Recent developments in widefield radio telescopes have enabled searches of a new region of parameter space in the time domain: timescales of seconds to minutes, that have been overlooked in traditional surveys. These searches have revealed a new population of sources: long period transients, which typically show periodic behaviour of minutes to hours. In addition they have detected phenomena ranging from extreme scintillation to stellar radio bursts. However, almost all searches to date have involved archival data that has been processed in offline, batch mode. In this context, we present VASTER, the first short-timescale imaging and transient detection pipeline running in real time on a widefield radio telescope. VASTER has been running on the Australian SKA Pathfinder (ASKAP) since July 2025, and images most of the ASKAP survey project data on timescales of 15 minutes. In this paper we describe the VASTER system, and present the results from the first two weeks of operation, including the discovery of two long period transients: ASKAP J165130.3–450520 with a period of 6.48 hours and ASKAP J170036.6–445758 with a period of 4.69 hours. The detection of these two sources adds to the small, but growing, population of long period transients, as well as demonstrating the potential of VASTER to explore this region of transient parameter space.

We describe the latest iteration of upgrades (designated Phase III) to the Murchison Widefield Array (MWA), in the fourth paper in a series that covers the evolution of the telescope from design concept to initial operational facility, and through two major upgrades. As part of the Phase III upgrade of the MWA, we report the completion of work to design, build, and deploy a new fleet of digital receivers that further optimise the MWA for Epoch of Reionisation observations. These receivers complement existing receivers, such that the MWA now supports the full correlation of all 256 antenna tiles currently in the array. This step releases the MWA from the prior constraint of having to correlate only 128 of the 256 tiles at any given time, which means that the maximum instantaneous sensitivity of the MWA is doubled and the maximum number of interferometric baselines is approximately quadrupled. The upgrade is fundamentally enabled by the new MWAX correlator and various other improvements to the MWA sub-systems. In this paper we describe the new digital receivers and the other improvements that result in the Phase III system. A range of operational benefits arise from the upgrade and scientific flexibility is increased. We also comment on the transition from the MWA to the SKA-Low facility near the end of the decade, including a description of some unique science opportunities utilising joint MWA/SKA-Low data during the Science Verification phase of the SKA-Low Array Assembly 2 (AA2) period.

Over the last decade, the Australian Dark Energy (OzDES) collaboration has used Reverberation Mapping to measure the masses of high redshift supermassive black holes. Here we present the final review and analysis of this OzDES reverberation mapping campaign. These observations use $6-7$ years of photometric and spectroscopic observations of 735 Active Galactic Nuclei (AGN) in the redshift range $z\in [0.13, 3.85]$ and bolometric luminosity range $\log_{10}(L_{\mathrm{bol}})\in [44.3, 47.5] \; \mathrm{erg/s}$. Both photometry and spectra are observed in visible wavelengths, allowing for the physical scale of the AGN broad line region to be estimated from reverberations of the H$\beta$, MgII and CIV emission lines. We successfully use reverberation mapping to constrain the masses of 62 super-massive black holes, and combine with existing data to fit a power law to the lag-luminosity relation for the H$\beta$ and MgII lines with a scatter of $\sim0.25$ dex, the tightest yet identified, fit specifically for consistency with high redshift AGN. We fit a similarly constrained relation for CIV, resolving a tension with the low luminosity literature AGN by accounting for selection effects arising from finite survey length. We also examine the impact of emission line width and luminosity (related to accretion rate) in reducing the scatter of these scaling relationships and find no significant improvement over the lag-only approach for any of the three lines. Using these relations, we further estimate the masses and accretion rates of 246 AGN with single epoch methods. We also use these relations to estimate the relative sizes of the H$\beta$, MgII and CIV emitting regions, and find evidence that the MgII emission may occur further out than H$\beta$. In short, we provide a comprehensive benchmark of high redshift AGN reverberation mapping at the close of this most recent generation of surveys, including light curves, time-delays, and a set of significantly improved radius-luminosity relations for use with high-redshift populations.

Techniques using multiple tracers of the large scale structure of the universe show great promise for examining the fundamentals of our Universe’s cosmology. Such techniques rely on the different relationship between the overdensity of tracers and the broader matter overdensity, enabling cosmic-variance-free tests of primordial non-Gaussianity in the initial curvature perturbations. There is a great opportunity for current and future all-sky extra-galactic radio surveys to make use of this technique to test for non-Gaussianity at a precision greater than existing all-sky constraints from the cosmic microwave background. To realise this goal, there is a need for accurate simulations. Previous radio galaxy simulations have either been realistic but covering only a small area (and so unhelpful for cosmological forecasts), or all-sky dark matter only cosmological simulations but having no connection to a real radio galaxy population. In this study, we use the FLAMINGO suite of cosmological surveys, as well as the matching of dark matter halos to radio galaxy population, to create an accurate sky simulation in order to examine the feasibility of multi-tracer techniques. We present an analysis of the clustering (with a bias model for the simulation), as well as redshift distributions, source counts and radio luminosity functions, and discuss future work on non-Gaussianity detection.

We report the discovery of a new long-period radio transient, ASKAP J142431.2–612611, with a 36 min period, identified in the Australian SKA Pathfinder Evolutionary Map of the Universe survey. We detected pulsed emission from ASKAP J142431.2–612611 over a period of eight days during follow-up observations with the Australia Telescope Compact Array, after which the source appears to have switched off. No optical or near-infrared counterpart is detected in archival surveys or in targeted Gemini South FLAMINGOS-2 observations. During its active state, the source exhibits a stable pulse profile with fractional polarisation consistent with 100%, evolving from elliptically to linearly polarised and tracing a well-defined great-circle trajectory on the Poincaré sphere. We show that this behaviour is consistent with fully linearly polarised intrinsic emission modified by propagation through a linearly polarised birefringent medium. This discovery expands the known population of long-period transients and highlights the intermittent nature of their activity. We discuss the implications for proposed models of long-period transients and outline future observations needed to constrain the origin of their intermittency and polarisation properties.

As a direct consequence of liquid kerosene injection, aeroengine combustors may be categorized as non-premixed combustion systems, characterized by a swirl-stabilized and highly complex flow field. In addition to the flow of air through the fuel injector, there are a large number of other features through which the oxidizer can enter the heat release region. These can have an impact on local fuel–air mixing, inducing strong spatial and temporal variations in stoichiometry, thereby affecting emissions and combustion system performance. This article discusses a novel statistical methodology, based on principal component analysis (PCA) and K-means clustering, that aims to improve the understanding of fuel–air mixing in realistic aeroengine combustors. The method is applied in a post-processing step to data sampled from a large-eddy simulation, where every chamber inflow has been tagged with a unique passive scalar, which allows it to be traced across space and time. PCA is used to construct a low-dimensional, visually interpretable representation of a spatially localized fuel–air mixing process, while K-means clustering is employed to produce an unsupervised discretization of the flow field into regions of similar fuel–air mixing characteristics. The proposed methodology is computationally inexpensive, and the easily interpretable outputs can help the combustion engineer make better-informed decisions about combustor design.

Whether in looking for resources or doing their work, voluntary and charitable organisations have always needed to publicise their existence. However, major changes in the role and funding of the sector in Britain have meant that the issue of publicity has gained particular salience. This article discusses these changes and provides preliminary findings from a large-scale investigation into media and public attitudes towards voluntary and charitable activity. It explores how voluntary activity is reported by mainstream news media, and how these presentations are framed by media professionals’ perceptions of, and value judgements about, different types of voluntary action.

We present the discovery of PSR J1728$-$4608, a new redback spider pulsar identified in images from the Australian SKA Pathfinder telescope. PSR J1728$-$4608 is a millisecond pulsar with a spin period of 2.86 ms, in a 5.05 h orbit with a companion star. The pulsar exhibits a radio spectrum of the form $S_{\nu} \propto \nu^\alpha$, with a measured spectral index of $\alpha = -1.8(3)$. It is eclipsed for 42% of its orbit at 888 MHz, and multi-frequency image–domain observations show that the egress duration scales with frequency as a power law with index $n = -1.74$, where longer duration eclipses are seen at lower frequencies. An optical counterpart is detected in archival Gaia data within $0.5''$ of the radio position. It has a mean G-band magnitude of 18.8 mag, and its light curve displays characteristics consistent with a combination of ellipsoidal modulation and irradiation effects. We also report the nearest Fermi $\gamma$-ray source, located 2′ away from our source, as a possible association. A radio timing study constrains the intrinsic and orbital properties of the system, revealing orbital period variations that we attribute to changes in the gravitational quadrupole moment of the companion star. At the eclipse boundary, we measure a maximum dispersion measure excess of $2.0 \pm 1.2 \ \mathrm{pc\ cm^{-3}}$, corresponding to an electron column density of $5.9 \pm 3.6 \times10^{18} \ \mathrm{cm^{-2}}$. Modelling of the eclipse mechanism suggests that synchrotron absorption is the dominant cause of the eclipses observed at radio wavelengths. The discovery and characterisation of systems like PSR J1728$-$4608 provide valuable insights into pulsar recycling, binary evolution, the nature of companion-driven eclipses, and the interplay between compact objects and their plasma environments.

This paper reports the discovery and follow-up of four candidate redback spider pulsars: GPM J1723$-33$, GPM J1734$-28$, GPM J1752$-30$, and GPM J1815$-14$, discovered with the Murchison Widefield Array (MWA) from an imaging survey of the Galactic Plane. These sources are considered to be redback candidates based on their eclipsing variability, steep negative spectral indices, and potential Fermi $\gamma$-ray associations, with GPM J1723$-33$ and GPM J1815$-14$ lying within a Fermi 95$\%$ error ellipse. Follow-up pulsation searches with MeerKAT confirmed pulsations from GPM J1723$-33$, while the non-detections of the other three are likely due to scattering by material ablated from their companion stars. We identify possible orbital periods by applying folding algorithms to the light curves and determine that all sources have short orbital periods ($\lt$24 h), consistent with redback spider systems. Following up on the sources at multiple radio frequencies revealed that the sources exhibit frequency-dependent eclipses, with longer eclipses observed at lower frequencies. We place broad constraints on the eclipse medium, ruling out induced Compton scattering and cyclotron absorption. Three sources are spatially consistent with optical sources in the Dark Energy Camera Plane Survey imaging, which may contain the optical counterparts. Each field is affected by strong dust extinction, and follow-up with large telescopes is needed to identify the true counterparts. Identifying potential radio counterparts to four previously unassociated Fermi sources brings us closer to understanding the origin of the unexplained $\gamma$-ray excess in the Galactic Centre.

The Autistic Spectrum, published almost 30 years ago, remains an important text for all those who work with autistic individuals. This brief article highlights the significant contribution of Lorna Wing to how we view autism, including the observation that many of the issues being highlighted today regarding the appropriate management of autistic individuals are not new and can be found in the thoughts of Dr Wing.

A paleotemperature reconstruction inferred from subfossil chironomid (non-biting midge) assemblages in a 13-meter, 14,500-yr lake sediment record from a montane forest in the Pacific Northwest is compared to existing quantitative temperature reconstructions from the Pacific Northwest. With updated temperatures, a regional training set was used to develop a midge-based mean July air temperature (MJAT) inference model (r2jack = 0.71, root mean square error of prediction = 1.09°C). The average inferred MJAT varied between 9.4°C and 13.2°C. During the late-glacial period, MJAT ranged between 9.4°C and 10.8°C, and the lowest MJAT (9.4°C) is inferred at ca. 12.7 ka during the Younger Dryas. The transition into the Early Holocene was marked by an increase from 11°C at 11 ka to 12°C at 9.2 ka. Following deposition of the Mazama tephra, chironomid concentration decreased rapidly, and MJAT rose to 12.3°C at ca. 7.6 ka. This change in chironomid assemblage may be due to the direct effects of the tephra on the surface energy balance. The reconstructed temperature did not track decreasing Holocene summer insolation but instead revealed Late Holocene warming, which is similar to a chironomid reconstruction in the eastern Sierra Nevada and a sea-surface temperature reconstruction from northern California.

Direct physical evidence for violent interpersonal conflict is seen only sporadically in the archaeological record for prehistoric Britain. Human remains from Charterhouse Warren, south-west England, therefore present a unique opportunity for the study of mass violence in the Early Bronze Age. At least 37 men, women and children were killed and butchered, their disarticulated remains thrown into a 15m-deep natural shaft in what is, most plausibly, interpreted as a single event. The authors examine the physical remains and debate the societal tensions that could motivate a level and scale of violence that is unprecedented in British prehistory.

The angular correlation is a method for measuring the distribution of structure in the Universe, through the statistical properties of the angular distribution of galaxies on the sky. We measure the angular correlation of galaxies from the second data release of the GaLactic and Extragalactic All-sky Murchison Widefield Array eXtended survey (GLEAM-X) survey, a low-frequency radio survey covering declinations below $+30^\circ$. We find an angular distribution consistent with the $\Lambda$CDM cosmological model assuming the best fitting cosmological parameters from Planck Collaboration et al. (2020, A&A, 641, A6). We fit a bias function to the discrete tracers of the underlying matter distribution, finding a bias that evolves with redshift in either a linear or exponential fashion to be a better fit to the data than a constant bias. We perform a covariance analysis to obtain an estimation of the properties of the errors, by analytic, jackknife, and sample variance means. Our results are consistent with previous studies on the topic, and also the predictions of the $\Lambda$CDM cosmological model.

We present the conclusions of the Focus Meeting 2, “Toward a Standard for Dark and Quiet Sky Protection”. The material is organised in two sections, corresponding to the days in which each subject was presented and discussed.