J/A+A/581/A47ivo://CDS.VizieR/J/A+A/581/A47doi:10.26093/cds/vizier.35810047CDSOliva E.Origlia L.Scuderi S.Benatti S.Carleo I.Lapenna E.,Mucciarelli A.Baffa C.Biliotti V.Carbonaro L.Falcini G.Giani E.,Iuzzolino M.Massi F.Sanna N.Sozzi M.Tozzi A.Ghedina A.,Ghinassi F.Lodi M.Harutyunyan A.Pedani M.2017-06-21T08:21:32Z2015-09-01T07:05:17ZCDS support team

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

cds-question@unistra.frinfrared-astronomyspectroscopyDetermining the intensity of lines and continuum airglow emission in the H-band is important for the design of faint-object infrared spectrographs. Existing spectra at low/medium resolution cannot disentangle the true sky-continuum from instrumental effects (e.g. diffuse light in the wings of strong lines). We aim to obtain, for the first time, a high resolution infrared spectrum deep enough to set significant constraints on the continuum emission between the lines in the H-band. During the second commissioning run of the GIANO high-resolution spectrograph at the La Palma Observatory, we pointed the instrument directly to the sky and obtained a deep spectrum that extends from 0.97 to 2.4 micron and includes the whole H-band. The spectrum shows about 1500 emission lines, a factor of two more than in previous works. Of these, 80% are identified as OH transitions; half of these are from highly excited molecules (hot-OH component). The other lines are attributable to O_2_ or unidentified. Several of the faint lines are in spectral regions that were previously believed to be free of lines emission. The continuum in the H-band is marginally detected at a level of about 300photons/m^2^/s/arcsec^2^/um. The observed spectrum and the list of observed sky-lines are published in electronic format. Our measurements indicate that the sky continuum in the H-band could be even darker than previously believed. However, the myriad of airglow emission lines severely limits the spectral ranges where very low background can be effectively achieved with low/medium resolution spectrographs. We identify a few spectral bands that could still remain quite dark at the resolving power foreseen for VLT-MOONS (R~6,600).2015A&A...581A..47Ohttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/581/A47CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/581/A47https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/581/A47http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/581/A47https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/581/A47https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/581/A47http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/581/A47GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapInfraredOpticaldefaultJ/A+A/581/A47/table1OH airglow line wavelengths and relative fluxesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda1[9792/22984] Vacuum wavelength of the first line of the doublet ({AA})0.1nmem.wl;spect.linedoubleIden1Line identification (1)meta.id;spect.linecharlambda2[9791/22988] Vacuum wavelength of the second line of the doublet ({AA})0.1nmem.wl;spect.linedoubleIden2Line identification (1)meta.id;spect.linecharFlux[3/10000] Relative line photon flux of doubletphot.flux;arith.ratiointJ/A+A/581/A47/table2*Non-OH line wavelengths and relative fluxesFlag[a-l] Notes to individual lines (1)meta.code.errorcharIdenLine identificationmeta.id;spect.linecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[10489/21794] Vacuum wavelength ({AA})0.1nmem.wldoubleFlux[4/820] Relative line photon fluxphot.flux;arith.ratiointJ/A+A/581/A47/table4Airglow spectrum covering the Y, J, H-bandsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[9790/18022] Vacuum wavelength ({AA})0.1nmem.wldoubleFlux[-1/421] Spectral flux (photons/m^2^/s/{AA})10m**-2.s**-1.nm**-1phot.fluxdouble