New method for estimating molecular cloud distances based on Gaia, 2MASS, and the TRILEGAL galaxy model
arxiv(2024)
摘要
We propose a new method for estimating the distances of molecular clouds
traced by CO line emission. Stars from 2MASS and Gaia EDR3 are selected as
on-cloud stars when they are projected on a cloud. The background on-cloud
stars have redder colors on average than the foreground stars. Instead of
searching for stars projected away from the cloud, we employed the TRILEGA
galaxy model to mimic the stellar population without cloud extinction along the
sightline toward the cloud. Our method does not require an exact boundary of a
cloud. The boundaries are highly variable and depend on the sensitivity of the
molecular line data. For each cloud, we compared the distributions of on-cloud
stars to the TRILEGAL stellar populations in the diagram of J-K_s color
versus distance. The intrinsic J-K_s colors of main-sequence and evolved
stars from TRILEGAL were considered separately, and they were used as the
baseline for subtracting the observed J-K_s colors. The baseline-corrected
J-K_s color was deployed with the Bayesian analysis and Markov chain Monte
Carlo sampling to determine the distance at which the J-K_s color jump is
largest. This method was successfully applied to measure the distances of 27
molecular clouds, which were selected from previously published cloud samples.
By replacing TRILEGAL with the GALAXIA galaxy model, we were able to measure
the distances for 21 of the 27 clouds. The distances of the 21 clouds based on
the GALAXIA model agree well with those based on the TRILEGAL model. The
distances of the 27 clouds estimated by this method are consistent with
previous estimates. We will apply this new method to a larger region of the
gaseous galactic plane, in particular, for the inner galactic region, where a
region free of CO emission is hard to separate from the crowded field of
clouds.
更多查看译文
AI 理解论文
溯源树
样例
![](https://originalfileserver.aminer.cn/sys/aminer/pubs/mrt_preview.jpeg)
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要