WR galaxies. We first identify H II regions in each datacube and carry out full spectral fitting to the stacked spectra. We then visually inspect the residual spectrum of each H II region and identify WR regions that present a significant "blue bump" at 4600-4750 A. The resulting WR catalog includes 267 WR regions of ~500pc (radius) sizes, distributed in 90 galaxies from the current sample of MaNGA (MaNGA Product Launch 7). We find WR regions are exclusively found in galaxies that show bluest colors and highest star formation rates for their mass. Most WR galaxies have late-type morphologies and show relatively large asymmetry in their images, implying that WR regions are more preferentially found in interacting/merging galaxies. We estimate the stellar mass function of WR galaxies and the mass-dependent detection rate. The detection rate of WR galaxies is typically ~2%, with weak dependence on stellar mass. This detection rate is about 40 times higher than previous studies with SDSS single fiber data, and by a factor of 2 lower than the CALIFA-based WR catalog. We make comparisons with SDSS and CALIFA studies, and conclude that different detection rates can be explained mainly by three factors: spatial coverage, spectral signal-to-noise ratio, and redshift ranges of the parent sample.
