We present a detailed characterisation of radio frequency interference (RFI) in the 2.4 GHz band around Murriyang, CSIRO’s Parkes radio telescope. The dominant sources of interference are Wi-Fi and Bluetooth transmissions. We quantify how the intensity and directionality of this RFI vary with time of day and document its evolution over several years. Although most observers currently discard data within this band, our analysis shows that the interference is confined in both time and frequency and can be effectively mitigated. Using 10 seconds of 16-bit voltage data recorded during observations of the Vela Pulsar (PSR J0835—4510), we demonstrate that the majority of the channelised data remain unaffected by RFI. We compare three RFI detection and mitigation algorithms and evaluate their relative performance. All methods perform effectively, and any could be implemented in real time to enable productive use of this observing band. A real time implementation would allow the scientific use of this 128MHz observing band to increase, from almost 70% of the band being completely unusable all of the time, to over 90% of becoming accessible for science. Given its simplicity and efficiency, a basic power-threshold approach offers a relatively straightforward solution.

As of mid-2026, 11 objects have been discovered prior to impacting the Earth, with warning times between 2 and 20 hours. Using real metre-sized Earth impactors from the last decade, we ask the question: ‘If the Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST) had been operating over the last decade, how many imminent impactors would it have observed and discovered pre-impact, and how early would these discoveries have been made?’ We use the LSST Solar System Survey Simulator Sorcha and a population of real fireballs observed by orbital sensors over the last decade to investigate which events would have been observed pre-impact. We find that the LSST would have observed 30 (13.9%) of the 216 simulated objects, with most objects receiving 2–4 observations. Using the default linking algorithm, only two (0.9%) of these objects would have been ‘discovered’ pre-impact. Using a modified linking algorithm better suited to fast moving objects, this increases to eight (3.7%). Based on this, we predict that the LSST will discover 8 $\pm$ 2 imminent impactors over its nominal 10-year survey, at the low end of previous estimations. However, we predict these objects to be discovered $\sim$4 days pre-impact, substantially earlier than the current average. This will bring significant opportunities for telescopic follow-up, targeted fireball observations, planetary defence planning, and public engagement. There is also significant potential for precovery for impactors observed by the LSST but discovered by other surveys, instantly lengthening observation arcs and thereby reducing the orbital and impact location uncertainties. In some cases, these observations may also enable the linkage of telescopic observations with observed fireballs post-impact, providing valuable pre-impact astrometric and photometric data. This has significant implications for both asteroid research and planetary defence.

Accurate spatially resolved dust corrections are critical for interpreting the structure and evolution of star-forming galaxies (SFGs). We present an empirical model for predicting spatially resolved dust attenuation ($A_V$) in SFGs using integral field spectroscopy from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. Using a sample of 5 155 galaxies over $7.20 \lt M_*\lt 11.14$ and $0.0002 \lt z \lt 0.1444$, we derive $A_V$ maps from the Balmer decrement across more than 1 898 954 star-forming spaxels. Using local star formation rate surface density ($\Sigma_{\text{SFR}}$) as a predictor, the model achieves $R^2 = 0.69$ and RMSE $=0.22$ mag, with residuals that are approximately Gaussian and centred near zero. It predicts $A_V$ within a factor of $\sim$1.3 on kpc scales. We also demonstrate that the relation can be applied iteratively to recover dust–corrected $\Sigma_{\mathrm{SFR}}$ from uncorrected values, converging by the fourth iteration with minimal residual bias ($-0.01$ mag) and low RMSE ($0.42$ mag). The model accurately reproduces $A_V$ maps across diverse morphologies and orientations, including edge-on systems. It also recovers the observed radial $A_V$ profiles, capturing their dependence on stellar mass and relative star formation activity, with more massive and more strongly star-forming galaxies showing steeper gradients.

We present the longest-term optical analysis of the AM CVn system KL Dra using $\sim$11 yr of monitoring from TESS and wide-field ground-based surveys. The continuous TESS coverage allows us to characterise its frequent outbursts with unprecedented detail, providing the first comprehensive study of an AM CVn during outbursts and enabling detailed modelling of these systems. The superoutbursts in KL Dra generally include a precursor and are followed by a series of rebrightenings after which a sequence of 3–4 large amplitude normal outbursts is observed. We fit parametric profiles to each superoutburst component (precursor, rise to plateau, plateau, and decay), to rebrightenings, and to normal outbursts, which let us quantify every high state feature and investigate correlations with the system’s long-term supercyle evolution. Our continuous coverage reveals an average value for the supercycles, superoutbursts, and normal outbursts of $60.4 \pm 0.1$ d, $5.67\pm0.03$ d and $1.17 \pm0.01$ d, respectively. The supercycle duration may be correlated with the rebrightenings duration and superoutburst amplitude, and anticorrelated with the plateau length. Within a supercycle, normal outbursts grow in amplitude and duration, and the first normal outburst is usually highly asymmetric, while subsequent normal outbursts are more symmetric. We detected superhumps in TESS superoutbursts but not in the rebrightenings or normal outbursts. We interpret the results within the disc instability model, considering additional effects, such as changes in the donor mass transfer rate.

It has been proposed that radio pulsars can be distinguished from other point-like radio sources in continuum images by their unique interstellar scintillation signatures. Using data from the Australian Square Kilometre Array Pathfinder Evolutionary Map of the Universe (EMU) survey, we conducted a pilot survey of radio pulsars at high Galactic latitude regions via the variance imaging method. Out of approximately 59,800 compact radio sources detected in a $\sim$480 square degree survey area, we identified 21 highly variable sources. Among them, 10 are known pulsars, 2 are known radio stars, 1 is a long period transient, 3 are radio star candidates, and the remaining 5 are pulsar candidates. Notably, we discovered two strongly scintillating pulsars: one with a period of 85.707 ms and a dispersion measure (DM) of 19.4 pc cm$^{-3}$, and another with a period of 5.492 ms and a DM of 29.5 pc cm$^{-3}$. In addition, a third pulsar was discovered in the variance images, with a period of 14.828 ms and a DM of 39.0 pc cm$^{-3}$. This source shows a steep radio spectrum and a high degree of circular polarisation. These results underscore the strong potential of variance imaging for pulsar detection in full EMU and future radio continuum surveys planned with Square Kilometre Array.

Identifying remnant radio-loud active galactic nuclei (AGNs) is challenging due to their diverse morphological and spectral characteristics. Using three-dimensional hydrodynamic simulations of 15 radio galaxies, we investigate how the spectral evolution of remnants depends on progenitor power, active lifetime, environment, and underlying dynamics. The simulations span low-density group and high-density cluster environments re-gridded from smooth-particle-hydrodynamic cosmological simulations. The resulting remnants exhibit a wide range of morphologies, from amorphous structures to double-lobed forms. We find that jet power correlates with the spectral slope. As the remnant lobes evolve, we find surface brightness depends strongly on environment: group remnants are systematically dimmer and more amorphous than cluster remnants, highlighting a potential observational bias against these low-surface-brightness sources. In our models, we estimate that the peak surface brightness of a low-redshift, 50 Myr-old remnant from a low-power progenitor in a 10$^{13}$ M$_{\odot}$ group environment should be routinely detectable at the 3$\sigma$ level with LOFAR, although 20–30% of the emission would remain undetectable within a reasonable integration time. We find young remnants exhibit low-frequency (150–$1\,400$ MHz) spectral indices that overlap with active sources and follow a consistent and established spectral-evolution sequence: significant curvature ($\alpha_{1\,400}^{6\,000} - \alpha_{150}^{1\,400} \gt 0.5$) develops before an ultra-steep low-frequency index ($\alpha_{150}^{1\,400} \gt 1.2$). The results presented in this work are intended as a reference point for current and upcoming low-frequency studies of radio remnants.

Although the spin parameter of dark matter halos is well known to follow a log-normal distribution at fixed epoch, its quantitative redshift evolution – encompassing both the mean and the dispersion – remains only partially explored. Prior studies either lack the mass resolution required to establish reliable evolutionary trends or do not provide analytical relations that enable forward modelling. Using a suite of $\Lambda$CDM N-body simulations with controlled resolution across the redshift range $0\leq z \leq 5$, we characterise the evolution of the mean and dispersion of the Peebles ($\lambda$) and Bullock ($\lambda^\prime$) definitions of spin. We find a mild but statistically robust linear evolution for $\ln\lambda$ and a non-monotonic trend with a turnover at $z\approx 1-2$ for $\ln\lambda^\prime$, which we verify are unaffected by mass resolution of choice of halo definition. We provide closed-form fitting functions for these trends that allow modellers to draw physically motivated spin values at any redshift within our range of validity. This is a practical, redshift-dependent alternative to the common assumption of a constant spin distribution and provides a useful input to semi-empirical and semi-analytic models of galaxy formation.

A subset of magnetic stars exhibits periodic radio pulses produced by the coherent electron cyclotron maser mechanism. These pulses are known to exhibit both temporal and spectral variations, which have been attributed to phenomena intrinsic to the stellar magnetosphere. However, in order to fully characterise the radio pulses and use them as magnetospheric probes (as suggested by past studies), it is also important to consider the effects of phenomena extrinsic to the magnetosphere. In this paper, we investigate whether interstellar scintillation could be a relevant mechanism for explaining spectral and temporal variations observed for coherent stellar radio emission. For that, we consider the case of the well-characterised magnetic hot star CU Vir. At 400 MHz, coherent radio emission from the star was reported to exhibit a peculiar spectral evolution that remains unexplained. We show that a plausible level of turbulence along the line of sight can produce the observed phenomenon of spectral features. Our analysis shows that diffractive interstellar scintillation can have a strong effect on the observed dynamic spectrum of radio emission from stars, for an assumed size of the emitting region of $0.01r_\odot$ and that caution should therefore be taken in separating intrinsic and extrinsic features, particularly at low frequencies. These results are preliminary and further work is required to fully model the scintillation of electron cyclotron maser emission from stars (in particular the change in source location with frequency) and to explore the full range of plausible scintillation parameters. We suggest how further observations may be used to test the interstellar scintillation hypothesis.