J/ApJ/903/111ivo://CDS.VizieR/J/ApJ/903/111doi:10.26093/cds/vizier.19030111CDSTanaka K.Nagai M.Kamegai K.Iino T.Sakai T.2025-01-07T12:39:14Z2022-02-22T06:54:09ZCDS support team

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

cds-question@unistra.frgalactic-centermolecular-cloudsstar-forming-regionsmillimeter-astronomyphotometrysubmillimeter-astronomyWe report a statistical analysis exploring the origin of the overall low star formation efficiency (SFE) of the Galactic central molecular zone (CMZ) and the SFE diversity among the CMZ clouds using a wide-field HCN J=4-3 map, whose optically thin critical density (~10^7^/cm^3^) is the highest among the tracers ever used in CMZ surveys. Logistic regression is performed to empirically formulate star formation probability of 195 HCN clumps, 13 of which contain star formation signatures. The explanatory parameters in the best-fit model are reduced into the virial parameter {alpha}_vir_ without significant contribution from other parameters, whereas the performance of the model without {alpha}_vir_ is no better than that using randomly generated data. The threshold {alpha}_vir_ is 6, which translates into a volume density (n_H_2__) of 10^4.6^/cm^3^ with the n_H_2__-{alpha}_vir_ correlation. The scarcity of the low-{alpha}_vir_ clumps, whose fraction to all HCN clumps is 0.1, can be considered as one of the immediate causes of the suppressed SFE. No correlation between the clump size or mass and star formation probability is found, implying that HCN J= 4-3 does not immediately trace the mass of star-forming gas above a threshold density. Meanwhile, star-forming and non-star-forming clouds are degenerate in the physical parameters of the CS J=1-0 clouds, highlighting the efficacy of the HCN J=4-3 line to probe star-forming regions in the CMZ. The timescale of the high-{alpha}_vir_ to low-{alpha}_vir_ transition is <~2Myr, which is consistent with the tidal compression and X1/X2 orbit transition models but possibly does not fit the cloud-cloud collision picture.2020ApJ...903..111Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/903/111CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/96 : 6-GHz methanol multibeam maser catalogue (Caswell+, 2010-12)VII/114 : Massachusetts-Stony Brook Galactic Plane CO Survey (Clemens+ 1986)J/ApJ/428/693 : Rosette Nebula and Maddalena Cloud structures (Williams+ 1994)J/A+A/432/369 : Leiden Atomic and Molecular Database (LAMDA) (Schoeier+, 2005)J/A+A/455/971 : Organic molecules in Galactic center (Requena-Torres+, 2006)J/ApJS/182/131 : Molecular clouds and clumps in the GRS (Rathborne+, 2009)J/ApJ/702/178 : YSOs in the central 400pc of the Galaxy (Yusef-Zadeh+, 2009)J/ApJ/723/492 : Physical properties GRS molecular clouds (Roman-Duval+, 2010)J/MNRAS/416/1764 : H_2_O Southern Galactic Plane Survey (HOPS) (Walsh+, 2011)J/A+A/563/A68 : CH_3_OH and H_2_O Galactic center masers (Chambers+, 2014)J/MNRAS/443/1555 : ATLASGAL mass star forming clumps sample (Urquhart+, 2014)J/MNRAS/453/4264 : JCMT Plane Survey: l=30{deg} field (Moore+, 2015)J/A+A/586/A50 : Central Molecular Zone H2CO temperature maps (Ginsburg+, 2016)J/ApJ/872/121 : Molecular cloud cores in the GC 50km/s cloud (Uehara+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/903/111https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/903/111http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/903/111https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/903/111https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/903/111http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/903/111GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/903/111/table1 (HCN clumps)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/903/111/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/903/111/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/903/111/table1?GETtext/xml+votable180.050000true266.03719-29.427840.0055555555555555566/28825 28827 28830-28831https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/903/111?format=asciiMillimeterdefaultJ/ApJ/903/111/table1HCN clumpsSFStar Formation flags (1)meta.codecharNoteAdditional note(s)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlchar_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.recordintGLON[0/360] Galactic Longitudedegpos.galactic.lonGLAT[-0.26/0.08] Galactic Latitudedegpos.galactic.latVLSR[-174/136] LSR Velocitykm/sphys.veloc;pos.lsrintMajAxis[0.04/2.09]? Semi Major Axis Lengthpcphys.size.smajAxisfloatnullableMinAxis[0.03/1.33]? Semi Minor Axis Lengthpcphys.size.sminAxisfloatnullablePA[0/359]? Position Angledegpos.posAngintnullableDelv[2.9/51.7]? Velocity FWHMkm/sphys.velocfloatnullableIHCN43[1.4/244] HCN 4-3 Integrated IntensityK.km/sphot.flux.densityfloatIH13CN[0.37/65.9]? H13CN 1-0 Integrated IntensityK.km/sphot.flux.densityfloatnullableIHNC[0.09/33.6]? HNC 1-0 Integrated IntensityK.km/sphot.flux.densityfloatnullableIHC3N[0.04/51.5]? HC3N 10-9 Integrated IntensityK.km/sphot.flux.densityfloatnullableMass[0.6/4.1]? Clump Masslog(solMass)phys.massfloatnullablealpVT[0.2/3.4]? Virial Parameterstat.fit.paramfloatnullablenH2[3.6/4.7]? Hydrogen Volume Densitylog(cm**-3)phys.densityfloatnullableTkin[1.8/2.5]? Gas Kinetic Temperaturelog(K)phys.temperaturefloatnullableClump[1/195] Clump IDmeta.id;meta.mainint