Astrophysics Science Division

ABSTRACT We present HECATEv2, the second release of the Heraklion Extragalactic Catalogue (HECATE), an all-sky, value-added galaxy catalogue comprising 204 733 galaxies from the Hyper Lyon-Meudon Extragalactic Database (HyperLEDA) with recession velocity $\lt 14\, 000 \, \rm {km\, s^{-1}}$ (D $\lesssim$ 200 Mpc). This release focuses on qualitative upgrades of the provided information while maintaining the same parent galaxy sample as HECATEv1. Improvements include a new cosmology-based distance framework, expanded and homogenized optical and mid-infrared (IR) photometry from SDSS-DR17/NSA, PS1-DR2, and All Wide-field Infrared Survey Explorer (AllWISE), and new quality-control flags for stellar contamination, incorrect photometry, and coordinate inconsistencies. We also extend the galaxy-size coverage and derive stellar population parameters for a substantially larger fraction of the sample. Star formation rates ($\mathrm{SFR}$) and stellar masses (${{M}_{\star }}$) are now available for $\gt 70$ per cent of galaxies using updated mid-IR/optical calibrations that account for stellar population age and dust attenuation, while gas-phase metallicities are derived for $\sim 90~{{\ \rm per\ cent}}$. Activity classifications are provided for $\gt 50$ per cent of galaxies based on spectroscopic and/or photometric diagnostics, and supermassive black hole (SMBH) masses for $\sim 86~{{\ \rm per\ cent}}$. In terms of $L_{B}$, $L_{Ks}$, $\mathrm{SFR}$, and ${{M}_{\star }}$, HECATEv2 is among the most complete local-universe catalogues with spectroscopic redshifts. We also provide spatial completeness maps as a function of distance and luminosity, highlighting variations across the sky. Compared to other catalogues (e.g. GLADE+ and NED-LVS), HECATEv2 offers broader (optical, near- and far-IR photometry, metallicity, and activity classifications) or comparable (mid-IR photometry, $\mathrm{SFR}$, and ${{M}_{\star }}$) coverage, making it a robust reference for studies of SMBH–host galaxy connections, gravitational-wave and high-energy transient hosts, population analyses, and rare galaxy subpopulations.

Abstract The General Coordinates Network (GCN) is NASA’s time-domain and multimessenger alert system. GCN distributes two data products: automated “Notices” and human-generated “Circulars” that report the observations of high-energy and multimessenger astronomical transients. The flexible and nonstructured format of GCN Circulars, comprising more than 40,500 Circulars accumulated over three decades, makes it challenging to manually extract observational information, such as redshift or observed wave bands. In this work, we employ large language models (LLMs) to facilitate the automated parsing of transient reports. We develop a neural topic modeling pipeline with open-source tools for the automatic clustering and summarization of astrophysical topics in the Circulars archive. Using neural topic modeling and contrastive fine-tuning, we classify Circulars based on their observation wave bands and messengers. Additionally, we separate gravitational-wave event clusters and their electromagnetic counterparts from the Circulars archive. Finally, using the open-source Mistral model, we implement a system to automatically extract gamma-ray burst (GRB) redshift information from the Circulars archive, without the need for any training. Evaluation against the manually curated Neil Gehrels Swift Observatory GRB table shows that our simple system, with the help of prompt-tuning, output parsing, and retrieval augmented generation (RAG), can achieve an accuracy of 97.2% for redshift-containing Circulars. Our neural search-enhanced RAG pipeline accurately retrieved 96.8% of redshift Circulars from the manually curated archive. Our study demonstrates the potential of LLMs to automate and enhance astronomical text mining and provides a foundational work for future advances in transient alert analysis.

We investigate how the orbital evolution and mass distribution of infalling satellite galaxies shape the phase-space and radial distributions of intracluster light (ICL) relative to the underlying cluster dark matter (DM) halo. Using N-body simulations, we follow the tidal stripping and orbital evolution of satellite galaxies as they are accreted into a live cluster halo, systematically varying satellite-to-host mass ratio and orbital circularity. We measure the specific orbital energy and angular momentum of stripped stellar and DM material, finding that the stripped stars consistently occupy lower-energy and lower-angular momentum regions of phase-space than the stripped DM. The magnitude of this difference increases strongly towards more equal satellite--to--host mass ratios, while the dependence on orbital circularity is weak. We construct a predictive model for the phase-space properties of stripped stars and DM from a whole infalling satellite population and find that the resulting phase-space difference between the components are driven primarily by the characteristic mass of the infalling satellite stellar mass function. We find that the ICL is always more centrally concentrated than the DM. The magnitude of this offset depends on the characteristic mass and increases towards higher characteristic masses. Comparisons with four independent cosmological hydrodynamical simulations show that, once the infalling satellite stellar mass function is matched, the model reproduces the radial stellar-to-DM density profile offsets to better than the inter-simulation scatter. This demonstrates that the radial relationship between the ICL and the DM distribution is largely governed by satellite demographics. With adequate constraints on the infalling satellite population, ICL density profiles can therefore be used as informative tracers of the underlying radial DM distribution in clusters.

Abstract This study investigates an ozone intrusion event observed during the Pre‐Asian Summer Monsoon Chemical and Climate Impact Project in August 2021, using 26 consecutive daily ozonesonde measurements over South Korea. A pronounced enhancement in total column ozone was observed between 17 and 19 August, which can be largely attributed to an ozone intrusion in the upper troposphere–lower stratosphere (UTLS), accounting for approximately 60% of the increase. The upper tropospheric circulation patterns demonstrate a clear signature of anticyclonic Rossby wave breaking (AWB) on the northeastern edge of the Asian summer monsoon anticyclone, aligned with the summertime jet stream. This AWB, accompanied by a cut‐off low and tropopause folding, facilitated downward transport of stratospheric ozone into the upper troposphere. In addition, the ozone variability is investigated in two chemical reanalysis data sets: Modern‐Era Retrospective Analysis for Research and Applications, Version 2 (MERRA‐2) and European Centre for Medium‐Range Weather Forecasts (ECMWF) Atmospheric Composition Reanalysis 4 (EAC4). MERRA‐2 and EAC4 capture the ozone intrusion event with relevant synoptic‐scale circulation patterns and ozone variability. However, discrepancies of ozone data in the chemical reanalyses were found in vertical ozone structures and persistence in the troposphere. MERRA‐2 better represented the secondary ozone peak in the UTLS but underestimated lower‐tropospheric ozone. In contrast, EAC4 showed a systematic positive bias particularly in the stratosphere and near the surface. Continued integration of temporally high‐resolution ozone measurements is beneficial for understanding synoptic‐scale ozone variability and evaluating emerging chemical reanalyses.

It is argued that the lens described in the paper commented upon has a focussing efficiency of less than 0.03% and an angular resolution for broadband radiation that is an order of magnitude worse that the diffraction limit. Furthermore incident radiation that is not focussed will lead to background fog in the image plane.

The 2024 X-ray/UV observation campaign of NGC 3783, led by XRISM, revealed the launch of an ultrafast outflow (UFO) with a radial velocity of 0.19 c (57 000 km s −1 ). This event is synchronized with the sharp decay, within less than half a day, of a prominent soft X-ray/UV flare. Accounting for the look-elsewhere effect, the XRISM Resolve data alone indicate a low probability of 2 × 10 −5 that this UFO detection is due to random chance. The UFO features narrow H-like and He-like Fe lines with a velocity dispersion of ∼1000 km s −1 , suggesting that it originates from a dense clump. Beyond this primary detection, there are hints of weaker outflow signatures throughout the rise and fall phases of the soft flare. Their velocities increase from 0.05 c to 0.3 c over approximately three days, and they may be associated with a larger stream in which the clump is embedded. The radiation pressure is insufficient to drive the acceleration of this rapidly evolving outflow. The observed evolution of the outflow kinematics instead closely resembles that of solar coronal mass ejections, implying magnetic driving and, conceivably, reconnection near the accretion disk as the likely mechanisms behind both the UFO launch and the associated soft flare.

Physics-based numerical models are essential for understanding atmosphere–space interactions. These include mechanisms that perturb the upper-atmosphere dynamics and energetics associated with terrestrial weather (impact from below) and solar-geomagnetic input (impact from above). The relevant physical phenomena range from global and synoptic scales down to the kilometer-scale of mesoscale dynamics. This manuscript discusses the impact of fine-scale processes in the ionosphere–thermosphere–mesosphere (ITM) region initiated from above and below, emphasizing the current status and perspectives of their realistic representation in whole-atmosphere and thermosphere–ionosphere models. The possible pathways to address challenges in realistic predictions of the ITM and its fast variability on global and regional scales are examined. They include three powerful modeling and data analysis techniques, namely nesting, nudging, and assimilation, that need to be carefully implemented for the highly dynamical ITM domain. Reasons for potential problems to constrain the high-resolution ITM predictions by data can be attributed to sparse and diverse observations performed in different layers and the increased complexity of the multi-scale ITM processes that need to be taken into account and properly coupled (e.g., dynamics, radiation, chemistry, and electrodynamics). The multi-scale ITM dynamics are dominated by tides, gravity waves, and small-scale eddies. Constraining these with assimilation and/or nudging algorithms requires rapid data analysis to properly adjust the global and regional diurnal and sub-diurnal oscillations to match space-borne and ground-based observations.

Abstract Colliding winds in massive binaries generate X-ray-bright shocks, synchrotron radio emission, and sometimes even dusty “pinwheel” spirals. We report the first X-ray detections of the dusty WC+O binary system WR 112 from Chandra and Swift, alongside 27 yr of Very Large Array/Australia Telescope Compact Array radio monitoring and new diffraction-limited Keck images. Because we view the nearly circular orbit almost edge-on, the colliding-wind zone alternates between heavy Wolf–Rayet wind self-absorption and near-transparent O-star wind foreground each 20 yr orbit, producing phase-locked radio and X-ray variability. This scenario leads to a prediction that the radio spectral index is flatter from a larger nonthermal contribution around the radio intensity maximum, which indeed was observed. Existing models that assume a single dust-expansion speed fail to reproduce the combined infrared (IR) geometry and radio light curve. Instead, we require an accelerating postshock flow that climbs from near-stationary to ∼1350 km s−1 in about one orbital cycle, naturally matching the IR spiral from 5″ down to within 0 . ″ 1, while also fitting the phase of the radio brightening. These kinematic constraints supply critical boundary conditions for future hydrodynamic simulations, which can link hot-plasma cooling, nonthermal radio emission, X-ray spectra, and dust formation in a self-consistent framework. WR 112 thus joins WR 140, WR 104, and WR 70-16 (Apep) as a benchmark system for testing colliding-wind physics under an increasingly diverse range of orbital architectures and physical conditions.

Abstract The Resolve micro-calorimeter onboard XRISM is set to significantly advance our understanding of the complex intracluster medium (ICM) in galaxy clusters. We present ${\sim}500$ ks XRISM observations covering the central and two northern regions of the Abell 2029 galaxy cluster. Resolve enables us to distinguish multiple emission lines from hydrogen-like and helium-like iron (Fe) ions. This study focuses on the multi-temperature structure of Abell 2029 using line-ratio diagnostics. Using a single-temperature collisionally ionized equilibrium (CIE) model, we measure average plasma temperatures of 6.73 keV, 7.61 keV, and 8.14 keV in the central, inner northern, and outer northern regions, respectively, spanning a radial range up to $700$ kpc. To further investigate thermal structure, we derive excitation and ionization temperatures by comparing observed emission-line flux ratios with atomic database predictions. Significant deviations from the single-temperature CIE model in the central and inner northern regions indicate the presence of multi-phase gas. The excitation and ionization temperatures range from 2.85 to 8.5 keV in the central region, 4.3 to 9.8 keV in the inner northern region, and 8.3 to 10.4 keV in the outer northern region. These temperature distributions are largely consistent with the previously observed temperature gradient of A2029. However, Resolve detects two notably cooler components—3.42 keV in the central region and ${\sim}4.3$ keV in the inner northern region—likely associated with displaced cool gas due to gas sloshing. Additionally, we thermally resolve a 2.85 keV gas component at the core of A2029—potentially a significant development in our understanding of gas cooling. We propose that this cooler gas is a direct product of ongoing cooling processes in A2029, having already cooled to its present temperature. If this temperature structure is stable and no heating mechanism is present, this reservoir is likely to cool to even lower temperatures and form stars.

Abstract We study the effects of neutrino lensing induced by a Damour–Solodukhin wormhole on the neutrino oscillation. We derive and calculate the flavour transition probabilities in the presence of Damour–Solodukhin factor $$\Lambda $$ Λ as a shift in the massive source to show that the neutrino flavour oscillation is also sensitive not only to the sign of difference between the squared masses but also to the individual mass of neutrinos in both the two-flavour and the three-flavour cases. As a consequence of parameter $$\Lambda $$ Λ within a region, a series of curves of probability function versus the azimuthal angle $$\phi $$ ϕ with definite masses of neutrino can be plotted and their shapes resemble each other in the case of two-flavoured neutrinos and of three-flavoured ones. In view of the probability functions due to the wormhole, we reveal that the contribution of the factor $$\Lambda $$ Λ is novel. Based on our analytical and numerical discussions on the probability expressions, the difference of the neutrino flavour oscillation arising from the shift in the wormhole factor $$\Lambda $$ Λ is detectable. It is crucial that the $$\Lambda $$ Λ as deviation from the black holes can change the shapes of the curves greatly, in the case of three-flavoured neutrinos in particular. The detailed comparisons can be made among our estimations depicted in the figures for neutrino oscillations and the measurements from the detector, which open a new window for judging whether the remote star as lens is black-hole-like wormhole or spherically symmetric black hole and further the wormhole factor $$\Lambda $$ Λ can be estimated.