J/ApJ/783/77ivo://CDS.VizieR/J/ApJ/783/77doi:10.26093/cds/vizier.17830077CDSRemijan A.J.Snyder L.E.McGuire B.A.Kuo H.-L.Looney L.W.,Friedel D.N.Golubiatnikov G.Y.Lovas F.J.Ilyushin V.V.Alekseev E.A.,Dyubko S.F.McCall B.J.Hollis J.M.2017-01-23T22:00:00Z2016-04-18T10:25:08ZCDS support team

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

cds-question@unistra.frinterstellar-mediumatomic-physicsIn this paper, we present the results of an observational search for gas phase urea [(NH_2_)_2_CO] observed toward the Sgr B2(N-LMH) region. We show data covering urea transitions from ~100GHz to 250GHz from five different observational facilities: the Berkeley-Illinois-Maryland-Association (BIMA) Array, the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the NRAO 12m telescope, the IRAM 30m telescope, and the Swedish-ESO Submillimeter Telescope (SEST). The results show that the features ascribed to urea can be reproduced across the entire observed bandwidth and all facilities by best-fit column density, temperature, and source size parameters which vary by less than a factor of two between observations merely by adjusting for telescope-specific parameters. Interferometric observations show that the emission arising from these transitions is cospatial and compact, consistent with the derived source sizes and emission from a single species. Despite this evidence, the spectral complexity of both (NH_2_)_2_ CO and of Sgr B2(N) makes the definitive identification of this molecule challenging. We present observational spectra, laboratory data, and models, and discuss our results in the context of a possible molecular detection of urea.2014ApJ...783...77Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/783/77CatalogResearchIsServedByTAP VizieR generic servicerelated-tohttp://www.cv.nrao.edu/php/splat/ : Splatalogue database for astronomicalhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/783/77https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/783/77http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/783/77https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/783/77https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/783/77http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/783/77GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/783/77/table6Measured and calculated frequencies and associated spectroscopic constants of urea [(NH_2_)_2_CO]RefReference (2)meta.ref;pos.framecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFreq1[1111.6/599859.1] Calculated FrequencyMHzem.freqdoublee_Freq1[0/4255] The 2{sigma} uncertainty in Freq (1)MHzstat.errorintFreq2[5816.6/232837]? Measured FrequencyMHzem.freqdoublenullablee_Freq2[1/500]? The 2{sigma} uncertainty in MFreq (1)MHzstat.errorintnullableElow[0/604.771] Lower state energy levelcm**-1phys.energy;phys.atmol.levelfloatJ1[1/40] J quantum number of the upper state (J')phys.atmol.qnintKa1[0/40] K_a_ quantum number of the upper state (K'_a_)phys.mol.qnintKc1[0/40] K_c_ quantum number of the upper state (K'_c_)phys.mol.qnintJ0[0/40] J quantum number of the lower state (J'')phys.atmol.qnintKa0[0/39] K_a_ quantum number of the lower state (K''_a_)phys.mol.qnintKc0[0/40] K_c_ quantum number of the lower state (K''_c_)phys.mol.qnintSij[0/39.5] Transition line strengthspect.line.intensityfloat