I'm a research fellow at Monash University in the OzGrav group led by Paul Lasky and Eric Thrane.
My scientific interests mainly focus on multi-messenger astrophysics of supermassive black hole binaries (especially their gravitational wave emission) and pulsars. I have observational experience with LOFAR and Parkes radio telescopes and work as a member of the Parkes Pulsar Timing Array (PPTA) and the MeerKAT Pulsar Timing Array (MPTA) collaborations. Probably, the biggest joy of my work is the opportunity to combine being an observer with pursuing theoretical studies.
In my free time, I enjoy playing violin in the orchestra and horseback riding.
Pulsars and pulsar timing
Click to read more →Supermassive black holes and galaxies
Click to read more →Pulsars and pulsar timing
Sixty years after their discovery, pulsars still puzzle us and yet they've become powerful physics probes. Their pulse profiles, polarimetry and timing encode information about neutron star interiors and emission mechanisms, but also about the interstellar medium and Galactic magnetic fields. Moreover, thanks to their extraordinary rotational stability, we can learn about gravitational waves from supermassive black holes residing in distant galaxy centres and possibly the early Universe. I observe pulsars with the Parkes Murriyang and MeerKAT radio telescopes, and develop wideband polarimetry and timing techniques to study them across frequency and time. As part of the PPTA and MPTA collaborations, I use these methods to search for gravitational waves. With this broad range of research topics, I am committed to building a bridge between pulsar timing arrays and galaxy studies.
Frequency- and phase-resolved polarimetry of millisecond pulsars and its application to timing
Pulsar timing is used for a variety of applications including tests of fundamental physics, probing the structure of neutron stars, and detecting nanohertz gravitational waves. Development of robust methods and generation of high-quality timing data is therefore of utmost importance. In this paper, we present a new technique for creating high-fidelity templates that can be used to measure the pulse times of arrival with significantly increased precision compared to existing methods. Our framework makes use of all available polarimetric information to generate frequency-dependent models of pulse-shape evolution of all four Stokes parameters. We apply this method to millisecond pulsars observed by the Parkes Pulsar Timing Array and show that it results in timing measurement uncertainties reduced up to ~20–30 per cent. We also present, for the first time, phase- and frequency-resolved polarimetric measurements of millisecond pulsars observed with the Parkes Murriyang ultra-wide-bandwidth low receiver. The data, plots, and codes underlying this analysis are made publicly available.
A comprehensive framework for phase-coherent mapping of the gravitational-wave sky with pulsar timing arrays
We present a practical implementation of a phase-coherent mapping technique for pulsar timing arrays that resolves the full complex polarisation state of the gravitational-wave sky as a function of direction and frequency. Unlike standard cross-correlation methods, this approach preserves the amplitude, phase, and polarisation of the signal in every sky pixel. The resulting maps constitute a compact, minimally processed summary of the data from which all subsequent analyses — characterisation of a stochastic background, searches for anisotropy, and identification of individual sources — can be derived within a single unified framework. Our implementation is fully compatible with established pulsar timing data analysis methods. We validate the framework through a series of realistic simulations with varying array configurations, noise properties, and signal types. We demonstrate robust recovery of source amplitudes and sky locations across different scenarios, and discuss the impact of polarisation leakage, noise, and direction-dependent array sensitivity on the recovery of astrophysical signals.
Wide-band Timing of the Parkes Pulsar Timing Array UWL Data
In 2018 an ultra-wide-bandwidth low-frequency (UWL) receiver was installed on the 64 m Parkes Radio Telescope, enabling observations with an instantaneous frequency coverage from 704 to 4032 MHz. Here we present the analysis of a 3 yr data set of 35 ms pulsars observed with the UWL by the Parkes Pulsar Timing Array, using wide-band timing methods. The two key differences compared to typical narrowband methods are (1) generation of two-dimensional templates accounting for pulse shape evolution with frequency and (2) simultaneous measurements of the pulse time of arrival (TOA) and dispersion measure (DM). This is the first time that wide-band timing has been applied to a uniform data set collected with a single large fractional bandwidth receiver, for which such techniques were originally developed. As a result of our study, we present a set of profile evolution models and new timing solutions, including initial noise analysis. Precision of our TOA and DM measurements is in the range of 0.005–2.08 μs and (0.043–14.24) × 10−4 cm−3 pc, respectively, with 94% of the pulsars achieving a median TOA uncertainty of less than 1 μs.
Supermassive black holes and galaxies
Supermassive black holes (SMBHs) sit at the centres of nearly every galaxy we look at, and we know they co-evolve with their hosts. However, the details of how this happens are still poorly understood. Tight binaries of SMBHs and their eventual mergers, together with the galaxy mergers that produce them, are fundamental building blocks in our picture of galaxy evolution, and yet we have never directly witnessed one. In my work I use large-scale cosmological simulations to study the connections between SMBH binaries and their host galaxies, and I link these predictions to observations — both gravitational waves detected by pulsar timing arrays and radio AGN in the electromagnetic band.
Massive black hole binaries as sources of low-frequency gravitational waves and X-shaped radio galaxies
We present the study of multimessenger signatures of massive black hole (MBH) binaries residing in the centres of galaxy merger remnants. In particular, we first focus on the gravitational wave background (GWB) produced by an ensemble of MBH binary inspirals in the frequency range probed by the Pulsar Timing Array (PTA) experiments. The improved estimates of the characteristic strain were obtained with the inclusion of environmental effects on the MBH binary orbital decay within the galaxy merger remnants, added in post-processing to the semi-analytical model of galaxy formation and evolution SHARK. Secondly, we explore two, intriguing in terms of the MBH binary evolution studies, hypotheses aiming to explain the origins of X-shaped radio galaxies – a peculiar type of objects with double lobe structures, constituting approximately 6–10 per cent of known radio loud galaxies. The two considered scenarios involve either an abrupt change in the jet direction after an MBH merger (a spin-flip) or an unresolved close binary, where each of the two components produces a jet. We find that the estimated GWB amplitude at the reference frequency f0 = 1 yr−1 is in the range of Ayr−1 = 1.20×10−15–1.46×10−15, which is 50 per cent lower than the strain of the signal detected by the PTA experiments. We also show that the spin-flip scenario considered in gas-poor mergers reproduces the observed properties of X-shaped radio galaxies well in terms of flip angle, redshift, and luminosity distributions.
Predictions for LISA and PTA based on SHARK galaxy simulations
We present our analysis of a set of populations of massive black hole (MBH) binaries generated in the recent semi-analytic model of galaxy evolution (SHARK). We focus on studying gravitational wave (GW) emission produced during MBH mergers in terms of their detectability with current and future detectors, namely, Pulsar Timing Arrays (PTAs) and Laser Interferometer Space Antenna (LISA). The key advantage of SHARK is that it provides a way to explore a number of distinct models of MBH and galaxy evolution processes within a consistent framework and it was also successfully tested against current constraints from electromagnetic observations. In our work, we studied 12 models that vary in terms of their MBH seed formation scenarios and we tested two different MBH growth and feedback models. Based on our estimates, we find that LISA will be able to detect several to several tens of merger events per year for the most and least massive seed scenarios, respectively. We also show that the strength of this relation depends on the MBH growth model, where in the most extreme case, we find twice as many detected events for the same initial seed masses. Finally, we estimated the amplitude of the GW background at nHz frequencies to be on the order of 1.4×10−16–1.1×10−15. This value depends solely on the time delay between the merger of galaxies and their MBHs.
Gosia (Małgorzata) Curyło
Research Interests
Pulsar timing, radio astronomy, gravitational waves, massive black holes, multi-messenger astrophysics.
Experience
Education
Grants and Awards
Student Supervision and Teaching
Leadership and Service
Publications
Significant contribution to 12 papers, of which 5 are first author (excluding large collaboration papers).
Selected Conferences
Total number of conference / seminar talks: 31.