Session B07: Time Domain Astrophysics

Probing the Origins of Fast Radio Bursts

Fast Radio Bursts (FRBs) are mysterious radio transients that occur at a prodigious rate of $\approx 10^3$ events per day above fluences of 1 Jansky-ms in the entire sky. Arriving from cosmological distances ($\sim$Gpc), FRBs show potential to be novel probes of cosmological parameters, the ionized baryon distribution, and the magnetic fields around and between galaxies. We do not know the origins of these bursts, which intrinsically seem to be $\sim10^{12}$ times more luminous than pulsar radio signals that they resemble. A plethora of FRB models have been proposed but the tests of these models are observationally limited by the small heterogeneously assembled sample of FRBs. However, the FRB population is now poised for an explosion with many large surveys starting observations allowing real-time detection, multi-wavelength follow up and the generation of a large, well-understood sample of FRBs. I will summarize the new results and recent advances in our understanding of FRBs, discuss the open questions about FRBs and the challenges of addressing them.   

Super-flaring stars

Magnetic reconnection events in the atmospheres of stars similar to and smaller than the Sun can last seconds to many hours and release copious amounts of energy. Such energetic flares could influence the atmosphere of any planetary bodies surrounding these stars, and thus could impact the potential habitability of these planets. In this talk, I will discuss how multi-wavelength, multi-epoch observations of flaring stars is informing our understanding of both the energetics and underlying physics of stellar flares, and the impact that both the duration and sampling of observations play in extracting flare properties. I will overview the role current large ground- and space-based time domain surveys (e.g. Kepler/K2, PTF, ZTF, DES) and future (e.g. TESS, LSST) are playing in improving our understanding of the fundamental physics that drive stellar flares.   

Rethinking the Fundamentals of Classical Nova Explosions

Over the past few years, a revolution has been taking place in our understanding of classical novae, largely driven by the discovery of GeV gamma-rays emanating from these garden-variety explosions. These gamma-rays hint that shocks are energetically important---perhaps even dominant---in novae. I will present our burgeoning understanding of shocks in novae, from both multi-wavelength observational and theoretical perspectives. I will also show that novae can be used as testbeds to understand other shock-powered explosions, like stellar mergers and super-luminous supernovae.