Treasures from the Zwicky Transient Facility Galactic Plane observations

Thomas Kupfer, Texas Tech University — 14.12.2020

The most compact binary stars have physical separations between components smaller than the Earth-Moon distance and orbital periods less than about 60 min. They are sources of low-frequency gravitational waves as will be probed by the Laser Interferometer Space Antenna, are crucial to our understanding of compact binary evolution and offer pathways towards one of the most luminous explosions in the universe: Type Ia supernovae. Although the known sample is still inhomogenous, ongoing and upcoming large scale sky surveys have the potential to discover and study them with well understood biases and selection effects.

In this talk I will present an overview of the field and some early results from a dedicated imaging survey of the Milky Way’s stellar plane as part of the Zwicky Transient Facility to find these compact binaries. As part of this survey we have already discovered the most compact known double white dwarf, a new class of accreting He-star binaries and a new class of pulsating stars. I will finish with an outlook on how upcoming large imaging surveys like BlackGEM combined with multi-wavelength resources like eROSITA will allow us to extend to the Southern hemisphere to finally study a homogenous sample of different populations of these unique binaries across both hemispheres.