J/A+A/689/A70ivo://CDS.VizieR/J/A+A/689/A70doi:10.26093/cds/vizier.36890070CDSAkras S.Aleman I.Goncalves R.D.Ramos-Larios G.Bouvis K.2024-11-29T20:06:02Z2024-09-03T09:44:23ZCDS support team

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

cds-question@unistra.frplanetary-nebulaeinterstellar-mediuminfrared-astronomyLow-ionisation structures (LISs) are commonly found in planetary nebulae (PNe), but they are still poorly understood. The recent discovery of unforeseen molecular hydrogen gas (H_2_) has impacted what we think we know about these microstructures and PNe. To obtain an overall understanding of LISs, we carried out an [FeII] 1.644um imagery survey in PNe with LISs, with the aim to detect the [FeII] 1.644um emission line, a common tracer of shocks. We present the first detection of [FeII] 1.644um line directly associated with the LISs in four out of five PNe. The theoretical H I 12-4 recombination line was also computed either from the Brgamma or the Hbeta line and subtracted from the observed narrow-band line fluxes. The [FeII] 1.644um flux ranges from 1 to 40x10^-15^erg/cm^2^/s and the intensity from 2 to 90x10^-5^erg/s/cm^2^/sr. The R(Fe)=[FeII]1.644mu/Brgamma line ratio was also computed and found to range between 0.5 and 7. In particular, the [FeII] 1.644um line was detected in NGC 6543 (R(Fe)<0.15), along with the outer pairs of LISs in NGC 7009 (R(Fe)<0.25) and the jet-like LISs in IC 4634 (R(Fe)~1) and in several LISs in NGC 6571 (2<R(Fe)<7). The low R(Fe) result for NGC 6543 is attributed to the UV radiation from the central star. In contrast, the higher values in NGC 6571 and IC 4634 are indicative of shocks. The moderate R(Fe) in NGC 7009 likely indicates the contribution of both mechanisms.2024A&A...689A..70Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/689/A70CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/689/A70https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/689/A70http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/689/A70https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/689/A70https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/689/A70http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/689/A70GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/689/A70/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/689/A70/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/689/A70/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/689/A70/list?GETtext/xml+votable180.050000true251.12323.79983330.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/689/A700/https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/689/A70?format=asciiInfrareddefaultJ/A+A/689/A70/listList of fits imagesTitleTitle of the FITS filemeta.title;meta.fitscharFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNamePN namemeta.id;meta.maincharRAJ2000Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainscaleScale of the imagearcsec/pixinstr.scalefloatNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintsizeSize of FITS fileKibytephys.size;meta.fitsintAssocDataAssociated Data web pagemeta.ref.urlchar