Status of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav)

Main Colloquium
Dr. Timothy Pennucci
Eötvös Loránd University, Institute of Physics, Budapest, Hungary

Supermassive black hole binaries, and possibly other sources, generate gravitational waves (GWs) at nanohertz frequencies. For almost a decade and a half, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has been using the 100-m Green Bank Telescope, the 305-m Arecibo Observatory, and, more recently, the 27 × 25-m Very Large Array to observe an ensemble of millisecond pulsars (MSPs) in a pulsar timing array (PTA) experiment. I will present our current observational program of 76 MSPs, an overview of our newest, 12.5-year dataset, recent results from searches for GWs, and new analysis techniques that are designed specifically for the current and future generation of wideband pulsar instrumentation. These wideband methods are also more generally applicable to known-pulsar observations, with use-cases in the CHIME and MeerTime experiments, as well as the pulsar data collected from the Effelsberg telescope.

Searches for fast radio transients in Parkes archival pulsar timing data

Master Colloquium
Aswin Manohar
Max-Planck-Institut für Radioastronomie

Pulsars are a class of rapidly rotating, highly magnetized neutron star - the remnant of supernova explosions of massive stars - where the electromagnetic emission beams are visible as they sweep past the Earth. In general, pulsar surveys of the Galactic plane offer opportunities to scan a small fraction of the transient radio sky for bright millisecond duration bursts. The transient radio sky harbors many types of exotic objects and the recent discovery of Fast Radio Bursts (FRBs - bright millisecond duration bursts of high dispersion measure and extra-Galactic origin) and Rotating Radio Transients (RRATs - a new type of sparsely-emitting pulsar) has spurred renewed interest in the search for single-pulse emission. FRBs are powerful probes of the ionized inter-galactic medium and the properties of space-time itself. In this talk, I will describe the preliminary results from a search for transient radio bursts, and single pulses from pulsars, in Parkes archival pulsar timing data (from 1996 onwards). As well as one convincing FRB candidate, I will discuss the limitations of machine learning algorithms for detecting single pulses and present the pulse energy distributions of selected pulsars detected in the search. [Refeeres: Prof. Dr. Michael Kramer, Prof. Dr. Pavel Kroupa]