A multi-survey approach to white dwarf discovery

Abstract

By selecting astrometric and photometric data from the Sloan Digital Sky Survey (SDSS), the Lépine & Shara Proper Motion North Catalog (LSPM-North), the Two Micron All Sky Survey (2MASS), and the USNO-B1.0 catalog, we use a succession of methods to isolate white dwarf (WD) candidates for follow-up spectroscopy. Our methods include reduced proper motion diagram cuts, color cuts, and atmospheric model adherence. We present spectroscopy of 26 WDs obtained from the CTIO 4m and APO 3.5m telescopes. Additionally, we confirm 28WDs with spectra available in the SDSS DR7 database but unpublished elsewhere, presenting a total of 54 WDs. We label one of these as a recovered WD while the remaining 53 are new discoveries. We determine physical parameters and estimate distances based on atmospheric model analyses. Three new WDs are modeled to lie within 25pc. Two additional WDs are confirmed to be metal-polluted (DAZ). Follow-up time series photometry confirms another object to be a pulsating ZZ Ceti WD. © 2012. The American Astronomical Society. All rights reserved.