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dc.creatorDionatos, O.en_US
dc.creatorJorgensen, J. K.en_US
dc.creatorGreen, J. D.en_US
dc.creatorHerczeg, G. J.en_US
dc.creatorEvans, Neal J.en_US
dc.creatorKristensen, L. E.en_US
dc.creatorLindberg, J. E.en_US
dc.creatorvan Dishoeck, E. F.en_US
dc.date.accessioned2016-04-22T19:48:53Z
dc.date.available2016-04-22T19:48:53Z
dc.date.issued2013-10en
dc.identifierdoi:10.15781/T2NN5D
dc.identifier.citationDionatos, Odyssefs, Jes Kristian Jørgensen, J. D. Green, G. J. Herczeg, Neal J. Evans, L. E. Kristensen, J. E. Lindberg, and E. F. Van Dishoeck. >Dust, ice and gas in time (DIGIT): Herschel and Spitzer spectro-imaging of SMM3 and SMM4 in Serpens.> Astronomy & Astrophysics, Vol. 558 (Oct., 2013): A88.en_US
dc.identifier.issn0004-6361en_US
dc.identifier.urihttp://hdl.handle.net/2152/34566
dc.description.abstractContext. Mid-and far-infrared observations of the environment around embedded protostars reveal a plethora of high excitation molecular and atomic emission lines. Different mechanisms for the origin of these lines have been proposed, including shocks induced by protostellar jets and radiation or heating by the embedded protostar of its immediate surroundings. Aims. By studying of the most important molecular and atomic coolants, we aim at constraining the physical conditions around the embedded protostars SMM3 and SMM4 in the Serpens molecular cloud core and measuring the CO/H-2 ratio in warm gas. Methods. Spectro-imaging observations from the Spitzer Infrared Spectrograph (IRS) and the Herschel Photodetector Array Camera and Spectrometer (PACS) provide an almost complete wavelength coverage between 5 and 200 mu m. Within this range, emission from all major molecular (H-2, CO, H2O and OH) and many atomic ([OI], [CII], [FeII], [SiII] and [SI]) coolants of excited gas are detected. Emission line maps reveal the morphology of the observed emission and indicate associations between the different species. The excitation conditions for molecular species are assessed through rotational diagrams. Emission lines from major coolants are compared to the results of steady-state C- and J-type shock models. Results. Line emission tends to peak at distances of similar to 10-20 '' from the protostellar sources with all but [CII] peaking at the positions of outflow shocks seen in near-IR and sub-millimeter interferometric observations. The [CII] emission pattern suggests that it is most likely excited from energetic UV radiation originating from the nearby flat-spectrum source SMM6. Excitation analysis indicates that H-2 and CO originate in gas at two distinct rotational temperatures of similar to 300 K and 1000 K, while the excitation temperature for H2O and OH is similar to 100-200 K. The morphological and physical association between CO and H2 suggests a common excitation mechanism, which allows direct comparisons between the two molecules. The CO/H2 abundance ratio varies from similar to 10(-5) in the warmer gas up to similar to 10(-4) in the hotter regions. Shock models indicate that C-shocks can account for the observed line intensities if a beam filling factor and a temperature stratification in the shock front are considered. C-type shocks can best explain the emission from H2O. The existence of J-shocks is suggested by the strong atomic/ionic (except for [CII]) emission and a number of line ratio diagnostics. Dissociative shocks can account for the CO and H-2 emission in a single excitation temperature structure. Conclusions. The bulk of cooling from molecular and atomic lines is associated with gas excited in outflow shocks. The strong association between H2 and CO constrain their abundance ratio in warm gas. Both C-and J-type shocks can account for the observed molecular emission; however, J-shocks are strongly suggested by the atomic emission and provide simpler and more homogeneous solutions for CO and H-2. The variations in the CO/H-2 abundance ratio for gas at different temperatures can be interpreted by their reformation rates in dissociative J-type shocks, or the influence of both C and J shocks.en_US
dc.description.sponsorshipInstrument Center for Danish Astrophysics (IDA)en_US
dc.description.sponsorshipDanish National Research Foundationen_US
dc.description.sponsorshipUniversity of Copenhagens programme of excellenceen_US
dc.description.sponsorshipNASA through Jet Propulsion Laboratory, California Institute of Technologyen_US
dc.language.isoEnglishen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectstars: formationen_US
dc.subjectism: jets and outflowsen_US
dc.subjectism: moleculesen_US
dc.subjectism:en_US
dc.subjectabundancesen_US
dc.subjectinfrared: ismen_US
dc.subjectsubmillimeter: ismen_US
dc.subjectyoung stellar objectsen_US
dc.subjectstar-forming regionsen_US
dc.subjectlow-mass protostarsen_US
dc.subjectmolecular line emissionen_US
dc.subjectfar-infrared emissionen_US
dc.subjectiso-lws mapen_US
dc.subjectcloud coreen_US
dc.subjectinterstellar extinctionen_US
dc.subjectpacs spectroscopyen_US
dc.subjectspace-telescopeen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleDust, Ice And Gas In Time (DIGIT) Herschel And Spitzer Spectro-Imaging Of SMM3 And SMM4 In Serpensen_US
dc.typeArticleen_US
dc.description.departmentAstronomyen_US
dc.identifier.doi10.1051/0004-6361/201220452en_US
dc.contributor.utaustinauthorGreen, Joel D.en_US
dc.contributor.utaustinauthorEvans, Neal J.en_US
dc.relation.ispartofserialAstronomy & Astrophysicsen_US


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