Photometric variability of candidate white dwarf binary systems from Palomar Transient Factory archival data

TL;DR

This paper identifies 59 periodic white dwarf candidate systems from the Palomar Transient Factory data, revealing their variability likely due to binary interactions, and provides new period estimates including previously unrecognized variables.

Contribution

It introduces a new sample of 59 white dwarf binary candidates with period estimates, including 45 newly identified periodic variables, based on archival survey data.

Findings

Most variables have periods shorter than a few days.

45 of the variables are newly identified as periodic.

Spectroscopic data provided for selected sources.

Abstract

We present a sample of 59 periodic variables from the Palomar Transient Factory, selected from published catalogues of white dwarf (WD) candidates. The variability can likely be attributed to ellipsoidal variation of the tidally distorted companion induced by the gravity of the primary (WD or hot subdwarf) or to the reflection of hot emission by a cooler companion. We searched 11311 spectroscopically or photometrically selected WD candidates from three hot star/WD catalogues, using the Lomb-Scargle periodogram to single out promising sources. We present period estimates for the candidates, 45 of which were not previously identified as periodic variables, and find that most have a period shorter than a few days. Additionally, we discuss the eclipsing systems in our sample and present spectroscopic data on selected sources.