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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 198343.0, MPI für Astronomie / Publikationen_mpia
Spectrophotometric information from the DIVA satellite
Authors:de Boer, K. S.; Willemsen, P. G.; Reif, K.; Poschmann, H.; Marien, K.-H.; Kaempf, T. A.; Hilker, M.; Evans, D. W.; Bailer-Jones, C. A. L.
Date of Publication (YYYY-MM-DD):2003
Title of Journal:Journal of Astronomical Data
Journal Abbrev.:Journal of Astronomical Data
Start Page:8
End Page:– +
Sequence Number of Article:2003JAD....9....8D
Review Status:not specified
Audience:Experts Only
Abstract / Description:The DIVA satellite will, in addition to the
astrometry, obtain photometric data for about 40
million survey stars and spectral data for about
a third of these. Relevant sections of the
CCD-data stream will be transmitted to Earth to
allow a photometric and a spectrophotometric
analysis. The DIVA photometric (SM) data can be
used to derive stellar colours. Colours are in
particular required for the chromaticity
correction of the astrometry. The UV telescope
(UV) is designed to obtain information about the
Balmer jump region of the spectral energy
distribution. The spectrophotometric (SC) data
consists of overlapping spectral orders in the
cross-scan direction. From these SC images the
dispi (dispersed position-coded intensity) will
be derived. The information on all stellar
parameters is, of course, contained in the dispi
and can be extracted without deconvolution. CCDs
of the type foreseen for DIVA are in the process
of being tested for their performance under the
special conditions of this space mission.
Methods are being tested, like artificial neural
networks (ANNs) and others, to derive the
astrophysical parameters Teff, log g, [M/H], and
E(B-V) from the dispi. We find that even with the
relatively modest spectral resolution of the
dispi the ANN can discriminate well in
temperature, moderately well in gravity and
extinction, and crudely in metallicity, all
clearly dependent on the brightness of the star.
Degeneracy in the temperature and extinction
determination can be lifted especially using
Balmer jump information from the DIVA UV
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bi... [ID No:1]
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