Abstract

Contributed Talk - Splinter GWAstronomy

Thursday, 18 September 2025, 14:25

Observing Ultracompact Binaries with the Oskar Lühning Telescope

Paul Teckenburg, Thomas Kupfer
Uni Hamburg (Thomas Kupfer)

Ultracompact binary systems are binary systems with ultrashort periods of less than 60 minutes, consisting of stellar remnants. These systems emit low-frequency gravitational waves (GWs). The emission of GWs is causing ultracompact binaries to lose angular momentum. This loss of angular momentum is detectable by observing the orbital decay of the period of the system. The proposed gravitational wave detector LISA is expected to detect GW signals from such systems. The system ZTFJ213056.71+442046.5 (J2130) is an ultracompact binary consisting of a Roche lobe-filling, blue helium-burning subdwarf (sdOB) and an accreting white dwarf. It has a period of 39.3401(1) minutes and a relative g-band magnitude of 15.33. The orbital period of the system is expected to decrease due to gravitational wave emission. In this talk I will give an overview of a new high-speed CMOS camera mounted at the 1.2-meter Oskar-Lühning-Telescope at the Hamburg Observatory. I will present results of timing measurements of J2130, using this telescope, to detect the orbital decay caused by the radiation of gravitational waves and put the results in context of a possible detectability for LISA.