Search

We present the first multi-frequency analysis of the candidate ultra-steep spectrum radio halo in the galaxy cluster PLCKESZ G171.94$-$40.65, using the upgraded Giant Metrewave Radio telescope (uGMRT; 400 MHz), and Karl G. Jansky Very Large Array (JVLA; 1-2 GHz) observations. Our radio data have been complemented with archival \textit{Chandra} X-ray observations to provide a crucial insight into the complex intracluster medium (ICM) physics, happening at large scales. We detect the radio halo emission to the extent of $\sim$ 1.5 Mpc at 400 MHz, significantly larger than previously reported, along with five tailed galaxies in the central region. We also report the discovery of an unknown diffuse source 'U', at the cluster periphery, with an extent of 300 kpc. Using the available observations, we have found that the radio spectrum of the halo is well-fitted with a single power law, having a spectral index of $-1.36 \pm 0.05$, indicating that it is not an ultra-steep spectrum radio halo. Our low-resolution (25$''$) resolved spectral map shows an overall uniform spectral index, with some patches of fluctuations. The X-ray and radio surface brightness are morphologically co-spatial, with a slight extension along the northwest-southeast direction, seen in both maps. The radio and X-ray surface brightness indicates strong positive correlations, with sub-linear correlation slopes ($\sim$ 0.71). Multiple tailed galaxies and the radio halo indicate a high dynamical activity at the cluster central region., Comment: 16 pages, 12 Figures, 6 Tables, Accepted for publication in ApJ

The galaxy cluster Abell 496 has been extensively studied in the past for the clear sloshing motion of the hot gas on large scales, but the interplay between the central radio galaxy and the surrounding cluster atmosphere is mostly unexplored. We present a dedicated radio, X-ray, and optical study of Abell 496 aimed at investigating this connection. We use deep radio images obtained with the Giant Metrewave Radio Telescope at 150, 330 and 617 MHz, Very Large Array at 1.4 and 4.8 GHz, and VLA Low Band Ionosphere and Transient Experiment at 340 MHz, with angular resolutions ranging from 0.''5 to 25''. Additionally, we use archival Chandra and Very Large Telescope MUSE observations. The radio images reveal three distinct periods of jet activity: an ongoing episode on sub-kpc scales with an inverted radio spectrum; an older episode that produced lobes on scales $\sim$20 kpc which now have a steep spectral index ($\alpha = 2.0 \pm 0.1$); and an oldest episode that produced lobes on scales of $\sim$50 - 100 kpc with an ultra-steep spectrum ($\alpha = 2.7 \pm 0.2$). Archival Chandra X-ray observations show that the older and oldest episodes have excavated two generations of cavities in the hot gas of the cluster. The outermost X-ray cavity has a clear mushroom-head shape, likely caused by its buoyant rise in the cluster's potential. Cooling of the hot gas is ongoing in the innermost 20 kpc, where H$\alpha$-bright warm filaments are visible in VLT-MUSE data. The H$\alpha$-filaments are stretched towards the mushroom-head cavity, which may have stimulated ICM cooling in its wake. We conclude by commenting on the non-detection of a radio mini-halo in this vigorously sloshing, but low-mass, galaxy cluster., Comment: Accepted for publication in Astronomy & Astrophysics

The clusters Abell 2061 and Abell 2067 in the Corona Borealis supercluster have been studied at different radio frequencies and are both known to host diffuse radio emission. The aim of this work is to investigate the radio emission in between them, suggested by low resolution observations. We analyse deep LOFAR HBA observations at 144 MHz to follow up on the possible intercluster filament suggested by previous 1.4 GHz observations. We investigate the radial profiles and the point-to-point surface brightness correlation of the emission in A2061 with radio and Xray observations, to describe the nature of the diffuse emission. We report the detection of diffuse radio emission on 800 kpc scale, more extended than previously known, reaching beyond the radio halo in A2061 towards A2067 and over the separation outside the two clusters R500 radii. We confirm the presence of a radio halo in A2061, while do not find evidence of diffuse emission in A2067. The surface brightness profile from the centre of A2061 shows an excess of emission with respect to the azimuthally averaged radio halo profile and X-ray background. We explore three different dynamical scenario to explain the nature of the diffuse emission. We analyse a trail of emission of 760 kpc between the radio halo and radio relic in A2061. This pre merger system closely resembles the two other cluster pairs where radio bridges connecting the radio halos on Mpc scales have been detected. The diffuse emission extends beyond each cluster R500 radius but in this unique case, the absence of the radio halo in A2067 is likely the reason for the observed 'gap' between the two systems. However, the point-to-point correlation results are challenging to explain. The classification of the emission remains unclear, and detailed spectral analysis and further Xray observations are required to understand the origin of the diffuse emission., Comment: Accepted for publication on Astronomy & Astrophysics 12 pages, 6 figures, 1 appendix

We present the first general-relativistic resistive magnetohydrodynamics simulations of self-consistent, rotating neutron stars with mixed poloidal and toroidal magnetic fields. Specifically, we investigate the role of resistivity in the dynamical evolution of neutron stars over a period of up to 100 ms and its effects on their quasi-equilibrium configurations. Our results demonstrate that resistivity can significantly influence the development of magnetohydrodynamic instabilities, resulting in markedly different magnetic field geometries. Additionally, resistivity suppresses the growth of these instabilities, leading to a reduction in the amplitude of emitted gravitational waves. Despite the variations in magnetic field geometries, the ratio of poloidal to toroidal field energies remains consistently 9:1 throughout the simulations, for the models we investigated.

CIZA J2242.8+5301, or the Sausage cluster, is well studied over a range of frequencies. Since its first discovery, a lot of interesting features and unique characteristics have been uncovered. In this work, we report some more new morphological features using the uGMRT band-3 and band-4 data. In the north relic, we observe variation in spectral index profiles across the relic width from the east to west, which may indicate a decrease in downstream cooling rate in that direction. We re-confirm the presence of an additional ~ 930 kpc relic in the north. We classify the filamentary source in the downstream region to be a narrow angle tail (NAT) radio galaxy. The bright arc in the east relic shows sub-structure in the spectral index profile, which may indicate the presence of finer filaments. We further report the presence of a double-strand structure in the east relic similar to the 'Toothbrush' relic. We categorize the bright 'L' shaped structure in the southern relic to be a NAT radio galaxy, as well as trace the actual ~ 1.1 Mpc relic component. We re-confirm the existence of the faint southern extent, measuring the relic length to be ~ 1.8 Mpc. Furthermore, we suggest the southern relic to be a union of individual component relics rather than a single giant filamentary relic. Lastly, based on the morphological symmetry between northern and southern relics, we suggest a schematic shock structure associated with the merger event in an attempt to explain their formation scenario., Comment: 23 pages, 18 figures, 3 tables, submitted to ApJ

We present a detailed study of the gas and galaxy properties of the cluster PSZ2 G282.28+49.94 detected in the Planck all-sky survey. The intracluster medium (ICM) of this object at z=0.56 exhibits a cometary-like shape. Combining Chandra and TNG observations, we characterised the spatially resolved thermodynamical properties of the gas and the spatial and velocity distribution of 73 galaxy members. The cluster structure is quite complex with an elongated core region containing the two brightest cluster galaxies and one dense group to the south-east. Since there is no velocity difference between the core and the south-east group, we suggest the presence of a merger along the plane of the sky. This structure is related to complex X-ray and radio features, and thus the merger has likely been caught during the post-merger phase. Comparing the distribution of the ICM and of member galaxies, we find a large offset of $\sim 350$ kpc between the position of the X-ray peak and the centre of a concentration of galaxies, preceding it in the likely direction of motion. This configuration is similar to the famous Bullet Cluster, leading us to dub PSZ2 G282.28+49.94 the "Planck bullet", and represents an ideal situation to provide astrophysical constraints to the self-interaction cross-section ($\sigma/m$) of dark matter particles. These results illustrate the power of a multi-wavelength approach to probe the merging scenario of such complex and distant systems., Comment: Accepted for publication in A&A

The active galactic nucleus (AGN) feeding and feedback process in the centers of galaxy clusters and groups is still not well understood. NGC5044 is the ideal system in which to study AGN feedback. It hosts the largest known reservoir of cold gas in any cool-core galaxy group, and features several past epochs of AGN feedback imprinted as cavities in the X-ray bright intragroup medium (IGrM), as well as parsec scale jets. We present Submillimeter Array (SMA) and Karl G. Jansky Very Large Array (VLA) high frequency observations of NGC5044 to assess the time variability of the mm-waveband emission from the accretion disk, and quantify the Spectral Energy Distribution (SED) from the radio to sub-millimeter band. The SED is well described by advection dominated accretion flow (ADAF) model and self-absorbed jet emission from an aging plasma with tau ~1kyr. We find a characteristic variability timescale of 150 days, which constrains the ADAF emission region to about 0.1pc, and the magnetic field to 4.7mG in the jets and and 870G in the accretion disk. A longer monitoring/sampling will allow to understand if the underlying process is truly periodic in nature., Comment: 17 pages, 6 figures, submitted to ApJ

Context. Tailed radio galaxies are shaped by ram pressure owing to the high-velocity motion of their host through the intracluster medium (ICM). Recent works have reported on the increasing complexity of the phenomenology of tailed galaxies, with departures from theoretical ageing models and evidence of re-energising mechanisms, which are yet unclear. Aims. The nearby (z = 0.0894) galaxy cluster Abell 2142 hosts two tailed galaxies, namely T1 and T2, which exhibit peculiar morphological features. We aim to investigate the properties of T1 and T2 and constrain their spectral evolution, dynamics, and interactions with the ICM. Methods. We combined LOw Frequency Array (LOFAR), upgraded Giant Metrewave Radio Telescope (uGMRT), Very Large Array (VLA), and MeerKAT data (from 30 MHz to 6.5 GHz) to carry out a detailed spectral analysis of T1 and T2. We analysed surface brightness profiles, measured integrated and spatially-resolved spectral indices, and performed a comparison with single injection ageing models. Chandra X-ray data were used to search for discontinuities in the ICM properties in the direction of the targets. Results. The spectral properties of T1 at low frequencies are predicted by ageing models, and provide constraints on the 3D dynamics of the host by assuming a constant velocity. However, sharp transitions along sub-regions of the tail, local surface brightness enhancements, and a spectral shape at high frequencies that is not predicted by models suggest a more complex scenario, possibly involving hydrodynamical instabilities and particle mixing. T2 exhibits unusual morphological and surface brightness features, and its spectral behaviour is not predicted by standard models. Two AGN outburst events during the infall of T2 towards the cluster centre could explain its properties., Comment: 23 pages (including Appendices). 15 figures. Accepted for publication in A&A

Superclusters are the largest-scale environments where a number of galaxy clusters interact with each other through minor/major mergers and grow via accretion along cosmic filaments. We focus on the A3528 complex in the core of the Shapley Supercluster. This system includes three clusters, A3528 (composed itself by two sub-clusters, namely A3528N and A3528S), A3532 and A3530, and presents a mildly active dynamical state. We study how minor mergers affect the evolution of radio galaxies and whether they are able to re-accelerate relativistic electrons in the ICM. We used observations from the uGMRT (Band 3, 4 and 5) and MeerKAT (L-band) telescopes to obtain images and spectral index maps over a wide frequency band and spatial resolutions. We compare these data with those from the SRG/eROSITA X-ray telescope. We detect faint diffuse radio emission associated with the radio galaxies. The BCGs in A3528S and A3532 show filaments of diffuse radio emission which extend for $\sim200-400$ kpc out of the radio galaxy. The spectral index of these filaments is extremely steep and almost constant ($\alpha\sim -2, -2.5$). Contrary to the radio tails in A3528N, the spectral properties of these radio filaments are not consistent with standard models of plasma ageing. We also detect roundish diffuse radio emission around the BCG in A3528S which could be classified as a radio mini-halo. The radio tail in this cluster appears longer that in earlier detections, being $\sim300$ kpc long at all frequencies. We linked the presence of extended radio emission in the form of filaments and threads in the A3528 complex with the effect of minor mergers. This is reinforced by the increasing X-ray fluctuations in correspondence with the radio extended emission in A3528S. Despite the less energy involved, our findings support the hypothesis that these events can re-energise plasma originating from radio galaxies., Comment: 28 pages, 23 figures and 5 tables; accepted for publication in Astronomy & Astrophysics

X-shaped radio galaxies (XRGs) are characterised by two pairs of misaligned lobes, namely the active lobes hosting radio jets and the wings. None of the formation mechanisms proposed so far can exhaustively reproduce the diverse features observed among XRGs. The emerging evidence is the existence of sub-populations of XRGs forming via different processes. The brightest cluster galaxy in Abell 3670 (A3670) is a dumbbell system hosting the XRG MRC 2011-298. The morphological and spectral properties of this interesting XRG have been first characterised through Karl G. Jansky Very Large Array (JVLA) data at 1-10 GHz. In the present work, we followed-up MRC 2011-298 with the upgraded Giant Metrewave Radio Telescope (uGMRT) at 120-800 MHz to further constrain its properties and origin. We carried out a detailed spectral analysis sampling different spatial scales. Integrated radio spectra, spectral index maps, radio colour-colour diagrams, and radiative age maps of both the active lobes and prominent wings have been employed to test the origin of the source. We confirm a progressive spectral steepening from the lobes to the wings. The maximum radiative age of the source is $\sim 80$ Myr, with the wings being older than the lobes by $\gtrsim 30$ Myr in their outermost regions. The observed properties are in line with an abrupt reorientation of the jets by $\sim 90$ deg from the direction of the wings to their present position. This formation mechanism is further supported by the comparison with numerical simulations in the literature, which additionally highlight the role of hydrodynamic processes in the evolution of large wings such as those of MRC 2011-298. Potentially, the coalescence of supermassive black holes could have triggered the spin-flip of the jets. Moreover, we show that the S-shape of the radio jets is likely driven by precession with a period $P \sim 10$ Myr., Comment: 23 pages (including Appendices), 14 figures. Accepted for publication in A&A

We present NIRSpec/MSA observations from the JWST large-area survey WIDE, targeting the rest-frame UV-optical spectrum of Ulema, a radio-AGN host at redshift z=4.6348. The low-resolution prism spectrum displays high equivalent width nebular emission, with remarkably high ratios of low-ionisation species of oxygen, nitrogen and sulphur, relative to hydrogen; auroral O$^+$ emission is clearly detected, possibly also C$^+$. From the high-resolution grating spectrum, we measure a gas velocity dispersion $\sigma$~400 km s$^{-1}$, broad enough to rule out star-forming gas in equilibrium in the gravitational potential of the galaxy. Emission-line ratio diagnostics suggest that the nebular emission is due to a shock which ran out of pre-shock gas. To infer the physical properties of the system, we model simultaneously the galaxy spectral energy distribution (SED) and shock-driven line emission under a Bayesian framework. We find a relatively low-mass, star-forming system (M* = 1.4$\times$10^{10} M$_\odot$, SFR = 70 M$_\odot$ yr$^{-1}$), where shock-driven emission contributes 50 per cent to the total H$\beta$ luminosity. The nebular metallicity is near solar - three times higher than that predicted by the mass-metallicity relation at z=4.6, possibly related to fast-paced chemical evolution near the galaxy nucleus. We find no evidence for a recent decline in the SFR of the galaxy, meaning that, already at this early epoch, fast radio-mode AGN feedback was poorly coupled with the bulk of the star-forming gas; therefore, most of the feedback energy must end up in the galaxy halo, setting the stage for future quenching., Comment: 20 pages, 10 figures, 4 tables. Submitted to MNRAS, comments welcome

Galaxy evolution emerges from the balance between cosmic gas accretion, fueling star formation, and supernova (SN) feedback, regulating the metal enrichment. Hence, the stellar mass ($M_*$) - gas metallicity relation (MZR) is key to understand the physics of galaxies. High-quality JWST data enable accurate measurements of the MZR up to redshift z=10. Our aims are to understand the observed MZR, its connection with the star formation rate (SFR), the role played by SFR stochasticity, and how it is regulated by SN feedback. We compare the MZR from the JADES, CEERS, and UNCOVER surveys, which comprise about 180 galaxies at $z=3-10$ with $10^6

We study the radio continuum emission of four galaxies experiencing ram-pressure stripping in four clusters of the Shapley supercluster at redshift z~0.05. Multi-band (235-1367 MHz) radio data, complemented by integral-field spectroscopy, allow us to detect and analyse in detail the non-thermal component both in the galaxy discs and the radio continuum tails. Three galaxies present radio continuum tails which are tens of kiloparsecs long. By deriving the radio spectral index in the inner and outer tails and comparing our findings with the distribution of the extraplanar ionised gas and the results of N-body/hydrodynamical simulations, we demonstrate that these tails are caused by the ram pressure which, together with the ionised gas, sweeps the magnetic field from the galaxy discs. We suggest that the radio continuum emission in these tails can be differently powered by (i) in situ star formation; (ii) relativistic electrons stripped from the disc; (iii) shock excitation or a combination of them. All the ram-pressure stripped galaxies are found in environments where cluster-cluster interactions occurred and/or are ongoing thus strongly supporting the thesis that cluster and group collisions and mergers may locally increase the ram pressure and trigger hydrodynamical interactions between the intracluster medium and the interstellar medium of galaxies., Comment: 18 pages, 14 figures, accepted for publication in MNRAS

Galactic outflows driven by star formation or active galactic nuclei are typically formed by multi-phase gas whose temperature spans over 4 orders of magnitude. Probing the different outflow components requires multi-wavelength observations and long exposure times, especially in the distant Universe. So far, most of the high-z studies have focused on a single gas phase, but this kind of analysis may potentially miss a non-negligible fraction of the total outflowing gas content. In this work, we analyze the spatially resolved rest-frame UV and optical emission from HZ4, the highest redshift main sequence star-forming galaxy having a detected [C II] outflow, which traces the neutral gas component. Our goal is to study the ionized interstellar medium in the galaxy and the properties of the ionized outflow as traced by the [O III]$\lambda$5007\r{A} and H$\alpha$ emission lines. We exploit JWST/NIRSpec observations in the integral field spectroscopy mode to investigate the galaxy properties by making use of the brightest rest-frame optical emission lines. Their high spectral and spatial resolution allows us to trace the ionized outflow from broad line wings and spatially resolve it. We also re-analyze the [C II] ALMA data to compare the neutral atomic and ionized outflow morphologies, masses, and energetics. We find that the system consists of a galaxy merger, instead of a rotating disk as originally inferred from low-resolution [C II] observations, and hosts an extended ionized outflow. The ionized outflow is being launched from a region hosting an intense burst of star formation and extends over 4 kpc from the launch site. The neutral and ionized outflows are almost co-spatial, but the mass loading factor in the ionized gas phase is two orders of magnitude smaller than in the neutral phase, as found for other lower redshift multi-phase outflows., Comment: 22 pages, 20 figures, submitted to A&A

Blockchain technology streamlines multi-party collaborations in decentralized settings, especially where trust is limited. While public blockchains enhance transparency and reliability, they conflict with confidentiality. To address this, we introduce Multi-Authority Approach to Transaction Systems for Interoperating Applications (MARTSIA). MARTSIA provides read-access control at the message-part level through user-defined policies and certifier-declared attributes, so that only authorized actors can interpret encrypted data while all blockchain nodes can verify its integrity. To this end, MARTSIA resorts to blockchain, Multi-Authority Attribute-Based Encryption and distributed hash-table data-stores.

We present JWST/NIRSpec integral-field spectroscopy observations of the z ~ 9.11 lensed galaxy MACS1149-JD1, as part of the GA-NIFS programme. The data was obtained with both the G395H grating (R~ 2700) and the prism (R~ 100). This target shows a main elongated UV-bright clump and a secondary component detected in continuum emission at a projected distance of 2 kpc. The R2700 data trace the ionised-gas morpho-kinematics in between the two components, showing an elongated emission mainly traced by [O III]5007. We spatially resolve [O II]3726,3729, [O III]4959,5007, and [O III]4363, which enable us to map the electron density (ne ~ 1.0 x 103 cm-3), temperature (Te ~ 1.6 x 104 K), and direct-method gas-phase metallicity (-1.2 to -0.7 dex solar). A spatially resolved full-spectrum modelling of the prism indicates a north-south gas metallicity and stellar age gradient between the two components. We found 3-sigma evidence of a spatially resolved anti-correlation of the gas-phase metallicity and the star formation rate density, which is likely driven by gas inflows, enhancing the star formation in JD1. We employ high-z sensitive diagnostic diagrams to rule out the presence of a strong AGN in the main component. These findings show the unambiguous presence of two distinct stellar populations, with the majority of the mass ascribed to an old star formation burst, as suggested by previous works. We disfavour the possibility of a rotating-disc nature for MACS1149-JD1; we favour a merger event that has led to a recent burst of star formation in two separate regions, as supported by high values of [O III]5007/Hbeta, ionised gas velocity dispersion, and gas-phase metallicity., Comment: 14 pages, 16 figures

We analyse ultra-deep JWST observations of the galaxy JADES-GS-z9-0 at z = 9.4327, and derive detailed stellar and interstellar medium (ISM) properties of this luminous (MUV=-20.43) high-redshift system. Complementary information from NIRCam imaging and NIRSpec (both low- and medium-resolution) spectroscopy reveal a compact system (Re ~110 pc) characterised by a steeply rising star formation history, which is reflected in the inferred young stellar age (t ~ 3 Myr, light-weighted), high star-formation rate surface density ({\Sigma}SFR ~ 72 M yr-1 kpc-2), high ionisation parameter (log(U) ~ -1.5), low metallicity (12+log(O/H) ~ 7.5), and low carbon-over-oxygen abundance ([C/O] = -0.64). Leveraging the detection of N iii]1750 we derive nitrogen-over-oxygen abundance ([N/O] ~ 0) higher than the plateau followed by low-redshift galaxies of similar metallicity, possibly revealing the imprint from (very) massive stars on the ISM enrichment and favouring a top-heavy Initial Mass Function (IMF) scenario. Massive stars powering a hard radiation field are also required to explain the rest-frame UV line ratios, though the presence of the high-excitation [Ne v]{\lambda}3426 emission line possibly hints at additional ionization from an AGN. We also report the tentative detection of Ly{\alpha} emission in the G140M spectrum, shifted by ~450 km/s redward of the systemic redshift. Combined with a modelling of the Ly{\alpha} spectral break, we rule out the presence of very high column densities of neutral gas pertaining to local absorbers, as well as any extended surrounding ionised bubble, suggesting that JADES-GS-z9-0 has not yet significantly contributed to cosmic Reionization., Comment: Submitted to A&A. Comments are welcome

The superpotential method is a reconstruction technique which has proven useful to build exact cosmological solutions. We here employ the superpotential method in order to reconstruct the features necessary for the inflaton potential to drive inflation and lead to the amplification of the curvature perturbations. Such an amplification, at wavelengths shorter than those observed in the CMB, is necessary in order to have a significant formation of Primordial Black Holes after inflation ends. The technique is applied to the cases of a minimally coupled inflaton, to the non-minimal coupling case and to f(R) theories of gravity. For such theories, a model dependent analysis of the features leading to the scalar spectrum enhancement is also presented., Comment: 30 pages

Abell 754 is a rich galaxy cluster at $z=0.0543$ and is considered the prototype of a major cluster merger. Like many dynamically unrelaxed systems, it hosts diffuse radio emission on Mpc-scales. Extended synchrotron sources in the intra-cluster medium (ICM) are commonly interpreted as evidence that a fraction of the gravitational energy released during cluster mergers is dissipated into nonthermal components. Here, we use new MeerKAT UHF- and L-band observations to study nonthermal phenomena in Abell 754. These data are complemented with archival XMM-Newton observations to investigate the resolved spectral properties of both the radio and X-ray cluster emission.For the first time, we employed the pipeline originally developed to calibrate LOFAR data to MeerKAT observations. This allowed us to perform a direction-dependent calibration and obtain highly sensitive radio images in UHF- and L-bands which capture the extended emission with unprecedented detail. By using a large XMM-Newton mosaic, we produced thermodynamic maps of the ICM. Our analysis reveals that the radio halo in the cluster center is bounded by the well-known shock in the eastern direction. Furthermore, in the southwest periphery, we discover an extended radio source that we classify as a radio relic which is possibly tracing a shock driven by the squeezed gas compressed by the merger, outflowing in perpendicular directions. The low-luminosity of this relic appears compatible with direct acceleration of thermal pool electrons. We interpret the observed radio and X-ray features in the context of a major cluster merger with a nonzero impact parameter. Abell 754 is a remarkable galaxy cluster showcasing exceptional features associated with the ongoing merger event. The high quality of the new MeerKAT data motivates further work on this system., Comment: 18 pages, 14 figures, 3 tables (excluding Appendix); Updated to match the accepted version in A&A

We present JWST NIRSpec observations in IFS mode of the galaxy GS5001 at redshift z=3.47, the brightest member of a candidate protocluster in the GOODS-S field. The data cover a field of view (FoV) of 4''$\times$4'' (~$30\times30$~kpc$^2$) and were obtained as part of the GA-NIFS GTO program. The observations include both high (R~2700) and low (R~100) spectral resolution data, spanning the rest-frame wavelength ranges 3700-6780A and 1300-11850A, respectively. We analyse the spatially resolved ionised gas kinematics and interstellar medium properties, including obscuration, gas metallicity, excitation, ionisation parameter, and electron density. In addition to the central galaxy, the NIRSpec FoV covers three components in the south, with velocities blue-shifted by -150 km/s with respect to the main galaxy, and another source in the north redshifted by ~200 km/s. The emission line ratios in the BPT diagram are consistent with star formation for all the sources in the FoV. We measure electron densities of ~500 cm$^{-3}$ in the different sources. The gas-phase metallicity in the main galaxy is 12+log(O/H) $= 8.45\pm0.04$, and slightly lower in the companions (12+log(O/H)$ = 8.34-8.42$), consistent with the mass-metallicity relation at $z\sim3$. We find peculiar line ratios (high log [NII]/H$\alpha$, low log [OIII]/H$\beta$) in the northern part of the main galaxy (GS5001). These could be attributed to either higher metallicity, or to shocks resulting from the interaction of the main galaxy with the northern source. We identify a spatially resolved outflow in the main galaxy, with an extension of about 3 kpc. We find maximum outflow velocities of ~400 km/s, an outflow mass of $(1.7\pm0.4)\times 10^8$ M$_{\odot}$, a mass outflow rate of $23\pm5$ M$_{\odot}$ yr$^{-1}$ and a mass loading factor of 0.23. These properties are compatible with star formation being the driver of the outflow., Comment: Submitted to A&A

In twisted layered materials (t-LMs), an inter-layer rotation can break inversion symmetry and create an interfacial array of staggered out-of-plane polarization due to AB/BA stacking registries. This symmetry breaking can also trigger the formation of edge in-plane polarizations localized along the perimeter of AB/BA regions (i.e., saddle point domains). However, a comprehensive experimental investigation of these features is still lacking. Here, we use piezo force microscopy to probe the electromechanical behavior of twisted hexagonal boron nitride (t-hBN). For a parallel stacking alignment of t-hBN, we reveal very narrow (width ~ 20 nm) saddle point polarizations, which we also measure in the anti-parallel configuration. These localized polarizations can still be found on a multiply-stacked t-hBN structure, determining the formation of a double moir\'e. We also visualize a t-hBN moir\'e superlattice in the topography maps with atomic force microscopy, related to the strain accumulated at the saddle point domains. Our findings imply that polarizations in t-hBN do not only point in the out-of-plane direction, but also show an in-plane component, giving rise to a much more complex 3D polarization field.

The $R$-hulloid, in the Euclidean space $\mathbb{R}^3$, of the set of vertices $V$ of a tetrahedron $T$ is the mimimal closed set containing $V$ such that its complement is union of open balls of radius $R$. When $R$ is greater than the circumradius of $T$, the boundary of the $R$-hulloid consists of $V$ and possibly of four spherical subsets of well defined spheres of radius $R$ through the vertices of $T$. The existence of a value $R^*$ such that these subsets collapse into one point $O^*\not \in V$ is investigated; in such case $O^*$ is in the interior of $T$ and belongs to four spheres of radius $R^*$, each one through three vertices of $T$ and not containing the fourth one. As a consequence, the range of $\rho$ such that $V$ is a $\rho$-body is described completely. This work generalizes to three dimensions previous results, proved in the planar case and related to the three circles Johnson's Theorem., Comment: 17 pages, 2 figures

JWST is discovering increasing numbers of quiescent galaxies 1--2 billion years after the Big Bang, whose redshift, high mass, and old stellar ages indicate that their formation and quenching were surprisingly rapid. This fast-paced evolution seems to require that feedback from AGN (active galactic nuclei) be faster and/or more efficient than previously expected \citep{Xie24}. We present deep ALMA observations of cold molecular gas (the fuel for star formation) in a massive, fast-rotating, post-starburst galaxy at $z=3.064$. This galaxy hosts an AGN, driving neutral-gas outflows with a mass-outflow rate of $60\pm20$ M$_{\odot}$ yr$^{-1}$, and has a star-formation rate of $<5.6$ M$_{\odot}$ yr$^{-1}$. Our data reveal this system to be the most distant gas-poor galaxy confirmed with direct CO observations (molecular-gas mass $< 10^{9.1}$ M$_{\odot}$; <0.8 % of its stellar mass). Combining ALMA and JWST observations, we estimate the gas-consumption history of this galaxy, showing that it evolved with net zero gas inflow, i.e., gas consumption by star formation matches the amount of gas this galaxy is missing relative to star-forming galaxies. This could arise both from preventive feedback stopping further gas inflow, which would otherwise refuel star formation or, alternatively, from fine-tuned ejective feedback matching precisely gas inflows. Our methods, applied to a larger sample, promise to disentangle ejective vs preventive feedback., Comment: 14 pages, 4 figures

The first observations of JWST have revolutionized our understanding of the Universe by identifying for the first time galaxies at $z\sim13$. In addition, the discovery of many luminous galaxies at Cosmic Dawn ($z>10$) has suggested that galaxies developed rapidly, in apparent tension with many standard models. However, most of these galaxies lack spectroscopic confirmation, so their distances and properties are uncertain. We present JADES JWST/NIRSpec spectroscopic confirmation of two luminous galaxies at redshifts of $z=14.32^{+0.08}_{-0.20}$ and $z=13.90\pm0.17$. The spectra reveal ultraviolet continua with prominent Lyman-$\alpha$ breaks but no detected emission lines. This discovery proves that luminous galaxies were already in place 300~million years after the Big Bang and are more common than what was expected before JWST. The most distant of the two galaxies is unexpectedly luminous and is spatially resolved with a radius of 260 parsecs. Considering also the very steep ultraviolet slope of the second galaxy, we conclude that both are dominated by stellar continuum emission, showing that the excess of luminous galaxies in the early Universe cannot be entirely explained by accretion onto black holes. Galaxy formation models will need to address the existence of such large and luminous galaxies so early in cosmic history., Comment: 15 figures, 3 tables, published in Nature

Controlling light at subwavelength scales is one of the main challenges of nanophotonics. Leveraging hyperbolic polaritons supporting arbitrarily large wavevectors can lead to extreme light confinement, effectively overcoming the diffraction limit. Hyperbolicity was initially realized in artificial metamaterials, but their performances are limited by high losses in the metallic components. While recently discovered natural low-loss hyperbolic phonon polaritons initiated a revival in the interest for hyperbolic materials, they are confined to the mid-infrared frequency range, limiting their use for several applications. Some hyperbolic materials at visible frequencies have been studied, but they are either very lossy or only feature out-of-plane hyperbolicity. Here, we demonstrate the presence of low-loss, in-plane hyperbolic plasmon polaritons in the visible and near-infrared in thin films of $\mathrm{MoOCl}_2$, a natural van der Waals crystal. The polariton dispersion is predicted based on the framework of light propagation in biaxial media, and experimentally confirmed by real space nano imaging on exfoliated flakes. $\mathrm{MoOCl}_2$ constitutes a novel material platform for visible-range applications leveraging the unboundedness of hyperbolic modes, such as hyperlensing, Purcell factor enhancement and super-resolution imaging, without the drawbacks of metamaterials.

Let a $R$-body be a closed set, complement of union of open balls of radius $R$ in the Euclidean space. Properties generalizing similar ones for convex sets are proved for the family of $R$-bodies; properties for the family of sets supported by spheres of radius $R$ (extension of the supporting hyperplane to convex bodies) are investigated. Comparison of that family with the sets of reach $R$ and with the $R$-rolling sets are studied. New properties for the previous families are proved, by using the $R$-cones, generalization of the convex cones.

The study of ionized gas kinematics in high-z active galaxies plays a key part in our understanding of galactic evolution, in an age where nuclear activity was widespread and star formation close to its peak. We present a study of TXS 0952-217, a radio galaxy at z=2.95, using VLT/MUSE integral field optical spectroscopy as part of a project aimed studying of the properties of ionized gas in high redshift radio galaxies (HzRGs). The Lyman $\alpha$ line profile of this object presents various emission and absorption components. By utilizing Voronoi binning, we obtained a comprehensive map of the kinematic properties of these components. These observations revealed the presence of a redshifted, high velocity (v $\sim 500$ km s$^-1$) bipolar structure of Lyman $\alpha$ emission, most likely corresponding to an outflow of ionized gas. The outflow extends beyond the compact radio source on both sides, with a total size of $\sim$ 21 kpc. Its kinetic power ($10^{42.1}$ erg s$^{-1}$) is about five orders of magnitude smaller than its radio power. Additional ionized lines, including HeII$\lambda$1640, CIV$\lambda$1550 and CIII]$\lambda$1908 were detected and their line flux ratios determined. The presence of HeII allowed for a precise redshift measurement (z=2.945$\pm$0.002). Along with the recent discovery of a similar structure in TN J1049-1258, another HzRG, it displays the feasibility of using Lyman $\alpha$ as a tracer of outflowing gas in high redshift sources, and particularly so when supported by non-resonant ionized lines such as HeII, which allow for accurate redshift and velocity measurements., Comment: 9 pages, 6 figures. Accepted for publication in Astronomy & Astrophysics

Among the bent tail radio galaxies common in galaxy clusters are some with long, collimated tails (so-called head-tail galaxies) shaped by their interactions with the intracluster medium (ICM). Here we report the discovery of intricate filamentary structure in and beyond the ~28' (570 kpc) long, helical radio tail of the Corkscrew Galaxy (1610-60.5, ESO137-G007), which resides in the X-ray bright cluster Abell 3627 (D = 70 Mpc). Deep radio continuum data were obtained with wide-field Phased Array Feeds on the Australian Square Kilometer Array Pathfinder (ASKAP) at 944 MHz and 1.4 GHz. The Corkscrew Galaxy is located 15' north of the prominent wide-angle tail (WAT) radio galaxy 1610-60.8 (ESO137-G006) near the cluster centre. While the bright (young) part of its radio tail is highly collimated, the faint (old) part shows increasing oscillation amplitudes, break-ups, and filaments. We find a stunning set of arc-shaped radio filaments beyond and mostly orthogonal to the collimated Corkscrew tail end, forming a partial bubble. This may be the first detection of a "proto-lobe" seen in 3D MHD simulations by Nolting et al. (2019), formed by the face-on impact of the Corkscrew Galaxy with a shock front in the cluster outskirts. Interactions of the radio galaxy tail with the ICM are likely responsible for the tail collimation and shear forces within the ICM for its increasingly filamentary structure. We also report the discovery of small (~20-30 kpc) ram-pressure stripped radio tails in four Abell 3627 cluster galaxies., Comment: 11 pages, 7 figures, MNRAS, submitted

Feedback is the key physical mechanism regulating galaxy formation. Stars in galaxies form when baryons radiatively cool down and fall into gravitational wells. Eventually, star formation quenches as gas is depleted and/or perturbed by feedback processes, no longer being able to collapse and condense. For massive galaxies, astronomers identify feedback from accreting supermassive black holes (active galactic nuclei, AGN) as the main agent responsible for quenching. We report the first spatially resolved spectroscopic observations of a massive, completely quiescent galaxy at $z=3.714$ (Jekyll) and its neighborhood. Jekyll is part of a galaxy pair with a compact, dusty, massive star-forming companion (Hyde). We find large amounts of ionized and neutral gas in the intergalactic medium around the pair, yet Jekyll has remained quiescent for more than 500~Myr. The emitting gas is consistent with AGN photoionization, but no AGN is observed in Jekyll. We find that, in contrast to standard scenarios, AGN in satellite galaxies can be critical contributors for keeping massive galaxies quiescent in the early Universe. After the accelerated formation and quenching of the massive central galaxy, tidally induced gas stripping additionally contributes to the star-formation regulation on subsequent satellite galaxy generations., Comment: Submitted. Comments welcome

We investigate the X-ray properties of a large sample of 71 broad line and narrow line AGN at 2

We present the third data release of JADES, the JWST Advanced Deep Extragalactic Survey, providing both imaging and spectroscopy in the two GOODS fields. Spectroscopy consists of medium-depth and deep NIRSpec/MSA spectra of 4,000 targets, covering the spectral range 0.6-5.3 $\mu$m and observed with both the low-dispersion prism (R=30-300) and all three medium-resolution gratings (R=500-1,500). We describe the observations, data reduction, sample selection, and target allocation. We measured 2,375 redshifts (2,053 from multiple emission lines); our targets span the range from z=0.5 up to z=13, including 404 at z>5. The data release includes 2-d and 1-d fully reduced spectra, with slit-loss corrections and background subtraction optimized for point sources. We also provide redshifts and S/N>5 emission-line flux catalogs for the prism and grating spectra, and concise guidelines on how to use these data products. Alongside spectroscopy, we are also publishing fully calibrated NIRCam imaging, which enables studying the JADES sample with the combined power of imaging and spectroscopy. Together, these data provide the largest statistical sample to date to characterize the properties of galaxy populations in the first billion years after the Big Bang., Comment: 41 pages, 26 figures, 10 tables. Submitted to ApJS

Object detection in remotely sensed satellite pictures is fundamental in many fields such as biophysical, and environmental monitoring. While deep learning algorithms are constantly evolving, they have been mostly implemented and tested on popular ground-based taken photos. This paper critically evaluates and compares a suite of advanced object detection algorithms customized for the task of identifying aircraft within satellite imagery. Using the large HRPlanesV2 dataset, together with a rigorous validation with the GDIT dataset, this research encompasses an array of methodologies including YOLO versions 5 and 8, Faster RCNN, CenterNet, RetinaNet, RTMDet, and DETR, all trained from scratch. This exhaustive training and validation study reveal YOLOv5 as the preeminent model for the specific case of identifying airplanes from remote sensing data, showcasing high precision and adaptability across diverse imaging conditions. This research highlight the nuanced performance landscapes of these algorithms, with YOLOv5 emerging as a robust solution for aerial object detection, underlining its importance through superior mean average precision, Recall, and Intersection over Union scores. The findings described here underscore the fundamental role of algorithm selection aligned with the specific demands of satellite imagery analysis and extend a comprehensive framework to evaluate model efficacy. The benchmark toolkit and codes, available via https://github.com/toelt-llc/FlightScope_Bench, aims to further exploration and innovation in the realm of remote sensing object detection, paving the way for improved analytical methodologies in satellite imagery applications., Comment: 15 figures, 4 tables, comprehensive survey, comparative study

PDS 456 is the most luminous RQQ at z<0.3 and can be regarded as a local counterpart of the powerful QSOs shining at Cosmic Noon. It hosts a strong nuclear X-ray ultra-fast outflow, and a massive and clumpy CO(3-2) molecular outflow extending up to 5 kpc from the nucleus. We analyzed the first MUSE WFM and AO-NFM optical integral field spectroscopic observations of PDS456. The AO-NFM observations provide an unprecedented spatial resolution, reaching up to 280 pc. Our findings reveal a complex circumgalactic medium around PDS 456, extending up to a maximum projected size of ~46 kpc. This includes a reservoir of gas with a mass of ~1e7-1e8 Modot, along with eight companion galaxies, and a multi-phase outflow. WFM and NFM MUSE data reveal an outflow on a large scale (~12 kpc from the quasar) in [OIII], and on smaller scales (within 3 kpc) with higher resolution (about 280 pc) in Halpha, respectively. The [OIII] outflow mass rate is 2.3 +/- 0.2 Modot/yr which is significantly lower than those typically found in other luminous quasars. Remarkably, the Ha outflow shows a similar scale, morphology, and kinematics to the CO(3-2) molecular outflow, with the latter dominating in terms of kinetic energy and mass outflow rate by two and one orders of magnitude, respectively. Our results therefore indicate that mergers, powerful AGN activity, and feedback through AGN-driven winds will collectively contribute to shaping the host galaxy evolution of PDS 456, and likely, that of similar objects at the brightest end of the AGN luminosity function across all redshifts. Moreover, the finding that the momentum boost of the total outflow deviates from the expected energy-conserving expansion for large-scale outflows highlights the need of novel AGN-driven outflow models to comprehensively interpret these phenomena., Comment: 15 pages, 13 figures accepted for publication in Astronomy & Astrophysics

Machine Learning (ML) algorithms have become increasingly popular for supporting Network Intrusion Detection Systems (NIDS). Nevertheless, extensive research has shown their vulnerability to adversarial attacks, which involve subtle perturbations to the inputs of the models aimed at compromising their performance. Recent proposals have effectively leveraged Graph Neural Networks (GNN) to produce predictions based also on the structural patterns exhibited by intrusions to enhance the detection robustness. However, the adoption of GNN-based NIDS introduces new types of risks. In this paper, we propose the first formalization of adversarial attacks specifically tailored for GNN in network intrusion detection. Moreover, we outline and model the problem space constraints that attackers need to consider to carry out feasible structural attacks in real-world scenarios. As a final contribution, we conduct an extensive experimental campaign in which we launch the proposed attacks against state-of-the-art GNN-based NIDS. Our findings demonstrate the increased robustness of the models against classical feature-based adversarial attacks, while highlighting their susceptibility to structure-based attacks., Comment: preprint submitted to IEEE TIFS, under review

We present the first statistical investigation of spatially resolved emission-line properties in a sample of 63 low-mass galaxies at $4\leq z<10$, using JWST/NIRSpec MSA data from the JWST Advanced Deep Extragalactic (JADES) survey focusing on deep, spatially resolved spectroscopy in the GOODS-S extragalactic field. By performing a stacking of the 2D spectra of the galaxies in our sample, we find an increasing or flat radial trend with increasing radius for [OIII]$\lambda5007$/H$\beta$ and a decreasing one for [NeIII]$\lambda3869$/[OII]$\lambda3727$ (3--4 $\sigma$ significance). These results are still valid when stacking the sample in two redshift bins (i.e., $4\leq z<5.5$ and $5.5\leq z<10$). The comparison with star-formation photoionization models suggests that the ionization parameter increases by $\sim 0.5$ dex with redshift. We find a tentative metallicity gradient that increases with radius (i.e., 'inverted') in both redshift bins. Moreover, our analysis reveals strong negative gradients for the equivalent width of \Hbeta (7$\sigma$ significance). This trend persists even after removing known AGN candidates, therefore, it is consistent with a radial gradient primarily in stellar age and secondarily in metallicity. Taken all together, our results suggest that the sample is dominated by active central star formation, with possibly inverted metallicity gradients sustained by recent episodes of accretion of pristine gas or strong radial flows. Deeper observations and larger samples are needed to confirm these preliminary results and to validate our interpretation., Comment: 15 pages, 13 Figures, 1 Table. Submitted to A&A

Functional Differential Equations (FDEs) play a fundamental role in many areas of mathematical physics, including fluid dynamics (Hopf characteristic functional equation), quantum field theory (Schwinger-Dyson equation), and statistical physics. Despite their significance, computing solutions to FDEs remains a longstanding challenge in mathematical physics. In this paper we address this challenge by introducing new approximation theory and high-performance computational algorithms designed for solving FDEs on tensor manifolds. Our approach involves approximating FDEs using high-dimensional partial differential equations (PDEs), and then solving such high-dimensional PDEs on a low-rank tensor manifold leveraging high-performance parallel tensor algorithms. The effectiveness of the proposed approach is demonstrated through its application to the Burgers-Hopf FDE, which governs the characteristic functional of the stochastic solution to the Burgers equation evolving from a random initial state., Comment: 16 pages, 7 figures

The study of gas-phase metallicity and its spatial distribution at high redshift is crucial to understand the processes that shaped the growth and evolution of galaxies in the early Universe. Here we study the spatially resolved metallicity in three systems at $z\sim6-8$, namely A2744-YD4, BDF-3299, and COSMOS24108, with JWST NIRSpec IFU low-resolution ($R\sim100$) spectroscopic observations. These are among the highest-$z$ sources in which metallicity gradients have been probed so far. Each of these systems hosts several spatial components in the process of merging within a few kpc, identified from the rest-frame UV and optical stellar continuum and ionised gas emission line maps. The sources have heterogeneous properties, with stellar masses log($M_*/M_\odot) \sim 7.6-9.3$, star formation rates (SFRs) $\sim1-15$ $M_\odot$ yr$^{-1}$, and gas-phase metallicities 12+log(O/H) $\sim 7.7-8.3$, which exhibit a large scatter within each system. Their properties are generally consistent with those of the highest-$z$ samples to date ($z\sim3-10$), though the sources in A2744-YD4 and COSMOS24108 are at the high end of the mass-metallicity relation (MZR) defined by the $z\sim3-10$ sources. Moreover, the targets in this work follow the predicted slope of the MZR at $z\sim 6-8$ from most cosmological simulations. The gas-phase metallicity gradients are consistent with being flat in the main sources of each system. Flat metallicity gradients are thought to arise from gas mixing processes on galaxy scales, such as mergers or galactic outflows and SN winds driven by intense stellar feedback, which wash out any gradient formed in the galaxy. The existence of flat gradients at $z\sim6-8$ sets also important constraints on cosmological simulations and chemical evolution models, whose predictions on the cosmic evolution of metallicity gradients differ significantly, but are mostly limited to $z<3$ so far., Comment: 15 pages (+5 appendix); 7 figures (+8 in appendix); in production on A&A

We present rest-frame optical data of the z~4 sub-millimeter galaxy GN20 obtained with JWST/NIRSpec in integral field spectroscopy (IFS) mode. The H$\alpha$ emission is asymmetric and clumpy and extends over a projected distance of more than 15 kpc. To first order, the large-scale ionised gas kinematics are consistent with a turbulent ($\sigma\sim90$ km/s), rotating disc ($v_{\rm rot}\sim500$ km/s), congruent with previous studies of its molecular and ionised gas kinematics. However, we also find clear evidence for non-circular motions in the H$\alpha$ kinematics. We discuss their possible connection with various scenarios, such as external perturbations, accretion or radial flows. In the centre of GN20, we find broad line emission (FWHM $\sim1000-2000$ km/s) in the H$\alpha$+[N II] complex, suggestive of fast, AGN-driven winds or, alternatively, of the broad-line region of an active black hole. Elevated values of [N II]$\lambda6583$/H$\alpha>0.4$ and EW(H$\alpha)>6$ \r{A}, throughout large parts of GN20 suggest that feedback from the active black hole is able to photo-ionise the interstellar medium. Our data corroborates that GN20 offers a unique opportunity to observe key processes in the evolution of the most massive present-day galaxies acting in concert, over 12 billion years ago., Comment: 12 pages, 8 figures; accepted for publication in MNRAS; doi:10.1093/mnras/stae1993

An increasing number of observations and simulations suggests that low-power (<10$^{44}$ erg s$^{-1}$) jets may be a significant channel of feedback produced by active galactic nuclei (AGN), but little is known about their actual effect on their host galaxies from the observational point of view. We targeted four luminous type 2 AGN hosting moderately powerful radio emission ($\sim$10$^{44}$ erg s$^{-1}$), two of which and possibly a third are associated with jets, with optical integral field spectroscopy observations from the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT) to analyze the properties of their ionized gas as well as the properties and effects of ionized outflows. We combined these observations with Very Large Array (VLA) and e-MERLIN data to investigate the relations and interactions between the radio jets and host galaxies. We detected ionized outflows as traced by the fast bulk motion of the gas. The outflows extended over kiloparsec scales in the direction of the jet, when present. In the two sources with resolved radio jets, we detected a strong enhancement in the emission-line velocity dispersion (up to 1000 km s$^{-1}$) perpendicular to the direction of the radio jets. We also found a correlation between the mass and the energetics of this high-velocity dispersion gas and the radio power, which supports the idea that the radio emission may cause the enhanced turbulence. This phenomenon, which is now being observed in an increasing number of objects, might represent an important channel for AGN feedback on galaxies., Comment: 18 pages, 17 figures

The connection between the thermal and non-thermal properties in galaxy clusters hosting radio halos seems fairly well established. However, a comprehensive analysis of such a connection has been made only for integrated quantities (e.g. $L_X - P_{radio}$ relation). In recent years new-generation radio telescopes have enabled the unprecedented possibility to study the non-thermal properties of galaxy clusters on a spatially resolved basis. Here, we perform a pilot study to investigate the mentioned properties on five targets, by combining X-ray data from the CHEX-MATE project with the second data release from the LOFAR Two meter Sky survey. We find a strong correlation ($r_s \sim 0.7$) with a slope less than unity between the radio and X-ray surface brightness. We also report differences in the spatially resolved properties of the radio emission in clusters which show different levels of dynamical disturbance. In particular, less perturbed clusters (according to X-ray parameters) show peaked radio profiles in the centre, with a flattening in the outer regions, while the three dynamically disturbed clusters have steeper profiles in the outer regions. We fit a model to the radio emission in the context of turbulent re-acceleration with a constant ratio between thermal and non-thermal particles energy density and a magnetic field profile linked to the thermal gas density as $B(r) \propto n_{th}^{0.5}$. We found that this simple model cannot reproduce the behaviour of the observed radio emission., Comment: 23 pages, 10 figures, accepted for publication in A&A

In this paper, we explore the impact of augmenting pre-trained Encoder-Decoder models, specifically T5, with linguistic knowledge for the prediction of a target task. In particular, we investigate whether fine-tuning a T5 model on an intermediate task that predicts structural linguistic properties of sentences modifies its performance in the target task of predicting sentence-level complexity. Our study encompasses diverse experiments conducted on Italian and English datasets, employing both monolingual and multilingual T5 models at various sizes. Results obtained for both languages and in cross-lingual configurations show that linguistically motivated intermediate fine-tuning has generally a positive impact on target task performance, especially when applied to smaller models and in scenarios with limited data availability., Comment: Accepted to LREC-COLING 2024

Stellar feedback in dwarf galaxies remains, to date, poorly explored, yet is crucial to understanding galaxy evolution in the early Universe. In particular, pre-supernova feedback has recently been found to play a significant role in regulating and disrupting star formation in larger spiral galaxies, but it remains uncertain if it also plays this role in dwarfs. We study the ionised gas properties and stellar content of individual star-forming regions across three nearby, low-metallicity, dwarf starburst galaxies (J0921, KKH046, and Leo P) to investigate how massive stars influence their surroundings and how this influence changes as a function of environment. To achieve this, we extracted integrated spectra of 30 HII regions from archival VLT/MUSE integral field spectroscopic observations of these three dwarf starburst galaxies. We fitted the HII regions' main emission lines with Gaussian profiles to derive their oxygen abundances, electron densities, and luminosities, and we used the Stochastically Lighting Up Galaxies (SLUG) code to derive the stellar mass, age, and bolometric luminosity of the stellar populations driving the HII regions. We then quantified two pre-supernova stellar feedback mechanisms, namely the direct radiation pressure and photoionisation feedback, and explored how feedback strength varies with HII region properties. Our findings suggest that stellar feedback has less of an impact on evolved regions, with both the pressure of the ionised gas and the direct radiation pressure decreasing as a function of HII region size. We also find that these stellar feedback mechanisms are dependent on the metallicity of the HII regions. These findings extend results from stellar feedback studies of more massive star-forming galaxies to the low-mass, low-metallicity regime., Comment: The paper has been published in A&A

We make a conceptual overview of a particular approach to the initial-value problem in canonical gauge theories. We stress how the first-class phase-space constraints may be relaxed if we interpret them as fixing the values of new degrees of freedom. This idea goes back to Fock and Stueckelberg, leading to restrictions of the gauge symmetry of a theory, and it corresponds, in certain cases, to promoting constants of Nature to physical fields. Recently, different versions of this formulation have gained considerable attention in the literature, with several independent iterations, particularly in classical and quantum descriptions of gravity, cosmology, and electromagnetism. In particular, in the case of canonical quantum gravity, the Fock--Stueckelberg approach is relevant to the so-called problem of time. Our overview recalls the work of Fock and Stueckelberg and its physical interpretation with the aim of conceptually unifying the different iterations of the idea that appear in the literature and of motivating further research.

In this paper, we unify the study of classical and non-classical algebra-valued models of set theory, by studying variations of the interpretation functions for identity and set-membership. Although, these variations coincide with the standard interpretation in Boolean-valued constructions, nonetheless they extend the scope of validity of ZF to new algebra-valued models.

We present HOMERUN (Highly Optimized Multi-cloud Emission-line Ratios Using photo-ionizatioN), a new approach to modelling emission lines from photoionized gas that can simultaneously reproduce all observed line intensities from a wide range of ionization levels and with high accuracy. Our approach is based on the weighted combination of multiple single-cloud photoionization models and, contrary to previous works, the novelty of our approach consists in using the weights as free parameters of the fit and constraining them with the observed data. One of the main applications of HOMERUN is the accurate determination of gas-phase metallicities and we show that a critical point is to allow for a variation of the N/O and S/O abundance ratios which can significantly improve the quality of the fit and the accuracy of the results. Moreover, our approach provides a major improvement compared to the single-cloud, constant-pressure models commonly used in the literature. By using high-quality literature spectra of H ii regions where 10 to 20 emission lines (including several auroral lines) are detected with high signal-to-noise ratio, we show that all lines are reproduced by the model with an accuracy better than 10%. In particular, the model is able to simultaneously reproduce [O i]6300, 6363, [O ii]3726, 3729, [O iii]4959, 5007, [S ii]6717, 6731, and [S iii]9069, 9532 emission lines which, to our knowledge, is an unprecedented result. Finally, we show that the gas metallicities estimated with our models for HII regions in the Milky Way are in agreement with the stellar metallicities than the estimates based on the Te-method. Overall, our method provides a new accurate tool to estimate the metallicity and the physical conditions of the ionized gas. It can be applied to many different science cases from HII regions to AGN and wherever there are emission lines from photoionized gas., Comment: A&A in press, new version following referee report

We present very-long-baseline interferometry (VLBI) observations of the hyperactive repeating FRB 20220912A using the European VLBI Network (EVN) with an EVN-Lite setup. We detected 150 bursts from FRB 20220912A over two observing epochs in October 2022. Combining the data of these bursts allows us to localise FRB 20220912A to a precision of a few milliarcseconds, corresponding to a transverse scale of less than 10 pc at the distance of the source. The precision of this localisation shows that FRB 20220912A lies closer to the centre of its host galaxy than previously found, although still significantly offset from the host galaxy's nucleus. On arcsecond scales, FRB 20220912A is coincident with a persistent continuum radio source known from archival observations, however, we find no compact persistent emission on milliarcsecond scales. The persistent radio emission is thus likely to be from star-formation in the host galaxy. This is in contrast to some other active FRBs, such as FRB 20121102A and FRB 20190520B., Comment: 13 pages, 7 figures, submitted to MNRAS, comments most welcome

A surprising finding of recent studies is the large number of Active Galactic Nuclei (AGN) associated with moderately massive black holes ($\rm \log(M_\bullet/M_\odot)\sim 6-8$), in the first billion years after the Big Bang ($z>5$). In this context, a relevant finding has been the large fraction of candidate dual AGN, both at large separations (several kpc) and in close pairs (less than a kpc), likely in the process of merging. Frequent black hole merging may be a route for black hole growth in the early Universe; however, previous findings are still tentative and indirect. We present JWST/NIRSpec-IFU observations of a galaxy at $z=7.15$ in which we find evidence for a $\rm \log(M_\bullet/M_\odot)\sim7.7$ accreting black hole, as traced by a broad component of H$\beta$ emission, associated with the Broad Line Region (BLR) around the black hole. This BLR is offset by 620 pc in projection from the centroid of strong rest-frame optical emission, with a velocity offset of $\sim$40 km/s. The latter region is also characterized by (narrow) nebular emission features typical of AGN, hence also likely hosting another accreting black hole, although obscured (type 2, narrow-line AGN). We exclude that the offset BLR is associated with Supernovae or massive stars, and we interpret these results as two black holes in the process of merging. This finding may be relevant for estimates of the rate and properties of gravitational wave signals from the early Universe that will be detected by future observatories like LISA., Comment: 12 pages, 5 figures; accepted for publication in MNRAS; doi:10.1093/mnras/stae943

We present radio and X-ray studies of A3444 and MS1455.0+2232, two galaxy clusters with radio minihalos in their cool cores. A3444 is imaged using the Giant Metrewave Radio Telescope (GMRT) at 333, 607 and 1300 MHz and the Very Large Array at 1435 MHz. Most of the minihalo is contained within r<120 kpc, but a fainter extension, stretching out to 380 kpc South-West of the center, is detected at 607 MHz. Using Chandra, we detect four X-ray sloshing cold fronts: three in the cool core at r=60, 120 and 230 kpc, and a fourth one at r=400 kpc - in the region of the southwestern radio extension - suggesting that the intracluster medium (ICM) is sloshing on a cluster-wide scale. The radio emission is contained within the envelope defined by these fronts. We also analyzed archival 383 MHz GMRT and Chandra observations of MS1455.0+2232, which exhibits a known minihalo with its bright part delineated by cold fronts inside the cool core, but with a faint extension beyond the core. Similarly to A3444, we find a cold front at r~425 kpc, containing the radio emission. Thus the entire diffuse radio emission seen in these clusters appears to be related to large-scale sloshing of the ICM. The radio spectrum of the A3444 minihalo is a power law with a steep index $\alpha=1.0\pm0.1$. The spectrum steepens with increasing distance from the center, as expected if the minihalo originates from re-acceleration of relativistic particles by the sloshing-induced turbulence in the ICM., Comment: 29 pages, 15 figures, accepted for publication in ApJ