论文标题
三个M81组矮星系中的红色可变星
Red Variable Stars in Three M81 Group Dwarf Galaxies
论文作者
论文摘要
档案[3.6]和[4.5]图像用于识别和表征麦芽素型星系中的可变恒星Holmberg II，NGC 2366和IC 2574。使用参数和非参数检测方法，74个确认或可疑的长期变量（LPV）。 NGC 2366和IC 2574中LPV的周期分布相似。 While the period distribution of LPVs in Ho II is uncertain due to small number statistics there appears to be a deficiency of LPVs with periods between 550 and 650 days when compared with NGC 2366 and IC 2574. The LPVs are diffusely distributed on the sky, and do not follow the underlying light from unresolved stars, as expected if episodes of star formation within the past few hundred Myr have occurred throughout the galaxies, including their外部区域。从周期 - 亮度关系（PLR）中计算出的HO II和NGC 2366的距离同意基于红色巨型分支（RGB）的尖端的幅度约为0.1个幅度。估计IC 2574的基于LPV的距离模量的努力使LPV之间的第一个夸张脉动脉动存在于600天，尽管长期末端的PLR与RGB-TIP估计的距离是一致的。除LPV外，还确定了10个候选SGB [E]或发光蓝色变量和2个候选红色超级巨头变量。还根据颜色刻度图中的位置确定了九个未显示可变性证据的候选sgb [e]恒星。
Archival [3.6] and [4.5] images are used to identify and characterize variable stars in the Magellanic-type galaxies Holmberg II, NGC 2366, and IC 2574. Using parametric and non-parametric detection methods, 74 confirmed or suspected long period variables (LPVs) are found. The period distributions of the LPVs in NGC 2366 and IC 2574 are similar. While the period distribution of LPVs in Ho II is uncertain due to small number statistics there appears to be a deficiency of LPVs with periods between 550 and 650 days when compared with NGC 2366 and IC 2574. The LPVs are diffusely distributed on the sky, and do not follow the underlying light from unresolved stars, as expected if episodes of star formation within the past few hundred Myr have occurred throughout the galaxies, including their outer regions. Distances computed for Ho II and NGC 2366 from the period-luminosity relations (PLRs) agree to within ~0.1 magnitudes with those based on the tip of the red giant branch (RGB). Efforts to estimate an LPV-based distance modulus for IC 2574 are complicated by the presence of first overtone pulsators among LPVs with periods ~ 600 days, although the PLR at the long period end is consistent with the distance estimated from the RGB-tip. In addition to the LPVs, 10 candidate sgB[e] or luminous blue variables and 2 candidate red supergiant variables are also identified. Nine candidate sgB[e] stars that do not show evidence of variability are also identified based on their locations in the color-magnitude diagram.
