J/A+A/711/A157ivo://CDS.VizieR/J/A+A/711/A157CDSVorster J.M.Montillaud J.Juvela M.Falgarone E.Oers J.,Mannfors E.Alina D.Gu Q.Kang H.Lee C.W.Li S.Liu T.,Pattle K.Pelkonen V.-M.Ristorcelli I.Zavagno A.Toth L.V.2026-08-10T11:52:03Z2026-08-10T12:34:20ZCDS support team

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

cds-question@unistra.frmolecular-cloudsco-line-emissionradio-astronomyOn average, in our Galaxy, the star formation efficiency (SFE) is of the order of a few percent, which is lower than theoretical predictions. Detailed observational studies of individual molecular clouds may offer insight into the contributing factors to the low galactic SFE. We investigated the high-latitude molecular cloud MBM12 as part of the B-fields and star formation across scales (B-FROST) survey with the Taeduk Radio Astronomical Observatory (TRAO) to assess why star formation activity in MBM12 is low. We estimated N(H2) with Herschel dust emission and a dust opacity kappa_mu_ derived from near-infrared extinction, 21cm HI column densities, and far-infrared emission. With ^12^CO and ^13^CO (J=1-0) line observations, covering an area of 2.5{deh}x3{deh} at 48" resolution, we mapped the CO column density N(CO), CO-to-H_2_ factor X(CO), and abundance [CO/H_2_]. We estimated the multi-scale virial parameter alpha_vir_ and constructed mass-size scaling laws of hierarchical structures with dendrograms. We computed the relative orientation between column density structures and magnetic fields using Planck observations of dust polarisation. We identified four main regions based on velocities with H2 column densities ranging from 2x10^20^-1.3x10^22^cm^-2^. The CO integrated line intensity, W(CO), increases linearly with N(H_2_), providing an average X(CO) factor close to the Galactic average. At a low N(H_2_), X(CO) varies below XGal due to the fall-off of collisional de-excitation in low-density gas, and above XGal due to the drop of CO abundances in poorly shielded cloud edges. The hierarchical structures follow a broken power law mass-size relation M=AR^alpha^. The values of alpha_vir_ ranged from 3-60, with the smallest values at 0.1pc scales. The mass-size relations for the structures with the lowest alpha_vir_ have scaling factors, A, three times larger than those of high alpha_vir_ structures, indicating external pressure one order of magnitude larger than the former. We found a transition from parallel to perpendicular relative orientations between column density structures and the magnetic field at N(H_2_)=4.5x10^21^cm^-2^. We provide the first integrated chemical, dynamical, and magnetic field analysis of MBM12. Further investigation into the scale dependence of the mass-size relation and virial parameter can highlight the role of external pressure in regulating the star-formation efficiency.2026A&A...711A.157Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/711/A157CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/BaltA/11/219 : Vilnius photometry in MBM12 (Kazlauskas+, 2002)J/BaltA/11/231 : Extinction in MBM12 (Straizys+, 2002)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/711/A157https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/711/A157http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/711/A157https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/711/A157https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/711/A157http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/711/A157GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/711/A157/list (List of fits maps and datacubes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/711/A157/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/711/A157/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/711/A157/list?GETtext/xml+votable180.050000true44.232818520.17593030.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/711/A1576/770https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/711/A157?format=asciiRadiodefaultJ/A+A/711/A157/listList of fits maps and datacubesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGLONGalactic longitude of centerdegpos.galactic.lonGLATGalactic latitude of centerdegpos.galactic.latNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintNz? Number of slcies for the datacubesmeta.id;meta.mainintnullablebVRAD? Lower value of VRAD interval for the datacubesm/sphys.veloc;pos.heliocentricintnullableBVRAD? Upper value of VRAD interval for the datacubesm/sphys.veloc;pos.heliocentricintnullabledVRAD? VRAD resolution for the datacubesm/sspect.resolutionintnullablesizeSize of FITS fileKibytephys.size;meta.fileintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.filecharnullableTitleTitle of the FITS filemeta.title;meta.filenullableAssocDataAssociated Data web pagecharnullable_RAicrsRight Ascension (ICRS) computed by CDSpos.eq.ranullable_DEicrsDeclination (ICRS) computed by CDSpos.eq.decnullable