J/A+A/578/A119ivo://CDS.VizieR/J/A+A/578/A119doi:10.26093/cds/vizier.35780119CDSGomez J.F.Rizzo J.R.Suarez O.Palau A.Miranda L.F.Guerrero M.A.,Ramos-Larios G.Torrelles J.M.2017-11-06T12:24:06Z2015-11-03T14:05:51ZCDS support team

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

cds-question@unistra.frastrophysical-masersradio-astronomygiant-starsplanetary-nebulaeWater maser emission at 22GHz is a useful probe for studying the transition between the nearly spherical mass loss in the asymptotic giant branch (AGB) to a collimated one in the post-AGB phase. In their turn, collimated jets in the post-AGB phase could determine the shape of planetary nebulae once photoionization starts. We intend to find new cases of post-AGB stars and planetary nebulae (PNe) with water maser emission, including some especially interesting and rare types: water fountains (evolved objects with high velocity collimated jets traced by water masers) or water-maser-emitting PNe. Since previous studies have shown a higher detection rate of water maser emission in evolved objects that are optically obscured, we selected a sample that contains a significant fraction of post-AGB and young PN candidate sources showing signs of strong obscuration. We searched for water maser emission in 133 evolved objects using the radio telescopes in Robledo de Chavela, Parkes, and Green Bank. We detected water maser emission in 15 sources of our sample, of which seven are reported here for the first time (IRAS 13483-5905, IRAS 14249-5310, IRAS 15408-5413, IRAS 17021-3109, IRAS 17348-2906, IRAS 17393-2727, and IRAS 18361-1203). We identified three water fountain candidates: IRAS 17291-2147, with a total velocity spread of =~96km/s in its water maser components and two sources (IRAS 17021-3109 and IRAS 17348-2906) that show water maser emission whose velocity lies outside the velocity range covered by OH masers. We have also identified IRAS 17393-2727 as a possible new water-maser-emitting PN. The detection rate is higher in obscured objects (14%) than in those with optical counterparts (7%), which is consistent with previous results. Water maser emission seems to be common in objects that are bipolar in the near-IR (43% detection rate in such sources). The water maser spectra of water fountain candidates like IRAS 17291-2147 show significantly fewer maser components than others (e.g., IRAS 18113-2503). We speculate that most post-AGBs may show water maser emission with wide enough velocity spread (>=100km/s) when observed with enough sensitivity and/or for long enough periods of time. Therefore, it may be necessary to single out a special group of "water fountains", probably defined by their high maser luminosities. We also suggest that the presence of both water and OH masers in a PN is a better tracer of its youth, than is the presence of just one of these species.2015A&A...578A.119Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/578/A119CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/458/173 : Optical spectroscopy of 253 IRAS sources (Suarez+, 2006)J/ApJS/211/15 : SiO & H2O maser survey toward AGB + post-AGB stars (Yoon+ 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/578/A119https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/578/A119http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/578/A119https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/578/A119https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/578/A119http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/578/A119GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/578/A119/table1 (Observed sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/578/A119/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/578/A119/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/578/A119/table1?GETtext/xml+votable180.050000true119.990417-41.1230560.0055555555555555566/14342 14355 14602 14611 14645 14672 15624 15663 28673 28711 28715 28734 28799 28804 28822 28848 28852-28853 28861-28862 28867-28868 28873 28886 28889 28900 28902 28907 28919 28924 28926-28927 29088 29094 29099 29103 29119 29178 29188 29200 29254 29259 29270 29459-29460 29467 29511 30218 30250 30271 30273 30313-30315 30331 30405 30452 30506 30600 30607 30621 30625 30631 30642 30654 30666 30688 32036 32068 32117 37720 37743 37749 37829 37854 37889 37892 37904 37906 38048 39223 39323 39365 41032 41433 41467 41566 41670 41679 41693 41701 41709 41712 41749 41769 41797 41811 41817 41829 41832 41904 41922 41967 42201 42214 42219 42233 42330 42347 42421 42429 42443 42447 42478 42486 42490 42493 42761 42833 42835 43013 43029 43064 43085 43130 43651https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/578/A119?format=asciiRadiodefaultJ/A+A/578/A119/table1Observed sourcesIRASIRAS namemeta.id;meta.maincharprimaryRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMindicates water maser detections in table2meta.ref.urlcharDEJ2000Declination (J2000)pos.eq.dec;meta.mainDateObservation datetime.epoch;obsnullablen_Date[g] Note (1)meta.notecharTelTelescope (2)meta.id;instr.telcharrmsOne-sigma noise level per spectral channelJyphot.flux.densityfloatl_SLimit flag (3{sigma} upper limit) for non-detections in previous observationsmeta.code.errorcharS? Previous water maser observations of the sources reported in the literatureJyphot.flux.density;em.radio.1500-3000MHzfloatnullablee_S? 2{sigma} rms uncertainty on SJystat.errorfloatnullablen_S[f] Note on S (1)meta.notecharr_SReferences for previous water maser observations, in refs.dat filemeta.ref;pos.framecharf_S[h] Note on Ref (1)meta.codecharImgVisibility of sources in optical and infrared images (3)meta.codecharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/578/A119/table2Water maser detectionsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIRASIRAS namemeta.id;meta.maincharVpeakLSR velocity of the peak emission in each spectrumkm/sspect.dopplerVeloc;stat.maxfloate_VpeakUncertainty on Vpeak (channel width)km/sstat.errorfloatVminMinimum LSR velocity of the detected emissionkm/sphys.veloc;pos.lsrfloatVmaxMaximum LSR velocity of the detected emissionkm/sphys.veloc;pos.lsrfloatNote[f] Note (1)meta.notecharSpeakFlux density of the peak emissionJyphot.flux.density;em.radio.12-30GHzfloate_Speakrms uncertainty on Speak (2{sigma})Jystat.errorfloatSIntVelocity-integrated flux density of the spectrumJy.km/sphot.flux.density;em.radio.12-30GHzfloate_SIntrms uncertainty on SInt (2{sigma})Jy.km/sstat.errorfloatDateObservation datetime.epoch;obsnullableJ/A+A/578/A119/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference numbermeta.id;meta.mainintBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notechar