J/A+A/662/A81ivo://CDS.VizieR/J/A+A/662/A81doi:10.26093/cds/vizier.36620081CDSEbenbichler A.Postel A.Przybilla N.Seifahrt A.Wessmayer D.,Kausch W.Firnstein M.Butler K.Kaufer A.Linnartz H.2022-08-26T06:31:28Z2022-06-21T14:02:42ZCDS support team

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

cds-question@unistra.frinterstellar-mediumsupergiant-starsinfrared-astronomyspectroscopyA high spectral resolution investigation of diffuse interstellar bands (DIBs) in the near-infrared (YJ band) is conducted to test new methods, to confirm and improve existing parameters, and to search for new DIBs. Methods: The CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) on the European Southern Observatory's Very Large Telescope was employed to obtain spectra of four reddened background supergiant stars (HD 183143, HD 165784, HD 92207, HD 111613) and an unreddened comparison star (HD 87737) at the highest resolution of R~100000 currently achievable at near-infrared wavelengths. The correction for telluric absorption was performed by a modelling approach. Non-local thermodynamic equilibrium spectral modelling of available optical and the new near-infrared spectra facilitated a comprehensive characterisation of the atmospheric properties of the background stars. A more precise and accurate determination of the reddening law along the sight lines could be achieved than feasible before by comparison of the observed and model spectral energy distributions. For DIBs that overlap with stellar lines the DIB profile shapes could be recovered. Results: Seventeen known near-infrared DIBs were confirmed, and 12 previously unknown and generally weaker DIBs were identified in the YJ band. Three DIBs that show uniform profiles along all sight lines were identified, possibly connected to transitions from a common lower state of the same carrier. The divergent extinction curve towards the frequently discussed DIB standard star HD 183143 could be reproduced for the first time, requiring extra absorption by ~3.5 mag due to polycyclic aromatic hydrocarbons (PAHs) to match the ultraviolet extinction bump. This extra absorption probably stems from a circumstellar bubble lying in front of the star which is intersected tangentially by the line of sight.2022A&A...662A..81Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/662/A81CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/662/A81https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/662/A81http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/662/A81https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/662/A81https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/662/A81http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/662/A81GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfrareddefaultJ/A+A/662/A81/tablea1*Characterisation of the detected DIBs and new DIB candidatesStarStar namemeta.id;meta.maincharlambdavacCentral wavelength in vacuum, {lambda}_vac_, in the barycentric rest frame0.1nmem.wl.centralfloatEWEquivalent width0.1pmspect.line.eqWidthinte_EWrms uncertainty on EW0.1pmstat.error;spect.line.eqWidthintAcCentral depth%phot.flux.density;arith.ratiofloate_Acrms uncertainty on Ac%stat.errorfloatFWHMFull width at half maximum0.1nmspect.line.widthfloatDIBDIB namemeta.id;spect.lineintn_DIBNote on DIB (1)meta.notecharr_DIBReference for DIB (2)meta.ref;pos.frameintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda0airRest wavelength, {lambda}_0,air_, in the barycentric rest frame (3)0.1nmem.wlfloate_lambda0airrms uncertainty on lambda0air0.1nmstat.errorfloatJ/A+A/662/A81/listList of spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTitleTitle of the spectrum filemeta.title;meta.filecharspShow the spectrummeta.ref.urlcharFileNameName of the spectrum file in subdirectory spmeta.id;meta.filechar