CTA Updates

• Gavin Rowell (School of Physical Sciences, University of Adelaide)
• Sabrina Einecke (The University of Adelaide, Australia)

CTA-Pol Update

• Nick Tothill (Western Sydney University)

With funding now available, we are starting the project to construct, deploy and operate the prototype polarimeter for CTA MWL observations. I will update the meeting on progress and plans.

Bayesian WIMP detection with CTA

• Csaba Balazs (School of Physics and Astronomy, Monash University)

I report on our work published in arXiv:2112.10371.

The Southern Wide-field Gamma-ray Observatory and its connection to CTA

• Jose Bellido

The design and detector prototype tests of the detectors for the Southern Wide-field Gamma-ray Observatory are underway. The University of Adelaide is contributing with the design and construction of the water Cherenkov tanks and the geo-membranes that will go inside the tanks.

Pilot Survey Science from the GASKAP-HI Survey

• Nickolas Pingel

The Galactic ASKAP (GASKAP) Survey provides an unprecedented view of the neutral hydrogen (HI) emission and absorption within the Milky Way disk and Magellanic System. I will summarize science results from our pilot survey fields on the Small and Large Magellanic Clouds, Magellanic Bridge, and Galactic Plane (centered on a longitude of 340 deg). These highlights include the characterization of the turbulent properties of HI down to 10 pc scales in the SMC and the analysis of the cold neutral medium as traced by HI absorption in the SMC and Galactic Plane. These new cubes are the result of an imaging pipeline designed to manage the unique challenges of imaging extremely extended emission. The GASKAP data and preliminary science results presented in this talk demonstrate, for the first time, the study of HI on similar spectral and angular scales as available molecular gas and dust data.

Update: Towards a Network of Cherenkov Telescopes

• Simon Lee (School of Physical Sciences, University of Adelaide)

The nature of the most extreme astronomical phenomena is better understood through observing their GeV and TeV gamma-ray flux, preferably by quickly following up on any transient events and continuously monitoring source flux variation. An Imaging Air Cherenkov Telescope (IACT) site in Australia, as part of a worldwide network of IACTs, would be a crucial part in achieving 24-hour all-sky coverage at these energies. Small arrays of telescopes were thus simulated to study the performance of an Australia-sited array with varying altitude, number of telescopes, layout, and telescope design. This update will include an overview of this telescope network idea, the results from the performance study, and the current work on improving the performance with stereoscopic and topological triggers.

Update: Quantifying New Sites for IACTs in Australia

• Sabrina Einecke (The University of Adelaide, Australia)
• Paddy McGee (School of Physical Sciences, University of Adelaide)

Improving CTA Event Reconstruction at the Highest Energies to Benefit PeVatron Searches

• Violet Harvey (The University of Adelaide)

To search for PeVatrons we need to make the absolute most of our highest energy event observations, but they are often at significant distances away from the detector array, potentially only triggering a single telescope, and the images may appear "truncated" or cut off in the telescope camera. Applying the pixel peak-time information is one way to try and recover these events, which may otherwise have been discarded. This is what I aim to do for the first part of my postdoctoral research.

Radio Observations of Galactic PeVatrons

• Sanja L

Short review of Milky Way PeVatrons in the latest surveys from the new-age radio telescopes. Cross-referencing these images with surveys in other frequencies, we are looking for previously not-detected SNRs.

Modelling Particles in the ISM: Including the ISM's Influence on the Spatial Distribution of Protons

• Robert Koenig

SNRs are believed to be a likely source of Galactic cosmic-ray protons with energies of PeV and above. High-energy protons, escaped from the shock front, diffuse in the ambient ISM and produce gamma rays as products of neutral pion decay from proton-proton interactions. Current models use a constant diffusion coefficient over the entire region to describe cosmic rays travelling through the ISM. The diffusion coefficient depends on the magnetic field a proton traverses. I estimate the local magnetic field along the pathway of cosmic-ray protons using the gas densities of the ISM they pass through, obtaining a position-dependent diffusion coefficient with a non-symmetric proton distribution around the accelerator.

The TeV Diffuse Gamma Ray Emission: Prospects for Future Detection with CTA

• Peter Marinos

We simulated the Galactic TeV diffuse gamma-ray emission with GALPROP for a wide variety of model parameters. These predictions are compared to the diffuse emission estimated by the H.E.S.S. telescope array in their Galactic plane survey, and the future prospects for CTA detecting the diffuse emission is discussed.

Update: Observations of Ionised Carbon towards SNR RXJ1713.7-3946

• Adnaan Thakur

SNR RXJ1713.7-3946 is one of the brightest young supernova remnants detected in the HESS Galactic Plane Survey. We have studied the C[II] emission towards the remnant and will provide an update on our analysis.

Update: Revisiting the HAlpha Outflow Feature towards the Scutum Supershell

• Rami Alsulami

I report about my investigation of the optical “outflow” towards the Scutum supershell using multi-wavelength observations of HI, CO, X-rays, gamma rays and optical Halpha. This also includes studying the possible origin scenario for such an extended outburst.

Estimating the Gamma-ray and Neutrino Fluxes from Supernova Remnants and Galactic Molecular Clouds

• Ryan Burley

Our Galaxy hosts numerous molecular gas clouds which act as targets for the high-energy particles produced by nearby particle accelerators. These particle interactions produce high-energy gamma rays and neutrinos which should be detectable which upcoming observatories, such as the Cherenkov Telescope Array (CTA) and IceCube-Gen2. In this work, we use a rapidly developing software which models the propagation of particles in the interstellar medium (partISM) to investigate the hadronic interactions of particles accelerated by supernova remnants (SNRs) with Galactic molecular gas clouds (GMCs). We present a selection of SNR and GMC combinations which should produce a 100TeV gamma-ray flux observable by CTA, and as such point towards the corresponding SNR as a promising PeVatron candidate.

Modelling the Transport of Electrons towards HESS J1825-137

• Tiffany Collins (The University of Adelaide)

HESS J1825-137 is one of the most powerful and luminous TeV gamma-ray pulsar wind nebulae (PWN). This makes HESS J1825-137 an excellent laboratory to study particle transportation in and around the powering pulsar. We have modelled the diffusive and advective transport of electrons from the powering pulsar, PSR 1826-1334. The resulting X-ray and gamma-ray emission was predicted through interactions with a 3D grid of interstellar medium (ISM) gas, soft photon fields and a spatially varying magnetic field.

Seeking Meaning in Mystery: Modeling the TeV Gamma Rays towards HESS J1804-216

• Kirsty Feijen (School of Physical Sciences, University of Adelaide)

HESS J1804-216 is one of the brightest yet most mysterious TeV gamma-ray sources discovered so far. Previous arcminute-scale investigations of the interstellar medium (ISM) surrounding this source revealed that HESS J1804-216 is likely powered by a middle-aged supernova remnant (SNR) or pulsar. SNRs are believed to accelerate cosmic-ray protons at their shock front. These cosmic rays interact with the ISM and produce TeV gamma rays. In this investigation, the spatial and spectral distributions of cosmic rays are generated for a range of model parameters, describing, amongst others, the diffusion or the injection spectrum of cosmic rays. Based on these cosmic-ray distributions and measurements of the ISM, the spatial and spectral distributions of gamma rays are created. A comparison between these models and gamma-ray observations may reveal the origin and corresponding acceleration processes at play for HESS J1804-216. In this contribution, the modelled morphologies of two nearby potential cosmic-ray accelerators -- SNR G8.7-0.1 and the progenitor SNR of PSR J1803-2137 -- and their comparison to recent observations will be discussed. More detailed features in the morphology may be resolved with the next-generation Cherenkov Telescope Array, which will provide unprecedented angular resolution and sensitivity.