The Relation Between Dust and Gas in the Taurus Molecular Cloud

¹ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA
² Department of Astronomy, LGRT 619, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003, USA
³ Observatoire Astronomique de Strasbourg, 67000 Strasbourg, France
⁴ Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK

Abstract

We report a study of the relation between dust and gas over a 100 deg² area in the Taurus molecular cloud. We compare the H₂ column density derived from dust extinction with the CO column density derived from the ¹²CO and ¹³CO J = 1 → 0 lines. We derive the visual extinction from reddening determined from 2MASS data. The comparison is done at an angular size of 200′′, corresponding to 0.14 pc at a distance of 140 pc. We find that the relation between visual extinction A_V and N(CO) is linear between A_V ≃ 3 and 10 mag in the region associated with the B213–L1495 filament. In other regions the linear relation flattens for A_V ≳ 4 mag. Accounting for the observed relation between the column density of CO and CO₂ ices and A_V, we find a linear relationship between the column of carbon monoxide and dust for observed visual extinctions up to the maximum value in our data  ≃23  mag.