26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Session

AIP GAP: Gamma-rays and gravitational waves

9 Dec 2026, 11:00

Belinda Hutchinson Building (The University of Sydney )

Conveners

AIP GAP: Gamma-rays and gravitational waves

• Ciaran O'Hare (Sydney)

160. Stellar Halos as Probes of Interstellar Cosmic-Ray Electrons with Fermi--LAT

Peter Marinos (Stanford University)

09/12/2026, 11:00

AIP | Astroparticle Physics (GAP)

Invited talk

High-precision measurements of cosmic-ray (CR) electrons are confined to the heliospheric environment, leaving the distribution in the nearby interstellar medium poorly constrained. We propose to probe the CR-electron spectrum outside the heliosphere by searching for extended Compton emissions from the stellar radiation fields surrounding individual stars in Fermi--LAT data. We have identified...

682. The Cherenkov Telescope Array Observatory, the present, and the future of extreme astrophysics

Simon Lee

09/12/2026, 11:30

AIP | Astroparticle Physics (GAP)

Contributed Oral

The Cherenkov Telescope Array Observatory (CTAO) is under construction to become the world's most powerful gamma-ray observatory. With 64 telescopes of three sizes across both Hemispheres, CTAO will have an order of magnitude better sensitivity than existing instruments. Very-high-energy gamma-ray astrophysics is crucial for understanding the most extreme phenomena in our universe. Observing...

151. Exploring the Millisecond Pulsar Origin of the Galactic Center Excess with the Cherenkov Telescope Array Observatory

Hayden James (The University of Adelaide)

09/12/2026, 11:45

AIP | Astroparticle Physics (GAP)

Contributed Oral

The Galactic Centre Excess has long attracted attention as a potential signature of dark matter self-annihilation. However, an astrophysical origin remains a possible alternative, with one leading hypothesis attributing the excess to an unresolved population of millisecond pulsars. The next-generation Cherenkov Telescope Array Observatory may discriminate between these hypotheses by detecting...

124. Precise, self-consistent predictions of gravitational waves from cosmological phase transitions

Csaba Balazs (Monash University)

09/12/2026, 12:00

AIP | Astroparticle Physics (GAP)

Contributed Oral

The detection of a stochastic gravitational wave background from the early Universe offers a unique window into beyond-the-Standard-Model physics. As we prepare for future space-based observatories such as LISA, TianQin, and others, precise theoretical predictions of the gravitational wave (GW) spectra generated by cosmological first-order phase transitions (FOPTs) are paramount. Conventional...

439. Consistent Gravitational Waves from Cosmological Phase Transitions

William Searle (Monash University)

09/12/2026, 12:15

AIP | Astroparticle Physics (GAP)

Contributed Oral

Gravitational waves (GWs) from first-order cosmological phase transitions provide a powerful probe of physics beyond the Standard Model, and upcoming space-based GW observatories necessitate greater precision in theoretical predictions for these signals. In this work, we present a systematic framework for consistently predicting the GW spectra for such transitions.

We first outline the...