photo

I am an Australian Research Council 'DECRA' Fellow based at Swinburne Universities Centre for Astrophysics and Supercomputing. My work primarily involves developing and using Bayesian inference techniques to learn more about the properties of pulsars - rotating neutron stars that emit beams of electromagnetic radiation from their magnetic poles - and their links to links to the mysterious fast radio burst (FRB) phenomena. These FRBs are extremely bright, but vanishingly short-lived bursts of radio waves that come from distant galaxies. I am also the priniciple investigator of the Parkes `P574' young pulsar timing project, which uses the CSIRO 64-m Parkes radio telescope (AKA 'Murriyang') to monitor 270 energectic pulsars.

Other interests of mine include follow-up parameter estimation of gravitational-wave events seen by Advanced LIGO and Virgo, and searches for the stochastic gravitational-wave background with pulsar timing arrays.

News

  • Sep 5 2024: Triple trouble with PSR J1618-3921: Mass measurements and orbital dynamics of an eccentric millisecond pulsar accepted to A&A! Read the accepted pre-print here: arXiv:2409.03615.
  • Aug 25 2024: I have been awarded a AUD $471k Australian Research Council Discovery Early Career Research Award fellowship!!! This means I'll be returning to Swinburne to work on the links between pulasrs, magnetars and the FRB phenomenon from 2025. Huge thanks to everyone that made this possible!
  • Aug 5 2024: MeerKAT observations of pair-plasma induced birefringence in the double pulsar eclipses submitted to MNRAS.
  • Jul 30 2024: You can catch a recording of my talk at Monash University on pulsar spin down here on the School of Physics and Astronomy Youtube channel.
  • Jul 29 2024: I am in Melbourne this week to give two colloquiua, one at Monash University where I did my undergrad, and one at Swinburne University. I'll be talking about mysteries in the spin-down and polarisation properties of pulsars.
  • Jun 18 2024: A two-minute burst of highly polarised radio emission originating from low Galactic latitude submitted to MNRAS
  • Jun 24 2024: This week I am in stunning Sexten, Italy for the 2024 IPTA Science week! I am presenting a poster on the `Parkes Young Pulsar Array'.
  • Jun 9 2024: I am again in Oxford for two weeks to work with the pulsar group on variable profile/spin-down bevaiours and wideband polarisation.
  • Jun 6 2024: VLBA Astrometry of the Fastest-spinning Magnetar Swift J1818.0−1607: A Large Trigonometric Distance and a Small Transverse Velocity accepted to ApJL! Read the pre-print here: arXiv:2406.04674
  • May 19 2024: Towards solving the origin of circular polarisation in FRB 20180301A submitted to MNRAS.
  • May 13 2024: A Fast Radio Burst monitor with a Compact All-Sky Phased Array (CASPA) submitted to PASA.
  • May 1 2024: A Millisecond Pulsar Binary Embedded in a Galactic Center Radio Filament accepted to ApJL! My collaborators and I have discovered the first millisecond pulsar located in the centre of our Galaxy!!!
  • Apr 27 2024: VLBA Astrometry of the Fastest-spinning Magnetar Swift J1818.0−1607: A Large Trigonometric Distance and a Small Transverse Velocity submitted to ApJL.
  • Apr 13 2024: The Snake's Beating Heart? A Millisecond Pulsar Binary in the Galactic Center Radio Filament G359.1−0.2 submitted to ApJL.
  • Apr 8 2024: Linear to circular conversion in the polarized radio emission of a magnetar has been published in Nature Astronomy!!! You can read the pre-print here: arXiv:2311.04195. Or catch my article in The Conversation on the results.
  • Apr 2 2024: The Thousand-Pulsar-Array programme on MeerKAT – XIII. Timing, flux density, rotation measure, and dispersion measure time series of 597 pulsars accepted to MNRAS! Read the pre-print here: arXiv:2404.02051
  • Mar 5 2024: Visitng the University of Manchester for a couple days to catch up with MeerKAT Thousand Pulsar Array and double pulsar collaborators!
  • Feb 25 2024: I am in Oxford for the next few weeks, where I am visiting the pulsar research group.
  • Feb 20 2024: This week I am in South Africa for the MeerKAT@5 conference! I'll be giving an overview of my work on characterising the double pulsar eclipses.
  • Feb 5 2024: Detection and confirmation of FRB 20240114A hyper-activity with Parkes/Murriyang. This repeating FRB discovered by CHIME has gone into a period of hyperactivity. We have begun a follow-up campaign with Murriyang..
  • Feb 1 2024: An emission-state-switching radio transient with a 54-minute period submitted to Nature Astronomy.
  • Nov 16 2023: The Thousand-Pulsar-Array programme on MeerKAT – XIII. Timing, flux density, rotation measure, and dispersion measure time series of 597 pulsars submitted to MNRAS.
  • Nov 10 2023: A MeerKAT view of the double pulsar eclipses Geodetic precession of pulsar B and system geometry has been accepted to A&A! Read the pre-print here: arXiv:2311.06445.
  • Oct 23 2023: I am in Perth for the next few days for a meeting of the Australia Telescope Users Committee, where we will discuss the views of the users community and make reccommendations to the ATNF.
  • Oct 18 2023: This week I am in hobart for the ATNF Science Retreat.
  • Oct 11 2023: Today we say farewell to the Molonglo Observatory Synthesis Telescope. After nearly 60 years of operation the telescope has been decomissioned. I was honored to give a talk on the science results that came out of the UTMOST East-West pulsar timing programme at the Molonglo Symposium, celebrating the history of this magnificent instrument.
  • Sep 10 2023: I am in Parkes the next few days visiting the Murriyang radio telescope with Lucy Oswald.
  • Sep 1 2023: A MeerKAT view of the double pulsar eclipses: Geodetic precession of pulsar B and system geometry submitted to A&A.
  • Aug 28 2023: The ASKAP Variables and Slow Transients collaboration is having a busy week here at CSIRO Marsfield.
  • Aug 14 2023: Propagation of a fast radio burst through a birefringent relativistic plasma has been accepted to PRD! Read the pre-print here: arXiv:2204.10816.
  • Jul 22 2023: Rotational and radio emission properties of PSR J0738-4042 over half a century has been accepted to MNRAS! You can catch the pre-print version on arXiv here.
  • Jul 3 2023: This week I am at Macquarie University in Sydney for this years' Astronomical Society of Australia annual meeting. I'll be presenting my work on asteroids around PSR J0738-4042.
  • Jun 29 2023: Big news! Today the international pulsar timing community announced tentative evidence for a stochastic gravitational-wave background in data collected by five major experiments. Results from the Parkes Pulsar Timing Array search can be found here. And here's a great summary of the results by study leads Daniel Reardon and Andrew Zic.
  • Jun 22 2023: Today I am visiting the Jodrell Bank Centre for Astrophysics at the University of Manchester. I'll be giving a seminar on our recent work to understand the peculiar polarisation properties of a radio-loud magnetar.
  • Jun 20 2023: Dr Lucy Oswald and I have won a Royal Society International Exhange Grant to work together on understanding the polarisation properties of radio pulsars!
  • Jun 18 2023: Off to visit collaborators at the University of Oxford for two weeks!
  • Jun 12 2023: Next stop Greece! This week I'm attending the 'Timing and Imaging of compact sources with SKA pathfinders' conference in the ancient village of Kerastari. I will be giving an invited presentation on how young pulsars spin-down over time.
  • May 28 2023: Starting my month of European travel with a two-week visit to the Max Planck Institute for Radioastronomie!
  • May 9 2023: Rotational and radio emission properties of PSR J0738-4042 over half a century has been submitted to MNRAS.
  • Mar 17 2023: The 2022 high-energy outburst and radio disappearing act of the magnetar 1E 1547.0-5408 has now been officially been published. Read the open access article here.
  • Mar 16 2023: George Younes, Zaven Arzoumanian and I wrote a short 'NICER/ISS Science Nugget' outlining our recent paper on 1E 1547.0-5408.
  • Feb 14 2023: The 2022 high-energy outburst and radio disappearing act of the magnetar 1E 1547.0-5408 has been accepted to ApJ! Read the pre-print here: arXiv:2302.07397.
  • Dec 21 2022: The 2022 high-energy outburst and radio disappearing act of the magnetar 1E 1547.0-5408 submitted to ApJ.
  • Dec 16 2022: I have officially graduated from my PhD at Swinburne University of Technology!
  • Dec 2 2022: Today I am giving the MQAAAstro colloquium at Macquarie University where I am talking about The Parkes magnetar monitoring programme.
  • Dec 1 2022: FRB20221128A found by UTMOST-NS! The first detection of a fast radio burst using the newly upgraded North-South arm of the Molonglo telescope. Huge congratualtions to the UTMOST team on this terrific miletone!!
  • Nov 11 2022: A birefringent pair plasma within the near-field environment of a radio-loud magnetar submitted to Nature Astronomy.
  • Oct 31 2022: This week I'm at the Parkes Obervatory for the 2022 Australiasian (AKA: Orange) Pulsar and FRB workshop. I will be talking about the magnetar monitoring programme on Parkes.
  • Sep 28 2022: Pulsar polarization: A broad-band population view with the Parkes Ultra-Wideband receiver submitted to MNRAS.
  • Aug 1 2022: I am in Busan, South Korea for the next two weeks for the 2022 IAU General Assembly! Along with attending various talks across a wide range of astronomy, I'll be giving a talk on Radio-loud magnetars as Galactic fast radio burst analogues at the IAU Symposium 369.
  • Jul 18 2022: This week I am attending the 2022 ATNF Science Retreat, being held in the Barossa Valley!
  • 27 July 2022: This week I am in Hobart, Tasmania for the 2022 ASA Meeting. I'll be giving a talk on Untangling the twisted polarised emission of a radio-loud magnetar.
  • Apr 22 2022: Propagation of a fast radio burst through a birefringent relativistic plasma submitted to PRD. Read the preprint here - arXiv:2204.10816.
  • Mar 8 2022: Circularly polarized radio emission from the repeating fast radio burst source FRB 20201124A accepted to MNRAS! Read the updated preprint here - arXiv:2109.11535.
  • Jan 21 2022: We performed follow-up observations of the FRB-emitting magnetar SGR 1935+2154 with Parkes/Murriyang after two recent outbursts. Read about our non-detections here - ATel #15172.
  • Jan 9 2022: I have moved to sunny Sydney to start my CSIRO postdoc in-person!
  • Nov 19 2021: I gave a talk on my recent paper on glitchy pulsars to the Monash gravitaional-wave research group. I was formerly a member of this group during my undergrad and honours years at Monash!
  • Nov 16 2021: This evening I presented my work on the apparent braking of glitchy pulsars to the Oxford Pulsar group!
  • Nov 8 2021: A warm welcome to the CSIRO Space and Astronomy community via the ATNF Daily Astronomy Picture!
  • Oct 18 2021: I have started my new postdoctoral research position at CSIRO Astronomy and Space Science! For the next 3 years I'll be working on studying young pulsars and magnetars observed primarily with the Parkes radio telescope.
  • Oct 4 2021: After 3-and-a-bit years, 4 published papers and two-(ish) still in prep., I have submitted my PhD thesis! This couldn't have been done without the support of my PhD advisors, nor my dozens of friend and colleagues at Swinburne, CSIRO and MeerTime collaborators.
  • Sep 23 2021: Circularly polarized radio emission from the repeating fast radio burst source FRB 20201124A submitted to MNRAS. Read the pre-print here - arXiv:2109.11535.
  • Sep 15 2021: The fourth and final publication of my PhD, The impact of glitches on young pulsar rotational evolution was accepted to MNRAS! Read the accepted manuscript here - arXiv:2109.07612.
  • Aug 21 2021: Technical document posted to arXiv on A phenomenological model for measuring generalised Faraday rotation. Check it out here!
  • Aug 5 2021: A short paper by Johston and Lower, A supernova remnant association for the fast-moving pulsar PSR J0908-4913 was published in MNRAS Letters! Read the accepted manuscript here - arXiv:2108.09827.
  • Jul 28 2021: This week I am attending the FRB 2021 conference.
  • Jul 25 2021: The Parkes Pulsar Timing Array weighs in on the common signal detected among millisecond pulsars! A fantastic paper, On the Evidence for a Common-spectrum Process in the Search for the Nanohertz Gravitational-wave Background with the Parkes Pulsar Timing Array, led by Boris Goncharov was accepted to ApJ Letters. Read the accepted manuscript here - arXiv:2107.12112.
  • Jul 24 2021: A new glitch in the Vela pulsar was detected by Liam Dunn with the Molonglo North-South system! Read about it here - ATel #14807.
  • Jul 19 2021: This week I am attending the 14th Edoardo Amaldi Conference on Gravitational Waves, where I am again talking about the Double Pulsar eclipses..
  • Jul 16 2021: My poster at the 2021 ASA meeting (How do young pulsars spin down?) won 3rd place in the student poster prize!
  • Jul 12 2021: This week I am attending the 2021 annual general meeting of the Astronomical Society of Australia.
  • Jun 21 2021: This week I am attending the 2021 IPTA Science Week, where I giving a talk about observations of the Double Pulsar eclipses with MeerKAT.
  • Apr 26 2021: I'm up in Sydney this week as the active Duty Astronomer for the Australia Telescope Compact Array.
  • Apr 14 2021: Effects of periodicity in observation scheduling on parameter estimation of pulsar glitches by Dunn, Lower and Melatos accepted to MNRAS. Read the accepted manuscript here - arXiv:2104.07363.
  • Mar 30 2021: FRB 20210630A found by UTMOST! Read about it here - ATel #14745.
  • Mar 6 2021: Multi-frequency observations of SGR J1935+2154 accepted to MNRAS.
  • Mar 3 2021: FRB 20210303A found by UTMOST, Molonglo's 1st FRB of 2021! Read about it here - ATel #14434.
  • Feb 9 2021: The Relativistic Binary Programme on MeerKAT: Science objectives and first results accepted to MNRAS. Read the accepted manuscript here - arXiv:2102.05160.
  • Feb 2 2021: My recent work on the dynamic magnetopshere of Swift J1818.0−1607 was featured in The Age, Unlocking the secrets of one of the universe’s strongest magnets.
  • Jan 26 2021: Non-detection of radio pulses from GRB 210119A/Swift J1851.2-6148 with Parkes, ATel #14347.
  • Dec 4 2020: My 3rd PhD paper, The dynamic magnetosphere of Swift J1818.0−1607, has been accepted to MNRAS. You can read the accepted manuscript here: arXiv:2011.12463.
  • Oct 30 2020: The dynamic magnetosphere of Swift J1818.0−1607 submitted to MNRAS.
  • Sep 21 2020: Bayesian inference for compact binary coalescences with Bilby: Validation and application to the first LIGO–Virgo gravitational-wave transient catalogue accepted to MNRAS. Read the accepted manuscript here - arXiv:2006.00714.
  • Sep 16 2020: A great press release covering the first magnetar parallax measurement made with the Very Long Baseline Array was posted on the NRAO website: "VLBA Makes First Direct Distance Measurement to Magnetar".
  • Sep 11 2020: ATel #14005 - We detected the new magnetar Swift J1818.0−1607 with the VLBA!
  • Aug 28 2020: The paper I co-authored with fellow Swinburne student Hao Ding on the parallax of XTE J1810-197 was featured on Space Australia: "Ancient Distance Measuring Technique Applied to Magnetar".
  • Aug 14 2020: A magnetar parallax accepted for publication in MNRAS. Read the accepted manuscript here - arXiv:2008.06438.
  • Jul 7 2020: Both the 2020 Fast Radio Burst and Astronomical Society of Australia annual meetings are being held virtually this week. I'm giving a presentation on the wideband properties of the magnetar XTE J1810-197.
  • Jun 30 3030: ATel #13840 - The magnetar XTE J1810-197 has undergone a resurgence in its radio brightness.
  • Jun 1 2020: Spectropolarimetric properties of Swift J1818.0−1607: a 1.4 s radio magnetar accepted for publication in ApJ Letters. Read the accepted manuscript here - arXiv:2004.11522.
  • May 29 2020: The MeerKAT Telescope as a Pulsar Facility: System verification and early science results from MeerTime accepted to PASA. Read the manuscript here - arXiv:2005.14366.
  • May 15 2020: ATel #13737 - We didn't see any radio emission during a chance observation of the X-ray pulsar binary IGR J18179-1621.
  • May 8 2020: ATel #13715, FRB 200508 detected by UTMOST - the first FRB seen by UTMOST in the new decade!
  • May 1 2020: Nice article by Michelle Starr from Science Alert dissecting some of my work on the new magnetar Swift J1818.0−1607: "Strangely Flaring Dead Star Could Be The 'Missing Link' Between Magnetars And Pulsars".
  • Apr 23 2020: Spectropolarimetric properties of Swift J1818.0−1607: a 1.4 s radio magnetar submitted to ApJ Letters. Read the pre-print here - arXiv:2004.11522.
  • Mar 25 2020: Multi-band follow up observations of the new magnetar with Parkes - ATel #13587.
  • Mar 22 2020: The Parkes Pulsar Timing Array Project: Second data release accepted to PASA. Read the accepted manuscript here - arXiv:2003.09780.
  • Mar 17 2020: The new magentar emits radio pulses! We followed up this latest discovery by observing it with the MeerKAT telesope - ATel #13562.
  • Mar 13 2020: A new magnetar called Swift J1818.0−1607 has been found by the Swift satellite (GCN #27373) and confirmed by the NICER X-ray telesope - ATel #13551.
  • Feb 28 2020: The UTMOST pulsar timing programme II: Timing noise across the pulsar population accepted to MNRAS. You can read the accepted manuscript here - arXiv:2002.12481.
  • Feb 26 2020: Today I was invited to give the weekly ATNF colloquium, where I spoke about Massive scale pulsar timing with the Molonglo Observatory Synthesis Telescope.
  • Feb 16 2020: I'm up in Sydney to visit the Australia Telescope National Facility in Marsfield for three weeks.
  • Jan 15 2020: The UTMOST Survey for Magnetars, Intermittent pulsars, RRATs and FRBs I: System description and overview accepted to MNRAS.
  • Dec 23 2019: ATel #13363 - A Christmas FRB found by UTMOST!
  • Dec 18 2019: I found a glitch in the pulsar PSR J0908−4913 using UTMOST! This is a pulsar that has been observed for over 20 years, and had never been seen to glitch. You can read the research note here, or the post on the UTMOST website.
  • Nov 18 2019: I am at the 3rd OzGrav annual retreat in Lorne, Australia this week.
  • Nov 7 2019: UTMOST found another fast radio burst: FRB191107 - ATel #13282.
  • Sep 19 2019: New paper submitted - Lower et al. The UTMOST pulsar timing programme II: Timing noise across the pulsar population. Submitted to MNRAS.
  • Aug 6 2019: Another FRB at UTMOST - ATel #12995.
  • Jun 27 2019: ASKAP has localised a lone FRB to its host galaxy! My supervisor Dr Ryan Shannon is one of the lead scientists of this project. You can read all about it in the ASKAP/CRAFT paper published in Science.
  • Jun 9 2019: I am in Pune, India for the next two weeks for the 2019 International Pulsar Timing Array meeting.
  • Apr 2 2019: "Wideband polarized radio emission from the newly revived radio magnetar XTE J1810−197" and "The 2018 X-ray and Radio Outburst of Magnetar XTE J1810−197" have both been accepted and published in ApJ Letters!
  • Mar 22 2018: FRB190322 - the 10th FRB seen to date by UTMOST.
  • Feb 22 2019: "The 2018 X-ray and Radio Outburst of Magnetar XTE J1810−197" submitted to ApJ (arXiv:1902.08358).
  • Feb 14 2019: "Wideband polarized radio emission from the newly revived radio magnetar XTE J1810−197" submitted to ApJ Letters (arxiv:1902.04689).
  • Dec 30 2018: FRB181228 - one for the holidays!
  • Dec 13 2018: radio emission from the magnetar XTE J1810-197 reactivated. You can read about our observations at Molonglo here and here.
  • Our paper describing the Bilby parameter estimation code has been submitted to ApJ Supplementary Series (arXiv:1811.02042).
  • 31 Oct 2018: my 1st ever paper has been finally published in PRD! You can read it on the Physical review website, or the pre-print on arXiv.
  • Oct 18 2018: in an amazing cosmic coincidence, we managed to see two FRBs at Molonglo in only two days (ATel #12124)! You can read more about them on the UTMOST website.
  • Aug 7 2018: we saw a glitch in the pulsar PSR J1709−4429. Read the research note on the RNAAS website.
  • Jul 31 2018: started PhD at Swinburne University of Technology. I'll be working on applying Bayesian inference to pulsar timing.
  • Jun 17 2018: 1st paper "Measuring eccentricity in binary black hole inspirals with gravitational waves" submitted to PRD (arXiv:1806.05350).
  • Mar 26 2018: started internship at Swinburne University of Technology
  • Dec 3 2017: finished my undergrad with 1st class honours!