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Physics Astrophysics

astro-ph Watch Astrophysics

Thursday 18 December

High Energy Astrophysical Phenomena

Pulsar B1237+25 at 111~MHz: average profile, mode switching, nullings, microstructure

M.V. Popov and T.V. Smirnova

The observations of B1237+25 at a frequency of 111 MHz were analyzed. For the first time in the normal radiation mode a new component in the central region in the average profile was detected. This component is manifested in all modes of pulsar emission: quiet-normal (QN), flare-normal (FN) and in the abnormal mode (AB). The subpulse drift is observed in the QN mode only in the first and last components of the average profile. The normal mode is interrupted by nullings and transitions into the abnormal AB mode. In the AB mode, the structure at the edge of the outer cone is destroyed, the distance between the inner and outer cones is almost doubled, and the distance between the inner cone and the central region is reduced.Analysis of our data has shown that the components of the outer and inner cones of the average profile are formed by an ordinary mode of radio emission (O-mode) and form a single cone radiation of the pulsar. The central components of the average profile (wide and narrow) are formed by an extraordinary mode (X-mode). Estimates of the height of the radiation output from the central region (X-mode) and the cone radiation (O-mode) are obtained: 80~km and 370~km, respectively. A microstructure with a time scale of $\tau_\mu\le0.5$~$\mu s$ has been detected. This time scale corresponds well to the time of the development of a spark discharge in the polar cap. For this value $\tau_\mu$, the height of the vacuum gap should be $h_p\le750$~cm. Based on the steepness of the individual pulse's trailing edge at the longitude of the first component, a limit was obtained on the value of the $\gamma$ factor of the relativistic secondary plasma: $\gamma\ge$260. The dependence of the distance between the components of the outer and inner cone of radiation on the frequency is the same and corresponds to a power law with an exponent of -0.16.
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High Energy Astrophysical Phenomena

XMM-Newton multi-year campaign on NGC 55 ULX-1: Resolving the wind and its variability with RGS

C. Pinto, S. Caserta, F. Barra et al. (+12 more)

Winds are an important ingredient in the evolution of X-ray binary (XRB) systems, particularly those at high accretion rates such as ultra-luminous X-ray sources (ULXs), because they may regulate the accretion of matter onto the compact object. We aim at understanding the properties of ULX winds and their link with the source spectral and temporal behavior. We performed high-resolution X-ray spectroscopy of the variable source NGC 55 ULX-1 to resolve emission and absorption lines as observed with XMM-Newton at different epochs. Optically-thin plasma models are used to characterise the wind. We confirmed and thoroughly strengthened previous evidence of outflows in NGC 55 ULX-1. The presence of radiative recombination signatures and the ratios between the fluxes of the emission lines favours photoionisation balance and low-to-moderate densities, which confirm that the lines originate from classical XRB disc winds. An in-depth parameter space exploration shows line emission from a slowly moving, cool, and variable plasma perhaps associated with a thermal wind. Mildly-relativistic Doppler shifts (about -0.15c) associated with the absorption lines confirm, at higher confidence, the presence of powerful, radiatively-driven, winds. The comparison between results obtained at different epochs revealed that the wind responds to the variability of the underlying continuum and these variations may be used to understand the actual accretion regime and the nature of the source.
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All authors C. Pinto, S. Caserta, F. Barra, Y. Xu, D. Barret, P. Kosec, N. La Palombara, A. Marino, F. Pintore, A. Riggio, T. P. Roberts, C. Salvaggio, L. Sidoli, R. Soria, D. J. Walton

Cosmology and Nongalactic Astrophysics

How massive neutrinos reshape the cosmic web

Leonor N. L. Simões, Krishna Naidoo, Benjamin Joachimi et al. (+2 more)

We explore the effects of massive neutrinos on the cosmic web using the FLAMINGO simulations. We classify the cosmic web into voids, sheets, filaments, and clusters, and find that massive neutrinos affect the environment by decreasing the volume occupied by clusters and voids. We find that increasing the neutrino mass shifts the volume-weighted density distribution towards higher densities and leads to a more narrow density distribution, which we interpret as neutrinos delaying structure formation. We construct the minimum spanning tree (MST) graph from the subhaloes, adopting a number density chosen to match that expected for DESI-like observations. We show that most MST edges lie in filaments, approximately 70% throughout different simulations, which we link to its sensitivity to neutrino mass. We also link the MST's edge length signal at different scales to different cosmic web environments, with clusters dominating the signal at small scales, voids at longer scales, and filaments at intermediate scales. The strong correlation between MST edges and cosmic web environments reinforces the MST's potential to be used as a classifier for large-scale structure in galaxy surveys. We compare the effects of baryonic physics and massive neutrinos and find that each produces distinct signatures in MST edge lengths. This analysis is performed in 3D space, using the true positions of subhaloes and not accounting for redshift space distortions. Nevertheless, these results emphasise the MST's capability to go beyond two-point statistics, motivating future applications to real observational data.
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All authors Leonor N. L. Simões, Krishna Naidoo, Benjamin Joachimi, Willem Elbers, Carlos S. Frenk

Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Cosmology with non-linear barotropic Israel-Stewart fluid with causal relaxation time

Vishnu A Pai and Titus K Mathew

We derive an extended expression for the relaxation time of a barotropic Israel-Stewart (IS) fluid using the non-linear causality constraint, and propose a new formulation for modeling causal viscous dissipation in barotropic fluids. With this generalized relaxation time, the non-linear IS equation simplifies to a first-order non-linear expression connecting bulk viscous pressure and energy density, which remains valid in any homogeneous and isotropic spacetime. In the case of spatially flat Friedmann universe, adopting this extended relation in the generalized non-linear IS theory, provides new class of analytical solutions in both, the linear, and the non-linear regimes. We also find that, the resulting effective equation of state in the linear regime naturally reproduces the generalized polytropic form which is often introduced phenomenologically in literature. Resulting dynamical implications are investigated and the constraints necessary for ensuring an acceptable evolutionary behavior for the fluid are determined. A detailed dynamical system analysis of the coupled Einstein-Israel-Stewart (EIS) system is also performed. Finally, we solve the coupled EIS equations numerically, and show that the model can support a transient Hubble slow-roll expansion phase with a smooth exit to a radiation-dominated universe, which is challenging to obtain in standard inflationary models.
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Cosmology and Nongalactic Astrophysics

Uniform Rolling: An LSST Observing Cadence Offering Sufficient Survey Uniformity for Comprehensive Cosmological Analysis

Boris Leistedt, Matthew R. Becker, Humna Awan et al. (+14 more)

The Legacy Survey of Space and Time (LSST) that will be carried out by the NSF-DOE Vera C. Rubin Observatory promises to be the defining survey of the next decade, supplying unprecedented access to the night sky to static science- and time-domain science-focused researchers alike. Maximizing the output of the broad remit of Rubin Observatory science requires a non-trivial survey strategy. For time-domain science, the most promising strategy designed so far is a rolling survey strategy, whereby a subset of the full LSST survey area is observed at higher rate compared with the nominal rate dictated by weather conditions and the observatory's technical constraints. This strategy is now the baseline approach for the LSST as a whole. Focusing on static science (galaxy clustering and weak lensing), we study how these time-domain-optimized rolling strategies affect the depth uniformity at intermediate years of the survey. We characterize the amount of survey area at high risk of being lost in static-science analyses of a baseline rolling LSST dataset due to an insufficient combination of survey contiguity and uniformity. At intermediate data releases, nearly half of the survey could be lost for static science, decreasing the Dark Energy figure of merit by approximately 40%. We describe additional metrics focused on key analysis tasks, such as photometric redshifts and galaxy clustering. We propose a new strategy that returns the survey to uniformity at key release years, enabling use of the full survey area and restoring our metrics to the values they would have in a non-rolling cadence without loss of time domain data relative to a rolling survey with the same number of rolling cycles. This work has informed the third round of optimization of the survey strategy, and the new uniform rolling strategies have been incorporated into the baseline strategy.
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All authors Boris Leistedt, Matthew R. Becker, Humna Awan, Eric Gawiser, Qianjun Hang, Renée Hložek, Saurabh W. Jha, R. Lynne Jones, Arun Kannawadi, Michelle Lochner, Rachel Mandelbaum, Jeffrey A. Newman, I. Sevilla-Noarbe, Hiranya V. Peiris, Eli S. Rykoff, M. A. Troxel, Peter Yoachim

High Energy Astrophysical Phenomena

Classification of the equation of state of neutron stars via sparse dictionary learning

Miquel Llorens-Monteagudo, Alejandro Torres-Forné and José A. Font

The post-merger phase of binary neutron star (BNS) mergers encodes valuable information about the equation of state (EOS) of supranuclear matter. Extracting this information from the analysis of the post-merger waveforms remains challenging due to the high-frequency limitations of current detectors. Future third-generation observatories, such as the Einstein Telescope (ET) and NEMO, will have the sensitivity required to resolve post-merger signals with high fidelity. In this work, we apply CLAWDIA, our recently developed sparse dictionary learning (SDL) framework, to classify different EOS models using only the post-merger gravitational-wave emission of simulated BNS mergers available in the CoRe database. Our dataset comprises five EOS models representative of a broad range of neutron star properties. The SDL framework is optimised under realistic detection conditions by injecting signals into simulated noise matching the sensitivity curves of ET and NEMO. Our results show that classification is primarily driven by the dominant post-merger frequency, $f_2$, which encodes EOS-dependent information. At a modest signal-to-noise ratio of 5, our method achieves $F_1$ scores of $0.76$ for ET and $0.70$ for NEMO, with performance improving for higher signal-to-noise ratios. The reliability and generalisation capabilities of the model are assessed with additional tests, including the classification of an EOS not included in the training dataset and the analysis of detector-specific biases.
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Instrumentation and Methods for Astrophysics

A direction-dependent framework for visibility plane mosaicing and primary beam correction

Keegan S. Trehaeven, Cyril Tasse, Oleg Smirnov et al. (+1 more)

With the increasing sensitivity of modern radio interferometers, it has become important to image objects larger than the field of view while optimising sensitivity and image fidelity. We present a coherent visibility plane direction-dependent imaging, calibration and mosaicing framework. Our simulations and application to real MeerKAT data show that this joint deconvolution and primary beam correction approach, coupled with direction-dependent calibration, allows for deeper mosaics with greater fidelity and increased accuracy of recovered flux densities and spectral indices, especially beyond the half-power beam width. Our best-case mosaic produces precise flux values within a 6% uncertainty and spectral indices within 20% throughout the imaged area, and is fully complete out to twice the radii and half the flux density than the image plane equivalent. The application to archival wideband MeerKAT 1283 MHz data produces the deepest high-resolution image of the Shapley Supercluster Core, with a sensitivity of 3.6 $\mu$Jy/beam within the primary beam at a 7$^{\prime\prime}$ resolution, constituting a $\sim$ 50% increase in dynamic range over the image plane counterpart, and a fluxscale that is consistent within 10% across the entire field of view. The compute time for the direction-dependent visibility plane mosaic was comparable to the sum of the times needed to perform direction-dependent calibration on the individual pointings. Our results suggest that visibility plane mosaicing with its capability for deeper deconvolution could improve the efficiency of deep and wide surveys, particularly for on-the-fly mapping and studies of low surface brightness sources, and could form the basis of future calibration pipelines for SKA-scale instruments.
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All authors Keegan S. Trehaeven, Cyril Tasse, Oleg Smirnov, Tiziana Venturi

High Energy Astrophysical Phenomena · Cross-listed from nucl-th

Constraining the nuclear equation of state from terrestrial experiments and neutron star observations using relativistic mean-field models

Tsuyoshi Miyatsu, Myung-Ki Cheoun, Kyungsik Kim et al. (+1 more)

We investigate the nuclear equation of state (EoS) for isospin-asymmetric matter using a new set of RMF interactions with the $\sigma$-$\delta$ and $\omega$-$\rho$ mixing, referred to as the OMEG family. These interactions are optimized so as to reproduce both terrestrial nuclear measurements and astrophysical constraints extracted from NICER and GW170817. The $\sigma$-$\delta$ mixing softens the nuclear symmetry energy and pressure around twice the saturation density, which enables relatively small neutron-star radii and tidal deformabilities while keeping the nuclear EoS sufficiently stiff at high densities to support $2M_{\odot}$ neutron stars. We find that the curvature parameter, $K_{\textrm{sym}}$, plays an important role in realizing the soft-to-hard behavior of the nuclear EoS, and the astrophysical data favor small or even negative values of $K_{\textrm{sym}}$.
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All authors Tsuyoshi Miyatsu, Myung-Ki Cheoun, Kyungsik Kim, Koichi Saito

Astrophysics of Galaxies

MUSE Analysis of Gas around Galaxies (MAGG) – VII. Emission line galaxies near strong blended Ly$\alpha$ absorption systems at $z\gtrsim3$

Marta Galbiati, Davide Tornotti, Michele Fumagalli et al. (+2 more)

We investigate the connection between strong, blended Ly$\alpha$ absorption systems (SBLAs) and $\approx1000$ Ly$\alpha$ emitting galaxies (LAEs) at $z\gtrsim3$ in 28 quasar fields from the MUSE Analysis of Gas around Galaxies (MAGG) survey. Selecting SBLAs as spectral regions with transmitted flux $-0.05<F<0.25$ over $\approx138\text{ km s}^{-1}$ bins, we find a strong correlation with LAEs within a projected distance of $R\le300\rm\,kpc$ and line-of-sight velocity separation of $|\Delta v|\le300 \text{ km s}^{-1}$. The association rate increases significantly with decreasing flux, a trend that persists also at smaller separations ($R<100$ kpc). A two-dimensional cross-correlation analysis confirms significant clustering of LAEs around SBLAs, while no such clustering is seen for spectral regions with $F>0.25$. The correlation appears to also depend on the width of the spectral window used to identify SBLAs, with a larger window yielding a stronger signal. Our analysis confirms that SBLAs serve as probes of the CGM at the interface between the Ly$\alpha$ forest and the optically-thick Lyman limit systems. The significant dependence of the LAE-SBLA cross-correlation on the spectral binning used to select these absorbers motivates future tests of the current SBLA framework as a tracer of halos.
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All authors Marta Galbiati, Davide Tornotti, Michele Fumagalli, Matteo Fossati, Matthew Pieri

Earth and Planetary Astrophysics

Understanding the chemistry of temperate exoplanets atmospheres through experimental and numerical simulations

O. Sohier, A. Y. Jaziri, L. Vettier et al. (+3 more)

Characterizing temperate exoplanet atmospheres remains challenging due to their small size and low temperatures. Recent JWST observations provide valuable data, but their interpretation has led to diverging conclusions. Complementary approaches combining laboratory experiments and photochemical modeling are essential for constraining atmospheric chemistry and interpreting observations. We aim to identify chemical pathways governing the formation and evolution of neutral species and to assess their sensitivity to key parameters such as C/O ratio and metallicity. Our approach combines experimental and numerical simulations on H2-rich gas mixtures representative of sub-Neptune atmospheres, spanning a wide range of CH4, CO, and CO2 mixing ratios. A cold plasma reactor simulates out-of-equilibrium upper-atmospheric chemistry. A 0D photochemical model reproduces reactor conditions, guiding interpretation of key pathways and abundance trends. We observe the formation of both reduced and oxidized organic compounds. In CH4-rich mixtures, hydrocarbons form efficiently through methane chemistry, correlating with CH4 concentration and agreeing with models. In more oxidizing environments, particularly CO2-rich mixtures, hydrocarbon formation is inhibited by complex reaction networks and oxidative losses. Oxygen incorporation enhances chemical diversity and promotes formation of oxidized organic compounds of prebiotic interest (H2CO, CH3OH, CH3CHO), especially in atmospheres containing both CH4 and CO2. Atmospheres containing CH4 and CO, which balance carbon and oxygen supply without excessive oxidative destruction, favor efficient production of hydrocarbons and oxidized compounds. Out-of-equilibrium chemistry plays a key role in the diversification and organic complexification of temperate exoplanet atmospheres.
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All authors O. Sohier, A. Y. Jaziri, L. Vettier, A. Chatain, T. Drant, N. Carrasco

Instrumentation and Methods for Astrophysics

Transformational astrophysics and exoplanet science with Habitable Worlds Observatory's High Resolution Imager

Vincent Van Eylen, Richard Massey, Saeeda Awan et al. (+168 more)

Habitable Worlds Observatory (HWO) will be NASA's flagship space telescope of the 2040s, designed to search for life on other planets and to transform broad areas of astrophysics. NASA are seeking international partners, and the UK is well-placed to lead the design and construction of its imaging camera - which is likely to produce the mission's most visible public impact. Early participation in the mission would return investment to UK industry, and bring generational leadership for the UK in space science, space technology, and astrophysics.
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All authors Vincent Van Eylen, Richard Massey, Saeeda Awan, Jo Bartlett, Louisa Bradley, Andrei Bubutanu, Kan Chen, Andrew Coates, Mark Cropper, Ross Dobson, Fabiola Antonietta Gerosa, Emery Grahill-Bland, Leah Grant, Daisuke Kawata, Tom Kennedy, Minjae Kim, Adriana Adelina Mihailescu, Jan-Peter Muller, Georgios Nicolaou, Mathew Page, Paola Pinilla, Louisa Preston, Ted Pyne, Hamish Reid, Santiago Velez Salazar, Jason L. Sanders, Giorgio Savini, Ralph Schoenrich, George Seabroke, Alan Smith, Philip J. Smith, Nicolas Tessore, Marina Ventikos, Esa Vilenius, Francesca Waines, Silvia Zane, James Betts, Sownak Bose, Cyril Borgsom, Shaun Cole, Jessica E. Doppel, Vincent Eke, Carlos Frenk, Leo W. H. Fung, Qiuhan He, Mathilde Jauzac, Owen Jessop, Zane Deon Lentz, Gavin Leroy, Simon Morris, Yuan Ren, Jurgen Schmoll, Ray Sharples, Fionagh Thomson, Maximilian von Wietersheim-Kramsta, Kai Wang, Stephane V. Werner, Subhajit Sarkar, Jacob Kegerreis, James Kirk, Subhanjoy Mohanty, John Southworth, John Philip Stott, Ashley King, James W. Nightingale, David Rosario, Paola Tiranti, Edward Gillen, Cynthia S. K. Ho, Christopher Watson, Andrzej Fludra, Chris Pearson, Yun-Hang Cho, Yu Tao, Joanna Barstow, James Bowen, Chris Castelli, Chiaki Crews, Angaraj Duara, Mark Fox-Powell, David Hall, Carole Haswell, Kit-Hung Mark Lee, Joan Requena, Anabel Romero, Jesper Skottfelt, Konstantin Stefanov, Olivia Jones, Sean McGee, Annelies Mortier, Graham P. Smith, Amalie Stokholm, Amaury Triaud, Becky Alexis-Martin, Malcolm Bremer, Katy L. Chubb, Joshua Ford, Ben Maughan, Daniel Valentine, Hannah Wakeford, Juan Paolo Lorenzo Gerardo Barrios, Chandan Bhat, Xander Byrne, Gregory Cooke, Natalie B. Hogg, Nikku Madhusudhan, Maximilian Sommer, Sandro Tacchella, Georgios N. Vassilakis, Nicholas Walton, Mark Wyatt, Manoj Joshi, Beth Biller, Mariangela Bonavita, Trent Dupuy, Aiza Kenzhebekova, Brian P. Murphy, Vincent Okoth, Cyrielle Opitom, Larissa Palethorpe, Paul Palmer, Mia Belle Parkinson, Ken Rice, Sarah Rugheimer, Colin Snodgrass, Ben J. Sutlieff, Souradeep Bhattacharya, Emma Curtis-Lake, Jan Forbrich, Darshan Kakkad, David J. Lagattuta, Brian Ongeri Momanyi Bichang'a, Peter Scicluna, Richard Booth, Martin Barstow, Sarah Casewell, Leigh Fletcher, Anushka Sharma, Christopher J. Conselice, Suzanne Aigrain, Jayne Birkby, Claire Guimond, Carly Howett, Mei Ting Mak, Richard Palin, Chris Pattison, Richard Robinson, Samantha Youles, Andrew Collier Cameron, Justin Read, David John Armstrong, David J. A. Brown, Mikkel N. Lund, Andrew Robertson, Pierre-Olivier Lagage, Lígia F. Coelho, Preethi R. Karpoor, Enric Palle, Leen Decin, Denis Defrère, Kaustubh Hakim, Swara Ravindranath, Jason Rhodes, Marc Postman, Iain Neill Reid, Fabien Malbet, Amirnezam Amiri, Marrick Braam, Qiuhan He, Haakon Dahle, Angharad Weeks

Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Implementing F (T ) Gravity in Boltzmann Codes: A Framework for Power Spectrum Computation

Robert Rugg, Shambel Akalu and Amare Abebe

This work investigates the nonlinearity of the power-law model of F(T) gravity, highlighting the inability of the Boltzmann solver CLASS to handle nonlinear models. As a workaround, a second-order Taylor expansion is applied to the nonlinear field equations, under the assumption that the extra degree of freedom n, which quantifies deviations from the currently favored cosmological model (\Lambda CDM), remains sufficiently small to preserve the key properties of the \Lambda CDM model. The validity of the Taylor expansion is supported by supernova data indicating n \leq 0.05, for which the power spectrum can be accurately computed within CLASS with a negligible truncation error.
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Solar and Stellar Astrophysics

High mass accretion rates onto evolved stripped-envelope massive stars by jet-induced mass removal

Yotham Cohen, Ealeal Bear and Noam Soker

Simulating one-dimensional stellar evolution models with MESA, we show that removing the outer inflated envelope of a mass-accreting evolved stripped-envelope star, like a Wolf-Rayet (WR) star, substantially moderates the stellar expansion during accretion at high-mass accretion rates. We study the accretion onto a star via an accretion disk, which launches jets that remove the high-entropy outer layers of the inflated envelope. This is the `jetted mass removal accretion scenario.' By manually removing the entire hydrogen-rich envelope from a red supergiant, we build a hydrogen-deficient WR stellar model with a mass of 6.03Mo and a radius of 0.67Ro. We then accrete mass onto it at a high rate. We mimic the real process of simultaneous mass addition near the equatorial plane and jet-induced mass removal from the outer envelope by dividing the accretion period into hundreds of pulses: in the first half of each pulse, we add mass, and in the second, we remove a fraction of this mass. The removal of tens of percent from the added mass decreases the stellar expansion by a factor of ~2-5. Our results show that WR stars can maintain a deep potential well and not expand much while accreting mass at high rates. This allows the formation of an accretion disk and the liberation of large amounts of gravitational energy. Our results strengthen models of intermediate-luminosity optical transients, such as luminous red novae, in which a non-degenerate star accretes at high rates and launches jets that power the transient event.
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Astrophysics of Galaxies

The AGN nature of strong CIII emitters in the Early Universe with JWST

F. Arevalo-Gonzalez, R. Tripodi, M. Llerena et al. (+21 more)

The semi-forbidden CIII] $\lambda\lambda$1907,1909 doublet is a key tracer of high-ionization emission in the early universe. We present a study of CIII] emission in galaxies at z=5-7, using publicly available JWST/NIRSpec prism data from programs including CEERS, JADES, RUBIES and CAPERS. We built a sample of 61 CIII]-emitting galaxies, and we classified them as star-forming or active galactic nuclei (AGN) host galaxies using (1) rest-frame UV and optical emission-line diagnostic diagrams, and (2) the presence/absence of broad Balmer emission lines. The UV diagnostics are based on the combination of the rest-frame equivalent width (EW) of CIII] versus CIII]/HeII $\lambda$1640, and the EW of CIV versus CIV/HeII $\lambda$1640. For optical diagnostics, we employ the OHNO diagram, which combines [OIII] $\lambda$5007, H$\beta$, [NeIII] $\lambda$3869, and [OII] $\lambda\lambda$3727,3729- and we find it has a low efficiency on separating AGN from SFG. We find that half of the sources in our sample (29 out of 61 galaxies) exhibit at least one secure indication of AGN activity while 13 are potential AGNs based on the CIII] diagnostic. Physical properties, including stellar mass and star formation rate, are derived through spectral energy distribution modeling with Bagpipes. Our analysis reveals that JWST is uncovering a population of strong CIII] emitters at high redshift (5<z<7) with a median EW of 22.8 A. This EW is higher than that of a control sample of CIII] emitters at redshift 3<z<4 with a median EW of 4.7 A. We find that for the same range of Muv, the CIII] EW increases by $\sim$0.67 dex from 3<z<4 to 5<z<7, indicating strong redshift evolution in the line's strength. Finally, we identify five sources in our sample as Little Red Dots (LRDs); while four of these have already been identified as LRD in the literature, one is presented here for the first time.
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All authors F. Arevalo-Gonzalez, R. Tripodi, M. Llerena, L. Pentericci, A. Plat, G. Barro, R. O. Amorín, B. Backhaus, A. Calabrò, N. J. Cleri, M. Dickinson, J. S. Dunlop, S. L. Finkelstein, M. Giavalisco, M. Hirschmann, J. Kartaltepe, A. M. Koekemoer, R. A. Lucas, L. Napolitano, E. Piconcelli, A. J. Taylor, F. Tombesi, J. R. Trump, X. Wang

Solar and Stellar Astrophysics

Observational methods for solar origin diagnostics of energetic protons

Rositsa Miteva

The aim of the present report is to outline the observational methods used to determine the solar origin - in terms of flares and coronal mass ejections (CMEs) - of the in situ observed solar energetic protons. Several widely used guidelines are given and different sources of uncertainties are summarized and discussed. In the present study, a new quality factor is proposed as a certainty check on the so-identified flare-CME pairs. In addition, the correlations between the proton peak intensity and the properties of their solar origin are evaluated as a function of the quality factor.
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Instrumentation and Methods for Astrophysics

Maximizing the sensitivity of ELT to habitable worlds with a space-based starshade

Markus Janson, Enric Palle, Thomas Henning et al. (+3 more)

The ELT will provide groundbreaking science across a wide range of areas, including small habitable-zone exoplanets; however, true Earth analogs in the habitable zones of Sun-like stars are generally beyond the reach even of the ELT, due to the extreme contrast ratio and small angular separation between the planet and star. Here, we note that the combination of ELT and a space-based starshade would provide the contrast needed to observe potentially tens of Earth analogs, as well as other planets. This would yield the scientific basis needed for addressing central scientific questions regarding the frequency and distribution of habitability and life in the Universe. The huge aperture of ELT, combined with a contrast otherwise only reachable in space, opens up scientific avenues that are unmatched by any other existing or foreseen facility. ESO could conceivably collaborate with ESA (and others) to facilitate a starshade mission suitable for synergy with the ELT, as well as to prepare the ELT instrumentation in order to maximize its potential for synergy with a starshade.
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All authors Markus Janson, Enric Palle, Thomas Henning, Sascha Quanz, Lars Buchhave, Alexis Brandeker

Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

GWTC-4.0: Searches for Gravitational-Wave Lensing Signatures

The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration: A. G. Abac et al. (+1765 more)

Gravitational waves can be gravitationally lensed by massive objects along their path. Depending on the lens mass and the lens–source geometry, this can lead to the observation of a single distorted signal or multiple repeated events with the same frequency evolution. We present the results for gravitational-wave lensing searches on the data from the first part of the fourth LIGO–Virgo–KAGRA observing run (O4a). We search for strongly lensed events in the newly acquired data by (1) searching for an overall phase shift present in an image formed at a saddle point of the lens potential, (2) looking for pairs of detected candidates with consistent frequency evolution, and (3) identifying sub-threshold counterpart candidates to the detected signals. Beyond strong lensing, we also look for lensing-induced distortions in all detected signals using an isolated point-mass model. We do not find evidence for strongly lensed gravitational-wave signals and use this result to constrain the rate of detectable strongly lensed events and the merger rate density of binary black holes at high redshift. In the search for single distorted lensed signals, we find one outlier: GW231123_135430, for which we report more detailed investigations. While this event is interesting, the associated waveform uncertainties make its interpretation complicated, and future observations of the populations of binary black holes and of gravitational lenses will help determine the probability that this event could be lensed.
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All authors The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration: A. G. Abac, I. Abouelfettouh, F. Acernese, K. Ackley, C. Adamcewicz, S. Adhicary, D. Adhikari, N. Adhikari, R. X. Adhikari, V. K. Adkins, S. Afroz, A. Agapito, D. Agarwal, M. Agathos, N. Aggarwal, S. Aggarwal, O. D. Aguiar, I.-L. Ahrend, L. Aiello, A. Ain, P. Ajith, T. Akutsu, S. Albanesi, W. Ali, S. Al-Kershi, C. Alléné, A. Allocca, S. Al-Shammari, P. A. Altin, S. Alvarez-Lopez, W. Amar, O. Amarasinghe, A. Amato, F. Amicucci, C. Amra, A. Ananyeva, S. B. Anderson, W. G. Anderson, M. Andia, M. Ando, M. Andrés-Carcasona, T. Andrić, J. Anglin, S. Ansoldi, J. M. Antelis, S. Antier, M. Aoumi, E. Z. Appavuravther, S. Appert, S. K. Apple, K. Arai, A. Araya, M. C. Araya, M. Arca Sedda, J. S. Areeda, N. Aritomi, F. Armato, S. Armstrong, N. Arnaud, M. Arogeti, S. M. Aronson, G. Ashton, Y. Aso, L. Asprea, M. Assiduo, S. Assis de Souza Melo, S. M. Aston, P. Astone, F. Attadio, F. Aubin, K. AultONeal, G. Avallone, E. A. Avila, S. Babak, C. Badger, S. Bae, S. Bagnasco, L. Baiotti, R. Bajpai, T. Baka, A. M. Baker, K. A. Baker, T. Baker, G. Baldi, N. Baldicchi, M. Ball, G. Ballardin, S. W. Ballmer, S. Banagiri, B. Banerjee, D. Bankar, T. M. Baptiste, P. Baral, M. Baratti, J. C. Barayoga, B. C. Barish, D. Barker, N. Barman, P. Barneo, F. Barone, B. Barr, A. Barsode, L. Barsotti, M. Barsuglia, D. Barta, A. M. Bartoletti, M. A. Barton, I. Bartos, S. Basak, A. Basalaev, R. Bassiri, A. Basti, M. Bawaj, P. Baxi, J. C. Bayley, A. C. Baylor, P. A. Baynard II, M. Bazzan, V. M. Bedakihale, F. Beirnaert, M. Bejger, D. Belardinelli, A. S. Bell, D. S. Bellie, L. Bellizzi, W. Benoit, I. Bentara, J. D. Bentley, M. Ben Yaala, S. Bera, F. Bergamin, B. K. Berger, S. Bernuzzi, M. Beroiz, C. P. L. Berry, D. Bersanetti, T. Bertheas, A. Bertolini, J. Betzwieser, D. Beveridge, G. Bevilacqua, N. Bevins, R. Bhandare, R. Bhatt, D. Bhattacharjee, S. Bhattacharyya, S. Bhaumik, V. Biancalana, A. Bianchi, I. A. Bilenko, G. Billingsley, A. Binetti, C. Binu, S. Biot, O. Birnholtz, S. Biscoveanu, A. Bisht, M. Bitossi, M.-A. Bizouard, S. Blaber, J. K. Blackburn, L. A. Blagg, C. D. Blair, D. G. Blair, N. Bode, N. Boettner, G. Boileau, M. Boldrini, G. N. Bolingbroke, A. Bolliand, L. D. Bonavena, R. Bondarescu, F. Bondu, E. Bonilla, M. S. Bonilla, A. Bonino, R. Bonnand, A. Borchers, S. Borhanian, V. Boschi, S. Bose, V. Bossilkov, Y. Bothra, A. Boudon, L. Bourg, M. Boyle, A. Bozzi, C. Bradaschia, P. R. Brady, A. Branch, M. Branchesi, I. Braun, T. Briant, A. Brillet, M. Brinkmann, P. Brockill, E. Brockmueller, A. F. Brooks, B. C. Brown, D. D. Brown, M. L. Brozzetti, S. Brunett, G. Bruno, R. Bruntz, J. Bryant, Y. Bu, F. Bucci, J. Buchanan, O. Bulashenko, T. Bulik, H. J. Bulten, A. Buonanno, K. Burtnyk, R. Buscicchio, D. Buskulic, C. Buy, R. L. Byer, G. S. Cabourn Davies, R. Cabrita, V. Cáceres-Barbosa, L. Cadonati, G. Cagnoli, C. Cahillane, A. Calafat, T. A. Callister, E. Calloni, S. R. Callos, G. Caneva Santoro, K. C. Cannon, H. Cao, L. A. Capistran, E. Capocasa, E. Capote, G. Capurri, G. Carapella, F. Carbognani, M. Carlassara, J. B. Carlin, T. K. Carlson, M. F. Carney, M. Carpinelli, G. Carrillo, J. J. Carter, G. Carullo, A. Casallas-Lagos, J. Casanueva Diaz, C. Casentini, S. Y. Castro-Lucas, S. Caudill, M. Cavaglià, R. Cavalieri, A. Ceja, G. Cella, P. Cerdá-Durán, E. Cesarini, N. Chabbra, W. Chaibi, A. Chakraborty, P. Chakraborty, S. Chakraborty, S. Chalathadka Subrahmanya, J. C. L. Chan, M. Chan, K. Chang, S. Chao, P. Charlton, E. Chassande-Mottin, C. Chatterjee, Debarati Chatterjee, Deep Chatterjee, M. Chaturvedi, S. Chaty, A. Chen, A. H.-Y. Chen, D. Chen, H. Chen, H. Y. Chen, S. Chen, Yanbei Chen, Yitian Chen, H. P. Cheng, P. Chessa, H. T. Cheung, S. Y. Cheung, F. Chiadini, G. Chiarini, A. Chiba, A. Chincarini, M. L. Chiofalo, A. Chiummo, C. Chou, S. Choudhary, N. Christensen, S. S. Y. Chua, G. Ciani, P. Ciecielag, M. Cieślar, M. Cifaldi, B. Cirok, F. Clara, J. A. Clark, T. A. Clarke, P. Clearwater, S. Clesse, F. Cleva, E. Coccia, E. Codazzo, P.-F. Cohadon, S. Colace, E. Colangeli, M. Colleoni, C. G. Collette, J. Collins, S. Colloms, A. Colombo, C. M. Compton, G. Connolly, L. Conti, T. R. Corbitt, I. Cordero-Carrión, S. Corezzi, N. J. Cornish, I. Coronado, A. Corsi, R. Cottingham, M. W. Coughlin, A. Couineaux, P. Couvares, D. M. Coward, R. Coyne, A. Cozzumbo, J. D. E. Creighton, T. D. Creighton, P. Cremonese, S. Crook, R. Crouch, J. Csizmazia, J. R. Cudell, T. J. Cullen, A. Cumming, E. Cuoco, M. Cusinato, L. V. Da Conceição, T. Dal Canton, S. Dal Pra, G. Dálya, B. D'Angelo, S. Danilishin, S. D'Antonio, K. Danzmann, K. E. Darroch, L. P. Dartez, R. Das, A. Dasgupta, V. Dattilo, A. Daumas, N. Davari, I. Dave, A. Davenport, M. Davier, T. F. Davies, D. Davis, L. Davis, M. C. Davis, P. Davis, E. J. Daw, M. Dax, J. De Bolle, M. Deenadayalan, J. Degallaix, U. Dekka, M. De Laurentis, F. De Lillo, S. Della Torre, W. Del Pozzo, A. Demagny, F. De Marco, G. Demasi, F. De Matteis, N. Demos, A. Depasse, N. DePergola, R. De Pietri, R. De Rosa, C. De Rossi, M. Desai, R. DeSalvo, A. DeSimone, R. De Simone, A. Dhani, R. Diab, M. C. Díaz, M. Di Cesare, G. Dideron, T. Dietrich, L. Di Fiore, C. Di Fronzo, M. Di Giovanni, T. Di Girolamo, D. Diksha, J. Ding, S. Di Pace, I. Di Palma, D. Di Piero, F. Di Renzo, Divyajyoti, A. Dmitriev, J. P. Docherty, Z. Doctor, N. Doerksen, E. Dohmen, A. Doke, A. Domiciano De Souza, L. D'Onofrio, F. Donovan, K. L. Dooley, T. Dooney, S. Doravari, O. Dorosh, W. J. D. Doyle, M. Drago, J. C. Driggers, L. Dunn, U. Dupletsa, P.-A. Duverne, D. D'Urso, P. Dutta Roy, H. Duval, S. E. Dwyer, C. Eassa, M. Ebersold, T. Eckhardt, G. Eddolls, A. Effler, J. Eichholz, H. Einsle, M. Eisenmann, M. Emma, K. Endo, R. Enficiaud, L. Errico, R. Espinosa, M. Esposito, R. C. Essick, H. Estellés, T. Etzel, M. Evans, T. Evstafyeva, B. E. Ewing, J. M. Ezquiaga, F. Fabrizi, V. Fafone, S. Fairhurst, A. M. Farah, B. Farr, W. M. Farr, G. Favaro, M. Favata, M. Fays, M. Fazio, J. Feicht, M. M. Fejer, R. Felicetti, E. Fenyvesi, J. Fernandes, T. Fernandes, D. Fernando, S. Ferraiuolo, T. A. Ferreira, F. Fidecaro, P. Figura, A. Fiori, I. Fiori, M. Fishbach, R. P. Fisher, R. Fittipaldi, V. Fiumara, R. Flaminio, S. M. Fleischer, L. S. Fleming, E. Floden, H. Fong, J. A. Font, F. Fontinele-Nunes, C. Foo, B. Fornal, K. Franceschetti, F. Frappez, S. Frasca, F. Frasconi, J. P. Freed, Z. Frei, A. Freise, O. Freitas, R. Frey, W. Frischhertz, P. Fritschel, V. V. Frolov, G. G. Fronzé, M. Fuentes-Garcia, S. Fujii, T. Fujimori, P. Fulda, M. Fyffe, B. Gadre, J. R. Gair, S. Galaudage, V. Galdi, R. Gamba, A. Gamboa, S. Gamoji, D. Ganapathy, A. Ganguly, B. Garaventa, J. García-Bellido, C. García-Quirós, J. W. Gardner, K. A. Gardner, S. Garg, J. Gargiulo, X. Garrido, A. Garron, F. Garufi, P. A. Garver, C. Gasbarra, B. Gateley, F. Gautier, V. Gayathri, T. Gayer, G. Gemme, A. Gennai, V. Gennari, J. George, R. George, O. Gerberding, L. Gergely, Archisman Ghosh, Sayantan Ghosh, Shaon Ghosh, Shrobana Ghosh, Suprovo Ghosh, Tathagata Ghosh, J. A. Giaime, K. D. Giardina, D. R. Gibson, C. Gier, S. Gkaitatzis, J. Glanzer, F. Glotin, J. Godfrey, R. V. Godley, P. Godwin, A. S. Goettel, E. Goetz, J. Golomb, S. Gomez Lopez, B. Goncharov, G. González, P. Goodarzi, S. Goode, A. W. Goodwin-Jones, M. Gosselin, R. Gouaty, D. W. Gould, K. Govorkova, S. Goyal, A. Grado, V. Graham, A. E. Granados, M. Granata, V. Granata, S. Gras, P. Grassia, J. Graves, C. Gray, R. Gray, G. Greco, A. C. Green, L. Green, S. M. Green, S. R. Green, C. Greenberg, A. M. Gretarsson, H. K. Griffin, D. Griffith, H. L. Griggs, G. Grignani, C. Grimaud, H. Grote, S. Grunewald, D. Guerra, D. Guetta, G. M. Guidi, A. R. Guimaraes, H. K. Gulati, F. Gulminelli, H. Guo, W. Guo, Y. Guo, Anuradha Gupta, I. Gupta, N. C. Gupta, S. K. Gupta, V. Gupta, N. Gupte, J. Gurs, N. Gutierrez, N. Guttman, F. Guzman, D. Haba, M. Haberland, S. Haino, E. D. Hall, E. Z. Hamilton, G. Hammond, M. Haney, J. Hanks, C. Hanna, O. A. Hannuksela, A. G. Hanselman, H. Hansen, J. Hanson, S. Hanumasagar, R. Harada, A. R. Hardison, S. Harikumar, K. Haris, I. Harley-Trochimczyk, T. Harmark, J. Harms, G. M. Harry, I. W. Harry, J. Hart, B. Haskell, C. J. Haster, K. Haughian, H. Hayakawa, K. Hayama, M. C. Heintze, J. Heinze, J. Heinzel, H. Heitmann, F. Hellman, A. F. Helmling-Cornell, G. Hemming, O. Henderson-Sapir, M. Hendry, I. S. Heng, M. H. Hennig, C. Henshaw, M. Heurs, A. L. Hewitt, J. Heynen, J. Heyns, S. Higginbotham, S. Hild, S. Hill, Y. Himemoto, N. Hirata, C. Hirose, D. Hofman, B. E. Hogan, N. A. Holland, K. Holley-Bockelmann, I. J. Hollows, D. E. Holz, L. Honet, D. J. Horton-Bailey, J. Hough, S. Hourihane, N. T. Howard, E. J. Howell, C. G. Hoy, C. A. Hrishikesh, P. Hsi, H.-F. Hsieh, H.-Y. Hsieh, C. Hsiung, S.-H. Hsu, W.-F. Hsu, Q. Hu, H. Y. Huang, Y. Huang, Y. T. Huang, A. D. Huddart, B. Hughey, V. Hui, S. Husa, R. Huxford, L. Iampieri, G. A. Iandolo, M. Ianni, G. Iannone, J. Iascau, K. Ide, R. Iden, A. Ierardi, S. Ikeda, H. Imafuku, Y. Inoue, G. Iorio, P. Iosif, M. H. Iqbal, J. Irwin, R. Ishikawa, M. Isi, K. S. Isleif, Y. Itoh, M. Iwaya, B. R. Iyer, C. Jacquet, P.-E. Jacquet, T. Jacquot, S. J. Jadhav, S. P. Jadhav, M. Jain, T. Jain, A. L. James, K. Jani, J. Janquart, N. N. Janthalur, S. Jaraba, P. Jaranowski, R. Jaume, W. Javed, A. Jennings, M. Jensen, W. Jia, J. Jiang, H.-B. Jin, G. R. Johns, N. A. Johnson, M. C. Johnston, R. Johnston, N. Johny, D. H. Jones, D. I. Jones, R. Jones, H. E. Jose, P. Joshi, S. K. Joshi, G. Joubert, J. Ju, L. Ju, K. Jung, J. Junker, V. Juste, H. B. Kabagoz, T. Kajita, I. Kaku, V. Kalogera, M. Kalomenopoulos, M. Kamiizumi, N. Kanda, S. Kandhasamy, G. Kang, N. C. Kannachel, J. B. Kanner, S. A. KantiMahanty, S. J. Kapadia, D. P. Kapasi, M. Karthikeyan, M. Kasprzack, H. Kato, T. Kato, E. Katsavounidis, W. Katzman, R. Kaushik, K. Kawabe, R. Kawamoto, D. Keitel, L. J. Kemperman, J. Kennington, F. A. Kerkow, R. Kesharwani, J. S. Key, R. Khadela, S. Khadka, S. S. Khadkikar, F. Y. Khalili, F. Khan, T. Khanam, M. Khursheed, N. M. Khusid, W. Kiendrebeogo, N. Kijbunchoo, C. Kim, J. C. Kim, K. Kim, M. H. Kim, S. Kim, Y.-M. Kim, C. Kimball, K. Kimes, M. Kinnear, J. S. Kissel, S. Klimenko, A. M. Knee, E. J. Knox, N. Knust, K. Kobayashi, S. M. Koehlenbeck, G. Koekoek, K. Kohri, K. Kokeyama, S. Koley, P. Kolitsidou, A. E. Koloniari, K. Komori, A. K. H. Kong, A. Kontos, L. M. Koponen, M. Korobko, X. Kou, A. Koushik, N. Kouvatsos, M. Kovalam, T. Koyama, D. B. Kozak, S. L. Kranzhoff, V. Kringel, N. V. Krishnendu, S. Kroker, A. Królak, K. Kruska, J. Kubisz, G. Kuehn, S. Kulkarni, A. Kulur Ramamohan, Achal Kumar, Anil Kumar, Praveen Kumar, Prayush Kumar, Rahul Kumar, Rakesh Kumar, J. Kume, K. Kuns, N. Kuntimaddi, S. Kuroyanagi, S. Kuwahara, K. Kwak, K. Kwan, S. Kwon, G. Lacaille, D. Laghi, A. H. Laity, E. Lalande, M. Lalleman, P. C. Lalremruati, M. Landry, B. B. Lane, R. N. Lang, J. Lange, R. Langgin, B. Lantz, I. La Rosa, J. Larsen, A. Lartaux-Vollard, P. D. Lasky, J. Lawrence, M. Laxen, C. Lazarte, A. Lazzarini, C. Lazzaro, P. Leaci, L. Leali, Y. K. Lecoeuche, H. M. Lee, H. W. Lee, J. Lee, K. Lee, R.-K. Lee, R. Lee, Sungho Lee, Sunjae Lee, Y. Lee, I. N. Legred, J. Lehmann, L. Lehner, M. Le Jean, A. Lemaître, M. Lenti, M. Leonardi, M. Lequime, N. Leroy, M. Lesovsky, N. Letendre, M. Lethuillier, Y. Levin, K. Leyde, A. K. Y. Li, K. L. Li, T. G. F. Li, X. Li, Y. Li, Z. Li, A. Lihos, E. T. Lin, F. Lin, L. C.-C. Lin, Y.-C. Lin, C. Lindsay, S. D. Linker, A. Liu, G. C. Liu, Jian Liu, F. Llamas Villarreal, J. Llobera-Querol, R. K. L. Lo, J.-P. Locquet, S. C. G. Loggins, M. R. Loizou, L. T. London, A. Longo, D. Lopez, M. Lopez Portilla, A. Lorenzo-Medina, V. Loriette, M. Lormand, G. Losurdo, E. Lotti, T. P. Lott IV, J. D. Lough, H. A. Loughlin, C. O. Lousto, N. Low, N. Lu, L. Lucchesi, H. Lück, D. Lumaca, A. P. Lundgren, A. W. Lussier, R. Macas, M. MacInnis, D. M. Macleod, I. A. O. MacMillan, A. Macquet, K. Maeda, S. Maenaut, S. S. Magare, R. M. Magee, E. Maggio, R. Maggiore, M. Magnozzi, M. Mahesh, M. Maini, S. Majhi, E. Majorana, C. N. Makarem, D. Malakar, J. A. Malaquias-Reis, U. Mali, S. Maliakal, A. Malik, L. Mallick, A.-K. Malz, N. Man, M. Mancarella, V. Mandic, V. Mangano, B. Mannix, G. L. Mansell, M. Manske, M. Mantovani, M. Mapelli, C. Marinelli, F. Marion, A. S. Markosyan, A. Markowitz, E. Maros, S. Marsat, F. Martelli, I. W. Martin, R. M. Martin, B. B. Martinez, D. A. Martinez, M. Martinez, V. Martinez, A. Martini, J. C. Martins, D. V. Martynov, E. J. Marx, L. Massaro, A. Masserot, M. Masso-Reid, S. Mastrogiovanni, T. Matcovich, M. Matiushechkina, L. Maurin, N. Mavalvala, N. Maxwell, G. McCarrol, R. McCarthy, D. E. McClelland, S. McCormick, L. McCuller, S. McEachin, C. McElhenny, G. I. McGhee, K. B. M. McGowan, J. McIver, A. McLeod, I. McMahon, T. McRae, R. McTeague, D. Meacher, B. N. Meagher, R. Mechum, Q. Meijer, A. Melatos, C. S. Menoni, F. Mera, R. A. Mercer, L. Mereni, K. Merfeld, E. L. Merilh, J. R. Mérou, J. D. Merritt, M. Merzougui, C. Messick, B. Mestichelli, M. Meyer-Conde, F. Meylahn, A. Mhaske, A. Miani, H. Miao, C. Michel, Y. Michimura, H. Middleton, D. P. Mihaylov, S. J. Miller, M. Millhouse, E. Milotti, V. Milotti, Y. Minenkov, E. M. Minihan, Ll. M. Mir, L. Mirasola, M. Miravet-Tenés, C.-A. Miritescu, A. Mishra, C. Mishra, T. Mishra, A. L. Mitchell, J. G. Mitchell, S. Mitra, V. P. Mitrofanov, K. Mitsuhashi, R. Mittleman, O. Miyakawa, S. Miyoki, A. Miyoko, G. Mo, L. Mobilia, S. R. P. Mohapatra, S. R. Mohite, M. Molina-Ruiz, M. Mondin, M. Montani, C. J. Moore, D. Moraru, A. More, S. More, C. Moreno, E. A. Moreno, G. Moreno, A. Moreso Serra, S. Morisaki, Y. Moriwaki, G. Morras, A. Moscatello, M. Mould, B. Mours, C. M. Mow-Lowry, L. Muccillo, F. Muciaccia, D. Mukherjee, Samanwaya Mukherjee, Soma Mukherjee, Subroto Mukherjee, Suvodip Mukherjee, N. Mukund, A. Mullavey, H. Mullock, J. Mundi, C. L. Mungioli, M. Murakoshi, P. G. Murray, D. Nabari, S. L. Nadji, A. Nagar, N. Nagarajan, K. Nakagaki, K. Nakamura, H. Nakano, M. Nakano, D. Nanadoumgar-Lacroze, D. Nandi, V. Napolano, P. Narayan, I. Nardecchia, T. Narikawa, H. Narola, L. Naticchioni, R. K. Nayak, L. Negri, A. Nela, C. Nelle, A. Nelson, T. J. N. Nelson, M. Nery, A. Neunzert, S. Ng, L. Nguyen Quynh, S. A. Nichols, A. B. Nielsen, Y. Nishino, A. Nishizawa, S. Nissanke, W. Niu, F. Nocera, J. Noller, M. Norman, C. North, J. Novak, R. Nowicki, J. F. Nuño Siles, L. K. Nuttall, K. Obayashi, J. Oberling, J. O'Dell, E. Oelker, M. Oertel, G. Oganesyan, T. O'Hanlon, M. Ohashi, F. Ohme, R. Oliveri, R. Omer, B. O'Neal, M. Onishi, K. Oohara, B. O'Reilly, M. Orselli, R. O'Shaughnessy, S. O'Shea, S. Oshino, C. Osthelder, I. Ota, D. J. Ottaway, A. Ouzriat, H. Overmier, B. J. Owen, R. Ozaki, A. E. Pace, R. Pagano, M. A. Page, A. Pai, L. Paiella, A. Pal, S. Pal, M. A. Palaia, M. Pálfi, P. P. Palma, C. Palomba, P. Palud, H. Pan, J. Pan, K. C. Pan, P. K. Panda, Shiksha Pandey, Swadha Pandey, P. T. H. Pang, F. Pannarale, K. A. Pannone, B. C. Pant, F. H. Panther, M. Panzeri, F. Paoletti, A. Paolone, A. Papadopoulos, E. E. Papalexakis, L. Papalini, G. Papigkiotis, A. Paquis, A. Parisi, B.-J. Park, J. Park, W. Parker, G. Pascale, D. Pascucci, A. Pasqualetti, R. Passaquieti, L. Passenger, D. Passuello, O. Patane, A. V. Patel, D. Pathak, A. Patra, B. Patricelli, B. G. Patterson, K. Paul, S. Paul, E. Payne, T. Pearce, M. Pedraza, A. Pele, F. E. Peña Arellano, X. Peng, Y. Peng, S. Penn, M. D. Penuliar, A. Perego, Z. Pereira, C. Périgois, G. Perna, A. Perreca, J. Perret, S. Perriès, J. W. Perry, D. Pesios, S. Peters, S. Petracca, C. Petrillo, H. P. Pfeiffer, H. Pham, K. A. Pham, K. S. Phukon, H. Phurailatpam, M. Piarulli, L. Piccari, O. J. Piccinni, M. Pichot, M. Piendibene, F. Piergiovanni, L. Pierini, G. Pierra, V. Pierro, M. Pietrzak, M. Pillas, F. Pilo, L. Pinard, I. M. Pinto, M. Pinto, B. J. Piotrzkowski, M. Pirello, M. D. Pitkin, A. Placidi, E. Placidi, M. L. Planas, W. Plastino, C. Plunkett, R. Poggiani, E. Polini, J. Pomper, L. Pompili, J. Poon, E. Porcelli, E. K. Porter, C. Posnansky, R. Poulton, J. Powell, G. S. Prabhu, M. Pracchia, B. K. Pradhan, T. Pradier, A. K. Prajapati, K. Prasai, R. Prasanna, P. Prasia, G. Pratten, G. Principe, G. A. Prodi, P. Prosperi, P. Prosposito, A. C. Providence, A. Puecher, J. Pullin, P. Puppo, M. Pürrer, H. Qi, J. Qin, G. Quéméner, V. Quetschke, P. J. Quinonez, N. Qutob, R. Rading, I. Rainho, S. Raja, C. Rajan, B. Rajbhandari, K. E. Ramirez, F. A. Ramis Vidal, M. Ramos Arevalo, A. Ramos-Buades, S. Ranjan, K. Ransom, P. Rapagnani, B. Ratto, A. Ravichandran, A. Ray, V. Raymond, M. Razzano, J. Read, T. Regimbau, S. Reid, C. Reissel, D. H. Reitze, A. I. Renzini, B. Revenu, A. Revilla Peña, R. Reyes, L. Ricca, F. Ricci, M. Ricci, A. Ricciardone, J. Rice, J. W. Richardson, M. L. Richardson, A. Rijal, K. Riles, H. K. Riley, S. Rinaldi, J. Rittmeyer, C. Robertson, F. Robinet, M. Robinson, A. Rocchi, L. Rolland, J. G. Rollins, A. E. Romano, R. Romano, A. Romero, I. M. Romero-Shaw, J. H. Romie, S. Ronchini, T. J. Roocke, L. Rosa, T. J. Rosauer, C. A. Rose, D. Rosińska, M. P. Ross, M. Rossello-Sastre, S. Rowan, S. K. Roy, S. Roy, D. Rozza, P. Ruggi, N. Ruhama, E. Ruiz Morales, K. Ruiz-Rocha, S. Sachdev, T. Sadecki, P. Saffarieh, S. Safi-Harb, M. R. Sah, S. Saha, T. Sainrat, S. Sajith Menon, K. Sakai, Y. Sakai, M. Sakellariadou, S. Sakon, O. S. Salafia, F. Salces-Carcoba, L. Salconi, M. Saleem, F. Salemi, M. Sallé, S. U. Salunkhe, S. Salvador, A. Salvarese, A. Samajdar, A. Sanchez, E. J. Sanchez, L. E. Sanchez, N. Sanchis-Gual, J. R. Sanders, E. M. Sänger, F. Santoliquido, F. Sarandrea, T. R. Saravanan, N. Sarin, P. Sarkar, A. Sasli, P. Sassi, B. Sassolas, R. Sato, S. Sato, Yukino Sato, Yu Sato, O. Sauter, R. L. Savage, T. Sawada, H. L. Sawant, S. Sayah, V. Scacco, D. Schaetzl, M. Scheel, A. Schiebelbein, M. G. Schiworski, P. Schmidt, S. Schmidt, R. Schnabel, M. Schneewind, R. M. S. Schofield, K. Schouteden, B. W. Schulte, B. F. Schutz, E. Schwartz, M. Scialpi, J. Scott, S. M. Scott, R. M. Sedas, T. C. Seetharamu, M. Seglar-Arroyo, Y. Sekiguchi, D. Sellers, N. Sembo, A. S. Sengupta, E. G. Seo, J. W. Seo, V. Sequino, M. Serra, A. Sevrin, T. Shaffer, U. S. Shah, M. A. Shaikh, L. Shao, A. K. Sharma, Preeti Sharma, Prianka Sharma, Ritwik Sharma, S. Sharma Chaudhary, P. Shawhan, N. S. Shcheblanov, E. Sheridan, Z.-H. Shi, M. Shikauchi, R. Shimomura, H. Shinkai, S. Shirke, D. H. Shoemaker, D. M. Shoemaker, R. W. Short, S. ShyamSundar, A. Sider, H. Siegel, D. Sigg, L. Silenzi, L. Silvestri, M. Simmonds, L. P. Singer, Amitesh Singh, Anika Singh, D. Singh, N. Singh, S. Singh, A. M. Sintes, V. Sipala, V. Skliris, B. J. J. Slagmolen, D. A. Slater, T. J. Slaven-Blair, J. Smetana, J. R. Smith, L. Smith, R. J. E. Smith, W. J. Smith, S. Soares de Albuquerque Filho, M. Soares-Santos, K. Somiya, I. Song, S. Soni, V. Sordini, F. Sorrentino, H. Sotani, F. Spada, V. Spagnuolo, A. P. Spencer, P. Spinicelli, A. K. Srivastava, F. Stachurski, C. J. Stark, D. A. Steer, N. Steinle, J. Steinlechner, S. Steinlechner, N. Stergioulas, P. Stevens, M. StPierre, M. D. Strong, A. Strunk, A. L. Stuver, M. Suchenek, S. Sudhagar, Y. Sudo, N. Sueltmann, L. Suleiman, K. D. Sullivan, J. Sun, L. Sun, S. Sunil, J. Suresh, B. J. Sutton, P. J. Sutton, K. Suzuki, M. Suzuki, B. L. Swinkels, A. Syx, M. J. Szczepańczyk, P. Szewczyk, M. Tacca, H. Tagoshi, K. Takada, H. Takahashi, R. Takahashi, A. Takamori, S. Takano, H. Takeda, K. Takeshita, I. Takimoto Schmiegelow, M. Takou-Ayaoh, C. Talbot, M. Tamaki, N. Tamanini, D. Tanabe, K. Tanaka, S. J. Tanaka, S. Tanioka, D. B. Tanner, W. Tanner, L. Tao, R. D. Tapia, E. N. Tapia San Martín, C. Taranto, A. Taruya, J. D. Tasson, J. G. Tau, D. Tellez, R. Tenorio, H. Themann, A. Theodoropoulos, M. P. Thirugnanasambandam, L. M. Thomas, M. Thomas, P. Thomas, J. E. Thompson, S. R. Thondapu, K. A. Thorne, E. Thrane, J. Tissino, A. Tiwari, Pawan Tiwari, Praveer Tiwari, S. Tiwari, V. Tiwari, M. R. Todd, M. Toffano, A. M. Toivonen, K. Toland, A. E. Tolley, T. Tomaru, V. Tommasini, T. Tomura, H. Tong, C. Tong-Yu, A. Torres-Forné, C. I. Torrie, I. Tosta e Melo, E. Tournefier, M. Trad Nery, K. Tran, A. Trapananti, R. Travaglini, F. Travasso, G. Traylor, M. Trevor, M. C. Tringali, A. Tripathee, G. Troian, A. Trovato, L. Trozzo, R. J. Trudeau, T. Tsang, S. Tsuchida, L. Tsukada, K. Turbang, M. Turconi, C. Turski, H. Ubach, N. Uchikata, T. Uchiyama, R. P. Udall, T. Uehara, K. Ueno, V. Undheim, L. E. Uronen, T. Ushiba, M. Vacatello, H. Vahlbruch, N. Vaidya, G. Vajente, A. Vajpeyi, J. Valencia, M. Valentini, S. A. Vallejo-Peña, S. Vallero, V. Valsan, M. van Dael, E. Van den Bossche, J. F. J. van den Brand, C. Van Den Broeck, M. van der Sluys, A. Van de Walle, J. van Dongen, K. Vandra, M. VanDyke, H. van Haevermaet, J. V. van Heijningen, P. Van Hove, J. Vanier, M. VanKeuren, J. Vanosky, N. van Remortel, M. Vardaro, A. F. Vargas, V. Varma, A. N. Vazquez, A. Vecchio, G. Vedovato, J. Veitch, P. J. Veitch, S. Venikoudis, R. C. Venterea, P. Verdier, M. Vereecken, D. Verkindt, B. Verma, Y. Verma, S. M. Vermeulen, F. Vetrano, A. Veutro, A. Viceré, S. Vidyant, A. D. Viets, A. Vijaykumar, A. Vilkha, N. Villanueva Espinosa, V. Villa-Ortega, E. T. Vincent, J.-Y. Vinet, S. Viret, S. Vitale, H. Vocca, D. Voigt, E. R. G. von Reis, J. S. A. von Wrangel, W. E. Vossius, L. Vujeva, S. P. Vyatchanin, J. Wack, L. E. Wade, M. Wade, K. J. Wagner, L. Wallace, E. J. Wang, H. Wang, J. Z. Wang, W. H. Wang, Y. F. Wang, G. Waratkar, J. Warner, M. Was, T. Washimi, N. Y. Washington, D. Watarai, B. Weaver, S. A. Webster, N. L. Weickhardt, M. Weinert, A. J. Weinstein, R. Weiss, L. Wen, K. Wette, J. T. Whelan, B. F. Whiting, C. Whittle, E. G. Wickens, D. Wilken, A. T. Wilkin, B. M. Williams, D. Williams, M. J. Williams, N. S. Williams, J. L. Willis, B. Willke, M. Wils, L. Wilson, C. W. Winborn, J. Winterflood, C. C. Wipf, G. Woan, J. Woehler, N. E. Wolfe, H. T. Wong, I. C. F. Wong, K. Wong, M. Wong, T. Wouters, J. L. Wright, M. Wright, B. Wu, C. Wu, D. S. Wu, H. Wu, K. Wu, Q. Wu, Y. Wu, Z. Wu, E. Wuchner, D. M. Wysocki, V. A. Xu, Y. Xu, N. Yadav, H. Yamamoto, K. Yamamoto, T. S. Yamamoto, T. Yamamoto, R. Yamazaki, T. Yan, K. Z. Yang, Y. Yang, Z. Yarbrough, J. Yebana, S.-W. Yeh, A. B. Yelikar, X. Yin, J. Yokoyama, T. Yokozawa, S. Yuan, H. Yuzurihara, M. Zanolin, M. Zeeshan, T. Zelenova, J.-P. Zendri, M. Zeoli, M. Zerrad, M. Zevin, L. Zhang, N. Zhang, R. Zhang, T. Zhang, C. Zhao, Yue Zhao, Yuhang Zhao, Z.-C. Zhao, Y. Zheng, H. Zhong, H. Zhou, H. O. Zhu, Z.-H. Zhu, A. B. Zimmerman, L. Zimmermann, M. E. Zucker, J. Zweizig

High Energy Astrophysical Phenomena · Cross-listed from gr-qc

Modified light-cylinder and centrifugal acceleration in Schwarzschild geometry

Nikoloz Kurtskhalia, Nikolai Maltsev and Zaza N. Osmanov

We examine the motion of an electron constrained to follow a magnetic field line near a primordial sub-stellar mass black hole. Earlier studies treated the problem in flat (Minkowski) spacetime, yielding qualitatively correct results and introducing a light cylinder (LC), a hypothetical surface where the linear velocity of rotation equals the speed of light. However, this picture changes significantly when gravity is included. By analyzing the electron's dynamics in the Schwarzschild metric, we obtain a modified light cylinder (MLC) whose geometry no longer resembles a cylinder. We then determine the maximum energies attainable by the electrons under the limiting effects of inverse Compton scattering, curvature radiation, and synchrotron radiation.
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High Energy Astrophysical Phenomena · Cross-listed from nucl-th

Modeling Ultra-High-Energy Cosmic Rays propagation using the input from Configuration Interaction Shell Model

O. Le Noan, E. Khan, S. Goriely et al. (+1 more)

The dipole response of a nuclear system, characterized by its photon strength function (PSF), is a key ingredient of many applications of nuclear structure, ranging from nuclear reactor design and nuclear waste transmutation to astrophysical models of nucleosynthesis and stellar evolution. While the majority of those applications require the knowledge of PSF of mid-mass and heavy nuclei, there is now renewed interest in $E1$ strength distributions of light nuclei in the framework of the PANDORA project, which aims at an understanding of the mass distribution of ultrahigh-energy cosmic radiation (UHECR).UHECR is of extragalactic origin and its interaction along the travel path is dominated by photoabsorption of cosmic background radiation boosted to the Giant Dipole Resonance (GDR) energy region in the center-of-mass system. Thus, systematic knowledge of the photoabsorption cross sections in light nuclei and of their subsequent particle decay is required. The purpose of this work is to enhance the database of available theoretical evaluations of PSF of light nuclei that are necessary in the studies of UHECR propagation. We employ the Configuration Interaction Shell Model (CI-SM) approach to provide predictions of $E1$ dipole response for $p$ and $sd$-shell nuclei, with mass number $A$ between 7 and 40. Theoretical predictions are compared to available data and to existing predictions from phenomenological and microscopic models. Finally, the impact of using of CI-SM PSF on the predicted propagation of a $^{40}$Ca UHECR source is studied.
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All authors O. Le Noan, E. Khan, S. Goriely, K. Sieja

Instrumentation and Methods for Astrophysics

New methods to improve the decontamination of slitless spectra

Mostafa Bella, Shahram Hosseini, Thierry Contini et al. (+1 more)

This paper proposes four new methods to decontaminate spectra of stars and galaxies resulting from slitless spectroscopy used in many space missions such as Euclid. These methods are based on two distinct approaches and simultaneously take into account multiple dispersion directions of light. The first approach, called the local instantaneous approach, is based on an approximate linear instantaneous model. The second approach, called the local convolutive approach, is based on a more realistic convolutive model that allows simultaneous decontamination and deconvolution of spectra. For each approach, a mixing model was developed that links the observed data to the source spectra. This was done either in the spatial domain for the local instantaneous approach or in the Fourier domain for the local convolutive approach. Four methods were then developed to decontaminate these spectra from the mixtures, exploiting the direct images provided by photometers. Test results obtained using realistic, noisy, Euclid-like data confirmed the effectiveness of the proposed methods.
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All authors Mostafa Bella, Shahram Hosseini, Thierry Contini, Hicham Saylani

High Energy Astrophysical Phenomena

Hydrodynamic Evolution and Detectability of Nova Remnants in the Galactic Center

Zhao Su and Zhiyuan Li

Thousands of X-ray sources have been detected in the Galactic center (GC), most believed to be cataclysmic variables (CVs). As a potential probe of the old stellar population, in particular CVs, the existence and detectability of novae in the GC remain elusive, due to the prohibitive extinction toward the GC and their relatively low occurrence rate. Nova remnants evolving in the characteristic hot ($T\sim{10^{6}~\rm K}$) and dense ($n_e\sim{10~\rm cm^{-3}}$) interstellar medium in the GC may shed light on recent novae and provide useful insight on the GC ecosystem. In this work, we perform hydrodynamical simulations of putative nova remnants in the GC environment and calculate their time-dependent multiwavelength emission to estimate the detectability. Among 79 models sampling the nova parameter space (primarily ejecta mass and velocity), 6, 44, and 51 modelled nova remnants are detectable at their X-ray, radio, and Paschen-$\alpha$ maximum, respectively, for existing Chandra, VLA, and HST observations of the GC. The predicted peak luminosities are $\sim10^{32}~\rm erg~s^{-1}$, $\sim10^{31}~\rm erg~s^{-1}$, and $\sim10^{36}~\rm erg~s^{-1}$ in these three bands and the detectable window ranges from weeks to notably hundred years. By specifying a CV population of the nuclear star cluster, we estimate the probability of detecting at least one remnant to be 20%, 8%, and 18% in X-rays, radio, and Pa$\alpha$. The nova remnant would be best resolved in the X-ray band. Our study highlights the potential for detecting nova remnants through further observations, leveraging JWST and the potentially forthcoming AXIS and SKA.
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Solar and Stellar Astrophysics

Discovery of a rapidly evolving global magnetic field in the M-dwarf YZ Cet and constraints on the magnetic field of its planet YZ Cet b

Ayan Biswas, Colin P. Folsom, James A. Barron et al. (+3 more)

We present a spectropolarimetric study of the nearby M4.5V exoplanet host star YZ Cet, based on near-infrared observations obtained with the SpectroPolarimètre InfraRouge (SPIRou) at the Canada–France–Hawaii Telescope. We detect striking changes in the large-scale magnetic field strength and geometry over the course of just a few stellar rotations, a level of short-term global magnetic field evolution rarely reported in M dwarfs. We modeled the temporal variation of the longitudinal magnetic field using a Gaussian regression process, which allowed us to robustly determine the stellar rotation period and quantify the evolution timescale of the magnetic field. Independent Zeeman Doppler Imaging reconstructions of the two epochs confirm a significant reconfiguration of the star's global magnetic strength and topology. The detection of a weaker, complex, axisymmetric magnetic field (mean $|B| \sim 201$~G), which changes into a stronger, non-axisymmetric, dipole-dominated field (mean $|B| \sim 276$~G) over a few rotation cycles, is in contrast to results from similar fully convective M-dwarf stars. YZ Cet is known to exhibit polarized radio bursts potentially driven by auroral radio emission from star–planet interaction (SPI). By combining our magnetic maps with recent radio observations, we refine the constraints on the magnetic field strength of the innermost planet, YZ Cet b. These results underscore the importance of monitoring stellar magnetic variability to interpret multi-wavelength SPI signatures and to characterize the magnetospheres of potentially habitable exoplanets.
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All authors Ayan Biswas, Colin P. Folsom, James A. Barron, Gregg A. Wade, Stefano Bellotti, Corrado Trigilio

Solar and Stellar Astrophysics

Multi-Energy Proton Events and Geomagnetic Storms in Solar Cycles 23 and 24

Rositsa Miteva, Susan W. Samwel and Svetoslav Zabunov

Solar energetic protons (SEPs) in different energy channels from 10 to above 100 MeV are analyzed and their relationship to solar and geomagnetic activity is investigated. We performed temporal association analysis between the SEPs, solar flares (SFs), coronal mass ejections (CMEs) and geomagnetic storms (GSs) that occurred during solar cycles 23 and 24. The energy dependencies between the SEPs and the strength of the space weather activity are evaluated and presented.
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Astrophysics of Galaxies

The dominant role of dark matter halo in quenching central galaxies

Dingyi Zhao and Yingjie Peng

Understanding the quenching of star formation in central galaxies remains a core challenge in galaxy evolution. Two decades ago, the concept of halo quenching was introduced as a dominant mechanism, positing that massive central galaxy quenching is governed by the thermodynamics of gas predominantly influenced by dark matter halos. However, a vastly increasing body of observational evidence consistently indicates that quenching correlates predominantly with central properties like velocity dispersion, bulge mass, and black hole mass. When these properties are controlled, halo mass appears to show weak influence, supporting AGN feedback as the primary mechanism. A recurring key issue, however, is that these studies rely on halo masses derived via abundance matching (AM). Direct observational measurements from weak lensing, satellite kinematics, and galactic dynamics reveal that AM systematically overestimates halo masses of star-forming centrals while underestimating those of passive ones. To accurately assess the true role of halo mass. we re-estimated halo masses for SDSS groups; the resulting halo mass function and stellar-to-halo mass relations (SHMRs) for both populations match theoretical predictions and weak lensing measurements. Using these improved masses, we find direct observational evidence that halo mass is the dominant factor in quenching central galaxies, with a clear threshold at $M_{h}\sim 10^{12.1}M_\odot; $. By applying a simple correction to AM data using weak lensing-derived SHMRs, we demonstrate that previous claims regarding the dominance of central properties stem primarily from systematic biases in AM halo masses. Our results suggest that the significance of AGN feedback is primarily manifested in halos above this mass threshold, in galaxies already primed for quenching. In other words, AGN feedback appears to become effective in halos above this mass threshold.
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High Energy Astrophysical Phenomena

Astrophysical Implications of Eccentricity in Gravitational Waves from Neutron Star-Black Hole Binaries

Isobel Romero-Shaw, Jakob Stegmann, Gonzalo Morras et al. (+2 more)

The gravitational-wave signal from the neutron star-black hole (NSBH) merger GW200105 is consistent with this binary having significant orbital eccentricity close to merger. This raises the question of how eccentric NSBHs form. Compact binaries that evolve in isolation radiate away any orbital eccentricity long before their gravitational-wave signal enters the sensitive frequency range of the LIGO-Virgo-KAGRA detector network. Meanwhile, dynamical environments – which can be conducive to mergers on eccentric orbits – produce very few NSBHs. Here, we focus on a formation channel that efficiently produces NSBHs with both misaligned spins and significant eccentricity close to merger: isolated field triples. We estimate the minimum measurable eccentricity of NSBHs at 10 Hz orbit-averaged gravitational-wave frequency, e_min,10, finding that for GW200105, GW200115, and GW230529-like systems, e_min,10 is O(0.01). For a GW190814-like unequal-mass binary with significant higher-order mode content, e_min,10 = 0.003; this is an order of magnitude lower than when higher modes are not present. For dominant-mode signals from binaries with $m_2=1.5$~M$_\odot$ and total masses from $3\,{\rm M_\odot} \leq M \leq50\,\rm M_\odot$, we find $0.008 \leq$ e_min,10 $\leq 0.022$. The relationship between $M$ and e_min,10 is linear when the binaries are non-spinning. When the binaries are maximally spin-precessing, e_min,10 decreases as mass ratio becomes more unequal. We estimate the sensitivity of a quasi-circular aligned-spin templated search to NSBH mergers from field triples, finding that we recover only 46% of systems that would have been detected with a search containing the full physics of the injected population. Finally, we show that if $\sim\nicefrac{1}{3}$ of present NSBH detections are measurably eccentric, then $\geq40\%$ are consistent with an isolated field triple origin.
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All authors Isobel Romero-Shaw, Jakob Stegmann, Gonzalo Morras, Andris Dorozsmai, Michael Zevin

Instrumentation and Methods for Astrophysics

Radio frequency interference identification using eigenvalue decomposition for multi-beam observations

Juntao Bai, Shi Dai, Na Wang et al. (+10 more)

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

Instrumentation and Methods for Astrophysics

Expanding Horizons - Transforming Astronomy in the 2040s Time-Domain Multi-Messenger Astronomy in the 2040s: EM Follow-up of LGWA Sources

F. Patat, S. Piranomonte, S. Benetti et al. (+10 more)

The coming decades will see gravitational-wave (GW) astronomy expand decisively into the mHz-Hz frequency range, opening access to a population of compact binaries that are currently invisible or only detectable moments before merger. The Lunar Gravitational Wave Antenna (LGWA) concept is designed to probe this gap, enabling continuous observation of compact binaries over months to years prior to coalescence, and detecting sources inaccessible to both space-based mHz detectors and current ground-based >10 Hz facilities. This new GW window fundamentally alters the landscape of time-domain multi-messenger astronomy. Rather than reacting to mergers after the fact, LGWA enables predictive, scheduled electromagnetic (EM) follow-up, transforming how compact-object mergers, their environments, and their astrophysical channels are studied. However, fully exploiting LGWA discoveries requires EM capabilities that do not exist today and are unlikely to be available by the 2030s, particularly for wide-area, rapid, spectroscopically rich follow-up at optical and near-infrared wavelengths. This White Paper identifies the key science cases enabled by LGWA that motivate new ground-based capabilities in the 2040s.
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All authors F. Patat, S. Piranomonte, S. Benetti, A. Bonforte, R. Della Ceca, G. Di Rico, A. Frigeri, J. Harms, M. Olivieri, A. Perali, P. Severgnini, A. Stallone, the LGWA Collaboration

Solar and Stellar Astrophysics

Weakened inspirals – I: High mass ratio common envelope interactions in RGB stars

Jack Patrick Nibbs, Orsola De Marco, Lionel Siess et al. (+2 more)

The common envelope (CE) interaction between an expanding giant star and a compact companion typically leads to a rapid orbital decay, ending in either a merger or the formation of a close binary. However, the existence of post-red giant and post-asymptotic giant branch binaries with separations of 100 to 800 Rsun challenges this standard picture, as these systems appear to have experienced strong interactions without undergoing a classic CE inspiral. In this work, we investigate the effect of high mass ratio, q = M2/M1, on the CE inspiral using three-dimensional hydrodynamical simulations performed with the smoothed particle hydrodynamics code PHANTOM. The primary is a 0.88 Msun, 90 Rsun red giant branch star, while the companion masses span q = 0.68 to 1.5. Higher mass ratios lead to wider post-CE separations, with a maximum of approximately 40 Rsun. The pre-CE mass transfer phase is longer for larger companion masses, and for q greater than or equal to 1 the inspiral becomes significantly more stable, broadly consistent with analytical expectations. This phase is not fully converged with respect to numerical resolution, and higher resolution simulations are expected to further increase its duration and stability. Although higher q systems show enhanced mass loss through the L2 and L3 Lagrange points, we find that circumbinary discs are more likely to form from fallback of bound envelope material. Fallback times are short, of order a few hundred years, and fallback radii lie well outside the binary, between 0.5 and 5 au, where discs are expected to spread efficiently through viscous torques. While high mass ratio systems produce wider post-interaction separations, these remain smaller than those observed. In contrast, fallback-formed discs have properties consistent with observed circumbinary discs.
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All authors Jack Patrick Nibbs, Orsola De Marco, Lionel Siess, Ryosuke Hirai, Daniel Price

Astrophysics of Galaxies

ALMA and JWST Identification of Faint Dusty Star-Forming Galaxies up to z~8

Jorge A. Zavala, Andreas L. Faisst, Manuel Aravena et al. (+44 more)

We exploit a new sample of around 400 bright dusty galaxies from the ALMA CHAMPS Large Program, together with the rich JWST multi-band data products in the COSMOS field, to explore and validate new selection methods for identifying dusty star-forming galaxies (DSFGs). Here, we present an effective empirical selection criterion based on a newly defined parameter: I_star = log(M_star) x log(SFR). Incorporating the F277W-F444W color as a second parameter further improves the purity of the selection. We then apply this method to the COSMOS2025 catalog to search for fainter dusty galaxy candidates below the ALMA CHAMPS detection limit and, through a stacking technique, identify a population of high-redshift (z=6-8) DSFGs with an average flux density of$S_1.2mm = 0.15uJy and a space density of ~6E-6 Mpc^-3. This faint population seems to have been missed by most of the previous submillimeter/millimeter surveys, and ground- and space-based UV-to-NIR surveys. Finally, we discuss the possibility of an evolutionary connection between the z > 10 UV-bright galaxies recently discovered by JWST, the faint dusty z=6-8 galaxies identified here, and the population of z=3-5 massive quiescent galaxies, potentially linked as progenitor-descendant populations based on their abundance, redshifts, and stellar masses.
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All authors Jorge A. Zavala, Andreas L. Faisst, Manuel Aravena, Caitlin M. Casey, Jeyhan S. Kartaltepe, Felix Martinez III, John D. Silverman, Sune Toft, Ezequiel Treister, Hollis B. Akins, Hiddo Algera, Karina Barboza, Andrew J. Battisti, Gabriel Brammer, Jackie Champagne, Nicole E. Drakos, Eiichi Egami, Xiaohui Fan, Maximilien Franco, Yoshinobu Fudamoto, Seiji Fujimoto, Steven Gillman, Ghassem Gozaliasl, Santosh Harish, Xiangyu Jin, Koki Kakiichi, Darshan Kakkad, Anton M. Koekemoer, Ruqiu Lin, Daizhong Liu, Arianna S. Long, Georgios E. Magdis, Sinclaire Manning, Crystal L. Martin, Jed McKinney, Romain Meyer, Giulia Rodighiero, Victoria Salazar, David B. Sanders, Marko Shuntov, Margherita Talia, Takumi S. Tanaka, Feige Wang, Wuji Wang, Stephen M. Wilkins, Jinyi Yang, Min S. Yun

Solar and Stellar Astrophysics

Infrared SED Modeling of Velocity-Excess Maser Sources: Identifying Incipient Water-Fountain Candidates

Jia-Yong Xie, Jun-ichi Nakashima and Yong Zhang

We investigated whether "velocity excess" in circumstellar maser lines can diagnose the earliest evolutionary phases of Water Fountains (WFs). Here we define "velocity excess" as maser emission (e.g., H$_2$O 22.235 GHz or OH 1665/1667 MHz) detected at velocities outside the velocity range of the OH 1612 MHz line, which traces the terminal expansion velocity of a spherical circumstellar envelope (CSE). Such excess velocities serve as an indicator of gas motions deviating from spherical expansion and may signify the onset of asymmetric outflows. Based on recent studies (Fan et al.2024; Xie et al.2025), we analyzed 17 sources showing velocity excess and fitted their infrared spectral energy distributions (SEDs) with the one-dimensional radiative transfer code DUSTY. Seven sources are well reproduced, implying outer CSEs that remain nearly spherical despite inner asymmetries. Among these, five exhibit single-peaked, AGB-like SEDs and two show double-peaked, post-AGB-like profiles. IRAS variability indices and NEOWISE-R light curves reveal pulsations (~600-1000 days) in three sources, supporting their AGB classification. Considering the magnitude of the velocity excess, two objects-IRAS 19229+1708 and IRAS 19052+0922-may represent the earliest or incipient WF phase, in which asymmetric outflows are beginning to emerge within otherwise spherical envelopes. These results support a morphological sequence in which bipolar jets and tori arise first in the central regions while the outer CSE remains spherical, and they show that selecting WF candidates via velocity excess effectively identifies objects at the onset of jet formation and early morphological transformation.
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