Publication Date:
2014-01-16
Description:
We present the result of the cross-matching between ultraviolet (UV)-excess sources selected from the UV-Excess Survey of the Northern Galactic Plane (UVEX) and several infrared (IR) surveys (2MASS, UKIDSS and WISE ). From the position in the ( J – H ) versus ( H – K ) colour–colour diagram, we select UV-excess candidate white dwarfs with an M-dwarf type companion, candidates that might have a lower mass, brown-dwarf type companion and candidates showing an IR-excess only in the K band, which might be due to a debris disc. Grids of reddened DA+dM and sdO+MS/sdB+MS model spectra are fitted to the U , g , r , i , z , J , H , K photometry in order to determine spectral types and estimate temperatures and reddening. From a sample of 964 hot candidate white dwarfs with ( g – r ) 〈 0.2, the spectral energy distribution fitting shows that ~2–4 per cent of the white dwarfs have an M-dwarf companion, ~2 per cent have a lower-mass companion, and no clear candidates for having a debris disc are found. Additionally, from WISE six UV-excess sources are selected as candidate quasi-stellar objects (QSOs). Two UV-excess sources have a WISE IR-excess showing up only in the mid-IR W 3 band of WISE , making them candidate luminous infrared galaxies (LIRGs) or Sbc starburst galaxies.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
Permalink