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Physics Astrophysics

astro-ph Watch Astrophysics

Wednesday 8 July

High Energy Astrophysical Phenomena

Multi-Wavelength Signatures of a Giant Cometary Radio Halo in MACSJ0417-1154

Ramananda Santra, Marco Balboni and Ruta Kale

Galaxy clusters hosting diffuse non-thermal radio emission offer direct insight into plasma processes of the intracluster medium (ICM). We present the first multi-frequency study of the radio halo in MACSJ0417 (z = 0.445) using uGMRT (300-850 MHz), MeerKAT (900-1670 MHz), and archival XMM-Newton data. The halo extends to $\sim$1.75 Mpc at 400 MHz, while two candidate relics (R1 and R2) are detected at 2.9 Mpc. The integrated spectra follow single power-laws with spectral indices $\alpha \simeq -1.3$ for the halo and $\alpha \simeq -1.6$ for the relics. Sensitive uGMRT imaging reveals a radio surface brightness edge $\sim$43$''$ SE of the cluster centre, which coincides with an X-ray discontinuity. Resolved spectral maps (400–1280 MHz) show significant fluctuations and a clear radial steepening of the spectral index. X-ray analysis reveals an elongated SE-NW morphology and high-temperature regions ($\sim$11 keV) along this axis. A strong radio and X-ray surface brightness correlation is found (correlation coefficient $\sim$ 0.85), with the correlation slope evolving from sublinear at 400 MHz to linear at 1280 MHz. These results, together with the spectral properties, support the turbulent re-acceleration model and point to inhomogeneous ICM conditions. The pure hadronic model is excluded owing to unrealistic energy requirements for cosmic-ray protons. We propose that MACSJ0417 is undergoing a minor off-axis dissociative merger (mass ratio $\sim$6:1) along the SE-NW axis, which has preserved its cool core while driving turbulence that powers the giant radio halo.
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Instrumentation and Methods for Astrophysics

Space and Lunar Interferometry: Emerging Concepts and Pathways

Gioia Rau

Space- and lunar-based interferometry are moving from aspiration toward a concrete landscape of mission studies, pathfinders, and staged architectures. This invited review surveys that landscape across two principal platform pathways: free-flying and lunar-surface interferometers - plus structurally connected designs and hybrid space-VLBI arrays. I trace how the science target sets the wavelength regime and angular resolution, which in turn fix the baseline, architecture, and implementation risk. Mid-infrared nulling concepts such as LIFE target temperate exoplanets through thermal-emission spectroscopy; lunar far-side radio arrays (FARSIDE, FarView) open the low-frequency Universe from the only radio-quiet site in the inner Solar System; lunar UV/optical concepts (Artemis-enabled Stellar Imager, MoonLITE) revisit imaging of stellar surfaces and open a path to microarcsecond astrometry for the dynamical masses that Habitable Worlds Observatory target selection requires; far-infrared interferometers (SPIRIT/SPICE), space VLBI (BHEX), and X-ray concepts extend the reach to planet formation, high-redshift galaxies, and black-hole physics; and lunar laser interferometry (LILA) applies the lunar platform to mid-band gravitational waves, measuring strain rather than angular position. Across this range, the concepts share enabling technologies - precision formation flying, absolute metrology, beam combination and nulling, cryogenics, and autonomous deployment - maturing largely as byproducts of flagship programs, a dynamic that increasingly governs which concepts become missions. I summarize the pathways in baseline, wavelength, science return, deployment strategy, and risk, and close with the decisions of the coming decade: pathfinder sequencing, technology tall poles, and the funding models that can carry technologies from laboratory demonstration to flight readiness.
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Cosmology and Nongalactic Astrophysics

The Subversive Role of Excessive External Shear in Concealing Lensing Anomalies

Amruth Alfred, Shashpal Singh, Rommulus Francis Lewis et al. (+5 more)

To best reproduce observed multiply-lensed lensed images, lens models usually incorporate shear attributed to objects unrelated to the lensing galaxy (i.e., external shear): whether it be neighbouring galaxies not explicitly included in the lens model or other cosmic structures along the sightline. When constrained solely by the positions of image counterparts, such lens models, even those utilising simple ellipsoidal mass distributions, can satisfactorily – if not near perfectly – reproduce the observed image positions, but often leave significant differences in flux ratios between the predicted and observed images. For the narrow-line regions (NLRs) of quasars, which are too large to be affected by micro-lensing from stars in the lensing galaxy, the flux ratio anomalies thus left are commonly attributed to small-scale structures (sub-structures) in Dark Matter associated with the lensing galaxy. Here, we show that external shear can always resolve, among the quadruply-lensed quasar NLRs studied, position anomalies in lens models constrained solely by the observed image positions, and in addition reduce although not fully resolving flux ratio anomalies when constrained by both the observed image positions and flux ratios – provided, usually, that the external shear incorporated have strengths that far exceed (as is the common practise) those typically inferred from weak lensing along general sightlines (i.e., cosmic shear). Our work highlights the subversive role of excessive external shear in concealing lensing anomalies, undermining inferences on the characteristics of Dark Matter sub-structures – and, correspondingly, the nature (mass and temperature) of the Dark Matter particle – when not sensibly incorporated into lens models.
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All authors Amruth Alfred, Shashpal Singh, Rommulus Francis Lewis, Alex Chow, Jeremy Lim, Masamune Oguri, Jose M. Diego, Tom Broadhurst

Earth and Planetary Astrophysics

Radio emission from close-in exoplanets: Can we extend the radio-magnetic scaling law to the sub-Alfvénic stellar wind regime?

Filip Elekes and Aline A. Vidotto

Observations of exoplanetary radio aurora can directly probe planetary magnetic fields and magnetic star-planet interactions. However, the search for exoplanetary radio aurora has been without confirmed detections despite favorable predictions based on extrapolations of the radio-magnetic scaling law (RMSL). The RMSL is based on solar system planets in the super-Alvenic solar wind and it is unclear whether the RMSL holds for close-in exoplanets in more magnetic, sub-Alfvenic winds. We aim to test whether the relation can be extended to sub-Alfvenic stellar winds. We employ 3D magnetohydrodynamic simulations of the magnetosphere of a Jupiter-like planet at various distances from the Sun to study the expected radio power, considering atmospheric photoionization, a solar wind model with nominal and enhanced magnetic field. Our radio predictions match the RMSL in the super-Alfvenic solar wind regime. We find that the RMSL overestimates the planetary radio power by one order of magnitude in sub-Alfvenic stellar winds. This discrepancy is significantly enhanced with a more magnetic wind due to a strong decrease in wind-magnetosphere energy transfer efficiency. We expect the overestimation by the RMSL to increase further with more magnetic cool stars. Furthermore, due to atmospheric photoionization and resulting high ionospheric electron densities, favorable conditions for generation and escape of electron-cyclotron maser instability (ECMI) driven radio emission are confined to larger orbits (> 0.1au) and to the planetary nightside in the solar wind case. This further decreases our predicted radio powers by up to one order of magnitude. In more magnetic winds, enhanced open planetary magnetic flux and reconnection driven outflows cause magnetospheric electron depletion, resulting in improved ECMI conditions, eliminating the mitigating effect of photoionization on ECMI emission.
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High Energy Astrophysical Phenomena

Coherent Signal Detection with Pruning – I. Finding Short-Period Binary Pulsars in Circular Orbits

Pravir Kumar and Barak Zackay

Detecting pulsars in short-period binary systems, which are unparalleled laboratories for fundamental physics and tests of general relativity, is a prime objective of radio astronomy. Their rapid orbital motion, however, presents a formidable computational challenge. Conventional searches are therefore limited to simplified signal models (e.g., constant acceleration) that remain valid for only short integrations ($\lesssim 4$-$10$% of an orbital period). This fundamental limitation severely degrades search sensitivity, placing much of the faint, relativistic pulsar population beyond the reach of current surveys. We present a novel hierarchical search framework based on extreme pruning that overcomes these limitations by progressively eliminating improbable regions of parameter space across successive coherent integration stages. The algorithm achieves $>90$% detection probability at the sensitivity threshold, with near-unity recovery for stronger signals, while reducing the computational complexity of full circular-orbit searches by up to 10 orders of magnitude relative to an unpruned hierarchical baseline. The resulting efficiency enables, for the first time, fully coherent integration over an entire orbital period and beyond. Compared to conventional acceleration searches, the proposed method delivers a 3- to 5-fold improvement in sensitivity, dramatically increasing the discovery potential for high-value targets such as pulsar-black hole binaries.
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Astrophysics of Galaxies

Tracing the Evolution of the Balmer Break from Cosmic Dawn to Cosmic Noon with JWST

Adarsh Kuruvanthodi, Daniel Schaerer, Rui Marques-Chaves et al. (+3 more)

The Balmer break (BB) is a key spectral feature for constraining stellar population ages, star formation histories, and redshifts of high-redshift sources. The redshift evolution and distribution of BB strength, together with the properties of BB galaxies, constrain stellar population characteristics and the nature of star formation across cosmic epochs. However, a systematic and unbiased characterization of BB strengths across the full galaxy population remains limited with the James Webb Space Telescope (JWST). We aim to characterize the redshift evolution of BB strength over $z=3.5$-10 and its distribution across different epochs using photometry. We also examine correlations between BB strength and key physical parameters within these redshift intervals. We further assess the implications of BB galaxies for the nature of star formation and stellar populations at $z>3.5$. We used the JWST NIRCam photometric observations taken as part of various programs, including CEERS, JADES, FRESCO, and PRIMER. We estimated the BB strength of the objects with two adjacent broadband filters in various redshift windows between redshifts 3 and 10, which exclude strong line contamination. We employ the SED-fitting code CIGALE for both SED fitting and the generation of mock galaxy simulations. We find that the median Balmer break strength (expressed as a flux ratio) increases from cosmic dawn to cosmic noon, from 1.1 to 1.5, primarily driven by the age of the stellar population. These estimations are in agreement with the latest spectroscopic estimations in the literature. We identify objects with extremely large BB strengths (BB$>3.0$) at $z=3.5$-4 and $z=7$-10, indicating strong extinction combined with an old stellar population and the presence of Little Red Dots (LRDs) in the former, and predominantly LRDs in the latter.[abridged]
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All authors Adarsh Kuruvanthodi, Daniel Schaerer, Rui Marques-Chaves, Andrea Weibel, Damien Korber, Corinne Charbonnel

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th

Unification of polynomial and exponential cosmological attractors

Renata Kallosh and Andrei Linde

We introduce a family of simple $\alpha$-attractor models that can interpolate between exponential and polynomial cosmological attractors. By varying the interpolation parameter $\mu$ in these models, one can scan a wide range of values of the spectral index $n_{s}$ matching any combination of CMB and DESI data.
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High Energy Astrophysical Phenomena

Subsolar-mass binary mergers of strange stars and neutron stars: gravitational waves and ejecta

Yong Gao, Ming-Zhe Han, Kenta Kiuchi et al. (+3 more)

We present the first numerical-relativity simulations of subsolar-mass binary strange star (SS) mergers and compare with binary neutron star (NS) mergers across equations of state, masses, and mass ratios. The self-bound nature of SSs makes them less deformed during the inspiral and keeps a sharp surface up to contact, driving strong shock heating and a large radial bounce that are far weaker in the NS. The more compact SS thus reaches a higher gravitational-wave cutoff frequency $f_\mathrm{cut}$ before contact but a lower post-merger peak frequency $f_2$. Within each class these frequencies follow quasi-universal relations with the tidal deformability, and their ratio $f_2/f_\mathrm{cut}$ cleanly separates the two classes. Both classes can eject $\sim10^{-2}\,M_\odot$ of material, neutron-rich for the NS and decompressed quark matter for the SS, a potential source of an electromagnetic counterpart whose observation could test the SS and NS hypotheses for subsolar-mass events.
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All authors Yong Gao, Ming-Zhe Han, Kenta Kiuchi, Masaru Shibata, Enping Zhou, Kenta Hotokezaka

Earth and Planetary Astrophysics

Extra Invariant in Magnetohydrodynamics of Planets and Stars

Alexander M. Balk

The paper establishes extra invariant in magnetohydrodynamics (MHD) of rotating and stratified fluid layer. This invariant is conserved adiabatically, i.e. approximately over long time. The existence of the invariant is interesting by itself, as such invariants are extremely rare. However, in addition, this invariant appears to be connected to the famous dynamo phenomenon.
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Cosmology and Nongalactic Astrophysics

Gamma-ray bursts reveal the history and faint contributors of cosmic reionization

Jing-Meng Hao, Paolo Cassata, Zhen-Ya Zheng et al. (+5 more)

Star-forming galaxies are generally believed to be the main drivers of cosmic reionization. However, the relative contributions of bright and faint galaxies to this process remain unclear. As the most luminous transient phenomena in the universe, long gamma-ray bursts (LGRBs) provide a unique opportunity to probe star formation occurring in both detectable and undetectable galaxies. In this Letter, we present new estimates of the cosmic star formation rate density (SFRD) at $4<z<10$ using Swift LGRBs detected over the past two decades, by considering LGRBs as unbiased tracers of total star formation at high redshifts. Crucially, we find that the new LGRB-inferred SFRD can naturally explain current measurements of hydrogen reionization without invoking extreme ionizing photon production efficiencies or escape fractions from galaxies. Using these LGRB-inferred SFRD values, we further investigate the faintest magnitude limits of high-redshift galaxies, finding a redshift evolution of the limiting magnitudes from $M_{\mathrm{lim}}\sim-14$ to $-15$ at $z\sim6$ to $M_{\mathrm{lim}}\sim-10$ to $-11$ at $z\sim10$. This result provides one independent piece of evidence for the presence of a large population of faint galaxies at redshifts $z\gtrsim6$, as an important complement to our understanding of the ionizing photon budget in the early universe.
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All authors Jing-Meng Hao, Paolo Cassata, Zhen-Ya Zheng, Andrea Grazian, Giulia Rodighiero, Alvio Renzini, Jun-Hui Fan, Andrea Ferrara

Cosmology and Nongalactic Astrophysics

When the Environment Speaks: Quantum Signatures in Non-Attractor Inflation

Mattia Cielo, Simone Scarlatella, Gianpiero Mangano et al. (+1 more)

We study the open quantum dynamics of the adiabatic curvature perturbation interacting with a massive entropic scalar environment during an inflationary scenario featuring a transient Ultra-Slow-Roll phase. Working within a Gaussian two-field effective Lagrangian, we employ the exact Transport Equations Method to track the full non-unitary, non-Markovian evolution of the system's covariance matrix across the SR-USR-SR transition. We find that the efficiency of decoherence is sensitive to the background kinematics at horizon crossing. Most importantly, the interaction with the environment leaves distinct observable imprints on the primordial scalar power spectrum: the characteristic interference dip preceding the USR-driven enhancement can be partially or completely erased, the growth slope modified, and oscillatory features induced near the peak. Propagated to second order, these distortions further imprint on the stochastic background of Scalar-Induced Gravitational Waves, breaking single-field predictions and yielding unique spectral signatures potentially accessible to LISA. Our results demonstrate that the quantum environment is not a passive spectator during inflation, but an active agent whose imprint on the primordial universe may be within reach of the next generation of cosmological observations.
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All authors Mattia Cielo, Simone Scarlatella, Gianpiero Mangano, Ofelia Pisanti

Instrumentation and Methods for Astrophysics

Decolonizing technosignatures: Reimagining technosignatures through an Indigenist lens

Hilding R. Neilson

There exist numerous proposals for potential technosignatures that we can search for, but they all tend to be deviations from possible naturally occurring signals. That is, technosignatures tend to be a search for pollution. Following a number of works by Indigenous scholars, pollution is colonization, even if that pollution is lightyears away. In this situations we are searching for colonial societies that are a reflection of colonial societies on Earth. This may help explain the Fermi Paradox. We are searching for systems that are highly polluting and potentially destructive, while we do not search for extraterrestrial societies that are less impactful on their celestial environment. This also suggests that we might consider technosignatures that act to support natural environments and might be more closely related to biosignatures, that is a technology that reflects a supportive relationship with nature.
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High Energy Astrophysical Phenomena

X-ray and Gamma-ray Emission from a High-Temperature Plasma and the Spectra of Accreting Black Holes

S. A. Grebenev

We present our numerical computations of broadband radiation spectra forming in a layer of high-temperature (kTe ~ 50 keV) semitransparent (with a Thomson optical depth ~1-3) plasma with an electron density Ne ~ 10^{17}-10^{19} cm^{-3}, typical for the accretion disk regions surrounding a black hole in X-ray binaries. The computations take into account the bremsstrahlung processes of photon production and absorption and their Comptonization. We show that the intrinsic radiation of such a plasma is sufficient to explain the X-ray spectra observed in the low (hard) state of Galactic black holes. No commonly assumed additional soft (with E < 1 keV) photons to maintain Comptonization are required; moreover, their presence would lead to severe distortions of the spectrum compared to the observed one. In the hard X-ray range the forming power-law spectrum with a photon index alpha ~ 1.4-1.7 and an exponential cutoff at E > 50 keV, exceeds considerably the bremsstrahlung flux that might be expected from such a plasma layer in the limit of its small depth. This is a result of the multiple Compton scattering of bremsstrahlung photons. It is important that the power-law spectrum of such a plasma should extend in an invariable form downward along the energy axis to the UV and OIR ranges (1-3 eV). At energies E < 1 eV the depth for bremsstrahlung absorption grows and the spectrum becomes the Rayleigh-Jeans one. To explain the steeper alpha ~ 2.1-2.5 X-ray spectra observed from black holes in their high (soft) state, it is indeed necessary that a large number of external photons enter a hot layer. Such photons could be emitted by the surface of an outer cold disk whose inner edge during these states approaches the black hole. The OIR emission from systems in these states is associated with that of the outer disk, whereas during their low state it can be produced directly in its central region.
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Solar and Stellar Astrophysics

Ionized gas emission in protoplanetary disks with the SKAO

Greta Guidi, Christian Rab, Barbara Ercolano et al. (+20 more)

Protoplanetary disks represent a crucial stage in the evolution of Young Stellar Objects towards the formation of fully formed planetary systems. While substantial progress has been made in the last decades in the characterization of the dust and molecular gas in these systems, the ionized component remains poorly understood. Ionized gas traces important processes such as photoevaporation, accretion, disk winds, and jets, and therefore is key to studying disk dynamics, evolution, and ultimately planet formation. In this paper, we investigate the capabilities of the forthcoming SKA telescope to probe this component in protoplanetary disks within nearby star forming regions. We present state-of-the-art simulations of photoevaporative, magneto-thermal, and magnetohydrodynamic winds, and generate theoretical predictions and synthetic SKAO observations to assess its potential in detecting and characterizing free-free emission and Hydrogen recombination lines. Finally, we discuss synergies with complementary facilities and how they will provide a comprehensive, multi-scale view of disk winds and offer critical insights on the mechanisms driving disk evolution and the onset of planet formation.
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All authors Greta Guidi, Christian Rab, Barbara Ercolano, Michael L. Weber, Claudio Codella, Izaskun Jiménez-Serra, Evgenia Koumpia, John D. Ilee, Enrique Macías, Elena Viscardi, Yinhao Wu, Francesca Bacciotti, Asmita Bhandare, Eleonora Bianchi, Tyler Bourke, Luca Cacciapuoti, Antonio Garufi, Geoffroy Lesur, Vincent Piétu, Linda Podio, Giovanni Sabatini, Leonardo Testi, Claudia Toci

High Energy Astrophysical Phenomena

Transient and Variable Ultra-luminous X-ray Sources in NGC 4552

V. Jithesh, A. S. Sreya, Riya Elza Mathew et al. (+2 more)

We searched for transient and variable X-ray sources in the elliptical galaxy NGC 4552 using the Chandra and XMM-Newton observations from 2001-2012. We detected 14 transient and variable X-ray sources within the 4$R_{e}$ region of the galaxy, which exhibited peak state and undetected flux behaviour in the Chandra observations. Among them, two sources (T1 and T14) exceed the X-ray luminosity $10^{39}\rm~erg~s^{-1}$ in the detected observations and have the peak state and undetected luminosity ratio of $\geq 14.3$ and $\geq 8.7$, respectively, which we classified as transient and variable ultra-luminous X-ray sources (ULXs). For the third relatively bright transient source, the flux varies by a factor of 3 across the detected observations, and the hardness ratio analysis suggests a normal X-ray binary system. The remaining sources have luminosities in the $10^{37}-10^{38} \rm~erg~s^{-1}$ range, and the spectral analysis indicates that the sources may belong to neutron star or black hole X-ray binary systems, either in the hard or thermal-dominated state. The identified transient and variable ULXs exhibited high variability and soft spectral characteristics, which are consistent with ULXs accreting at super-Eddington rates. The near-infrared (NIR) counterpart search using JWST observations identified potential NIR counterparts for three mildly variable sources, and their magnitudes in different NIR bands suggest a red supergiant companion for each source. Deep X-ray monitoring observations can shed further light on the new transient and variable ULXs.
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All authors V. Jithesh, A. S. Sreya, Riya Elza Mathew, E. Sreeraj, R. Arun

Astrophysics of Galaxies

Chemical diversity of dense cores in Orion B: The role of the environment

Helena J. Mazurek, Maryvonne Gerin, Pierre Gratier et al. (+26 more)

Prestellar cores are the sites of the earliest stages of star formation. Dust continuum observations are often used to identify and characterize their properties yet only a small fraction of them was observed and studied in terms of their composition and dynamical status. We explore the chemical diversity of prestellar cores and protostellar cores residing in the Orion B giant molecular cloud selected on their dust continuum emission to provide an unbiased view of their line emission properties and how they vary as function of the core parameters and environment. We make use of the large scale maps of Orion B in 25 molecular lines from which we extract information for a sample of 1001 cores selected using positions extracted from Herschel dust continuum observations. The main properties of the core sample are derived using the Principal Component Analysis and additional maps of physical parameters: column density $N_{\rm{H_2}}$, far-ultraviolet (FUV) radiation field $G_0$ and mean volume gas density $n$. Additional high spectral resolution observations of $\rm C^{18}O(1-0)$ serve to evaluate the dynamical status of cores. The average line width of the cores is larger than what is typically expected for prestellar cores of closer star forming regions, which suggests that cores in Orion B are subjected to stronger turbulence affecting their stability. The first factor of the PCA analysis explaining the variation of the detected line intensities is the core column density of molecular gas. The second factor explains how the core chemical composition is strictly linked to their environment, which can be traced by the ratio of the external FUV radiation field over the core volume density, $G_0/n$. The third factor explaining the core chemical diversity is the mean density along the core line of sight, which is also associated with freeze-out and fractionation signatures.
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All authors Helena J. Mazurek, Maryvonne Gerin, Pierre Gratier, Jérôme Pety, Emeric Bron, Evelyne Roueff, Antoine Roueff, Ivana Bešlić, Lucas Einig, Jan H. Orkisz, Pierre Palud, Miriam G. Santa-Maria, Léontine Ségal, Antoine Zakardjian, Sébastien Bardeau, Pierre Chainais, Simon Coudé, Karine Demyk, Victor de Souza Magalhaes, Javier R. Goicoechea, Annie Hughes, David Languignon, François Levrier, Franck Le Petit, Dariusz C. Lis, Harvey S. Liszt, Nicolas Peretto, Albrecht Sievers, Pierre-Antoine Thouvenin

High Energy Astrophysical Phenomena

Population statistics of nanohertz gravitational wave sources

Jiming Yu, Zhen Pan, Xiao Xue et al. (+1 more)

The recent detection of a nanohertz gravitational wave (GW) background by pulsar timing arrays (PTA) has sparked extensive discussions regarding its origin-whether it arises from astrophysical supermassive black hole binaries (SMBHBs) or from primordial GWs generated by various early universe processes. Previous studies suggest that a key discriminant between these two origins is the non-Gaussianity of the GW background prior to the detection of any individual source. In this Letter, we introduce a hierarchical Bayesian inference framework for inferring population properties of GW sources. This approach enables not only the measurement of evidence for different GW origins using PTA data but also the inference of population properties of astrophysical SMBHBs, by optimally leveraging non-Gaussian information in individual bright sources and in power spectrum fluctuations of the GW background.
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All authors Jiming Yu, Zhen Pan, Xiao Xue, Liang Dai

High Energy Astrophysical Phenomena

Relativistic Common-envelope Dynamics of a Stellar-mass Black Hole II: Kerr Black Hole

Alejandro Cruz-Osorio and Fabio D. Lora-Clavijo

The common envelope phase plays a critical role in binary system evolution. In this study, we investigate the mass and momentum accretion rates during the interaction between a stellar mass black hole and the envelope of a red supergiant using simplified two dimensional simulations. We explore various Mach numbers and density gradients, finding that our simulations align with previous Bondi Hoyle Lyttleton accretion analyses. We observe the formation of a shock cone in the downstream flow, bow shocks in specific configurations, and subsonic regions within shocked flows. The shock cone is dragged when significant pressure gradients are present in the common envelope, with additional dragging near the black hole for highly rotating cases. We provide analytical fits for mass and momentum accretion rates, as well as bremsstrahlung luminosity, as functions of black hole spin, density gradients, and Mach number, offering first insights into general relativistic hydrodynamics modelling of the secular evolution of the common envelope phase.
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Astrophysics of Galaxies

Milky Way Atlas: A radial-velocity-resolved, three-dimensional map of H I within 1.25 kpc

Lewis McCallum, Laurin Söding, Mareike Berkner et al. (+9 more)

We present a velocity-resolved three-dimensional map of local atomic hydrogen (HI) within 1.25 kpc of the Sun, tackling the challenge of converting emission from position-position-velocity space into true 3D structure. Our method combines the HI4PI full-sky survey with the Edenhofer et al. (2024) 3D dust map in the framework of Information Field Theory, enabling a joint reconstruction of the local HI density, radial velocity field, and effective line width while also separating emission arising inside the mapped local volume from more distant Galactic HI. The inference is driven by morphological matching between dust and HI structures together with kinematic coherence in 3D space. Synthetic data tests show that the method recovers the local density and velocity structure, even in the presence of substantial contamination from distant emission. The resulting map reveals a smoother, more diffuse local HI distribution than the dust, a declining HI-to-dust ratio toward high dust column densities consistent with the atomic-to-molecular transition, and a velocity field that captures both large-scale Galactic rotation and local non-circular velocities. Independent comparisons with maser and young stellar cluster velocities agree with the recovered kinematics. This HI map provides a new three-dimensional, kinematically resolved view of the nearby atomic interstellar medium and a foundation for localising other velocity-resolved Galactic emission in physical space.
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All authors Lewis McCallum, Laurin Söding, Mareike Berkner, Philipp Frank, Matteo Guardiani, Jakob Roth, Juan D. Soler, Robert Benjamin, Torsten Enßlin, Philipp Mertsch, Konstantinos Tassis, Vasiliki Pavlidou

Solar and Stellar Astrophysics

Double-periodic pulsations simultaneously detected in mid-infrared and hard X-ray emissions during an X1.5 flare

Dong Li, Yuyang Ye, Xianyong Bai et al. (+1 more)

Quasi-periodic pulsations (QPPs) have been observed in a broad electromagnetic spectrum, encompassing radio, ultraviolet, white light, X-rays, and Gama-rays. Yet, flare-associated QPPs remain rarely detected in mid-infrared emission. Here, we explored dual-period QPPs in the mid-infrared waveband, hard X-rays (HXRs), and microwave emission during an X1.5 flare on 2024 December 30 (SOL2024-12-30T04:01). Flare QPPs with dual quasi-periods at about 8.5 s and 4.6 s were simultaneously detected in the AIMS 8-10 um, Fermi 26-50 keV, and HXI 20-50 keV wavebands during the impulsive phase. Imaging observations show that the flare emission sources in the mid-infrared, HXR, and white-light wavebands are spatially coincident. Mid-infrared emissions are primarily localized at the loop top and double footpoints, which are connected by a hot plasma loop. These observational features support intermittent and rapid energy release via oscillatory magnetic reconnection during the solar flare. Differential emission measure analysis confirms fast sausage waves in flaring loops, while the WST observation indicates a white-light flare. We localized the flare QPPs with double periods in mid-infrared, HXR, and microwave emissions during a white-light flare. The flare-associated QPPs may be attributed to a quasi-periodic regime of magnetic reconnection, with the double periods likely modulated by quasi-harmonics of sausage waves.
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All authors Dong Li, Yuyang Ye, Xianyong Bai, Xu Yang

Astrophysics of Galaxies

A machine learning approach to estimating HI deficiency in galaxies

Filip Janák, Boris Deshev, Roman Nagy et al. (+1 more)

Measurements of the HI content of galaxies serve as an important tracer for probing the impact of environment on galaxy evolution. More specifically, the HI deficiency (defined as the difference between expected unaltered and observed HI content of a galaxy) is closely related with environmental effects, which are most significant in large groups and clusters. In this work, we aim to estimate the HI deficiency of ALFALFA galaxies and investigate its relation with galactic environment. Using a random forest machine learning algorithm, we developed a predictive model capable of estimating the original HI content of a galaxy based solely on its optical properties. The model was trained on a subsample of 6 982 isolated ALFALFA galaxies with optical photometric data from the Sloan Digital Sky Survey (SDSS). Our predictive model outperforms the traditional approach, in which HI mass is linearly related to optical size (both on a logarithmic scale). The model achieves RMSE $\approx$ 0.22 dex and $R^2 \approx$ 0.80, compared with RMSE $\approx$ 0.26 dex and $R^2 \approx$ 0.70 for the traditional method. We applied this model to predict the expected HI content for non-isolated ALFALFA galaxies, enabling the calculation of HI deficiency. Controlling for the effects of internal factors, like stellar mass and presence of AGN, we find an increase in binned median HI deficiency of 0.15 dex attributable to environmental effects. In addition, we evaluate the temporal evolution of the predicted HI mass, and associated HI deficiency, due to the evolving stellar populations, following a gas removal event.
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All authors Filip Janák, Boris Deshev, Roman Nagy, Rhys Taylor

Instrumentation and Methods for Astrophysics

SETI's blind spot: Technological Acceleration and fleeting technosignatures

Michael A. Garrett

The search for extraterrestrial intelligence (SETI) has traditionally framed the detection challenge with a focus on the parameter $L$ in the Drake equation - the communicative lifetime of a civilisation. I argue that the more pertinent quantity is $\tau_d$, the duration during which a civilisation produces technosignatures that are actually detectable by us, now. Modelling technological progress as an exponential process, we show that $\tau_d = \alpha^{-1}\ln(K_{\rm max}/K_{\rm min})$, where $\alpha$ is the rate of technological acceleration and $[K_{\rm min},K_{\rm max}]$ brackets the technology levels accessible to our instruments. As $\alpha$ increases, $\tau_d$ can shrink to mere decades, dramatically narrowing the window in which civilisations overlap technically. This “technology mismatch” has implications for future search strategies, emphasising broadband and technology-agnostic approaches, as well as anomaly detection across multi-wavelength/messenger survey data.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Impact of $H_0$ on gravitational wave propagation: prospects for the LISA mission

Nil Blanco and Domenec Espriu

It was previously shown that $H_0$ influences gravitational wave propagation beyond simple redshift, by modifying the effective wavenumber. While earlier studies focused on Pulsar Timing Arrays, we analyze the observability of this effect with LISA. Modeling the LISA arm geometry, we derive the timing residual and identify a clear angular enhancement at frequencies above 100 mHz. Using the stationary phase approximation and numerical methods, we show that the optimal incidence angle depends on $Z_A H_0$, providing a direct, redshift-independent measurement of the Hubble parameter. We estimate that LISA could determine $H_0$ to within a few percent using this method, independent of standard siren approaches.
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Astrophysics of Galaxies

Divergent Evolution of Radial Metallicity Gradients in the Thin and Thick Disks of the Milky Way

Weixiang Sun, Gaohuan Long, Hui Li et al. (+6 more)

Using 200,388 red clump stars from LAMOST and APOGEE, we investigate the radial metallicity gradients of the Galactic disk as a function of vertical height and stellar age. The thin disk displays a pronounced negative radial metallicity gradient near the Galactic mid-plane that progressively flattens with increasing $|Z|$, following $\Delta \mathrm{[Fe/H]}/\Delta R$ = $-$0.0784 $+$ 0.0776 (1 $-$ exp ($-$ $|Z|$/1.42)). The thin disk also exhibits a clear age dependence in radial metallicity gradients, evolving smoothly from a strong gradient regime for young stars to a weak gradient regime for old stars, following $\Delta \mathrm{[Fe/H]}/\Delta R$ = $-$0.0438 $+$ 0.0233 tanh (($\tau$ $-$ 11.29)/4.21). The thick disk shows weakly positive radial metallicity gradients that remain statistically invariant with respect to both vertical height and stellar age, following respectively, $\Delta \mathrm{[Fe/H]}/\Delta R$ = 0.0038 $+$ 0.0009 $|Z|$ and $\Delta \mathrm{[Fe/H]}/\Delta R$ = 0.0146 $-$ 0.0007 $\tau$. These results indicate that the thin disk retains radial metallicity gradients shaped by relatively ordered inside-out growth and long-term secular evolution processes. The thick disk exhibits spatially and temporally homogeneous radial metallicity gradients, which are consistent with a formation environment characterized by mergers of gas-rich systems and/or the turbulent ISM.
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All authors Weixiang Sun, Gaohuan Long, Hui Li, Han Shen, Shu Wang, Xiaodian Chen, Biwei Jiang, Xiaowei Liu, Di Li

High Energy Astrophysical Phenomena · Cross-listed from cs.LG

Generalist Vision-Language Models for Fast Radio Burst detection: a zero-shot benchmark against a specialized detector

Raiff H. Santos, Amilcar R. Queiroz, Tharcisyo S. S. Duarte et al. (+2 more)

Fast Radio Burst (FRB) detection increasingly relies on specialized deep learning models that require large task-specific training sets and cannot be redefined without retraining. We evaluate whether small, open-weight, locally run generalist Vision-Language Models (VLMs) can detect FRBs in dynamic spectra under a zero-shot, prompt-only regime. On a balanced binary benchmark of 2000 simulated L-band spectra, Gemma 4 E2B reaches an accuracy of 94.05%, statistically indistinguishable from the specialized detector SwinYNet (92.85%), with a far lower false-positive rate on structured RFI (4.8% vs. 24.6%) and none on pure noise, though SwinYNet ranks perfectly (ROC-AUC 1.0000 vs. 0.9520). Rewriting the prompt alone reconfigures the same models for three-class FRB/RFI/noise classification, reaching up to 86.0% accuracy without a single false FRB while classifying each 2 s spectrum in 1.0–1.5 s, faster than the observation itself. Applied unchanged to the 1600 real FAST observations of FAST-FREX, they reject real interference almost perfectly (2 and 5 false positives in 1000 negatives) but recover only 28.5% and 27.0% of the 600 catalogued bursts, against 95.7% reported for SwinYNet on the same files. Stratifying those bursts by the dispersed signal in the image shows the limit to be the input representation rather than the classifier, recall rising to 84–85% where the sweep is unambiguous and collapsing to 1% on the 13% of positives carrying no detectable signal in a 2 s undedispersed full-band view. The simulated bursts are nearly 30 times brighter in median, and at matched brightness the recalls agree to within a few points.
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All authors Raiff H. Santos, Amilcar R. Queiroz, Tharcisyo S. S. Duarte, K. E. L. de Farias, Rafael A. Batista

High Energy Astrophysical Phenomena

Multiband ALMA polarimetry of the jet base and kiloparsec-scale jet of 3C 273: A multicomponent Faraday structure in the nucleus

T. Hovatta, S. P. O'Sullivan, I. Marti-Vidal et al. (+1 more)

Polarization observations at millimeter wavelengths can be used to study magnetized plasma in jets launched by supermassive black holes. We used multiband Atacama Large Millimeter Array (ALMA) data to study the polarization structure of both the nucleus and the kiloparsec-scale jet of the archetypal quasar 3C 273. We modeled the wavelength-dependent polarization of the nucleus using multiband observations (2, 1.3, and 0.85 mm) and applied QU-fitting to constrain Faraday rotation models with one or more polarized components. We also produced total intensity and polarization maps of the kiloparsec-scale jet to study the evolution of the magnetic field structure along and across the jet. The data of the nucleus were best fit by two Faraday components: a high rotation measure (RM) component with RM = +(2.6 +/- 0.1) x 10^5 rad/m^2 and comparable RM dispersion, and a second component with RM = +(1.5 +/- 0.2) x 10^4 rad/m^2 and lower dispersion. The high RM is comparable to previous ALMA observations at 1.3 mm, although we found clear evidence of variability when compared to previous single-band ALMA studies, highlighting the importance of broad wavelength coverage. On kiloparsec scales, the millimeter polarization structure closely resembled that observed at centimeter wavelengths, revealing a complex magnetic field configuration around the jet head and brightest hotspot region. Our results indicate a multicomponent, time-variable Faraday screen in the nuclear region of 3C 273 that is likely associated with a dense, magnetized environment close to the jet base. Future spatially resolved millimeter polarimetry with the Event Horizon Telescope will be crucial to disentangling these components and directly localizing the high-RM emission region.
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All authors T. Hovatta, S. P. O'Sullivan, I. Marti-Vidal, T. Savolainen

Cosmology and Nongalactic Astrophysics

Present Day Cosmic Acceleration from SDSS and DESI BAO: A Call for Finer Tomography of the DESI Bright Galaxy Survey

Anna Chiara Ferri, Ruchika and Alessandro Melchiorri

The DESI collaboration's Data Release~2 (DR2) provides baryon acoustic oscillation (BAO) measurements from over 14 million galaxies and quasars, and a joint analysis of DESI BAO, CMB, and Type~Ia Supernovae reveals a preference for time-evolving dark energy. We quantify this preference relative to SDSS BAO and report three key results. First, DESI+Planck favors a higher $w_0 = -0.41^{+0.21}_{-0.22}$ than SDSS+Planck ($w_0 = -0.71^{+0.19}_{-0.18}$). Second, DESI+Planck prefers a deceleration parameter whose median lies on the decelerating side ($q_0 = 0.10^{+0.21}_{-0.23}$, consistent with $q_0 = 0$ at $1\sigma$), while SDSS+Planck prefers a negative value ($q_0 =-0.22^{+0.20}_{-0.21}$) indicating accelerated expansion. Third, we argue that this discrepancy arises from the difference in the lowest effective redshift probed by each survey: $z_{\rm eff} \approx 0.295$ for DESI versus $z_{\rm eff} \approx 0.15$ for SDSS. As present-day quantities, $w_0$ and $q_0$ are sensitive to the lowest probed redshift: data near $z = 0$ constrain them directly, whereas higher-redshift data rely on extrapolating the dark energy parametrization (here CPL). Reaching $z_{\rm eff} \approx 0.15$, SDSS constrains $w_0$ and $q_0$ in a data-driven way, finding consistency with $w_0 = -1$ and acceleration. Limited to $z_{\rm eff} \gtrsim 0.295$, DESI relies more on extrapolation, driving $q_0$ positive and $w_0$ well above $-1$. Adding the Pantheon+ supernova sample restores low-redshift information, returning $q_0$ to negative values and reducing tension with $\Lambda\text{CDM}$. We therefore propose that the apparent DESI preference for a non-accelerating present epoch in the BAO+CMB combination reflects redshift sampling rather than new physics, and suggest future DESI analyses adopt finer tomographic binning of the Bright Galaxy Survey sample to access lower mean redshifts and test this conclusion.
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Astrophysics of Galaxies

Beyond traditional emission-line diagnostics: using autoencoders to uncover active galactic nuclei in DESI spectra

J. A. Alcolea, M. Siudek, M. Eriksen et al. (+49 more)

The growing volume of spectroscopic data in modern surveys motivates data-driven approaches that complement traditional emission-line diagnostics for active galactic nuclei (AGN) identification. We present a machine learning framework that exploits the full optical spectrum using unsupervised representation learning within a semi-supervised classification scheme. We use the SPENDER autoencoder to compress DESI galaxy spectra into a low-dimensional latent space and classify sources through a k-d tree nearest-neighbor search. The model is trained on 50,222 DESI Main Survey spectra from the Guadalupe dataset and released as part of Data Release 1 (DR1), restricted to z <= 0.5. We validate the performance using labels derived from FastSpecFit's emission line measurements defining seven galaxy classes: AGN, broad-line (BL), composite, star-forming, passive, retired, and Other. The method achieves high accuracies for AGN (0.952) and broad-line AGN (0.965), reliably identifying these sources even in low signal-to-noise spectra and recovering AGN missed by standard single-diagnostic methods. Our classification metrics are benchmarked against traditional diagnostics, and we show they represent lower limits of the model's true performance. We also find that the learned latent space correlates with key galaxy properties such as stellar mass and star-formation rate, demonstrating that it captures physically meaningful information. These results show that unsupervised spectral representation learning, implemented within a semi-supervised classification framework, provides a scalable and effective approach for constructing more complete AGN catalogues for current and future spectroscopic surveys.
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All authors J. A. Alcolea, M. Siudek, M. Eriksen, M. Mezcua, R. Pucha, S. Juneau, S. Gontcho A Gontcho, S. Panda, J. Aguilar, S. Ahlen, D. Bianchi, A. Brodzeller, D. Brooks, F. J. Castander, T. Claybaugh, A. Cuceu, A. de la Macorra, B. Dey, P. Doel, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, G. Gutierrez, C. Hahn, H. K. Herrera-Alcantar, D. Joyce, R. Kehoe, D. Kirkby, T. Kisner, A. Kremin, O. Lahav, C. Lamman, M. Landriau, L. Le Guillou, A. Meisner, R. Miquel, J. Moustakas, S. Nadathur, W. Percival, F. Prada, I. Pérez-Ràfols, G. Rossi, E. Sanchez, E. Schlafly, D. Schlegel, M. Schubnell, J. Silber, D. Sprayberry, G. Tarlé, B. A. Weaver, H. Zou

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Reappraisal of the Constraints on Heavy Axion-like Particles from Gamma-Ray Bursts

Christopher V. Cappiello, Saurav Das, P. S. Bhupal Dev et al. (+2 more)

We reassess existing limits and derive new constraints on heavy axion-like particle (ALP) coupling to photons using gamma-ray bursts (GRBs). ALPs can be produced in the hot dense fireball plasma during the initial stage of GRB outflow, thus potentially disrupting the primary fireball and altering the GRB luminosity. We consider the ALP production rate for various GRB parameters in two different energy injection scenarios of GRB fireball formation, and point out that ALP production is less efficient than previously assumed unless a GRB event is exceptionally energetic. We update the existing energy loss bounds using more realistic GRB parameters. We also point out that in the region of parameter space previously constrained by GRB luminosity criterion, ALP production turns out to be still efficient enough to form a secondary fireball via ALP decay to two photons and their subsequent annihilation to electron-positron pair. This secondary fireball reprocesses the gamma-rays from heavy ALP decay into $X$-rays, emitted isotropically from its surface, thus allowing us to probe $\mathcal{O}(100~\mathrm{MeV})$-scale ALPs indirectly using $X$-ray (or future MeV gamma-ray) telescopes, not necessarily directed toward the GRB jet itself. We show that the future point-source sensitivity of $X$-ray and MeV gamma-ray telescopes may allow us to constrain new ALP parameter space.
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All authors Christopher V. Cappiello, Saurav Das, P. S. Bhupal Dev, Takuya Okawa, Soebur Razzaque

Astrophysics of Galaxies

Euclid Quick Data Release (Q1). Searching for radio-selected \Euclid-dark galaxies in the EDF-N

Euclid Collaboration: M. Giulietti, I. Prandoni, L. Bisigello et al. (+307 more)

We present and investigate the properties of a sample of radio-selected, Euclid-dark galaxies, identified from LOFAR HBA observations at 144 MHz within the Euclid Deep Field-North (EDF-N). Starting from radio sources lacking optical counterparts in previous surveys, but detected with Spitzer/IRAC, we identified 166 galaxies with no emission at a more than $3\sigma$ level in Euclid Quick Release 1 (Q1) images, and no matches in the Euclid Q1 catalogue. To minimise contamination from nearby sources, we selected a sub-sample of 88 isolated galaxies. By exploiting multi-band images and catalogues available for the EDF-N, we inferred the physical properties of our sample via SED fitting. The resulting redshift distribution spans $0.4 \leq z_\mathrm{ph} \leq 5.0$. We used recent sub-arcsecond imaging from the International LOFAR Telescope to constrain the nature of the compact radio emission through brightness temperature estimates. By combining this information with the radio excess relative to the infrared/radio correlation (IRRC), we searched for possible active galactic nuclei (AGN) activity. Approximately 40% of our sources show evidence of AGN activity. The Euclid-dark sources detected in the far-infrared are consistent with a population of heavily obscured, massive star-forming galaxies with high star formation rates. Their location above the star-forming main sequence is consistent with similar near-infrared-dark galaxy populations reported in the literature. We also performed a UV-to-radio median stacking analysis, finding that the two subsamples exhibit similar global physical properties and differ primarily in their radio emission. These preliminary results indicate that the wide area covered by Euclid enables the identification of a higher fraction of systems in which intense star formation and AGN activity coexist, likely capturing a key phase of galaxy–black hole co-evolution.
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All authors Euclid Collaboration: M. Giulietti, I. Prandoni, L. Bisigello, G. Rodighiero, M. Talia, F. Gentile, G. Girardi, M. Bondi, L. Wang, A. La Marca, P. A. C. Cunha, R. Hill, A. Abghari, D. Scott, G. Zamorani, G. A. Mamon, A. Lapi, M. Behiri, G. Santhosh, H. J. A. Rottgering, R. Gilli, R. Scaramella, G. Gandolfi, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, A. Balestra, S. Bardelli, P. Battaglia, A. Biviano, M. Bolzonella, E. Branchini, M. Brescia, J. Brinchmann, S. Camera, G. Cañas-Herrera, V. Capobianco, C. Carbone, J. Carretero, S. Casas, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, A. Costille, F. Courbin, H. M. Courtois, M. Cropper, A. Da Silva, H. Degaudenzi, G. De Lucia, C. Dolding, H. Dole, F. Dubath, C. A. J. Duncan, X. Dupac, S. Dusini, S. Escoffier, M. Farina, R. Farinelli, F. Faustini, S. Ferriol, F. Finelli, S. Fotopoulou, M. Frailis, E. Franceschi, M. Fumana, L. Gabarra, S. Galeotta, K. George, B. Gillis, C. Giocoli, J. Gracia-Carpio, A. Grazian, F. Grupp, S. Gwyn, W. G. Hartley, S. V. H. Haugan, S. Hemmati, J. Hoar, W. Holmes, A. Hornstrup, M. Huertas-Company, K. Jahnke, M. Jhabvala, B. Joachimi, E. Keihänen, S. Kermiche, A. Kiessling, M. Kilbinger, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, A. M. C. Le Brun, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, M. Magliocchetti, G. Mainetti, D. Maino, E. Maiorano, O. Mansutti, S. Marcin, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. J. Massey, N. Mauri, E. Medinaceli, S. Mei, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, P. Monaco, A. Mora, M. Moresco, C. Moretti, L. Moscardini, R. Nakajima, C. Neissner, R. C. Nichol, S.-M. Niemi, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, W. J. Percival, V. Pettorino, A. Pezzotta, S. Pires, G. Polenta, M. Poncet, L. A. Popa, C. Porciani, L. Pozzetti, F. Raison, A. Renzi, J. Rhodes, G. Riccio, I. Risso, E. Romelli, M. Roncarelli, R. Saglia, Z. Sakr, D. Sapone, B. Sartoris, J. A. Schewtschenko, M. Schirmer, P. Schneider, T. Schrabback, A. Secroun, G. Seidel, S. Serrano, P. Simon, C. Sirignano, G. Sirri, L. Stanco, J.-L. Starck, J. Steinwagner, P. Tallada-Crespí, A. N. Taylor, H. I. Teplitz, I. Tereno, N. Tessore, S. Toft, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, L. Valenziano, J. Valiviita, T. Vassallo, A. Veropalumbo, Y. Wang, J. Weller, A. Zacchei, E. Zucca, V. Allevato, M. Ballardini, E. Bozzo, C. Burigana, R. Cabanac, M. Calabrese, A. Cappi, J. A. Escartin Vigo, R. Maoli, J. Martín-Fleitas, S. Matthew, M. Maturi, R. B. Metcalf, M. Pöntinen, V. Scottez, M. Sereno, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, I. T. Andika, S. Anselmi, M. Archidiacono, F. Atrio-Barandela, D. Bertacca, M. Bethermin, A. Blanchard, L. Blot, M. Bonici, S. Borgani, M. L. Brown, S. Bruton, A. Calabro, B. Camacho Quevedo, F. Caro, C. S. Carvalho, T. Castro, F. Cogato, S. Conseil, A. R. Cooray, O. Cucciati, S. Davini, G. Desprez, A. Díaz-Sánchez, J. J. Diaz, S. Di Domizio, J. M. Diego, M. Y. Elkhashab, A. Enia, Y. Fang, A. Finoguenov, A. Franco, K. Ganga, J. García-Bellido, T. Gasparetto, V. Gautard, E. Gaztanaga, F. Giacomini, F. Gianotti, G. Gozaliasl, M. Guidi, C. M. Gutierrez, A. Hall, C. Hernández-Monteagudo, H. Hildebrandt, J. Hjorth, J. J. E. Kajava, Y. Kang, V. Kansal, D. Karagiannis, K. Kiiveri, J. Kim, C. C. Kirkpatrick, S. Kruk, L. Legrand, M. Lembo, F. Lepori, G. F. Lesci, J. Lesgourgues, L. Leuzzi, T. I. Liaudat, A. Loureiro, J. Macias-Perez, F. Mannucci, C. J. A. P. Martins, L. Maurin, M. Miluzio, G. Morgante, K. Naidoo, P. Natoli, A. Navarro-Alsina, S. Nesseris, D. Paoletti, F. Passalacqua, K. Paterson, L. Patrizii, A. Pisani, D. Potter, S. Quai, M. Radovich, S. Sacquegna, M. Sahlén, D. B. Sanders, E. Sarpa, A. Schneider, D. Sciotti, E. Sellentin, F. Shankar, A. Shulevski, L. C. Smith, J. G. Sorce, K. Tanidis, C. Tao, G. Testera, R. Teyssier, S. Tosi, A. Troja, M. Tucci, A. Venhola, D. Vergani, G. Verza, P. Vielzeuf, N. A. Walton