title: Interstellar medium. Pseudo-three-dimensional maps of the diffuse interstellar band at 862 nm.
abstract: The diffuse interstellar bands (DIBs) are absorption lines observed in visual and near-infrared spectra of stars. Understanding their origin in the interstellar medium is one of the oldest problems in astronomical spectroscopy, as DIBs have been known since 1922. In a completely new approach to understanding DIBs, we combined information from nearly 500,000 stellar spectra obtained by the massive spectroscopic survey RAVE (Radial Velocity Experiment) to produce the first pseudo-three-dimensional map of the strength of the DIB at 8620 angstroms covering the nearest 3 kiloparsecs from the Sun, and show that it follows our independently constructed spatial distribution of extinction by interstellar dust along the Galactic plane. Despite having a similar distribution in the Galactic plane, the DIB 8620 carrier has a significantly larger vertical scale height than the dust. Even if one DIB may not represent the general DIB population, our observations outline the future direction of DIB research.
authors.affiliation: Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia. janez.kos@fmf.uni-lj.si.
authors.forename: Janez
authors.initials: J
authors.lastname: Kos
authors.affiliation: Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
authors.forename: Tomaž
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authors.lastname: Zwitter
authors.affiliation: Johns Hopkins University, Homewood Campus, 3400 North Charles Street, Baltimore, MD 21218, USA.
authors.forename: Rosemary
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authors.affiliation: Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, 11 rue de l'Université, F-67000 Strasbourg, France.
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authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, Keble Road, Oxford OX1 3NP, UK.
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authors.affiliation: Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2008, Australia.
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authors.affiliation: Chair, Computational Astrophysics, Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK.
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authors.affiliation: Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK.
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authors.initials: EK
authors.lastname: Grebel
authors.affiliation: Kapteyn Astronomical Institute, Post Office Box 800, NL-9700 AV Groningen, Netherlands.
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authors.lastname: Helmi
authors.affiliation: Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK.
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authors.affiliation: Instituto Nazionale di Astrofisica Astronomical Observatory of Padova, 36012 Asiago (VI), Italy.
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authors.affiliation: University of Victoria, Victoria BC, Canada V8P 5C2.
authors.forename: Julio
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authors.lastname: Navarro
authors.affiliation: Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109, Australia. Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109, Australia. Australian Astronomical Observatory, Post Office Box 915, North Ryde, NSW 1670, Australia.
authors.forename: Quentin
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authors.lastname: Parker
authors.affiliation: Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109, Australia. Centre for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney, NSW 2109, Australia.
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authors.initials: WA
authors.lastname: Reid
authors.affiliation: Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking RH5 6NT, UK.
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authors.lastname: Seabroke
authors.affiliation: Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2008, Australia.
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authors.affiliation: Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, 11 rue de l'Université, F-67000 Strasbourg, France.
authors.forename: Arnaud
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authors.lastname: Siebert
authors.affiliation: Department of Physics and Astronomy, Padova University, Vicolo dell'Osservatorio 2, I-35122 Padova, Italy. Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany.
authors.forename: Alessandro
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authors.lastname: Siviero
authors.affiliation: Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany.
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authors.lastname: Steinmetz
authors.affiliation: Australian Astronomical Observatory, Post Office Box 915, North Ryde, NSW 1670, Australia.
authors.forename: Fred G
authors.initials: FG
authors.lastname: Watson
authors.affiliation: Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany.
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authors.initials: ME
authors.lastname: Williams