The beginning of a new era - the systematic search for gravitational wave sources using synoptic surveys

Thomas Kupfer, California Institute of Technology - 15.5.17


Ultracompact binaries (UCB) are a rare class of binary systems with periods below 60 min (detached or semidetached), consisting of a neutron star (NS)/white dwarf (WD) primary and a He-star/WD/NS secondary. The study of ultracompact binaries and their subsequent mergers are important to our understanding of such diverse areas as supernova Ia progenitors, production of r-process elements, binary evolution and they are predicted to be the strong gravitational wave sources in the eLISA and LIGO-Virgo band.

The Zwicky Transient Facility is the next generation of optical synoptic surveys utilizing the entire focal plane of 47 deg^2 of the 1.2m telescope on Mount Palomar, providing the largest instantaneous field-of-view of any camera on a telescope of aperture greater than 0.5m. The field-of-view allows us to cover the entire visible sky in one night revisiting fields on timescales of a few hours and providing hundreds of visits per field each year. Science operations is expected to start by the end of 2017.

In this talk I will give an overview of the survey design and our effort to identify the optical counterpart to NS mergers triggered by LIGO. I am lead investigator of an approved high-cadence survey covering the full inner Plane visible from the northern hemisphere as part of ZTF. We will obtain 2 - 3 hr continuous lightcurves of each field with a cadence of 40 sec starting winter 2017 to identify the Galactic population of ultracompact binaries. I will give an overview of the survey as well as discuss the expected numbers of ultracompact eLISA sources from this survey.