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Small-scale physical and chemical structure of diffuse and translucent molecular clouds along the line of sight to Sgr B2

hal.structure.identifierGeoscience Centre (GZG)
dc.contributor.authorTHIEL, V.
hal.structure.identifierDépartement d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée [DAPNIA]
dc.contributor.authorBELLOCHE, A.
hal.structure.identifierMax-Planck-Institut für Radioastronomie [MPIFR]
dc.contributor.authorMENTEN, K. M.
dc.contributor.authorGIANNETTI, A.
hal.structure.identifierMax-Planck-Institut für Radioastronomie [MPIFR]
dc.contributor.authorWIESEMEYER, H.
hal.structure.identifierMax-Planck-Institut für Radioastronomie [MPIFR]
dc.contributor.authorWINKEL, B.
hal.structure.identifierAMOR 2019
dc.contributor.authorGRATIER, P.
dc.contributor.authorMÜLLER, H. S. P.
dc.contributor.authorCOLOMBO, D.
hal.structure.identifierDepartment of Physics, The Ohio State University
dc.contributor.authorGARROD, R. T.
dc.date.issued2019
dc.identifier.issn0004-6361
dc.description.abstractEnThe diffuse and translucent molecular clouds traced in absorption along the line of sight to strong background sources have so far been investigated mainly in the spectral domain because of limited angular resolution or small sizes of the background sources. We aim to resolve and investigate the spatial structure of molecular clouds traced by several molecules detected in absorption along the line of sight to SgrB2(N). We have used spectral line data from the EMoCA survey performed with ALMA, taking advantage of the high sensitivity and angular resolution. We identify, on the basis of the spectral analysis of c-C3H2 across the field of view, 15 main velocity components along the line of sight to SgrB2(N) and several components in the envelope of SgrB2. The c-C3H2 column densities reveal two categories of clouds. Clouds in Category I (3 kpc arm, 4 kpc arm, and some GC clouds) have smaller c-C3H2 column densities, smaller linewidths, and smaller widths of their column density PDFs than clouds in Category II (Scutum arm, Sgr arm, and other GC clouds). To investigate the spatial structure we derive opacity maps for the following molecules: c-C3H2, H13CO+, 13CO, HNC, HN13C, HC15N, CS, C34S, 13CS, SiO, SO, and CH3OH. These maps reveal that most molecules trace relatively homogeneous structures that are more extended than the field of view defined by the background continuum emission (about 15", that is 0.08-0.6pc depending on the distance). SO and SiO show more complex structures with smaller clumps of size ~5-8". Our analysis suggests that the driving of the turbulence is mainly solenoidal in the investigated clouds. On the basis of HCO+, we conclude that most line-of-sight clouds towards SgrB2 are translucent, including all clouds where complex organic molecules were recently detected. We also conclude that CCH and CH are good probes of H2 in both diffuse and translucent clouds.
dc.language.isoen
dc.publisherEDP Sciences
dc.subject.enAstrophysics - Astrophysics of Galaxies
dc.title.enSmall-scale physical and chemical structure of diffuse and translucent molecular clouds along the line of sight to Sgr B2
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/201834467
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
dc.identifier.arxiv1901.03231
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageA68
bordeaux.volume623
bordeaux.peerReviewedoui
hal.identifierhal-01981657
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-01981657v1
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