J/A+A/615/A158ivo://CDS.VizieR/J/A+A/615/A158doi:10.26093/cds/vizier.36150158CDSTiwari M.Menten K.M.Wyrowski F.Perez-Beaupuits J.P.Wiesemeyer H.,Gusten R.Klein B.Henkel C.2018-08-23T08:10:48Z2018-07-31T07:10:35ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frh-ii-regionsinterstellar-mediumMessier 8 (M8) is one of the brightest HII regions in the sky. We collected an extensive dataset comprising multiple submillimeter spectral lines from neutral and ionized carbon and from CO. Based on this dataset, we aim to understand the morphology of M8 and that of its associated photodissociation region (PDR) and to carry out a quantitative analysis of the physical conditions of these regions such as kinetic temperatures and volume densities. We used the Stratospheric Observatory For Infrared Astronomy (SOFIA), the Atacama Pathfinder Experiment (APEX) 12m, and the Institut de Radioastronomie Millimetrique (IRAM) 30m telescopes to perform a comprehensive imaging survey of the emission from the fine structure lines of CII and CI and multiple rotational transitions of carbon monoxide (CO) isotopologs within 1.3x1.3pc around the dominant Herschel 36 (Her 36) system, which is composed of at least three massive stars. To further explore the morphology of the region, we compared archival infrared, optical, and radio images of the nebula with our newly obtained fine structure line and CO data, and in particular with the velocity information these data provide. We performed a quantitative analysis, using both LTE and non-LTE methods to determine the abundances of some of the observed species, kinetic temperatures, and volume densities. Bright CO, CII and CI emission have been found toward the HII region and the PDR in M8. Our analysis places the bulk of the molecular material in the background of the nebulosity illuminated by the bright stellar systems Her 36 and 9 Sagitarii. Since the emission from all observed atomic and molecular tracers peaks at or close to the position of Her 36, we conclude that the star is still physically close to its natal dense cloud core and heats it. A veil of warm gas moves away from Her 36 toward the Sun and its associated dust contributes to the foreground extinction in the region. One of the most prominent star forming regions in M8, the Hourglass Nebula, is particularly bright due to cracks in this veil close to Her 36. We obtain H_2_ densities ranging from ~10^4^-10^6^cm^-3^ and kinetic temperatures of 100-150K in the bright PDR caused by Her 36 using radiative transfer modeling of various transitions of CO isotopologs.2018A&A...615A.158Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/615/A158CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/395/499 : XMM observations in M8 and NGC6530 (Rauw+, 2002)J/MNRAS/407/1170 : IRAC photometry of M8 (Kumar+, 2010)J/MNRAS/453/1026 : Lagoon Nebula M8 T tauri accretion rates (Kalari+, 2015)J/A+A/604/A135 : Dynamics of ionized and neutral gas in M8 (Damiani+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/615/A158https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/615/A158http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/615/A158https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/615/A158https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/615/A158http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/615/A158GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/615/A158/list (List of fits data cubes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/615/A158/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/615/A158/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/615/A158/list?GETtext/xml+votable180.050000true270.91669-24.379080.0055555555555555566/28890https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/615/A158?format=asciidefaultJ/A+A/615/A158/listList of fits data cubesNzNumber of slicesmeta.numberintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintbVRADLower value of radial velocity intervalkm/sphys.veloc;pos.heliocentricdoubleBVRADUpper value of radial velocity intervalkm/sphys.veloc;pos.heliocentricdoubledVRADRadial velocity resolutionkm/sspect.resolutiondoublesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fits