A systematic search for outbursting AM CVn systems with the Zwicky Transient Facility

TL;DR

This paper reports the discovery of nine new AM CVn systems using the Zwicky Transient Facility by targeting blue, outbursting stars, demonstrating an effective method for identifying these rare binary systems and estimating their orbital periods.

Contribution

The study introduces a systematic approach combining ZTF alerts with Gaia and Pan-STARRS data to efficiently discover new outbursting AM CVn systems.

Findings

Discovered 9 new AM CVn systems.

Estimated orbital periods range from 29 to 50 minutes.

Validated targeted follow-up as an effective detection method.

Abstract

AM CVn systems are a rare type of accreting binary that consists of a white dwarf and a helium-rich, degenerate donor star. Using the Zwicky Transient Facility (ZTF), we searched for new AM CVn systems by focusing on blue, outbursting stars. We first selected outbursting stars using the ZTF alerts. We cross-matched the candidates with $Gaia$ and Pan-STARRS catalogs. The initial selection of candidates based on the $Gaia$ $BP$-$RP$ contains 1751 unknown objects. We used the Pan-STARRS $g$-$r$ and $r$-$i$ color in combination with the $Gaia$ color to identify 59 high-priority candidates. We obtained identification spectra of 35 sources, of which 18 are high priority candidates, and discovered 9 new AM CVn systems and one magnetic CV which shows only He-II lines. Using the outburst recurrence time, we estimate the orbital periods which are in the range of 29 to 50 minutes. We conclude that targeted followup of blue, outbursting sources is an efficient method to find new AM CVn systems, and we plan to followup all candidates we identified to systematically study the population of outbursting AM CVn systems.