The post-outburst pulsations of the accreting white dwarf in the cataclysmic variable GW Librae

TL;DR

This study reports new observations of pulsations in the white dwarf of GW Librae, revealing a new pulsation mode and a 3-hour modulation, highlighting the dynamic nature of accreting white dwarf pulsations.

Contribution

The paper provides new time-series photometry data showing the re-emergence of a pulsation mode and identifies a previously unreported modulation period in GW Librae.

Findings

Detection of a ~19 minute pulsation mode in 2012 data.

Identification of a new pulsation mode not previously observed.

Discovery of a 3-hour modulation period related to known periods.

Abstract

We present new time-series photometry of the accreting pulsating white dwarf system GW Librae obtained in 2012 and 2013 at the University of Canterbury Mt John Observatory in New Zealand. Our 2012 data show the return of a $\sim$19 minute periodicity that was previously detected in 2008. This pulsation mode was a dominant feature of our quality May 2012 data set, which consisted of six contiguous nights; a detailed analysis indicated a degree of frequency variability. We show by comparison with the previously identified pulsation modes that this periodicity is best explained as a new mode, and that the quasi-stability of the periods appears to be a general feature of the pulsations in these systems. We also find a previously unreported 3-hour modulation period, which we believe to be related to the known two and four hour periods of so far unknown origin.