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dc.contributor.authorForbrich, Jan
dc.contributor.authorÖberg, Karin
dc.contributor.authorLada, Charles J.
dc.contributor.authorLombardi, Marco
dc.contributor.authorHacar, Alvaro
dc.contributor.authorAlves, João
dc.contributor.authorRathborne, Jill M.
dc.date.accessioned2017-07-21T14:57:59Z
dc.date.available2017-07-21T14:57:59Z
dc.date.issued2014-08-08
dc.identifier.citationForbrich , J , Öberg , K , Lada , C J , Lombardi , M , Hacar , A , Alves , J & Rathborne , J M 2014 , ' Some like it cold: molecular emission and effective dust temperatures of dense cores in the Pipe Nebula ' Astronomy & Astrophysics , vol. 568 . https://doi.org/10.1051/0004-6361/201423913
dc.identifier.issn0004-6361
dc.identifier.otherPURE: 11212789
dc.identifier.otherPURE UUID: 3fef3f75-2824-4f11-b4f9-828272d369e0
dc.identifier.otherArXiv: http://arxiv.org/abs/1406.0540v1
dc.identifier.otherScopus: 84905721228
dc.identifier.urihttp://hdl.handle.net/2299/19045
dc.descriptionJ. Forbrich, et al., “Some like it cold: molecular emission and effective dust temperatures of dense cores in the Pipe Nebula”, Astronomy & Astrophysics, Vol. 568, August 2014. This version of record is available online at: https://www.aanda.org/articles/aa/abs/2014/08/aa23913-14/aa23913-14.html Reproduced with Permission from Astronomy and Astrophysics, © ESO 2014.
dc.description.abstractAims. The Pipe Nebula is characterized by a low star-formation rate and is therefore an ideal environment to explore how initial conditions, including core characteristics, affect star-formation efficiencies. Methods. In a continued study of the molecular core population of the Pipe Nebula, we present a molecular-line survey of 52 cores. Previous research has shown a variety of different chemical evolutionary stages among the cores. Using the Mopra Radio Telescope, we observed the ground rotational transitions of HCO+, H13CO+, HCN, H13CN, HNC, and N2H+. These data are complemented with near-infrared extinction maps to constrain the column densities, effective dust temperatures derived from Herschel data, and NH3-based gas kinetic temperatures. Results. The target cores are located across the nebula, span visual extinctions between 5 and 67 mag, and effective dust temperatures (averaged along the lines of sight) between 13 and 19 K. The extinction-normalized integrated line intensities, a proxy for the abundance in constant excitation conditions of optically thin lines, vary within an order of magnitude for a given molecule. The effective dust temperatures and gas kinetic temperatures are correlated, but the effective dust temperatures are consistently higher than the gas kinetic temperatures. Combining the molecular line and temperature data, we find that N2H+ is only detected toward the coldest and densest cores, while other lines show no correlation with these core properties. Conclusions. Within this large sample, N2H+ is the only species to exclusively trace the coldest and densest cores, in agreement with chemical considerations. In contrast, the common high-density tracers HCN and HNC are present in a majority of the cores, demonstrating the utility of these molecules for characterizing cores over a wide range of extinctions. The correlation between the effective dust temperatures and the gas kinetic temperatures suggests that the former are dominated by dust that is both dense and thermodynamically coupled to the dense gas traced by NH3. A direct use of the effective dust temperatures in a determination of dust column densities from dust emission measurements would, however, result in an underestimate of the dust column densities.en
dc.format.extent7
dc.language.isoeng
dc.relation.ispartofAstronomy & Astrophysics
dc.rights/dk/atira/pure/core/openaccesspermission/open
dc.subjectastro-ph.SR
dc.subjectastro-ph.GA
dc.titleSome like it cold: molecular emission and effective dust temperatures of dense cores in the Pipe Nebulaen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dc.description.versiontypeFinal Published version
dcterms.dateAccepted2014-05-29
rioxxterms.versionAM
rioxxterms.versionVoR
rioxxterms.versionofrecordhttps://doi.org/10.1051/0004-6361/201423913
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeopenAccess


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