Cluster environments influence galaxy evolution by curtailing star formation activity, notably through ram-pressure stripping (RPS). This process can leave observable signatures—such as gas tails and truncated gas disks—that are crucial for understanding how RPS affects galaxies. In this study, using spatially resolved spectroscopic data from the SAMI Galaxy Survey, we identify galaxies undergoing or recently affected by RPS in eight nearby clusters (0.029 < z < 0.058), through a visual classification scheme based on the ionised gas (Hα +[NII]λ6584) morphologies, split into “unperturbed”, “asymmetric”, and “truncated”. Alongside, we measure non-parametric structural parameters (concentration, asymmetry, and offset between gas and stars) to quantify the ionised gas morphologies. We find that combinations of parameters such as concentration, shape asymmetry, and stellar–ionised gas centre offsets are useful in categorising the degree of RPS in line with their ionised gas morphologies. The projected phase-space analysis shows that asymmetric galaxies are found in a narrow region in cluster-centric distance (0.1 < R/R200 < 0.6, where R200 is the characteristic cluster radius) and have a larger dispersion in line-of-sight velocity (, with σ200 being the cluster velocity dispersion within R200), compared to the truncated and unperturbed samples that are more broadly distributed and predominantly located at larger cluster-centric distances. This suggests that asymmetric galaxies are likely recent infallers—having crossed within 0.5 R200 in the past ∼1 Gyr. In terms of star formation activity, we find that the resolved star-forming main sequence (rSFMS; ΣSFR –Σ*) of unperturbed and RPS candidates (asymmetric and truncated) differ. RPS candidates yield a much steeper rSFMS relation compared to the unperturbed counterparts, primarily emerging from having lower ΣSFR values for the low mass density regime (i.e., log Σ* ≲ 8 M⊙ kpc–2), with the steepest gradient deriving from the truncated sample. Moreover, radial specific star formation rate profiles introduce different trends for unperturbed and RPS candidates. Star formation in RPS candidates is suppressed in the outskirts relative to unperturbed galaxies and is more prominent for the truncated sample compared to the asymmetric counterparts. In contrast, central (i.e., r/reff < 0.5) star formation activity in RPS candidates is comparable with that in their unperturbed and field counterparts, suggesting no elevated activity. Taken together, this suggests an evolutionary trend linked to the RPS stage, where unperturbed galaxies likely represent recently accreted systems (pre-RPS), while asymmetric and truncated galaxies may correspond to populations undergoing RPS and post-RPS phases, respectively, favouring outside-in quenching.

Double white dwarf (DWD) binaries are natural outcomes of binary stellar evolution and key sources for future space-based gravitational wave (GW) observatories such as Laser Interferometer Space Antenna (LISA). We investigate how different binary interaction channels shape the physical and orbital properties of DWD systems, focusing on component masses, orbital separations, core compositions, and mass transfer rates. Using the binary population synthesis code COMPAS, we evolve 107 binaries with physically motivated initial distributions of binary parameters. Our simulations reproduce the strong bimodality in the final orbital separations, including a pronounced deficit of systems around 100−500 R⊙, arising from distinct evolutionary pathways: wide DWDs predominantly originate from stable Roche lobe overflow (RLOF), while close DWDs form through unstable RLOF leading to at least one common envelope (CE) phase. Moreover, we show that the core compositions of WDs provide a powerful tracer of evolutionary history: He-core WDs are strongly concentrated in close systems, whereas CO-core WDs span the full separation range and exhibit a small mass gap in wide binaries. We further identify a correlation between the accreted mass and the final orbital separation, highlighting the impact of non-conservative mass transfer on the resulting orbital configuration of DWD systems. These results underscore the links among evolutionary channels, chemical composition, and mass transfer rates; thereby provide a unique framework for interpreting Gaia DWD samples and forecasting the joint electromagnetic and GW population accessible to LISA.

Understanding the connection between active galactic nuclei and star-formation (the AGN-SF connection) is one of the longest standing problems in modern astrophysics. In the age of large Integral Field Unit (IFU) surveys, studies of the AGN-SF connection greatly benefit from spatially resolving AGN and SF contributions to study the two processes independently. Using IFU data for 54 local active galaxies from the S7 sample, we present a new method to separate emission from AGN activity and SF using mixing sequences observed in the [Nii] λ6584Å/Hα vs. [Oiii]λ5007Å/Hβ Baldwin-Phillips-Terlevich (BPT) diagram. We use the new decomposition method to calculate the Hα star-formation rate and AGN [Oiii] luminosity for the galaxies. Our new method is robust to outliers in the line ratio distribution and can be applied to large galaxy samples with little manual intervention. We infer star-formation histories (SFHs) using pPXF, conducting detailed recovery tests to determine the quantities that can be considered robust. We test the correlation between the AGN Eddington ratio, using the proxy L[Oiii]/σ4∗, and star-formation properties. We find a moderately strong correlation between the Eddington ratio and the star-formation rate (SFR). We also observe marginally significant correlations between the AGN Eddington ratio and the light-weighted stellar age under 100 Myr. Our results point to higher AGN accretion being associated with young nuclear star-formation under 100 Myr, consistent with timelines presented in previous studies. The correlations found in this paper are relatively weak; extending our methods to larger samples, including radio-quiet galaxies, will help better constrain the physical mechanisms and timescales of the AGN–SF connection.

Fast radio bursts (FRBs) probe the electron column density along the line of sight and hence can be used to probe foreground structures. One such structure is the Galactic halo. In this work, we use a total of 98 high Galactic latitude (|b| > 20°) FRBs detected by ASKAP, Parkes, DSA and FAST with 32 associated redshifts to constrain the dispersion measure (DM) contribution from the Galactic halo. We simultaneously fit unknown FRB population parameters, which show correlations with the Galactic halo but are not completely degenerate. We primarily use an isotropic model for the halo, but find no evidence favouring a particular halo model. We find , which is in agreement with other results within the literature. Previous constraints on DMMW,halo with FRBs have used a few, low-DM FRBs. However, this is highly subject to fluctuations between different lines of sight, and hence using a larger number of sightlines as we do is more likely to be representative of the true average contribution. Nevertheless, we show that individual FRBs can still skew the data significantly and hence will be important in the future for more precise results.

Galaxies undergo perturbations, either gravitational or hydrodynamic in origin, which can generate extragalactic structures such as rings and tails, where in situ star formation may take place. We selected a sample consisting of JO201 and JW100, undergoing ram-pressure stripping, and NGC 5291 and NGC 7252, formed through gravitational interactions, to investigate how different perturbation mechanisms influence dust content and star formation in extragalactic features. In both cases, star formation can be observed outside the main disks of the galaxies. We present new results of dust attenuation for JO201 and JW100, while for NGC 5291 and NGC 7252 we use results from our previous study, based on high-resolution observations obtained with the Ultraviolet Imaging Telescope onboard AstroSat. Dust attenuation is determined from the ultraviolet continuum slope (β) calculated using the FUV–NUV colour, and the star formation rates of the star-forming knots are corrected accordingly. It is seen that dust attenuation and dust-corrected SFR densities of the knots in the ram-pressure stripped tails of JO201 and JW100 are comparable to those in the collisional ring of the NGC 5291 system and the tidal tails of the NGC 7252 system. We conclude that, though the formation scenarios of the tails of JO201 and JW100, the NGC 5291 ring, and the NGC 7252 tails are different, their dust content and star formation activity are notably similar.

Reverberation mapping is a technique in which the mass of a Seyfert I galaxy’s central supermassive black hole is estimated, along with the system’s physical scale, from the timescale at which variations in brightness propagate through the galactic nucleus. This mapping allows for a long baseline of time measurements to extract spatial information beyond the angular resolution of our telescopes, and is the main means of constraining supermassive black hole masses at high redshift. The most recent generation of multi-year reverberation mapping campaigns for large numbers of active galactic nuclei (AGN) (e.g. OzDES) have had to deal with persistent complications of identifying false positives, such as those arising from aliasing due to seasonal gaps in time-series data. We introduce LITMUS (Lag Inference Through the Mixed Use of Samplers), a modern lag recovery tool built on the “damped random walk” model of quasar variability, built in the automatic differentiation framework jax. LITMUS is purpose-built to handle the multimodal aliasing of seasonal observation windows and provides Bayesian evidence integrals for model comparison and null hypothesis testing, a more quantified alternative to existing post-fit selection methods. LITMUS also offers a flexible and modular framework for using more expressive high dimensional models for the AGN variability, and includes jax-enabled implementations of other popular lag recovery methods like nested sampling and the interpolated cross correlation function. We test LITMUS on a number of mock light curves modelled after the OzDES sample and find that it recovers their lags with high precision and successfully identifies spurious lag recoveries, reducing its false positive rate to drastically outperform the state of the art program JAVELIN. LITMUS’s high performance is accomplished by an algorithm for mapping the Bayesian posterior density which both constrains the lag and provides Bayesian evidences for model comparison and null hypothesis testing while outperforming nested sampling in computational cost by an order of magnitude.

Resonance lines encode rich information about astrophysical sources and their environments, yet fully analytic treatments of multi-line radiative transfer remain almost entirely unexplored. We present exact, closed-form solutions for steady-state resonant-line radiative transfer in “V-shaped” atomic networks, where a single ground state couples to multiple transitions. Starting from the full angle-dependent transfer equation, we generalise absorption and emission coefficients to an arbitrary number of lines, derive a modified Fokker–Planck expansion of the frequency-redistribution integral, and use a judicious change of variables to reduce the problem to a Helmholtz equation with pointlike sources in frequency space. This transformation admits analytic solutions for arbitrary sets of lines with fixed frequency offsets and strengths in both slab and spherical geometries. We implement V-shaped line networks in the colt Monte Carlo radiative transfer code and find excellent agreement with the analytic predictions across a wide range of line separations, optical depths, and damping parameters, establishing our solutions as stringent validation benchmarks. For concrete applications related to the Lyman-alpha (Lyα) transition of neutral hydrogen, we examine how fine-structure splitting and deuterium injection modify the emergent spectra, internal radiation field, and radiative force multiplier. We show that these effects leave previous conclusions about Lyα feedback in the early universe essentially unchanged. Even when direct observational diagnostics are subtle, our framework provides novel analytic and numerical insights into coupled resonance-line transport and facilitates progress in general modelling of multi-line radiative transfer in diverse astrophysical settings.

Accurate estimation of dark matter halo masses for galaxy groups is central to studies of galaxy evolution and for leveraging group catalogues as cosmological probes. In this work, we present a comprehensive evaluation and calibration of two complementary halo mass estimators: a dynamical estimator based on a modified virial theorem (MVT), and an empirical summed stellar mass to halo mass relation (sSHMR) which uses the summed mass of the three most massive group galaxies as a proxy for halo mass. Using a suite of state-of-the-art semi-analytic models (SAMs; Shark, SAGE, and GAEA) to produce observationally motivated mock light-cone catalogues, we rigorously quantify the accuracy, uncertainty, and model dependence of each method. The MVT halo mass estimator achieves negligible systematic bias (mean Δ = −0.01 dex) and low scatter (mean σ = 0.20 dex) as a function of the predicted halo mass, with no sensitivity to the SAM baryonic physics. The calibrated sSHMR yields the highest precision, with mean Δ = 0.02 dex and mean σ = 0.14 dex as a function of the predicted halo mass but exhibits greater model dependence due to its sensitivity to varying baryonic physics and physical prescriptions across the SAMs. We demonstrate the application of these estimators to observational group catalogues, including the construction of the empirical halo mass function and the mapping of quenched fractions in the stellar mass–halo mass plane. We provide clear guidance on the optimal application of each method: the MVT is recommended for GAMA-like surveys (i < 19.2) calibrated to z < 0.1 and should be used for studies that require minimal model dependence, while the sSHMR is optimal for high-precision halo mass estimation across diverse catalogues with magnitude limits of Z < 21.2 or brighter and to redshifts of z ≤ 0.3. These calibrated estimators will be of particular value for upcoming wide-area spectroscopic surveys, enabling robust and precise analyses between the galaxy–halo connection and the underlying dark matter distribution.

Star clusters are well known for their dynamical interactions, an outcome of their high stellar densities; in this paper we use multiwavelength observations to search for the unique outcomes of these interactions in three nearby Galactic open clusters: IC 2602 (30 Myr), NGC 2632 (750 Myr) and M67 (4 Gyr). We compared X-ray observations from all-sky surveys like eROSITA, plus archival observations from Chandra X-ray Observatory, survey radio observations from ASKAP’s Evolutionary Map of the Universe survey plus archival VLA observations, in conjunction with new cluster catalogs with Gaia. From X-ray, we found 77 X-ray sources likely associated with IC 2602, 31 X-ray sources in NGC 2632, and 31 near M67’s central regions. We were further able to classify these X-ray sources based on their optical variability and any radio emission. Three IC 2602 X-ray sources had radio counterparts, which are likely all chromospherically active binary stars. We also identified luminous radio and X-ray variability from a spectroscopic triple system in M67,WOCS 3012/S1077, which is either consistent with a quiescent black hole binary, or due to an active binary stellar system. A recent population study of optical variables by Anderson & Hunt 2025 shows that the population of optical variables in open clusters clearly changes over cluster age; this pilot study gives evidence that the X-ray population also changes with time, and demonstrates the need for a broader multiwavelength study of Galactic open clusters.

We present results from the first application of the Global Navigation Satellite System (GNSS; e.g., the Global Positioning System, GPS) for radio beam calibration using a commercial GNSS receiver with the Deep Dish Development Array (D3A) at the Dominion Radio Astrophysical Observatory (DRAO). Several GNSS satellites pass through the main and sidelobes of the beam each day, enabling efficient mapping of the 2D beam structure. Due to the high SNR and abundance of GNSS satellites, we find evidence that GNSS can probe several sidelobes of the beam through repeatable measurements of the beam over several days. Over three days of measurements, the smallest observed difference in the primary beam’s main lobe was 0.56 dB-Hz. We also compare our results in the sidelobes to simulations and find rough agreement in shape. When scaling the observations and simulations to match in the main lobe power levels, we find deviations in at least one of the first few nulls of approximately 5 dB or less. There is saturation in the main lobe for most satellites, which can likely be mitigated by better attenuation before the receiver input. We compare our work to other satellite systems that have been successful and are likely complementary to this technique. However, GNSS offers key advantages, including continuous transmission, broader frequency coverage relevant to CHORD, SKA-mid, and the DSA-2000, as well as more frequent satellite passes, making it a promising calibration method. These results also motivate further development of this technique for radio astronomy applications.

We estimate key parameters for the Galactic globular clusters NGC1904 (M79) and NGC4372. Additionally, we update the parameters for NGC288, NGC362, NGC5904 (M5), NGC6205 (M13), and NGC6218 (M12), which were analysed in our previous papers, to incorporate significant advancements in data sets and isochrones in recent years. We fit various colour–magnitude diagrams (CMDs) of the clusters using isochrones from the Dartmouth Stellar Evolution Database and the Bag of Stellar Tracks and Isochrones, adopting an α–enrichment value of [α/Fe] = +0.4. The CMDs are constructed fromdata sets provided by the Hubble Space Telescope, Gaia, SkyMapper Southern Sky Survey Data Release 4, a large compilation of ground-based observations by Stetson, and other sources, using multiple filters for each cluster. Our cross-identification of almost all the data sets with those from Gaia or Hubble Space Telescope allows us to use their astrometry to precisely select cluster members in all the data sets. We obtain the following estimates, along with their total uncertainties, for NGC288, NGC362, NGC1904, NGC4372, NGC5904, NGC6205 and NGC6218, respectively: metallicities [Fe/H]= –1.28 ± 0.08, –1.26 ± 0.07, –1.64 ± 0.09, –2.28 ± 0.09, –1.33 ± 0.10, –1.56 ± 0.09, and –1.27 ± 0.10 dex; ages 12.94±0.76, 10.33±0.75, 13.16±0.76, 12.81±0.81, 11.53±0.76, 12.75±0.76, and 13.03±0.81 Gyr; distances 8.83±0.21, 9.00±0.21, 12.66±0.36, 5.17±0.15, 7.24±0.16, 7.39±0.08, and 4.92±0.13 kpc; reddenings E(B–V) = 0.022±0.024, 0.029±0.025, 0.031±0.018, 0.545±0.032, 0.045±0.027, 0.024±0.021, and 0.210±0.028mag; extinctions AV = 0.09±0.06, 0.09±0.06, 0.11±0.06, 1.58±0.06, 0.13±0.06, 0.09±0.06, and 0.67±0.06mag; and extinction-to-reddening ratio RV = 3.9±0.7, 3.0±0.5, 3.8±0.5, 2.9±0.4, 2.9±0.2, 3.6 ± 0.7, and 3.2 ± 0.1. The RV estimates are fairly accurate, as the cross-identification of data sets enables us to calculate extinction across all ultraviolet, optical, and infrared filters used, thereby allowing us to derive an empirical extinction law for each combination of cluster, data set, and model. We confirm that the differences in horizontal branch morphology among the 16 Galactic globular clusters analysed in our studies can be explained by variations in their metallicity, age, mass-loss efficiency, and the loss of low-mass members during cluster evolution. Accordingly, most clusters indicate a relatively high mass-loss efficiency, consistent with the Reimers mass-loss law with η > 0.3.

We present the discovery of 15 well-resolved giant radio galaxies (GRGs) with angular sizes $\ge$5 arcmin and physical sizes $\gt$1 Mpc in wide-field Phased Array Feed 944 MHz observations on the Australian Square Kilometre Array Pathfinder (ASKAP). We identify their host galaxies, examine their radio properties as well as their environment, and classify their morphologies as FR I (4), FR II (8), intermediate FR I/II (2), and hybrid (1). The combined $\sim$40 deg$^2$ ASKAP image of the Sculptor field, which is centred near the starburst galaxy NGC 253, has a resolution of 13″ and an rms sensitivity of $\gtrsim$10 $\unicode{x03BC}$Jy beam$^{-1}$. The largest GRGs in our sample are ASKAP J0057–2428 ($z_{\mathrm{phot}}$ = 0.238), ASKAP J0059–2352 ($z_{\mathrm{phot}}$ = 0.735), and ASKAP J0107–2347 ($z_{\mathrm{phot}}$ = 0.312), for which we estimate linear projected sizes of 2.7, 3.5, and 3.8 Mpc, respectively. In total, we catalog 232 extended radio galaxies of which 77 (33%) are larger than 0.7 Mpc and 35 (15%) are larger than 1 Mpc. The radio galaxy densities are 5.8 deg$^{-2}$ (total) and 0.9 (1.9) deg$^{-2}$ for those larger than 1 (0.7) Mpc, similar to previous results. Furthermore, we present the ASKAP discovery of a head-tail radio galaxy, a double-lobe radio galaxy with a spiral host, and radio emission from several galaxy clusters. As the ASKAP observations were originally conducted to search for a radio counterpart to the gravitational wave detection GW190814 ($z \sim 0.05$), we highlight possible host galaxies in our sample.

Double-peaked Lyman-α (Lyα) profiles provide critical insights into gas kinematics and the distribution of neutral hydrogen (H i) from the interstellar to the intergalactic medium (ISM to IGM), and serve as valuable diagnostics of ionising Lyman continuum (LyC) photon escape. We present a study of the global and spatially resolved properties of double-peaked Lyα emitters (LAEs), based on VLT/MUSE data from the Middle Ages Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey. From a parent sample of 417 LAEs at z = 2.9 – 6.6 in the first 35 fields, we identify 108 double-peaked LAEs using an automated peak classification technique. We measure a double-peak fraction of ∼ 37% at z < 4, decreasing to ∼ 14% at z > 4, likely due to enhanced IGM attenuation. Approximately 17% of the double-peaked LAEs are blue-dominated, possibly tracing gas inflows, though backscattering remains a viable alternative for sources without systemic redshift. The blue-to-total flux ratio exhibits a luminosity dependence: fainter lines generally show higher blue flux, though a few luminous sources also show strong blue peaks. We find a significant narrowing of the red peak at z > 4, despite the presence of the blue peak, indicating intrinsic galaxy evolution rather than an effect of IGM attenuation. Several LAEs exhibit residual flux in the absorption trough, with normalised trough flux anticorrelating with peak separation, reflecting variations in H I column density. We further investigate spatially-resolved properties of ten red-dominated LAEs with extended Lyα halos. Despite azimuthal variations, both the blue-to-total flux ratio and normalised trough flux density increase with radius, while peak separation decreases. The red peak asymmetry shows only minor radial changes. These trends are consistent with variations in shell outflow velocity and H I column density across the halos. However, some exceptions to these patterns are also noted. Based on peak separation, red peak asymmetry, and residual trough flux, we identify five LAEs as strong LyC leaker candidates.

Some of the most interesting insights into solar physics and space weather come from studying radio emissions associated with solar activity, which remain inherently unpredictable. Hence, a real-time triggering system is needed for solar observations with the versatile new-generation radio telescopes to efficiently capture these episodes of solar activity with the precious and limited solar observing time. We have developed such a system, Solar Triggered Observations of Radio bursts using MWA and Yamagawa (STORMY) for the Murchison Widefield Array (MWA), the precursor for the low frequency telescope of upcoming Square Kilometre Array Observatory (SKAO). It is based on near-real-time data from the Yamagawa solar spectrograph, located at a similar longitude to the MWA. We have devised, implemented, and tested algorithms to perform an effective denoising of the data to identify signatures of solar activity in the Yamagawa data in near real time. End-to-end tests of triggered observations have been successfully carried out at the MWA. STORMY is operational at the MWA for the routine solar observations, a timely development in the view of the ongoing solar maximum. We present this new observing framework and discuss how it can enable efficient capturing of event-rich solar data with existing instruments, like the LOw Frequency ARray (LOFAR), Owens Valley Radio Observatory – Long Wavelength Array (OVRO-LWA), etc., and pave the way for triggered observing with the SKAO, especially the SKA-Low.

We examine the potential improvements in constraints on the dark energy equation of state parameter w and matter density $\Omega_M$ from using clustering information along with number counts for future samples of thermal Sunyaev-Zel’dovich selected galaxy clusters. We quantify the relative improvement from including the clustering power spectrum information for three cluster sample sizes from 33 000 to 140 000 clusters and for three assumed priors on the mass slope and redshift evolution of the mass-observable relation. As expected, clustering information has the largest impact when (i) there are more clusters and (ii) the mass-observable priors are weaker. For current knowledge of the cluster mass-observable relationship, we find the addition of clustering information reduces the uncertainty on the dark energy equation of state, $\sigma(w)$, by factors of $1.023\pm 0.007$ to $1.079\pm 0.011$, with larger improvements observed with more clusters. Clustering information is more important for the matter density, with $\sigma(\Omega_M)$ reduced by factors of $1.068 \pm 007$ to $1.145 \pm 0.012$. The improvement in w constraints from adding clustering information largely vanishes after tightening priors on the mass-observable relationship by a factor of two. For weaker priors, we find clustering information improves the determination of the cluster mass slope and redshift evolution by factors of $1.389 \pm 0.041$ and $1.340 \pm 0.039$, respectively. These findings highlight that, with the anticipated surge in cluster detections from next generation surveys, self-calibration through clustering information will provide an independent cross-check on the mass slope and redshift evolution of the mass-observable relationship as well as enhancing the precision achievable from cluster cosmology.

The brown dwarf desert describes a range of orbital periods (${\lt}5$ yr) in which fewer brown dwarf-mass companions have been observed around Sun-like stars, when compared to planets and low mass stellar companions. It is therefore theorised that brown dwarf companions are unlikely to form or remain in this period range. The Gaia space telescope is uniquely sensitive to companions in this period range, making it an ideal tool to conduct a survey of the brown dwarf desert. In this study, we use Bayesian inference to analyse data from nearby (${\lt}200$ pc) Sun-like stars in Gaia’s DR3 catalogue, assuming single companions. From this, we identify 2 673 systems (2.41% of the sample) with possible brown dwarf companions in this period range. Accounting for observational biases, we find that $10.4^{+0.8}_{-0.6}$% of nearby Sun-like stars have astrometric errors consistent with a brown dwarf-mass companion with a period less than 5 yr, significantly higher than previous studies which reported occurrence rates of ${\lt}1$%. However, we acknowledge the limitations of DR3 and are unable to make a definitive statement without epoch data. By simulating epoch data with multiple companions, we find that, while some of the data can be explained by multiple low-mass brown dwarf companions and high-mass planets (${\gt}10$ M$_{\mathrm{J}}$), high-mass brown dwarfs (${\gt}50$ M$_{\mathrm{J}}$) in this period range are comparatively rare. Finally, we used our studies of the brown dwarf distribution to predict the number of companions in the brown dwarf desert we can expect to discover in DR4.

The mechanical feedback from the central active galactic nuclei (AGNs) can be crucial for balancing the radiative cooling of the intracluster medium (ICM) at the cluster centre. We aim to understand the relationship between the power of AGN feedback and the cooling of gas in the centres of galaxy clusters by correlating the radio properties of the brightest cluster galaxies (BCGs) with the X-ray properties of their host clusters. We used the catalogues from the first SRG/eROSITA All-Sky Survey (eRASS1) along with radio observations from the Australian SKA Pathfinder (ASKAP). In total, we identified 134 radio sources associated with BCGs of the 151 eRASS1 clusters located in the PS1, PS2, and SWAG-X ASKAP fields. Non-detections were treated as upper limits. We correlated the radio properties of the BCGs (radio luminosity, largest linear size/LLS, and BCG offset from the cluster centre) with the integrated X-ray luminosity of the host clusters. We utilised the concentration parameter, $c_{R_{500}}$, to categorise the clusters into cool cores (CCs) and non-cool cores (NCCs). By combining $c_{R_{500}}$ with the BCG offset, we assessed the dynamical states of the clusters in our sample. Furthermore, we analysed the correlation between radio mechanical power and X-ray luminosity within the CC subsample. We observe a potential positive trend between LLS and BCG offset, which may hint at an environmental influence on the morphology of central radio sources. We find a weak trend suggesting that more luminous central radio galaxies are found in clusters with higher X-ray luminosity. Additionally, there is a positive but highly scattered relationship between the mechanical luminosity of AGN jets and the X-ray cooling luminosity within the CC subsample. This finding is supported by bootstrap resampling and flux-flux analyses. The correlation observed in our CC subsample indicates that AGN feedback is ineffective in high-luminosity (high-mass) clusters. At a cooling luminosity of $L_{\mathrm{X},\,r} \lt \mathrm{R}_{\mathrm{cool}}\approx 5.50\times10^{43}\,\mathrm{erg\,s^{-1}}$, on average, AGN feedback appears to contribute only about $13\%-22\%$ of the energy needed to offset the radiative losses in the ICM.

With the installation of next-generation phased array feed (PAF) receivers on radio telescopes, there is an urgent need to develop effective and computationally efficient radio frequency interference (RFI) mitigation methods for large-scale surveys. Here, we present a new RFI mitigation package, called mRAID (multi-beam RAdio frequency Interference Detector), which uses the eigenvalue decomposition algorithm to identify RFI in cross-correlation matrix (CCM) of data recorded by multiple beams. When applied to high time-resolution pulsar search data from the Five-hundred-meter Aperture Spherical Radio Telescope (FAST), mRAID demonstrates excellent performance in identifying RFI over short timescales, thereby enhancing the efficiency of pulsar and fast radio burst (FRB) searches. Since the computation of the CCM and the eigenvalue decomposition for each time sub-integration and frequency channel are independent, the process is fully parallelisable. As a result, mRAID offers a significant computational advantage over commonly used RFI detection methods.

The transient and variable optical sky is relatively poorly characterised on fast (${\lt}$1 h) timescales. With the dark energy camera (DECam), the Deeper, Wider, Faster programme (DWF) probes a unique parameter space with its deep (median of $g\sim22.2$ AB mag), minute-cadence imaging. In this work, we present DWF’s first data release which comprises high cadence photometry extracted from $\sim$12 000 images and 166 h of telescope time. We present a novel data processing pipeline, dwf-postpipe, developed to identify sources and extract their light curves. The accuracy of the photometry is assessed by cross-matching to public catalogues. In addition, we injected a population of synthetic GRB afterglows into a subset of the DWF DECam imaging to compare the efficiency of our pipeline with a standard difference imaging approach. Both pipelines show performance and reliably recover injected transients with peak magnitudes $g\lt22$ AB mag with an efficiency of $97.24^{+0.7}_{-1.0}$ percent for dwf-postpipe and $96.14^{+0.9}_{-1.1}$ percent for a difference imaging approach. However, we find that dwf-postpipe is less likely to recover transients appearing in galaxies that are brighter or comparable in brightness to the transient itself. To demonstrate the power of the data in this release, we conduct a search for uncatalogued variable stars in a single night of DWF DECam imaging and find ten pulsating variables, two eclipsing binaries and one ZZ ceti. We also conduct a search for variable phenomena in the Chandra Deep Field South, a Rubin deep drilling field, and identify two flares from likely UV ceti type stars.