Distances to molecular clouds at high galactic latitudes based on Gaia DR2

¹ Purple Mountain Observatory, Nanjing 210008, PR China
² Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, PR China
³ School of Astronomy and Space Science, University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049, PR China
⁴ International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth WA 6845, Australia
⁵ Department of Physics and Astronomy and MQ Research Centre in Astronomy, Astrophysics and Astrophotonics, Macquarie University, NSW 2109, Australia

Received: 28 September 2018
Accepted: 8 February 2019

Abstract

We report the distances of molecular clouds at high Galactic latitudes (|b| > 10°) derived from parallax and G-band extinction (A_G) measurements in the second Gaia data release, Gaia DR2. Aided by Bayesian analyses, we determined distances by identifying the breakpoint in the extinction A_G toward molecular clouds and using the extinction A_G of Gaia stars around molecular clouds to confirm the breakpoint. We used nearby star-forming regions, such as Orion, Taurus, Cepheus, and Perseus, whose distances are well known to examine the reliability of our method. By comparing with previous results, we found that the molecular cloud distances derived from this method are reliable. The systematic error in the distances is approximately 5%. In total, 52 molecular clouds have well-determined distances, most of which are at high Galactic latitudes, and we provide reliable distances for 13 molecular clouds for the first time.