Kendall Ackley (Monash): Multimessenger Astronomy

The first detection of a binary neutron star merger made with Advanced LIGO and Virgo, GW170817, led to incredible advancements in the field of Multimessenger Astronomy. We will review how the electromagnetic community responded GW170817, how to uncover and attempt to explain the astrophysical mechanisms behind this and other types of LIGO sources in a hands-on presentation, and how the future of Multimessenger Astronomy will help to uncover great mysteries of the Universe.

• Slides found here.

Stefan Oslowski (Swinburne): Pulsar Timing Arrays

The gravitational waves spectrum spans a large range of frequencies with various experiments covering different parts of the spectrum. At the low end of the spectrum, in the nanoHertz regime, we use so-calledPulsar Timing Arrays (PTAs) to try and detect gravitational waves. PTAs observe tens of millisecond pulsars spread throughout our Galaxy to form a galactic-scale detector. The primary signal PTAs attempt to detect are mergers of supermassive blackholes. During this school I'll provide you with an overview of the history of PTAs, current efforts and struggles, as well as the outlook into the bright future.

• Slides found here.

Rory Smith (Monash): LIGO Data Analysis and Parameter Inference

Gravitational-wave astronomy began on September 14th, 2015 with the observation of the merger of two black holes, each weighing approximately thirty times the mass of the sun and located 1.5 billion light years away. During the collision, three times the mass of the sun was converted into gravitational-wave energy in a fraction of a second - with a peak power output 50 times that of the whole visible universe. This was measured by LIGO detectors as a stretching and squeezing of space-time on the order of a thousandth of the width of the proton over 4km. How were we able to detect such a small signal? And how did we infer so much information from the signal which barely lasted for a fifth of a second? In this hands-on session we will cover the basics of detecting gravitational waves from merging black holes and neutron stars. In the second half of the session we will work through some of the methods for decoding astrophysical information that is encoded in gravitational waves.

• Slides found here.

Jade Powell (Swinburne): Astrophysics of LIGO sources

The first direct detections of gravitational waves from compact binary mergers were made in the recent observing runs of the Advanced LIGO and Virgo gravitational-wave detectors. The number of detections of compact binaries is expected to increase as the detectors reach their design sensitivity, and further detections may occur from other types of astrophysical sources. Gravitational-wave detections can improve our understanding of the astrophysics of the sources and of source populations. We review the astrophysics that is enabled by gravitational wave detections made in the advanced detector era.

• Slides found here.

Rob Ward (ANU): How LIGO works (instrumentation)

From space-time strain to digital bits: how modern gravitational wave detectors work. The advanced laser interferometric gravitational wave detectors currently operating are the most sensitive measurement devices ever constructed. They employ sophisticated interferometric techniques including nested optical cavities, highly effective active and passive seismic isolation, ultra-low-loss, high optical quality materials, and bespoke digital and analog control systems. We will discuss how these methods come together at a systems level to transduce the “ripples in the fabric of spacetime” into the data products that can be analysed to extract the information carried by gravitational waves.