A systematic search of Zwicky Transient Facility data for ultracompact binary LISA-detectable gravitational-wave sources

TL;DR

This paper reports the discovery of fifteen ultracompact binary systems with short orbital periods using ZTF data, aiming to identify new gravitational-wave sources for LISA detection.

Contribution

It presents the first systematic search results for ultracompact binaries in ZTF data, including detailed follow-up and LISA signal estimates.

Findings

Fifteen ultracompact binary systems discovered with periods from 6.91 to 56.35 minutes.

Seven systems are eclipsing without significant mass transfer.

Two AM CVn systems and six ellipsoidal variation systems identified.

Abstract

Using photometry collected with the Zwicky Transient Facility (ZTF), we are conducting an ongoing survey for binary systems with short orbital periods ($P_{\rm b}<1\rm \,hr)$ with the goal of identifying new gravitational-wave sources detectable by the upcoming Laser Interferometer Space Antenna (LISA). Here, we present a sample of fifteen binary systems discovered thus far, with orbital periods ranging from $6.91\rm\,min$ to $56.35\rm\,min$. Of the fifteen systems, seven are eclipsing systems which do not show signs of significant mass transfer. Additionally, we have discovered two AM Canum Venaticorum (AM CVn) systems and six systems exhibiting primarily ellipsoidal variations in their light curves. We present follow-up spectroscopy and high-speed photometry confirming the nature of these systems, estimates of their LISA signal-to-noise ratios (SNR), and a discussion of their physical characteristics.