Ultraviolet-excess sources with a red/infrared counterpart: low-mass companions, debris discs and QSO selection

Wright, Nicholas J.

Abstract

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 W3 band of WISE, making them candidate luminous infrared galaxies (LIRGs) or Sbc starburst galaxies.

Citation

Wright, N. J. (2014). Ultraviolet-excess sources with a red/infrared counterpart: low-mass companions, debris discs and QSO selection. Monthly Notices of the Royal Astronomical Society, 2-13. https://doi.org/10.1093/mnras/stt1492

• Acceptance Date: Aug 6, 2013
• Publication Date: Feb 11, 2014
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Publisher: Oxford University Press
• Pages: 2-13
• DOI: https://doi.org/10.1093/mnras/stt1492
• Keywords: surveys, binaries, general, white dwarfs, ISM, galaxy, stellar content, infrared
• Publisher URL: http://dx.doi.org/10.1093/mnras/stt1492