أعرض تسجيلة المادة بشكل مبسط

dc.creator Moneti, Andrea
dc.creator Cernicharo, José
dc.creator Pardo Carrión, Juan Ramón
dc.date 2008-01-22T13:44:06Z
dc.date 2008-01-22T13:44:06Z
dc.date 2000-12-13
dc.date.accessioned 2017-01-31T00:59:42Z
dc.date.available 2017-01-31T00:59:42Z
dc.identifier The Astrophysical Journal Letters. Volume 549, Issue 2, Page L203–L207, Mar 2001
dc.identifier arXiv:astro-ph/0012292v1
dc.identifier 1538-4357
dc.identifier http://hdl.handle.net/10261/2728
dc.identifier 10.1086/319168
dc.identifier.uri http://dspace.mediu.edu.my:8181/xmlui/handle/10261/2728
dc.description We present observations of CO, 13CO and of H2O in the middle and far-infrared taken with the ISO-SWS and ISO-LWS spectrometers toward two positions in the Galactic Center region (Sgr A* and GCS-3). Both ice and gas phase molecules are detected. The ISO data have been complemented with observations of the J=3-2 and J=7-6 lines of CO carried out at the Caltech Submillimeter Observatory. The ISO and CSO data indicate that the absorbing gas is extremely cold, T_K ~ 10 K, suggesting that it is located in the dark clouds of the different spiral arms that intersect the line of sight towards the Galactic Center. From the analysis of the CO absorption we derive 13CO gas phase column densities of 1.1 and 0.7E17 cm-2 towards Sgr A* and GCS-3, respectively. The H2O gas column density in the direction of Sgr A* is ~ 2E16 cm-2. The derived CO/H2O and gas/solid abundance ratios corresponding to these cold clouds are remarkably similar along the two lines of sight. We find that nearly all the CO is in the gas phase, while the H2O is almost entirely frozen onto the surfaces of cold dust grains. Finally, the N_{gas+ice}(CO)/N_{gas+ice}(H2O) abundance ratio is ~5 implying that H2O formation processes are highly efficient.
dc.description Peer reviewed
dc.format 528225 bytes
dc.format application/pdf
dc.language eng
dc.publisher American Astronomical Society
dc.relation Preprint
dc.rights openAccess
dc.subject Infrared: ISM
dc.subject ISM: abundances
dc.subject ISM: individual (Sagittarius A*, GCS 3)
dc.subject ISM: lines and bands
dc.subject ISM: molecules
dc.title Cold H2O and CO ice and gas toward the Galactic Center
dc.type Pre-print


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أعرض تسجيلة المادة بشكل مبسط