J/ApJS/260/34ivo://CDS.VizieR/J/ApJS/260/34doi:10.26093/cds/vizier.22600034CDSZhang Y.-K.Chen XiSobolev A.M.Shen Z.-Q.Li B.Zhao Z.2022-09-14T06:00:31Z2022-09-08T11:42:35ZCDS support team

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

cds-question@unistra.frstar-forming-regionsmolecular-physicsradio-astronomyastrophysical-masersradio-spectroscopyinterstellar-mediumA four-epoch monitoring program spanning ~three months (from 2020-January-8 to April-7) for ammonia, water, and methanol transitions toward the high-mass star-forming region W51 IRS2 was conducted using the Shanghai 65m Tianma Radio Telescope with its K-band (18-26.5GHz) receiver. In total, 33 ammonia transitions and 16 methanol transitions were detected toward the target at least once during this monitoring program. Among them, 14 ammonia and 4 methanol transitions show maser emission characteristics. Rapid variabilities (including both increases and decreases) in the ammonia and methanol transitions were detected from both maser and thermal emissions during the three months of the monitoring. In addition, H_2_O masers with obvious variability were also detected. The results of the rotation diagram analysis for the ammonia and methanol quasi-thermal transitions show the variations in their rotational temperatures during the monitoring. The derived temperatures from the transitions with larger upper energies (E_u_/{kappa}) generally decreased over the whole monitoring period, from January 8 to April 7, but those with smaller E_u_/{kappa} first increased from January 8 to April 1, then rapidly decreased from April 1 to April 7. These findings support the suggestion that an inside-out heatwave propagation in W51 IRS2 was involved with the accretion burst over a short duration (only on the order of months) and caused the drastic variability behaviors of the different line transitions during high-mass star formation.2022ApJS..260...34Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/260/34CatalogResearchIsServedByTAP VizieR generic servicerelated-toVIII/96 : 6-GHz methanol multibeam maser catalogue (Caswell+, 2010-12)J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)J/ApJS/206/22 : Newly EGOs from GLIMPSE II survey. II. MoC (Chen+, 2013)J/ApJ/783/130 : Parallaxes of high mass star forming regions (Reid+, 2014)J/MNRAS/439/2584 : Southern methanol masers at 36 and 44GHz (Voronkov+, 2014)J/A+A/595/A27 : JVLA images of W51A (Ginsburg+, 2016)J/ApJ/854/170 : Methanol (CH_3_OH) & OH masers in NGC 6334I (Hunter+, 2018)http://splatalogue.online/ : Splatalogue database for astronomical spectroscopyhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/260/34https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/260/34http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/260/34https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/260/34https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/260/34http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/260/34GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapRadiodefaultJ/ApJS/260/34/table1Details of the observed NH_3_ transitionsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNlNumber of line parameter measurements for this transition (link to Table 2)meta.numberintnullableTransThe observed NH_3_ (J,K) transitionsmeta.id;phys.atmol.transitioncharprimaryFreq[18017.3/25715.2] Rest frequencyMHzem.freqdoubleEu[23.3/1449.9] Upper level energy, E_u_/KKphys.energy;phys.atmol.levelfloatSmu2[1.37/130.3] Transition strength, S_{mu}_^2^ (1)D**2spect.line.intensityfloatObsObservation epoch(s) (2)meta.code;obscharDetDetected epoch(s) (2)meta.code;obscharCommComment (3)meta.notecharJ/ApJS/260/34/table2Line parameters of the quasi-thermal and maser components in the detected NH_3_ spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTransTransition (J,K)meta.id;phys.atmol.transitioncharAbs[*] *=Detected in absorption on that date (1)meta.codecharDateUT Observation datetime.epoch;obsnullableVc-qt[49.4/68.2]? Centroid velocity, quasi-thermal comp (2)km/sspect.dopplerVelocfloatnullablee_Vc-qt[0.03/2.8]? Uncertainty in Vc-qt (2)km/sstat.errorfloatnullablel_TpLimit flag for Tp (3)meta.code.errorcharTp[0.03/22.81]? peak main-beam temperatureKphys.temperature;stat.maxfloatnullablee_Tp[0.01/2]? Uncertainty for TpKstat.errorfloatnullableFWHM[2.7/27]? line width, full width at half-maxkm/sspect.line.widthfloatnullablee_FWHM[0.08/6.2]? Uncertainty in FWHMkm/sstat.error;phys.angSizefloatnullablel_WLimit flag on W (3)meta.code.errorcharW[0.4/145]? Integrated intensity, main componentK.km/sspect.line.intensityfloatnullablee_W[0.07/2.3]? Uncertainty in WK.km/sstat.error;pos.cartesian.zfloatnullabletau[0.9/25.3]? optical depth (4)phys.absorption.opticalDepthfloatnullablee_tau[0.2/3.3]? Uncertainty in taustat.errorfloatnullableVc-MF[47.35/72.56]? line centroid, maser feature (2)km/sspect.dopplerVelocfloatnullablee_Vc-MF[0/0.5]? Uncertainty in Vc-MF (2)km/sstat.errorfloatnullablel_SpLimit flag on Sp (3)meta.code.error;src.spTypecharSp[0.06/28.5]? Peak flux densityJyphot.flux.density;em.radio.12-30GHzfloatnullablee_Sp[0.01/1.4]? Uncertainty in SpJystat.error;src.spTypefloatnullableVr-min[44.6/70.3]? Velocity range of the narrow maser features, minkm/sphys.veloc;stat.minfloatnullableVr-max[48.7/74.8]? Velocity range of the narrow maser features, maxkm/sphys.veloc;stat.maxfloatnullable