论文标题
M31和M33中的红色Supergiant。
Red Supergiants in M31 and M33 I. The Complete Sample
论文作者
论文摘要
本文的目的是在M31和M33中建立一个完整的红色超级总体样本（RSG）。这两个星系的成员恒星是从$ J-H/H-K $图中从其明显分支中删除前景矮人的近红外（NIR）点源，并使用UKIRT/WFCAM获取的存档光度数据。矮人的NIR颜色与巨人的分离是通过光学/红外颜色图（$ r-z/z-h $和$ b-v/v/v/v-r $）确认的，以及盖亚的视差和适当的运动。然后，由于高光度和低有效温度，RSG通过其在成员$ J-K/K $图中的出色位置确定。所得样品分别在M31和M33中分别具有5,498和3,055 RSG，这应该是完整的，因为在两种情况下，下部限制$ K $ k $ k $ k $ a的幅度都比UKIRT光度计的完整幅度更明亮。对控制场的分析发现，RSGS样品中的污染率小于1 \％。副产品是富含氧气的渐近巨型分支星（AGB），富含碳的AGB，热脉冲AGB和Extreme AGB的完整样品。另外，TIP-RGB与对M31和M33的距离模量的暗示一起确定。
The aim of this paper is to establish a complete sample of red supergiants (RSGs) in M31 and M33. The member stars of the two galaxies are selected from the near-infrared (NIR) point sources after removing the foreground dwarfs from their obvious branch in the $J-H/H-K$ diagram with the archival photometric data taken by the UKIRT/WFCAM. This separation by NIR colors of dwarfs from giants is confirmed by the optical/infrared color-color diagrams ($r-z/z-H$ and $B-V/V-R$), and the Gaia measurement of parallax and proper motion. The RSGs are then identified by their outstanding location in the members' $J-K/K$ diagram due to high luminosity and low effective temperature. The resultant sample has 5,498 and 3,055 RSGs in M31 and M33 respectively, which should be complete because the lower limiting $K$ magnitude of RSGs in both cases is brighter than the complete magnitude of the UKIRT photometry. Analysis of the control fields finds that the pollution rate in the RSGs sample is less than 1\%. The by-product is the complete sample of oxygen-rich asymptotic giant branch stars (AGBs), carbon-rich AGBs, thermally pulsing AGBs and extreme AGBs. In addition, the tip-RGB is determined together with its implication on the distance modulus to M31 and M33.
