A determination of the space density and birth rate of hydrogen-line (DA) white dwarfs in the Galactic plane, based on the UVEX survey

Verbeek, Kars; Groot, Paul J.; Nelemans, Gijs; Scaringi, Simone; Napiwotzki, Ralf; Drew, Janet E.; Steeghs, Danny; Casares, Jorge; Corral-Santana, Jesus M.; Gänsicke, Boris T.; González-Solares, Eduardo; Greimel, Robert; Heber, Ulrich; Irwin, Mike J.; Knigge, Christian; Wright, Nicholas J.; Zijlstra, Albert A.

Abstract

We present a determination of the average space density and birth rate of hydrogen-line (DA) white dwarfs within a radius of 1 kpc around the Sun, based on an observational sample of 360 candidate white dwarfs with g < 19.5 and (g − r) < 0.4, selected from the UV-Excess (UVEX) survey of the northern Galactic plane, in combination with a theoretical white dwarf population that has been constructed to simulate the observations, including the effects of reddening and observational selection effects. The main uncertainty in the derivation of the white dwarf space density and current birth rate lies in the absolute photometric calibration and the photometric scatter of the observational data, which influences the classification method on colours, the completeness and the pollution. Corrections for these effects are applied. We derive an average space density of DA white dwarfs with Teff > 10 000 K (MV < 12.2) of (3.8 ± 1.1) × 10−4 pc−3, and an average DA white dwarf birth rate over the last 7×107 yr of (5.4 ± 1.5) × 10−13 pc−3 yr−1. Additionally, we show that many estimates of the white dwarf space density from different studies are consistent with each other, and with our determination here.

Citation

Verbeek, K., Groot, P. J., Nelemans, G., Scaringi, S., Napiwotzki, R., Drew, J. E., …Zijlstra, A. A. (2013). A determination of the space density and birth rate of hydrogen-line (DA) white dwarfs in the Galactic plane, based on the UVEX survey. Monthly Notices of the Royal Astronomical Society, 434(4), 2727-2741. https://doi.org/10.1093/mnras/stt1005

• Journal Article Type: Article
• Acceptance Date: Jun 5, 2013
• Online Publication Date: Aug 6, 2013
• Publication Date: Oct 1, 2013
• Deposit Date: Jun 13, 2023
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 434
• Issue: 4
• Pages: 2727-2741
• DOI: https://doi.org/10.1093/mnras/stt1005
• Keywords: Space and Planetary Science; Astronomy and Astrophysics; surveys, stars: general, white dwarfs, ISM: general, Galaxy: disc, Galaxy: stellar content