The Optical Gravitational Lensing Experiment. Dwarf Novae in the OGLE Data. I. Three New Dwarf Novae: One in the Period Gap and Two Longer Period Objects

TL;DR

This paper reports the discovery of three new dwarf novae in the Galactic bulge using OGLE data, including one in the period gap with a superhump period of 2.61 hours, revealing new insights into their outburst behaviors.

Contribution

First detection of three new dwarf novae in the Galactic bulge with detailed period measurements, including one in the orbital period gap, using high-cadence OGLE survey data.

Findings

One dwarf nova in the period gap with a superhump period of 2.61 hours.

Two dwarf novae with orbital periods of 5.4 and 9.5 hours.

Observation of superhump period change during superoutburst.

Abstract

We report serendipitous discovery of three new dwarf novae which eruptions in 2010 were observed by the ongoing microlensing survey OGLE-IV. All three objects are located in the Galactic bulge fields observed with the highest cadence of 20 minutes. In the OGLE-III and OGLE-IV data we revealed a total of 23 outbursts for one of the stars. What makes this object most interesting is the derived superhump period of 2.61 h placing it in the orbital period gap. The superhump period changed during the superoutburst with a very short timescale. For two other objects, for which we observed outburst, the orbital periods of 5.4 h and 9.5 h were measured in the quiescence.