J/ApJ/770/L13ivo://CDS.VizieR/J/ApJ/770/L13doi:10.26093/cds/vizier.17709013CDSTercero B.Kleiner I.Cernicharo J.Nguyen H.V.L.Lopez A.,Munoz Caro G.M.2015-02-17T11:20:42Z2015-02-03T14:06:29ZCDS support team

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

cds-question@unistra.fratomic-physicsmolecular-cloudsradio-astronomyWe report on the discovery of methyl acetate, CH_3_COOCH_3_, through the detection of a large number of rotational lines from each one of the spin states of the molecule: AA species (A_1_ or A_2_), EA species (E_1_), AE species (E_2_), and EE species (E_3_ or E_4_). We also report, for the first time in space, the detection of the gauche conformer of ethyl formate, CH_3_CH_2_OCOH, in the same source. The trans conformer is also detected for the first time outside the Galactic center source SgrB2. From the derived velocity of the emission of methyl acetate, we conclude that it arises mainly from the compact ridge region with a total column density of (4.2+/-0.5)x10^15^/cm2. The derived rotational temperature is 150K. The column density for each conformer of ethyl formate, trans and gauche, is (4.5+/-1.0)x10^14^/cm2. Their abundance ratio indicates a kinetic temperature of 135K for the emitting gas and suggests that gas-phase reactions could participate efficiently in the formation of both conformers in addition to cold ice mantle reactions on the surface of dust grains.2013ApJ...770L..13Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/770/L13CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/572/A44 : Vibrationally excited vinyl cyanide in Orion-KL (Lopez+, 2014)J/ApJ/768/81 : Ethyl cyanide, CH_3_CH_2_CN, vibrational states (Daly+, 2013)J/A+A/559/A51 : HC_3_N in Orion KL (Esplugues+, 2013)J/A+A/548/A71 : Spectroscopy and ISM detection of formamide (Motiyenko+, 2012)J/A+A/538/A119 : ^18^O-methyl formate (HCO^18^OCH_3_) spectrum (Tercero+ 2012)J/A+A/532/A32 : HCOOCH3 map of Orion-KL (Favre+, 2011)J/ApJ/714/1120 : Rotational spectrum and DCOOCH_3_ in Orion (Margules+, 2010)J/A+A/500/1109 : Rotational spectrum of HCOO^13^CH_3_ (Carvajal+, 2009)J/A+A/493/565 : Deuterated and ^15^N ethyl cyanides (Margules+, 2009)J/A+A/473/177 : A search for pre-biotic molecules (Wirstrom+, 2007)J/A+A/466/255 : Isotopic ethyl cyanide (Demyk+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/770/L13https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/770/L13http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/770/L13https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/770/L13https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/770/L13http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/770/L13GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapRadiodefaultJ/ApJ/770/L13/table1Detected lines of CH_3_COOCH_3_ at IRAM (30m)Tmb[0.02/0.7]? Mean beam temperatureKphys.temperature;stat.meanfloatnullableSijmu2[3.2/71.8] Line strength S_ij_{mu}^2^D**2spect.line.intensityfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJ[6/30] J quantum number of upper levelphys.atmol.qnintKa[-17/18] K_a_ quantum number of upper levelphys.mol.qnintKc[0/28] K_c_ quantum number of upper levelphys.mol.qnintp[-1/1]? Parity of upper levelphys.atmol.parityintnullableJ'[5/30] J' quantum number of lower levelphys.atmol.qnintK'a[-16/17] K'_a_ quantum number of lower levelphys.mol.qnintK'c[0/29] K'_c_ quantum number of lower levelphys.mol.qnintp'[-1/1]? Parity of lower levelphys.atmol.parityintnullableStateMolecule symmetry state: AA (A_1_/A_2_), EA (E_1_), AE (E_2_), E3 or E4phys.atmol.configurationcharFlab[82779/277629] Predicted lab frequencyMHzem.freqdoublee_Flab[0.006/3.4] Error in FlabMHzstat.errorfloatEu[15.5/217.4] Upper level energyKphys.energy;phys.atmol.levelfloatFobs[82780/277629] Observed frequency assuming a v_LSR_ of 8km/sMHzem.freqdoublef_Fobs[d] d = blended with previous line , b = blend with next linemeta.codecharBlendBlended line identifier (U=unknown)meta.id;spect.line