A new method to determine the CO-to-H2 conversion factor XCO using absorption of diffuse X-ray emission by local molecular clouds was developed. It was applied to the Ophiucus (G353+17) and Corona Australis (G359-18) clouds using CO-line and soft X-ray archival data. We obtained a value XCO=1.85±0.45×1020H2cm−2/(Kkms−1) as the average of least-chi2 fitting results for R4 (0.7 keV) and R5 (0.8 keV) bands. Full resolution pdf available at http://www.ioa.s.u-tokyo.ac.jp/~sofue/htdocs/2016Xco/
@article{arxiv.1603.04302,
title = {CO-to-H_2 Conversion Factor of Molecular Clouds using X-Ray Shadows},
author = {Yoshiaki Sofue and Jun Kataoka},
journal= {arXiv preprint arXiv:1603.04302},
year = {2016}
}