P-MaNGA: full spectral fitting and stellar population maps from prototype observations
P-MaNGA: full spectral fitting and stellar population maps from prototype observations
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DOI：
10.1093/mnras/stv301
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发表时间：
2015-03
影响因子：
4.8
通讯作者：
D. Wilkinson;C. Maraston;D. Thomas;L. Coccato;R. Tojeiro;M. Cappellari;F. Belfiore;M. Bershady-
中科院分区：
文献类型：
--
作者：
D. Wilkinson;C. Maraston;D. Thomas;L. Coccato;R. Tojeiro;M. Cappellari;F. Belfiore;M. Bershady-
MaNGA（阿帕奇点天文台附近星系测绘）是一项为期 6 年的 SDSS-IV（斯隆数字巡天 IV）巡天项目，将为超过 10 000 个附近星系的代表性样本获取 3600 至 10 300 A 范围内的分辨光谱。在本文中，我们通过对 P-MaNGA（MaNGA 仪器原型）观测到的星系光谱进行全光谱拟合，得出空间分辨的恒星种群特性和径向梯度。这些数据包括 18 个星系的光谱，涵盖了大范围的形态类型。我们使用高光谱分辨率恒星种群模型得出年龄、金属丰度、尘埃和恒星质量图及其径向梯度，并评估改变恒星库输入到模型中的影响。我们引入了一种确定尘埃消光的方法，即使在尘埃衰减高且空间不均匀的情况下，该方法也能够给出平滑的恒星质量图。通过光谱拟合，我们生成了详细的恒星种群特性图，这使我们能够识别这些不同样本中的星系特征，例如螺旋结构、球状星系中几乎没有方位角结构的平滑径向剖面，以及空间上不同的星系子组件。与文献一致，我们发现早期类型星系的梯度平均年龄平坦，金属丰度为负（-0.15 dex/Re），而晚期类型星系的梯度平均年龄为负（-0.39 dex/Re）并且金属丰度平坦。我们演示了不同级别的数据质量如何改变径向梯度测量的精度。我们展示了这种分析如何扩展到大量的 MaNGA 星系，将有可能揭示星系的结构和演化。
MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) is a 6-yr SDSS-IV (Sloan Digital Sky Survey IV) survey that will obtain resolved spectroscopy from 3600 to 10 300 A for a representative sample of over 10 000 nearby galaxies. In this paper, we derive spatially resolved stellar population properties and radial gradients by performing full spectral fitting of observed galaxy spectra from P-MaNGA, a prototype of the MaNGA instrument. These data include spectra for 18 galaxies, covering a large range of morphological type. We derive age, metallicity, dust, and stellar mass maps, and their radial gradients, using high spectral-resolution stellar population models, and assess the impact of varying the stellar library input to the models. We introduce a method to determine dust extinction which is able to give smooth stellar mass maps even in cases of high and spatially non-uniform dust attenuation. With the spectral fitting, we produce detailed maps of stellar population properties which allow us to identify galactic features among this diverse sample such as spiral structure, smooth radial profiles with little azimuthal structure in spheroidal galaxies, and spatially distinct galaxy sub-components. In agreement with the literature, we find the gradients for galaxies identified as early type to be on average flat in age, and negative (−0.15 dex/Re) in metallicity, whereas the gradients for late-type galaxies are on average negative in age (−0.39 dex/Re) and flat in metallicity. We demonstrate how different levels of data quality change the precision with which radial gradients can be measured. We show how this analysis, extended to the large numbers of MaNGA galaxies, will have the potential to shed light on galaxy structure and evolution.