J/A+A/673/A76ivo://CDS.VizieR/J/A+A/673/A76doi:10.26093/cds/vizier.36730076CDSSkalidis R.Gkimisi K.Tassis K. Panopoulou G.V.Pelgrims V.,Tritsis A.Goldsmith P.F.2024-11-28T20:03:28Z2023-05-10T07:35:06ZCDS support team

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

cds-question@unistra.frpolarimetryinterstellar-mediummagnetic-fieldsco-line-emissionThe formation of molecular gas in interstellar clouds is a slow process, but can be enhanced by gas compression. Magnetohydrodynamic (MHD) waves can create compressed quasiperiodic linear structures, referred to as striations. Striations are observed at column densities where the atomic to molecular gas transition takes place. We explore the role of MHD waves in the CO chemistry in regions with striations within molecular clouds. We target a region with striations in the Polaris Flare cloud. We conduct a CO J=2-1 survey in order to probe the molecular gas properties. We use archival starlight polarization data and dust emission maps in order to probe the magnetic field properties and compare against the CO morphological and kinematic properties. We assess the interaction of compressible MHD wave modes with CO chemistry by comparing their characteristic timescales. The estimated magnetic field is 38-76uG. In the CO integrated intensity map, we observe a dominant quasi-periodic intensity structure, which tends to be parallel to the magnetic field orientation and has a wavelength of one parsec approximately. The periodicity axis is ~17 degrees off from the mean magnetic field orientation and is also observed in the dust intensity map. The contrast in the CO integrated intensity map is ~2.4 times larger than the contrast of the column density map, indicating that CO formation is enhanced locally. We suggest that a dominant slow magnetosonic mode with estimated period 2.1-3.4Myr, and propagation speed 0.30-0.45km/s, is likely to have enhanced the formation of CO, hence created the observed periodic pattern. We also suggest that, within uncertainties, a fast magnetosonic mode with period 0.48Myr and velocity 2.0km/s could have played some role in increasing the CO abundance.2023A&A...673A..76Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/673/A76CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/452/715 : Optical polarization of the Polaris Flare (Panopoulou+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/673/A76https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/673/A76http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/673/A76https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/673/A76https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/673/A76http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/673/A76GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/673/A76/list (Informations of CO (1-0) datacube)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/673/A76/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/673/A76/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/673/A76/list?GETtext/xml+votable180.050000true91.567929888.46079940.0055555555555555566/8187https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/673/A76?format=asciiRadiodefaultJ/A+A/673/A76/listInformations of CO (1-0) datacubeNxNumber of pixels along X-axismeta.numberint_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.raindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decindexedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGLONGalactic longitude of center (J2000)degpos.galactic.lonGLATGalactic latitude of center (J2000)degpos.galactic.latNyNumber of pixels along Y-axismeta.numberintNzNumber of slicesmeta.numberintbVELO-LSRLower value of VELO-LSRm/sphys.veloc;pos.lsrdoubleBVELO-LSRUpper value of VELO-LSRm/sphys.veloc;pos.lsrfloatdVELO-LSRVELO-LSR resolutionm/sspect.resolutionfloatsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar