Spectroscopic follow-up of ultraviolet-excess objects selected from the UVEX survey

Kars Verbeek, Paul J. Groot, Simone Scaringi, Ralf Napiwotzki, Ben Spikings, Roy H. østensen, Janet E. Drew, Danny Steeghs, Jorge Casares, Jesus M. Corral-Santana, Romano L M Corradi, Niall Deacon, Jeremy J. Drake, Boris T. Gänsicke, Eduardo González-Solares, Robert Greimel, Ulrich Heber, Mike J Irwin, Christian Knigge, Gijs Nelemans

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13 Citations (Scopus)


We present the results of the first spectroscopic follow-up of 132 optically blue ultraviolet (UV)-excess sources selected from the UV-Excess Survey of the Northern Galactic Plane (UVEX). The UV-excess spectra are classified into different populations and grids of model spectra are fitted to determine spectral types, temperatures, surface gravities and reddening. From this initial spectroscopic follow-up 95 per cent of the UV-excess candidates turn out to be genuine UV-excess sources such as white dwarfs, white dwarf binaries, subdwarf types O and B, emission-line stars and quasi stellar objects. The remaining sources are classified as slightly reddened main-sequence stars with spectral types later than A0V. The fraction of DA white dwarfs is 47 per cent with reddening smaller than E(B - V) ≤ 0.7mag. Relations between the different populations and their UVEX photometry, Galactic latitude and reddening are shown. A larger fraction of UVEX white dwarfs is found at magnitudes fainter than g > 17 and Galactic latitude smaller than |b| < 4 compared to main-sequence stars, blue horizontal branch stars and subdwarfs.

Original languageEnglish
Pages (from-to)1235-1261
Number of pages27
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Publication statusPublished - 21 Oct 2012
Externally publishedYes


  • Galaxy: disc
  • Galaxy: stellar content
  • ISM: general
  • Subdwarfs
  • Surveys
  • White dwarfs

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