Detections and constraints on white dwarf variability from time-series GALEX observations. Issue 4 (20th April 2019)

• Record Type: Journal Article
• Authors: Rowan, D M; Tucker, M A; Shappee, B J; Hermes, J J
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 486:Issue 4(2019)
• Page Start: 4574
• Page End: 4589
• Publication Date: 2019-04-20
• Subjects: stars: oscillations -- white dwarfs; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stz1116
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We search for photometric variability in more than 23 000 known and candidate white dwarfs (WDs), the largest ultraviolet survey compiled for a single study of WDs. We use gphoton, a publicly available calibration/reduction pipeline, to generate time-series photometry of WDs observed by GALEX . By implementing a system of weighted metrics, we select sources with variability due to pulsations and eclipses. Although GALEX observations have short baselines (≤30 min), we identify intrinsic variability in sources as faint as Gaia G = 20 mag. With our ranking algorithm, we identify 48 new variable WDs in archival GALEX observations. We detect 40 new pulsators: 36 have hydrogen-dominated atmospheres (DAVs), including one possible massive DAV, and four are helium-dominated pulsators (DBVs). We also detect eight new eclipsing systems; five are new discoveries, and three were previously known spectroscopic binaries. We perform synthetic injections of the light curve of WD 1145+017, a system with known transiting debris, to test our ability to recover similar systems. We find that the 3σ maximum occurrence rate of WD 1145+017-like transiting objects is $\le 0.5{{\ \rm per\ cent}}$ .