Category: News

We are delighted to celebrate two incredible OzGrav members who have been featured in the September issue of Nature Astronomy. OzGrav’s Creative Technologist and Scientific Visualisation Specialist, Carl Knox, created the captivating cover image depicting CSIRO’s ASKAP radio telescope alongside two versions of a mysterious celestial object: a neutron star or a white dwarf. The artwork brings to life the groundbreaking research led by OzGrav Associate Investigator, Dr. Manisha Caleb.

Dr. Caleb’s paper, published in Nature Astronomy in July, reveals the discovery of a slow-spinning neutron star that defies conventional astrophysics. Most neutron stars rotate in mere seconds, but this one takes nearly an hour—a finding that challenges our understanding of these dense celestial objects. Dr. Caleb explained, “It is highly unusual to discover a neutron star candidate emitting radio pulsations in this way. The fact that the signal is repeating at such a leisurely pace is extraordinary.”

Carl’s visualisation accompanies Dr. Caleb’s incredible research and perfectly captures the intrigue and mystery of this unusual celestial phenomenon. Their work together represents the power of combining science and art to deepen public understanding and appreciation of space discoveries.

Congratulations to both Manisha and Carl for their outstanding contributions to astronomy and for representing OzGrav on the international stage!

Read more about the discovery here

As part of National Science Week, the ARC Centre of Excellence (OzGrav) and the Centre for Astrophysics and Supercomputing (CAS) at Swinburne University proudly hosted “A Virtual Tour of Einstein’s Universe”, an inspiring public lecture presented by Professor Matthew Bailes, Director of OzGrav. Held on campus, the event attracted a strong turnout of science enthusiasts of all ages eager to learn about the universe’s greatest mysteries—from gravitational waves to black holes and pulsars.

Hosted by Professor Alan Duffy, the evening began with a warm introduction to Professor Bailes, followed by a fascinating journey through space and time. Professor Bailes explained how Einstein’s theories are shaping our understanding of the cosmos today. The audience was captivated by discussions on cutting-edge science, with a lively Q&A session rounding out the event.

The event also featured our National Science Week Ambassador, Dr Sara Webb, who helped create an engaging and educational experience, fostering an exciting atmosphere for learning and exploration during National Science Week.

In addition to the public lecture, OzGrav’s Outreach Ambassadors hosted interactive workshops, providing hands-on activities for attendees of all ages and fostering an exciting atmosphere for learning and exploration.

This successful event wouldn’t have been possible without the dedication of the OzGrav team and the Swinburne outreach staff. Stay tuned for more exciting events from OzGrav and Swinburne!

For those who missed the event, a recording of the lecture is below and you can also explore the gallery to view photos from the event.

We are delighted to share that the Einstein-First project, a groundbreaking science education initiative, has been awarded the Science Engagement Initiative of the Year at the 2024 WA Premier’s Science Awards. This recognition highlights the exceptional impact Einstein-First has made in transforming the way young students, especially girls, engage with and understand modern science.

Einstein-First began as an outreach effort at the Gravity Discovery Centre and has since evolved into a national program that brings Einstein’s 21st-century science to students aged 7 to 15. The program’s innovative approach disrupts traditional teaching paradigms by using toys, songs, and hands-on activities to make complex scientific concepts accessible and engaging.

The program’s success is evident in its rapid expansion. Launched nationally by Prof. David Blair, Prof. Ju Li, Prof. Susan Scott and Prof. Marjan Zadnik, along with others, Einstein-First has already trained 150 teachers across 55 schools, impacting over 10,000 students, including 3,000 First Nations students in Queensland. The train-the-trainer model has been particularly effective, empowering teachers to bring Einstein’s science into classrooms across the country.

OzGrav has been a proud supporter and collaborator of Einstein-First. This partnership is a testament to our shared commitment to advancing public understanding of modern physics and inspiring the next generation of scientists.

We congratulate the entire Einstein-First team for their outstanding achievement and well-deserved recognition and look forward to continuing our collaboration to further science education and engagement across Australia.

About the Western Australia Premier’s Science Awards

Now in its 23rd year, the Western Australia Premier’s Science Awards celebrate the outstanding scientific research and engagement efforts in the region. The Science Engagement Initiative of the Year category specifically recognises initiatives that have made a significant contribution to raising community awareness, interest, and participation in science.

Check out the announcement here!

Neutron stars are extremely dense objects, second only to black holes. A teaspoon of neutron star matter weighs as much as Mt. Everest. Under such high densities, neutron stars possess exotic physics that cannot be reproduced on Earth.

We have been studying a subgroup of neutron stars, namely pulsars, that release their energies mainly through electromagnetic radiation. But these stars are only a fraction of the total neutron star population in the Milky Way Galaxy. We are missing out on other types of neutron stars that may not produce much electromagnetic radiation.

As a neutron star rotates, any mountains on its surface – even if they are just a few millimetres tall – will create ripples in the four-dimensional fabric of space- time. Such ripples are known as continuous gravitational waves, or continuous waves for short. Compared to the gravitational waves that have been detected, continuous waves are fainter but constant – similar to the humming of a fridge, as opposed to a loud bang.

Observing neutron stars through continuous waves provides us with information that is complementary to what can be learnt from pulsars, so that we can paint a more complete picture of the unknown physics that lies within. However, continuous waves from neutron stars are still undetected. To know whether they are detectable, and what we can learn from them, we need to perform simulations to see if our current and future gravitational wave detectors can detect continuous waves.

In this study, we looked at the capabilities of two detectors: LIGO, the first to detect gravitational waves in 2015; and the Einstein Telescope, a next- generation detector that is expected to be constructed in the 2030s. The first step to detecting continuous waves is to make sure that we are looking at the right place. The current catalogue of neutron stars contains only pulsars that may not emit any continuous waves. To get a full picture of the neutron star population in the Galaxy, we also need neutron stars that emit continuous waves. We simulated the entire neutron star population in the Galaxy, which includes continuous wave-emitting neutron stars. These stars have different energies and release different amounts of electromagnetic and continuous waves.

From this population of neutron stars, we then estimated the continuous waves produced by these stars, and how the two detectors respond to them. Using a technique called Bayesian inference, we performed searches on the faint “hums” amidst all the additional noise from the detectors. Being a next- generation detector, the Einstein Telescope is larger and more sensitive than LIGO, so the weak continuous wave signals can be more easily identified – just like how you can hear fainter sounds when you are in a quieter room.

The factor that determines the amount of continuous waves generated, known as the ellipticity, could be measured by the Einstein Telescope with an error of between 5 and 50% with 5 years of observation. This property of the neutron star cannot be determined by other methods. The limiting factor, we found, is the preciseness of our measurement of a quantity called the braking index. This number determines the fraction of a neutron star’s energy that is released as continuous waves. The ability to measure this number directly affects our measurement of ellipticity.

Our study demonstrated that future detectors, such as the Einstein Telescope, can detect continuous waves. Neutron star properties such as ellipticity, which previously could not be determined, can then be measured through the detected continuous waves. Our work provides a new way to probe the physics of neutron stars, and additional motivation to construct the next generation of gravitational wave detectors.

Reference: “Population Synthesis and Parameter Estimation of Neutron Stars with Continuous Gravitational Waves and Third-Generation Detectors”

Yuhan Hua, Karl Wette, Susan M. Scott, Matthew D. Pitkin.

Published on arXiv.

 

A neutron star close to Earth is spinning as fast as a blender. Known as a millisecond pulsar, it is rotating at 174 times per second but much of its characteristics have remained a mystery. Now, thanks to almost 30 years of observations from Murriyang, CSIRO’s Parkes radio telescope, we know its mass. And that’s the key to knowing so much more.  

In a series of three papers accepted for publication in Astrophysical Journal Letters, a global group of scientists describe how Murriyang together with NICER (Neutron Star Interior Composition ExploreR), NASA’s X-ray telescope on the International Space Station, have accurately measured the mass and radius of this nearby neutron star. 

According to the Australian lead researcher on the project Dr Daniel Reardon, from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) and Swinburne University of Technology, a neutron star is made of extreme matter on the brink of becoming a black hole.  

“Being able to measure its mass and radius tells us how squeezable neutron stars are and how matter behaves inside their dense core, which is denser than the nucleus of an atom,” he said.  

Particle accelerators, such as the Large Hadron Collider, are also used to study matter at its extremes, but these experiments fail to predict the behaviour of the unique matter in the cores of neutron stars. This means neutron stars are some of the best laboratories for physics. Measuring their masses and sizes is a way to get new insights into fundamental nuclear physics.  

NICER is on a mission to study neutron star interiors by detecting and mapping X-ray emission from million-degree hot spots on the surface of the star. Dr Reardon, the OzGrav team, and other researchers using radio data from Murriyang, owned and operated by CSIRO, Australia’s national science agency, provided the mass of the pulsar, a key part of the NICER mission to measure the radius. 

Dr Reardon has been observing this neutron star since he was a student ten years ago. 

“There were researchers studying the same pulsar with Murriyang for twenty years before me. It’s important that we have long-term data on the star to get accurate information,” he said.  

This is part of the Parkes Pulsar Timing Array (PPTA) collaboration to monitor a set of pulsars over long timescales. 

Dr Andrew Zic (CSIRO), Primary Investigator of the PPTA project, says the collaboration’s precise measurements of pulsars with Murriyang has produced highly valuable datasets for many projects. 

“This has been made possible by regular upgrades to Murriyang, which has meant that our PPTA data have consistently been of world-leading quality, as seen in this work,” Dr Zic said. 

By compiling and analysing this large data set, researchers are getting closer to detecting gravitational waves with pulsars. Dr Reardon and the team used this data to support the NICER mission in a novel way.  

“At CSIRO’s Parkes Observatory we have been tracking – for decades – tiny (microsecond) delays in the arrival times of pulses sent out the neutron star, caused by space compressing due to the mass of its white-dwarf companion star,” Dr Reardon said.  

Space is stretched and squashed by the mass of objects, which is described in Einstein’s theory of gravity. The microsecond delays are predicted by the theory and the detailed information collected over many years allowed the team to accurately calculate the mass of both the dwarf star and the pulsar.  

With the mass confirmed, the NICER team could then calculate the radius of the pulsar from their data. This helps build a picture of the matter making up a neutron star.  

Understanding the matter will allow scientists to better predict the gravitational wave signatures created when neutron stars collide and collapse into black holes. Neutron star collisions release a burst of gravitational waves in an enormous explosion called a kilonova, which can be seen by many telescopes, including Xray telescopes and radio ones.  

According to OzGrav’s Dr Anais Möller from Swinburne University of Technology, an expert in searching for these collisions, measuring the mass and radius of pulsars tells us how neutron stars might get ripped apart and what we can expect to see in the resulting kilonova. 

Dr Reardon says because this pulsar has a mass similar to a typical neutron star, measuring its mass and radius is crucial for understanding the behaviour of matter at extreme densities.  

“This research advances our fundamental understanding of how the Universe operates.” 

Australian scientists from the University of Sydney and Australia’s national science agency, CSIRO, have detected what is likely a neutron star spinning slower than any other ever measured.

No other radio-emitting neutron star, out of the more than 3000 discovered so far, has been discovered rotating so slowly. The results are published today in Nature Astronomy.

Lead author Dr Manisha Caleb from the University of Sydney Institute for Astronomy said: “It is highly unusual to discover a neutron star candidate emitting radio pulsations in this way. The fact that the signal is repeating at such a leisurely pace is extraordinary.”

This unusual neutron star is emitting radio light at a rate that is too slow to fit with current descriptions of radio neutron star behaviour. This provides new insights into the complex life cycles of stellar objects.

At the end of their life, large stars about 10 times the mass of the Sun use up all their fuel and explode in a spectacular blast we call a supernova. What remains is a stellar remnant so dense that 1.4 times the mass of our Sun is packed into a ball just 20 kilometres across.

Matter is so dense that negatively charged electrons are crushed into positively charged protons and what’s left is an object made up of trillions of neutrally charged particles. A neutron star is born.

Given the extreme physics with which these stars collapse, neutron stars typically rotate mind-bendingly fast, taking just seconds or even fractions of a second to fully spin on their axis.

Now, astronomers at the University of Sydney and CSIRO have discovered a compact object repeating its signal with a comparatively leisurely period just shy of one hour.

The discovery was made using CSIRO’s ASKAP radio telescope on Wajarri Yamaji Country in Western Australia.

The ASKAP radio telescope can see a large part of the sky at once, which means it can capture things researchers aren’t even looking for. CSIRO scientist Dr Emil Lenc, co-lead author on the paper, said they wouldn’t have found this strange object if it wasn’t for ASKAP’s unique design.

“We were simultaneously monitoring a source of gamma rays and seeking a fast radio burst when I spotted this object slowly flashing in the data. Three very different things in one field-of-view,” he said.

“ASKAP is one of the best telescopes in the world for this sort of research, as it is constantly scanning so much of the sky, allowing us to detect any anomalies.”

The origin of such a long period signal remains a profound mystery, although two types of stars are prime suspects – white dwarfs and neutron stars.

“What is intriguing is how this object displays three distinct emission states, each with properties entirely dissimilar from the others. The MeerKAT radio telescope in South Africa played a crucial role in distinguishing between these states. If the signals didn’t arise from the same point in the sky, we would not have believed it to be the same object producing these different signals,” Dr Caleb said.

While an isolated white dwarf with an extraordinarily strong magnetic field could produce the observed signal, it is surprising that nearby highly-magnetic isolated white dwarfs have never been discovered. Conversely, a neutron star with extreme magnetic fields can quite elegantly explain the observed emissions.

While a slow-spinning neutron star is the likely explanation, researchers said they cannot rule out that the object is part of a binary system with a neutron star or another white dwarf.

More research will be required to confirm whether the object is a neutron star or white dwarf. Either way, it will provide valuable insights into the physics of these extreme objects.

“It might even prompt us to reconsider our decades-old understanding of neutron stars or white dwarfs; how they emit radio waves and what their populations are like in our Milky Way galaxy,” Dr Caleb said.

Professor Tara Murphy, leading radio astronomer and head of the School of Physics at the University of Sydney, said: “Until the advent of our new telescopes, the dynamic radio sky has been relatively unexplored. Now we’re able to look deeply, and often, we are seeing all kinds of unusual phenomena. These events give us insights into how physics works in extreme environments.”

Advancing Equity Award
Winner: Sareh Rajabi
Sareh, who joined the ANU OzGrav node in 2017, has played a pivotal role in promoting equity, diversity, and inclusivity (EDI) at the ANU node. Through initiatives such as creating a quiet room, establishing a culture bookshelf, implementing an anonymous feedback system, and providing mental health and mentoring support, Sareh has significantly contributed to fostering a cohesive and inclusive workplace culture, transforming the ANU node’s environment over the years.

Cross-Nodal Collaboration Award
Winner: Bram Slagmolen
Bram is a unique contributor to OzGrav, having established collaborations with every node, engaging in diverse projects such as student exchanges, site selection studies, and commissioning efforts. His impactful leadership extends to mentoring personnel across nodes and Centres of Excellence, highlighting his broad influence within the gravitational wave research community.

Runners up: Bram Slagmolen, Ju Li, Zhang Ya, Aaron Jones, Sheon Chua, Carl Blair, Jennie Wright, Avanish Kulur Ramamohan
The weekly connections of the Low-Frequency group, a collaborative effort between ANU and UWA, showcase a vibrant and supportive environment where research is shared with enthusiasm. The successful collaboration led to the installation of a displacement sensor from ANU into UWA’s Gingin Laboratory, demonstrating the team’s commitment to collaborative research and achieving extraordinary results in improving the interferometer performance.
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Highly Commended: Ryan Shannon, Valentina di Marco, Andrew Zic
Valentina di Marco’s collaboration across Monash, Swinburne, and CSIRO involved co-supervisors Andrew Zic and Ryan Shannon to support her growth and experience in radio astronomy and pulsar timing research. This project uncovered issues in IPTA pulsar timing analyses and led to important improvements to the background estimation code, helping to ensure confidence in subsequent results from PPTA and MeerTime.

Mentor Award
Winner: Karl Wette
Since joining OzGrav in 2017, Karl has actively engaged in both formal and informal mentoring, formally supervising multiple PhD and Honours students with empathy and flexibility, particularly navigating challenges posed by COVID disruptions and mental health issues. In addition to serving as a LIGO Scientific Collaboration Continuous Wave working group co-chair, Karl provided substantial mentoring to students and postdocs globally, offering guidance on research aspects, standard software packages, and LVK policies.

Runner up: Dan Brown
The nomination for Dan describes how he consistently and proactively tries to improve the experience of students at the Adelaide node. He listens to concerns and suggestions and acts to make students’ lives better.  He willingly uses his connections to create opportunities, like reaching out to potential PhD supervisors or connecting people with LSC colleagues. Dan is regarded as a go-to person for advice, contributing significantly to creating a positive and enjoyable office environment.

Runner up: Andrew Melatos
Andrew is nominated for being a wonderful mentor for his postdocs and students. Apart from the vast and deep knowledge on all the projects, he is a good mentor on a personal level. He incentivises his group to have a good work-life balance and is always promoting good physical and mental health habits.
Andrew brings a wealth of knowledge and resourcefulness to discussions with his research group, contributing significantly to the progress of the mentee’s research. His empathetic and understanding nature, along with consistent support in both academic and mental aspects, makes him deserving of acknowledgment and commendation.

Highly Commended: Bram Slagmolen
The nomination for Bram highlights his contribution to creating a positive working culture aligned with the award’s spirit. Described as approachable, embodying scientific temperament, and maintaining a friendly nature, Bram is recognized for understanding individual student situations, providing tailored guidance, and consistently supporting the well-being of everyone in the centre. His creativity and innovativeness are also commended, contributing to a positive and enjoyable working environment.

Highly Commended: Magdelena Kersting
Magdalena was nominated for providing valuable guidance on career priorities, navigating challenging work situations, and research practices. Her support, relatable experiences, and introductions to colleagues have enhanced her mentee’s experience within OzGrav, offering insights into potential research paths and contributing to a positive mentoring relationship.

Research Translation Pioneer Award
Winner: Zac Holmes, Peter Veitch, and Sebastian Ng
Zac Holmes, Peter Veitch, and Sebastian Ng collaborated with the Australian Plant Phenomics Facility on a pioneering research translation project utilizing their expertise in 2um lasers for an industry application—weed control. The project showed success in preliminary tests, demonstrating the potential of OzGrav technology in providing an economic, organic, and herbicide-free solution for weed control in agriculture, marking a promising application beyond gravitational wave research with implications for the farming industry.

Rising Star Award – Postdoc
Winner: Johannes Eichholz
Johannes, joining OzGrav ANU in 2019, introduced a new research field by designing a stable 2-micron laser architecture that has been adopted internationally. Recognizing the potential of an acquired optical coater, he successfully re-established it in a new clean room, securing a contract to coat main beam splitters for the next LIGO upgrade, showcasing his diverse skill set and hands-on approach in experimental physics.

Runner up: Ryosuke Hirai
Ryo was nominated for being a remarkable young scientist, making significant contributions to understanding high-energy transients through his deep physical insights and innovative computational models. Recognized for his broad knowledge of astrophysics, keen intellect, dedication, and leadership in research, Ryo is anticipated to be a rising star and a leading figure in theoretical astrophysics for years to come.

Highly Commended: Zhang Ya
Zhang Ya was nominated for being a very creative and innovative researcher. She works effectively across multiple projects, and was recently awarded a fellowship for a new project. She never hesitates to share her ideas and support the rest of the team. She is curious, asks important questions and helps the team progress in the right direction.

Rising Star Award – Student
Winner: Isobel Romero Shaw
Isobel, nominated for the Rising Star award, authored eight first-author papers during her impactful PhD, focusing on binary black hole formation and developing methods to measure their eccentricity. Her leadership in Bilby’s development and contributions to high-impact LIGO–Virgo papers, along with being awarded the Robert Street Doctoral Prize, exemplify her exceptional promise, making her a strong candidate for the award.

Runner up: Natasha Van Bemmel
Natasha is nominated for her significant achievements during her PhD, including awards, international collaborations, invited presentations, and successful telescope proposals. Her leadership in restarting the Journal Club, active engagement in outreach events, and contributions to teaching demonstrate her dedication and growth as a researcher, making her a deserving candidate for the award.

Highly Commended: Pratyasha Gitika
Pratyasha is nominated for her exceptional promise and significant professional growth within OzGrav. Recognized for sharing knowledge, fostering collaboration, and actively seeking opportunities for learning and skill development, Pratyasha’s positive attitude and collaborative mindset position her as a potential influential leader in her chosen field.

Highly Commended: Julian Carlin
Julian, nominated for his outstanding contributions since joining OzGrav in 2019, has demonstrated considerable innovation in linking theory and data, publishing lead-author papers in the fields of pulsar glitches, continuous gravitational waves, and most recently solar flares. Julian is showcasing a novel approach to abstract complex microphysics and actively contributing to collaborative efforts within and beyond the UniMelb OzGrav node.

Scientific Achievement in the Astro Theme
Winner: Ryosuke Hirai
Ryo has published around 30 papers in less than 4 years at OzGrav and has addressed core challenges in theoretical astrophysics, including high-mass X-ray binaries, stripped envelope supernovae, and a novel framework for the common-envelope phase in massive binary evolution. Instrumental to the success of the Monash research group, he provides expert advice, invaluable guidance to junior researchers, and actively leads the OzGrav relativistic astrophysics program.

Scientific Achievement in the Data Theme
Winner: Colm Talbot
Colm is nominated for his outstanding contributions to our understanding of binary black hole populations in gravitational-wave astronomy. Colm developed frameworks for measuring the properties of black hole spins and masses, contributing significantly to gravitational-wave astrophysics and making a lasting impact on population studies of binary black holes.

Runner up: Dana Jones
Dana has significantly contributed to the development of a novel data analysis method for detecting gravitational-wave signals from vector boson clouds around black holes. Leading the publication of a high-quality method paper and assuming key roles in the LVK O4 boson search, Dana demonstrates creativity, initiative, and impactful leadership within OzGrav.

Scientific Achievement in the Instrumentation Theme
Winner: Sheon Chua, Nutsinee Kijbunchoo, David McClelland, Kirk McKenzie, Terry McRae, Bram Slagmolen, Andrew Wade
The OzGrav squeezing team, including Chua, Kijbunchoo, McClelland, McKenzie, McRae, Wade, and Slagmolen, is nominated for their groundbreaking contributions to implementing squeezing technology in LIGO. Their efforts, highlighted by the installation and commissioning of the Advanced LIGO squeezer, resulted in significant sensitivity enhancement, showcasing an exceptional achievement in the field of gravitational-wave detection.

Runner up: Thomas Roocke
Tom is nominated for his exceptional contributions to the development of a new wavefront sensor for LIGO, showcasing remarkable skills in electronics. Notably, he designed and built circuits for multiple photodetector units, played a key role in assembling TSAMs installed at LIGO, and developed a vacuum-compatible quad-quadrant photodetector, surpassing design specifications and demonstrating significant achievements in a short period.

Service Award
Winner: Ruby Chan
Ruby is lauded as the heart of the UWA OzGrav node, contributing to a positive community atmosphere through her enthusiasm, support, and efficient administrative work, including travel bookings and IT support. Ruby loves to hear about everybody’s research and endeavours to help the students connect with each other, creating a warm community.

Runner up: Yeshe Fenner
Yeshe is nominated for her indispensable role in coordinating and managing OzGrav’s operations, fostering inclusivity, and advocating for equity. Her commitment to creating a positive work environment and her behind-the-scenes efforts to ensure smooth collaboration make her an integral part of OzGrav’s success.

Superstars of Outreach Award
Winner: Kyla Adams
Kyla is a dedicated OzGrav member who has made substantial contributions to science outreach through diverse initiatives, including developing workshops, training students in outreach and science communication, and presenting at various events, such as Pint of Science and the International Astronomical Union’s ‘Communicating Astronomy with the public’ conference. Her multifaceted efforts, spanning public talks, parliamentary presentations, and involvement in international science communication competitions, showcase her commitment to fostering scientific interest and understanding across different audiences.

Runner up: Jennifer Wright
Jennifer has made significant contributions to outreach activities since joining our Centre in 2022, expanding initiatives at the ANU node and raising public awareness of gravitational astrophysics. Passionate about promoting STEM careers, especially for women, she actively engages in outreach events, including panel discussions, media promotions, and LIGO tours, using her expertise, communication skills, and cheerful personality to inspire and connect with students.

Highly Commended: Rowina Nathan
Rowina has made exceptional contributions to outreach efforts. Actively involved in OzGrav events, such as Astrofest Adelaide and video training, she goes above and beyond by independently visiting schools, participating in physics breakfasts, and contributing to the Monash Women and Non-Binary People in Astronomy committee. Rowina’s dedication extends to social media, news appearances, and podcasts, making significant efforts to communicate science and inspire others in astronomy, deserving recognition for her outstanding outreach contributions.

Highly Commended: Sara Webb
Sara has significantly contributed to outreach by writing 17 articles for The Conversation, amassing over 1 million reads, and engaging with students in the SHINE program to design experiments for the ISS. Recognized as a Superstar of STEM, her creative TikTok videos, with hundreds of thousands of views, have enhanced OzGrav’s visibility, providing a unique approach to science communication and inspiring future researchers.

Date: 19-21 July 2023

Location: University of Western Australia
The OzGrav Early Career Researcher (ECR) Winter School will be held on the 19-21 of July in Perth. The Winter School is open to OzGrav students and postdocs, and is an opportunity to learn about the instrumentation and astrophysics of gravitational wave science. You will also have the chance to network and get to know your fellow OzGrav students and postdocs!

TRAVEL SUPPORT: Accommodation, main meals, and a social activity will be organised and paid for by the Centre. The Centre will also contribute some funding towards travel, which should be booked by the attendee’s home institution and then invoiced to Swinburne.

REGISTRATION HAS CLOSED

CONTACTS: If you have any questions, please contact the organisers Damon Beveridge (damon.beveridge@research.uwa.edu.au) and Ruby Chan (ruby.chan@uwa.edu.au)

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ACCOMODATION
Accommodation has been booked for everyone that has requested at the Ibis Perth hotel (334 Murray St, Perth WA 6000). Accommodation details have been emailed to attendees individually. Please email Damon Beveridge (damon.beveridge@research.uwa.edu.au) or Ruby Chan (ruby.chan@uwa.edu.au) for any questions you have about the bookings.

TRAVEL
Public transport:
Public transport is the recommended method for travelling between the city and the airport. The Perth Airport train line runs directly from all terminals into the city. Upon the train arriving in the city, it is a short ~8 minute walk to the hotel.
If arriving/departing at Terminals 3 and 4, there is short TransPerth bus (bus 292) that you will need to take to get to the Redcliffe Train Station which services the airport train line.
If arriving/departing at Terminals 1 and 2, there is a dedicated “Airport Central” train station across the road from the exit of the terminal.
There are additional bus routes that service the Airport and travel to the city if you would like to do that instead. These include bus routes 39, 935 and 940.
All buses and trains run on the Perth public transport system (TransPerth). For buses, you can purchase a ticket onboard with cash but no change will be given. The train stations have dedicated ticket machines where you can purchase a ticket for your journey. For the 292 bus that takes you to Redcliffe Station, it is recommended that you buy a 2 zone ticket on the bus, which you can then use as your ticket for the train ride into the city as well. A 2 zone ticket is the maximum price for TransPerth, which is listed as $5.10.

Taxi or ride share: Outside arrivals for each terminal there are separate dedicated taxi and rideshare pickup areas. For information on rideshare pickup locations, please refer to the following information on the Perth Airport website.
https://www.perthairport.com.au/to-and-from-the-airport/transport-options/rideshare

MEALS
All main meals will be provided for the duration of the workshop (Wednesday to Friday). For interstate attendees, you have access to the buffet breakfast at the hotel (breakfast won’t be provided for local attendees). Lunches (except Wednesday) are organised with a voucher system, where you can take the vouchers to any UWA Guild Cafe, or the Tavern, to redeem them. There is also one voucher per person per day set aside for a coffee/drink/snack at one of the cafes during one of the day’s breaks. Dinners are also provided, and information about them can be found in the program below. No alcoholic drinks will be provided.

The lunch on the Wednesday will be at the UWA Tavern, and a menu can be found here. Please look at the menu and list your order on this spreadsheet by Monday the 17th so that there are no delays on the day.

PROGRAM
Location:
The Winter School is being hosted on campus at The University of Western Australia. The morning session on Wednesday will be hosted in the Physics Building in room 2.17, and we will have signs up and people available for directions on the day. From the afternoon session on Wednesday to the end of the workshop, it will be hosted in the EZONE North building in room 1.11 (except for Friday morning which will be one room over in EZONE North room 1.10). An interactive campus map can be found here.

To get to campus each day, we recommend catching the Purple CAT Bus from the city. The bus stop in the city is a 5-6 minute walk from the hotel, directions can be found here. We recommend getting off the bus on Stirling Hwy and walking to the Physics building or EZONE North, directions here and here respectively (for both of these journeys, there is a tunnel under Stirling Hwy to cut the walk shorter, just walk east from the bus stop instead of west and there is a path through some trees)

The Purple CAT Bus can also be caught from campus to the same area in the city.

Wednesday 19 July 2023

• 09:00 – 09:30 : Introduction, Welcomes from OzGrav Node Leader and Head of School (Physics)
• 09:30 – 10:00 : Icebreakers
• 10:00 – 10:30 : Morning Break
• 10:30 – 12:00 : Rotating Tours of Einstein First and Instrumentation Labs
• 12:00 – 13:00 : Lunch at UWA Tavern. Please fill in orders here by Monday the 17th.
• 13:00 – 15:00 : COMPAS & Population Synthesis Workshop (Yuzhe Song, Swinburne)
  • Workshop resources:
    https://docs.google.com/document/d/1pmeHj_gKBuJ2frpxUaB8eknf_gd6emqu0ijE8JQFSio/edit?usp=sharing
• 15:00 – 15:30 : Afternoon Break
• 15:30 – 16:00 : Talk #1 (Angira Mahida, UWA)
• 16:00 – 16:30 : Talk #2 (Liana Rauf, Queensland)
• 16:30 – 17:00 : Talk #3 (David Coward, UWA)
• 17:00 – 19:00 : Dinner at Varsity Nedlands
• 20:00 : Social Activity – Kings Park Lightscape

Thursday 20 July 2023

• 09:00 – 09:30 : Talk #4 (Alistair Mcleod, UWA)
• 09:30 – 10:00 : Talk #5 (Ori Henderson-Sapir, Adelaide)
• 10:00 – 10:30 : Talk #6 (Yuzhe Song, Swinburne)
• 10:30 – 11:00 : Morning Break
• 11:00 – 12:00 : Lecture on Compact Object Mergers in Dense Environments (Evgeni Grishin, Monash)
• 12:00 – 13:00 : Lunch
• 13:00 – 15:00 : Education and Public Outreach Workshop (Jackie Bondell)
• 15:00 – 15:30 : Afternoon Break
• 15:30 – 17:00 : GW Parameter Estimation with Machine Learning Workshop (Chayan Chatterjee, UWA)
• 17:30 : Dinner at Steve’s Bar & Cafe. We have booked the cellar dining venue, and the set menu allows for choices from the following on the night.
  • Entree
    • Heirloom tomato, Stracciatella, basil, garlic crumb, vincotto (vegetarian)
    • Premium seared scallops, lemon, butter, citrus salad (gluten free)
    • Crumbed chicken katsu, steamed rice, tonkatsu sauce, kewpie mayo
  • Main
    • Grilled cauliflower steak, yellow curry, spicy peanut & roast pumpkin salad (vegetarian, vegan, gluten free)
    • Roasted market fish, stone fruit, soft herbs, goat’s fetta (gluten free)
    • Slow-roasted WA lamb rack, cooked medium, herbed potato cake, broccolini, jus (gluten free)
  • Dessert
    • Textures of chocolate: flourless almond cake, creme, brownie, snow, soil, salted caramel macadamias (vegetarian)
    • Baked custard, palm sugar caramel, blood orange, toasted coconut, lemon balm (vegetarian, gluten free)

Friday 21 July 2023

• 09:00 – 12:00 : Python Best Practices Workshop (Nick Swainston & Joel Dunstan)
  https://adacs-australia.github.io/2023-07-21_OzGrav_Python_Training/
  https://uwa.zoom.us/j/81308859132?pwd=RDZSdlg2QUtQejdkSll6MFp3QUZmdz09
• 12:00 – 13:00 : Lunch
• 13:00 – 15:00 : Lecture and Workshop on GW Instrumentation (Carl Blair & Jian Liu, UWA)
• 15:00 – 15:30 : Afternoon Break
• 15:30 – 17:00 : Workshop on GW Instrumentation (continued)
• 17:00 : Wrap Up
• 17:15 : Pizza Dinner on the EZONE Sky Garden

TALKS

• Talk #1: Searching for Gravitational Waves with the Parkes Pulsar Timing Array (Angira Mahida, UWA)
  Abstract: Domain walls are cosmological defects that occur in the early universe. These defects leave behind traces of their decay in the form of standard model particles and dark radiation, which can be observed in the form of gravitational waves. Pulsar timing arrays provide a means to detect these gravitational waves. Our study aims to investigate the presence and characteristics of the stochastic gravitational wave background originating from different scenarios of domain walls decay using Parks pulsar timing data.
• Talk #2: Exploring BBH Mergers with Shark & COMPAS (Liana Rauf, Queensland)
  Abstract: With GW astronomy becoming a fast-growing field, we require tools/simulations to understand how they can help solve some of the biggest mysteries in the Universe. In this talk, I will discuss how I generate populations of stars using the population synthesis code COMPAS and evolve them in galaxies from a semi-analytic model called Shark, to determine the number of mergers occurring in each simulation time-step. This allows us to track the formation and evolution of these binary black holes, link their merger rates to host galaxy properties and forecast the number of GW events in future galaxy surveys. I will discuss the possible reasons for the discrepancies between our simulation and current observations, and solutions to resolve this. I will also discuss the merger rate completeness of SHARK as a function redshift, which is ideal for tracing host galaxies with high merger rates. The implications of this work can be utilised for constraining stellar evolution models and measuring cosmological parameters such as the Hubble constant.
• Talk #3: Zadko Updates (David Coward, UWA)
• Talk #4: Detecting Compact Binary Coalescence Gravitational Waves (Alistair Mcleod, UWA)
• Talk #5: Mid-IR Fibre Lasers for LIGO Thermal Compensation System (Ori Henderson-Sapir, Adelaide)
  Abstract: In this talk I will give a brief overview of LIGO’s thermal compensation system (TCS) including ring heaters and CO2 lasers to mitigate thermal lensing effects. I will also mention the prospective FROSTY system which offers promising enhancements. I will then move to talk about exploring the potential of using 3.5-µm fibre laser systems for dynamic thermal actuation. I will discuss the development and current state of these fibre lasers at the University of Adelaide and in general and how their advancement can potentially redefine the TCS in LIGO.
• Talk #6: Invisible Gamma-Ray Pulsars & Where to Find Them (Yuzhe Song, Swinburne)
  Abstract: The continuing survey of the gamma-ray sky with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope has discovered over 300 gamma-ray pulsars in the last 14 years. However, they only account for 10% of the known pulsars to date. The remaining 90% could simply be below the detection limit of Fermi-LAT. To verify this, I developed novel stacking techniques to analyse Fermi-LAT data beyond the limit of point source sensitivity. A significant detection of a stacked signal over the background was made, and a characterisation of a pulsar-like spectral index and a characteristic flux well below the Fermi-LAT point source sensitivity. A follow up analysis on these pulsar populations using COMPAS, a rapid binary population synthesis code, is being conducted. Combining existing models of pulsar gamma-ray emission mechanisms and current prescriptions of canonical and binary neutron star evolution in COMPAS, we will be able to provide a best fit model that can describe all the catalogued pulsars observed individually in radio and gamma-ray surveys, as well as the stacking analysis.

Astronomers using data collected by CSIRO’s Parkes radio telescope, Murriyang, have found their strongest evidence yet for low-frequency gravitational waves.

For nearly 20 years the Parkes Pulsar Timing Array collaboration has monitored a set of rapidly spinning stars that pulse like a lighthouse, called pulsars.

They are looking for nanosecond pulse delays caused by gravitational waves to provide further evidence for Einstein’s general theory of relativity and build on our understanding of the Universe.

By compiling and analysing this large data set, the team has taken another step towards detecting gravitational waves through the study of pulsars.

Their latest results have been published today in The Astrophysical Journal Letters and Publications of the Astronomical Society of Australia.

In 1916 Albert Einstein proposed space-time as a four-dimensional fabric, and that events such as exploding stars and merging black holes create ripples – or gravitational waves – in this fabric.
Almost a century later, in 2015, researchers from the LIGO and Virgo collaborations made the first direct observation of gravitational waves caused by the collision of two stellar-mass black holes.

In contrast to these gravitational waves, which oscillate multiple times per second, the Parkes Pulsar Timing Array collaboration is searching for gravitational waves emitted by binary supermassive black holes at the centres of galaxies. These gravitational waves oscillate over timescales of many years.

OzGrav and Swinburne University of Technology researcher Dr Daniel Reardon, who led the searches, said that as these gravitational waves pass through our galaxy and wash over the Earth, they will change the apparent rotation frequency of fast-spinning pulsars.

“We can detect gravitational waves by searching for pulses that arrive earlier or later than we expect. Previous studies have shown an intriguing signal in pulsar timing array observations, but its origin was unknown,” Dr Reardon said.

“Our latest research has found a similar signal among the set of pulsars we’ve been studying, and we now see a hint of the fingerprint that identifies this signal as gravitational waves.
“Unlike stellar-mass bursts of gravitational waves, supermassive black holes take years or decades to complete their orbits, and so their signature takes a decade or more to emerge,” he said.

Astronomers around the globe have been busy chasing this gravitational-wave signal by studying pulsars.

Other collaborations in China (CPTA), Europe (EPTA), India (InPTA) and North America (NANOGrav) see a similar signal in their data; their results are also published today in several journal papers.

CSIRO astronomer Dr Andrew Zic, who co-led the analysis, said that while it is exciting all the major collaborations are seeing hints of the waves the true test will come in the near future, when all of the data is combined into a global dataset..

“This signal could still be caused by things like variations in a pulsar’s rotation over a long period of time, or may simply be a statistical fluke,” Dr Zic said.
“Our Parkes radio telescope, Murriyang, has an advanced receiver and an excellent view of the best pulsars in the southern sky, which are essential for this work.

“The next step is to combine pulsar data sets collected by telescopes in both the northern and southern hemispheres to improve the sensitivity of our observations,” he said.

Through the International Pulsar Timing Array consortium, the individual groups around the globe – including the Parkes Pulsar Timing Array collaboration in Australia – are working together to combine their data to better characterise the signal and confirm its origin.

“The next stage of our research will combine the full power of the global array, and rule out any anomalies,” said Dr Zic.

Using pulsars to confirm the detection of low-frequency gravitational waves will expand this emerging area of science, to be explored further by new instruments including the SKA telescopes currently being built in Australia and South Africa.

The Parkes Pulsar Timing Array project is a combined effort from astronomers across several institutions in which pulsars are observed using CSIRO’s Parkes Radio Telescope, Murriyang.
CSIRO’s Parkes radio telescope, Murriyang, is part of the Australia Telescope National Facility, which is funded by the Australian Government for operation as a National Facility managed by CSIRO – Australia’s national science agency. We acknowledge the Wiradjuri People as the Traditional Owners of the Parkes Observatory site.
This research was undertaken with the support of the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav). Headquartered at Swinburne University of Technology, OzGrav is a collaboration between several Australian universities including the University of Queensland, The Australian National University, The University of Sydney, Monash University, The University of Adelaide, The University of Western Australia and The University of Melbourne, and CSIRO.
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Media contact
CSIRO: James Chesters, james.chesters @ csiro.au
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