dc.contributor.author | Kong, S. | |
dc.contributor.author | Lada, C. J. | |
dc.contributor.author | Lada, E. A. | |
dc.contributor.author | Román-Zúñiga, C. | |
dc.contributor.author | Bieging, J. H. | |
dc.contributor.author | Lombardi, M. | |
dc.contributor.author | Forbrich, J. | |
dc.contributor.author | Alves, J. F. | |
dc.date.accessioned | 2017-07-13T17:06:41Z | |
dc.date.available | 2017-07-13T17:06:41Z | |
dc.date.issued | 2015-05-20 | |
dc.identifier.citation | Kong , S , Lada , C J , Lada , E A , Román-Zúñiga , C , Bieging , J H , Lombardi , M , Forbrich , J & Alves , J F 2015 , ' The Relationship Between the Dust and Gas-Phase CO Across the California Molecular Cloud ' , The Astrophysical Journal , vol. 805 , no. 1 . https://doi.org/10.1088/0004-637X/805/1/58 | |
dc.identifier.issn | 0004-637X | |
dc.identifier.other | ArXiv: http://arxiv.org/abs/1503.03564v2 | |
dc.identifier.other | ORCID: /0000-0001-8694-4966/work/62751208 | |
dc.identifier.uri | http://hdl.handle.net/2299/18930 | |
dc.description | S. Kong, et al., “The Relationship Between the Dust and Gas-Phase CO Across the California Molecular Cloud”, The Astrophysical Journal, Vol. 805(1), May 2015. © 2015. The American Astronomical Society. | |
dc.description.abstract | A deep, wide-field, near-infrared imaging survey was used to construct an extinction map of the southeastern part of the California Molecular Cloud (CMC) with $\sim$ 0.5 arc min resolution. The same region was also surveyed in the $^{12}$CO(2-1), $^{13}$CO(2-1), C$^{18}$O(2-1) emission lines at the same angular resolution. Strong spatial variations in the abundances of $^{13}$CO and C$^{18}$O were found to be correlated with variations in gas temperature, consistent with temperature dependent CO depletion/desorption on dust grains. The $^{13}$CO to C$^{18}$O abundance ratio was found to increase with decreasing extinction, suggesting selective photodissociation of C$^{18}$O by the ambient UV radiation field. The cloud averaged X-factor is found to be $ $ $=$ 2.53 $\times$ 10$^{20}$ ${\rm cm}^{-2}~({\rm K~km~s}^{-1})^{-1}$, somewhat higher than the Milky Way average. On sub-parsec scales we find no single empirical value of the X-factor that can characterize the molecular gas in cold (T$_{\rm k}$ $\lesssim$ 15 K) regions, with X$_{\rm CO}$ $\propto$ A$_{\rm V}$$^{0.74}$ for A$_{\rm V}$ $\gtrsim$ 3 magnitudes. However in regions containing relatively hot (T$_{\rm ex}$ $\gtrsim$ 25 K) gas we find a clear correlation between W($^{12}$CO) and A$_{\rm V}$ over a large (3 $\lesssim$ A$_{\rm V}$ $\lesssim$ 25 mag) extinction range. This suggests a constant X$_{\rm CO}$ $=$ 1.5 $\times$ 10$^{20}$ ${\rm cm}^{-2}~({\rm K~km~s}^{-1})^{-1}$ for the hot gas, a lower value than either the average for the CMC or Milky Way. We find a correlation between X$_{\rm CO}$ and T$_{\rm ex}$ with X$_{\rm CO}$ $\propto$ T$_{\rm ex}$$^{-0.7}$ suggesting that the global X-factor of a cloud may depend on the relative amounts of hot gas within it. | en |
dc.format.extent | 19 | |
dc.format.extent | 7886298 | |
dc.language.iso | eng | |
dc.relation.ispartof | The Astrophysical Journal | |
dc.subject | astro-ph.GA | |
dc.title | The Relationship Between the Dust and Gas-Phase CO Across the California Molecular Cloud | en |
dc.contributor.institution | Centre for Astrophysics Research (CAR) | |
dc.contributor.institution | School of Physics, Engineering & Computer Science | |
dc.contributor.institution | Department of Physics, Astronomy and Mathematics | |
dc.description.status | Peer reviewed | |
rioxxterms.versionofrecord | 10.1088/0004-637X/805/1/58 | |
rioxxterms.type | Journal Article/Review | |
herts.preservation.rarelyaccessed | true | |