Current date: 2025-07-09

Setting default datestamp limit: 0

Datestamp limit: 2025-07-09 (0 days ago)

Created/updated limit: 2025-07-02 (7 days ago)

Suggested sets: physics, physics:astro-ph, physics:gr-qc, physics:physics

Setting default set: physics

OAI-PMH request: http://export.arxiv.org/oai2?verb=ListRecords&from=2025-07-09&until=2025-07-09&set=physics&metadataPrefix=arXiv

Scoring abstracts

Number of records retrieved: 657

Keyword score statistics

score 8 -- 1 abstracts

score 6 -- 1 abstracts

score 5 -- 3 abstracts

score 4 -- 4 abstracts

score 3 -- 8 abstracts

score 2 -- 11 abstracts

in total -- 28 abstracts

Articles that appeared on 2025-07-09

[abstract 1 / 28] Wow! (score: 8)
arXiv:2507.05968 [pdf, ps, other]

Title: Interpreting the multi-TeV emission from GRB 221009A with a second electron component accelerated by turbulence in the JET

Authors: Xing-Wei Gong, Ruo-Yu Liu, Ze-Lin Zhang, Katsuaki Asano, Martin Lemoine,

Comments: 14 pages, 6 figures; ApJ accepted

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

The detection of very high-energy (VHE) afterglow emission of the GAMMA-RAY BURST (GRB) 221009A by the Large High Altitude Air Shower Observatory (LHAASO) provides a unique opportunity to probe particle acceleration in RELATIVISTIC outflows. The hard spectrum at multi-TeV band cannot be fully explained by SYNCHROTRON-self-Compton radiation of the conventional one-zone afterglow model. In this work, we introduce a second component of RELATIVISTIC electrons from stochastic acceleration via downstream turbulence of the external shock. Using a Fokker-Planck approach to model the evolution of protons and electrons, and the non-linear feedback of turbulence damping, we show that the inverse Compton radiation of the second electron component may harden the observed spectrum above multi-TeV energy, and significantly ameliorate the fitting to the spectral evolution measured by LHAASO without violating lower-energy observations. We also discuss the potential presence of the second electron component in other GRB afterglows, which may provide a possible observational signature for future studies.

[abstract 2 / 28] Yes (score: 6)
arXiv:2507.03088 [pdf, ps, other]

Title: Towards a unified scheme of BLAZAR evolution

Authors: E. Oukacha, Y. Becherini,

Comments: 20 pages, 16 figures, 3 tables, accepted for publication in A&A

Subjects: astro-ph.HE astro-ph.CO astro-ph.GA

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

Machine learning (ML) and deep learning (DL) techniques are increasingly used across astrophysics, enabled by the growing availability of data and improved acquisition methods. These approaches now support tasks from redshift estimation to source classification. In this work, we aim to (i) classify BLAZARs from the FERMI 4LAC-DR3 catalogue, in particular to identify the likely origin of BLAZARs of uncertain type (BCUs), and (ii) investigate the full BLAZAR sample to study their structure and redshift-luminosity evolution. We focus especially on the transition region between Flat Spectrum Radio Quasars (FSRQs) and BL Lacertae objects (BL Lacs), which may yield insights into accretion disk evolution. We examine Changing-Look Blazars (CLBs) as potential intermediates in this transition. We implement a classification pipeline using both a strong benchmark model (XGBoost) and a foundation model pre-trained on millions of tabular datasets (TabPFN). By extracting and reducing the high-dimensional latent space of the best model, we provide a 2D representation of the BLAZAR population. This reveals a continuum between FSRQs and BL Lacs, including CLBs as transitional sources. These results support a scenario of gradual evolution from radiatively efficient (FSRQ-like) to inefficient (BL Lac-like) accretion. Ultimately, we show that a single probability score, combined with the latent space, offers a new framework for interpreting BLAZAR diversity beyond discrete classes.

[abstract 3 / 28] Yes (score: 5)
arXiv:2405.10281 [pdf, ps, other]

Title: The dynamics and electroMAGNETic signatures of accretion in unequal mass binary BLACK HOLE inspirals

Authors: Madeline Clyburn, Jonathan Zrake,

Comments: 15 pages, 15 figures

Subjects: astro-ph.HE

Created: 2025-07-07; Updated: 2025-07-09; Datestamp: 2025-07-09

We present a theoretical study of the gravitational wave (GW) driven inspirals of accreting BLACK HOLE binaries with mass $M = 10^7 M_\odot$ and mass ratios between $10^{-3}$ and $10^{-1}$. Our results are based on analytic estimates, and grid-based hydrodynamics simulations run for many thousands of binary orbits before the merger. We show that the GW inspiral is evident in the light curves and color evolution of a binary-hosting QUASAR, over years to decades before a merger. The long-term electroMAGNETic (EM) signature is characterized by a gradual UV brightening, and X-ray dimming, followed by an X-ray disappearance hours to days before the GW burst, and finally a years-like re-brightening as the disk relaxes and refuels the remnant BLACK HOLE. These timescales are surprisingly insensitive to the amplitude of viscous stress in the disk. The spectrum of quasi-thermal disk emission shows two peaks: one in the UV, and another in the X-ray, associated with the outer and circum-secondary disks respectively; emission from the inner disk is suppressed because the secondary consumes most of the inflowing gas. We discuss implications for real-time and archival EM followup of GW bursts detected by LISA.

[abstract 4 / 28] Yes (score: 5)
arXiv:2507.05571 [pdf, ps, other]

Title: NUSTAR Analysis of the 2024 Periastron Passage of TeV Binary PSR B1259-63

Authors: Oliver J. Roberts, Philip Kaaret, M. Lynne Saade, Chien-Ting Chen, Steven R. Ehlert, Ioannis Liodakis, Martin C. Weisskopf,

Comments:

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

PSR B1259-63 is a well studied TeV binary, with an energetic pulsar in orbit around a Be star. Using NUSTAR observations during the 2024 passage of the pulsar through the circumstellar disk, we find the spectrum to be the most energetic ($Γ$ = 1.5) around 27 days after periastron, during the first of two variable, short-term emission episodes of a contemporaneous GeV flare. We discuss the variability in the X-ray flux and the hardening of the spectrum with time, and in the context of previous observations and what that means for the competing energy loss and acceleration timescales.

[abstract 5 / 28] Yes (score: 5)
arXiv:2507.06110 [pdf, ps, other]

Title: Constraining the contribution of Seyfert galaxies to the diffuse neutrino flux in light of point source observations

Authors: Lena Saurenhaus, Francesca Capel, Foteini Oikonomou, Johannes Buchner,

Comments: 18 pages, 11 figures, submitted to PRD

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

Recently, the IceCube Collaboration reported evidence for TeV neutrino emission from several nearby Seyfert galaxies, with the highest significance found for NGC 1068. Assuming stochastic proton acceleration in MAGNETized turbulence inside the corona, we model the neutrino emission of Seyfert galaxies as a function of their X-ray luminosity. Applying our model to NGC 1068, we obtain a good fit to the public IceCube data and constrain the coronal radius to $\lesssim 5 R_S$ by comparing our MeV $γ$-ray predictions to FERMI-LAT observations. Extending to the full Seyfert population, we estimate their diffuse neutrino contribution and find that they can explain a significant fraction of the observed flux below $10\,\mathrm{TeV}$. However, scenarios with highly turbulent coronae and high cosmic-ray pressure across the population are ruled out. In particular, if all sources shared the best-fit parameters obtained for NGC 1068, their cumulative neutrino emission would exceed current upper limits at TeV energies by $3.8σ$. Our results, informed by both neutrino and $γ$-ray data, show that those Seyfert galaxies that emerge as neutrino point sources must be exceptionally efficient neutrino emitters and are not representative of the broader population.

[abstract 6 / 28] Yes (score: 4)
arXiv:2503.15590 [pdf, ps, other]

Title: JADES and SAPPHIRES: Galaxy Metamorphosis Amidst a Huge, Luminous Emission-line Region

Authors: Francesco D'Eugenio, Jakob M. Helton, Kevin Hainline, Fengwu Sun, Roberto Maiolino, Pablo G. Pérez-González, Ignas Juodžbalis, Santiago Arribas, Andrew J. Bunker, Stefano Carniani, Emma Curtis-Lake, Eiichi Egami, Daniel J. Eisenstein, Benjamin D. Johnson, Brant Robertson, Sandro Tacchella, Christopher N. A. Willmer, Chris Willott, William M. Baker, A. Lola Danhaive, Qiao Duan, Yoshinobu Fudamoto, Gareth C. Jones, Xiaojing Lin, Weizhe Liu, Michele Perna, Dávid Puskás, Pierluigi Rinaldi, Jan Scholtz, Yang Sun, James A. A. Trussler, Hannah Übler, Giacomo Venturi, Christina C. Williams, Yongda Zhu,

Comments: 21 pages, 12 figures, accepted by MNRAS

Subjects: astro-ph.GA

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

We report the discovery of a remarkably large and luminous line-emitting nebula extending on either side of the Balmer-break galaxy JADES-GS-518794 at z=5.89, detected with JADES JWST/NIRCam imaging in [O III]$λλ$4959,5007 and H$α$ and spectroscopically confirmed with NIRCam/WFSS thanks to the pure-parallel SAPPHIRES programme. The end-to-end velocity offset is $Δv=830\pm130$ km s$^{-1}$. Nebulae with such large size and high luminosity (25-pkpc diameter, L[O III] = $1.2\times 10^{10}$ L$_\odot$) are routinely observed around bright QUASARs, unlike JADES-GS-518794. With a stellar mass of $10^{10.1}$ M$_\odot$, this galaxy is at the knee of the mass function at z=6. Its star-formation rate declined for some time (10-100 Myr prior to observation), followed by a recent (10 Myr) upturn. This system is part of a candidate large-scale galaxy overdensity, with an excess of Balmer-break galaxies compared to the field (3 $σ$). We discuss the possible origin of this nebula as material from a merger or gas expelled by an ACTIVE GALACTIC NUCLEus (AGN). The symmetry of the nebula, its bubble-like morphology, kinematics, high luminosity, and the extremely high equivalent width of [OIII] together favour the AGN interpretation. Intriguingly, there may be a physical connection between the presence of such a large, luminous nebula and the possible metamorphosis of the central galaxy towards quenching.

[abstract 7 / 28] Yes (score: 4)
arXiv:2507.05380 [pdf, ps, other]

Title: BASS LII: Clues from Twin Peaks -- Investigating the structure of the AGN broad-line region at low accretion rates with double-peaked emitters

Authors: Charlotte Ward, Michael J. Koss, Michael Eracleous, Benny Trakhtenbrot, Franz E. Bauer, Turgay Caglar, Fiona Harrison, Arghajit Jana, Darshan Kakkad, Macon Magno, Ignacio del Moral-Castro, Richard Mushotzky, Kyuseok Oh, Alessandro Peca, Meredith C. Powell, Claudio Ricci, Alejandra Rojas, Krista Lynne Smith, Daniel Stern, Ezequiel Treister, C. Megan Urry,

Comments: 23 pages, 12 figures, 4 tables. Submitted to ApJ. Comments welcome!

Subjects: astro-ph.GA astro-ph.HE

Created: 2025-07-07; Updated: 2025-07-09; Datestamp: 2025-07-09

A fraction of ACTIVE GALACTIC NUCLEi (AGN) have double-peaked H$α$, H$β$ and Mg II broad lines attributed to emission from rotating gas in the accretion disk. Using optical spectroscopy of a flux-limited sample of AGN selected via ultrahard X-rays from the BAT AGN Spectroscopic Survey (BASS), we systematically identify 71 double-peaked emitters amongst 343 broad-line AGN with redshifts $0.004AGN are double-peaked emitters (DPEs), consistent with rates previously reported for $z<0.2$ broad-line AGN selected for strong optical variability in ZTF. 11 of 71 DPEs (15%) exhibited a single-peaked Gaussian component to the broad line profile in addition to the double-peaked disk profile. In this sample, DPEs have intrinsically higher masses by ~0.4 dex and lower Eddington ratios by ~0.3 dex than other broad-line AGN, and have a preference for elliptical host galaxies, higher X-ray luminosities, and higher [OI] $λ$6302 to narrow H$α$ flux ratios than other broad-line AGN. We find that DPEs are not segregated from other broad-line AGN in the $L_{\rm bol}$ vs $M_{\rm BH}$ relation or their X-ray to radio luminosity ratios, and do not show a preference for intermediate Seyfert types over Seyfert 1s. We do not find differences in a wide range of multi-wavelength properties when comparing DPEs to other broad-line AGN, including optical and mid-IR variability levels, and the rate of changing-look events. We discuss the two populations in the context of multi-component disk-wind models of the AGN broad line region and consider how unrecognized contributions of disk emission to the broad lines introduce biases in virial SMBH mass estimates.

[abstract 8 / 28] Yes (score: 4)
arXiv:2507.05637 [pdf, ps, other]

Title: Axion-like Particles and their Possible Impact on the Very High-Energy Spectrum of M87 Observed by LHAASO

Authors: A. Pratts, D Avila Rojas, J. Serna-Franco, M. M. González, R. Alfaro,

Comments:

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

The detection of very high-energy (VHE) gamma rays from the active galaxy M87 by LHAASO, showing a possible spectral hardening around $20$ TeV, motivates the search for new physics beyond standard emission models. One promising candidate is axion-like particles (ALPs), hypothetical pseudo-scalar BOSONs that can oscillate into photons in the presence of cosmic MAGNETic fields. In this work, we investigate whether photon-ALP oscillations and an additional ALP-induced component can account for the tentative hardening observed in M87's VHE spectrum. We model the propagation of photons and ALPs through the JET, the Virgo cluster, the intergalactic medium, and the Galactic MAGNETic field, over a broad ALPs parameter space. Our statistical analysis finds that, with current LHAASO data, the inclusion of an ALPs component yields only a modest improvement over a standard scenario (maximum significance $\sim$1.56$σ$). However, if future observations transform current flux upper limits at tens of TeV into measured fluxes, the significance could reach $\sim$3$σ$, providing potential evidence for ALP-induced effects. Our results suggest that M87 remains a promising target to test fundamental physics, and upcoming VHE data could play a key role in probing ALPs parameter space.

[abstract 9 / 28] Yes (score: 4)
arXiv:2507.05896 [pdf, ps, other]

Title: Search for Sub-Relativistic Magnetic Monopoles with the IceCube Neutrino Observatory

Authors: Jonas Häußler, Nicolas Moller,

Comments: Presented at the 39th International Cosmic Ray Conference (ICRC2025)

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

Magnetic monopoles are beyond standard model particles, predicted by Grand Unified Theories (GUTs) to be created during the early universe. At typical masses of the GUT-scale - above $10^{14}$ GeV - these particles would move at sub-RELATIVISTIC speeds. The Rubakov-Callan effect predicts that MAGNETic monopoles can catalyze nucleon decays, in particular the decay of protons. This results in a unique signature of small particle cascades along the trajectory of the slow moving MAGNETic monopole. Since 2012, a dedicated Slow-Particle Filter has been implemented in the IceCube Neutrino Observatory for the detection of MAGNETic monopoles. Current limits set an upper bound for the monopole flux at $Φ_{\mathrm{90}}\leq 10^{-17}$ to $10^{-18} \mathrm{cm}^{-2}\mathrm{s}^{-1}\mathrm{sr}^{-1}$ depending on the catalysis cross section for the proton decay. A detection of the monopole flux thus requires exceptional background rejection and signal efficiency. This is accomplished using machine learning methods. In this analysis, we use a multi-level boosted decision tree classifier. We present the strategy behind the background and signal simulation, the classification efficiency, and IceCube's projected sensitivity for the detection of sub-RELATIVISTIC MAGNETic monopoles.

[abstract 10 / 28] (score: 3)
arXiv:2501.15676 [pdf, ps, other]

Title: Gravity as emergent phenomena for spherically symmetric BLACK HOLE accretion of multi-component flow with RELATIVISTIC equation of state

Authors: Tuhin Paul, Aishee Chakraborty, Souvik Ghose, Tapas K. Das,

Comments: 13 pages, 6 figures, Revtex double column Style, New version corrects typos and improves clarity

Subjects: gr-qc astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

We investigate analogue gravity phenomena arising as a result of the linear perturbation of the spherically symmetric accretion flows onto non rotating BLACK HOLEs, where the gravitational field is determined by a set of post Newtonian pseudo Schwarzschild BLACK HOLE potentials and the infaling matter is described by a RELATIVISTIC multi-species equation of state. The stationary transonic integral accretion solutions corresponding to the steady state of aforementioned type of accreting systems are constructed and the stability analysis of such solutions are performed through the time dependent linear perturbation of the accretion flow. Such linear stability analysis leads to the formation of a BLACK HOLE like sonic metric embedded within the infalling matter. The acoustic horizons are then identified by constructing the causal structure, i.e., the Carter-Penrose diagrams. The variation of the analogue surface gravity corresponding to the aforementioned sonic metric has been studied as a function of various parameters governing the accretion flow.

[abstract 11 / 28] (score: 3)
arXiv:2506.03244 [pdf, ps, other]

Title: Cosmic Outliers: Low-Spin Halos Explain the Abundance, Compactness, and Redshift Evolution of the Little Red Dots

Authors: Fabio Pacucci, Abraham Loeb,

Comments: Accepted for publication in The Astrophysical Journal Letters. 12 pages, 5 figures

Subjects: astro-ph.GA astro-ph.CO astro-ph.HE

Created: 2025-07-07; Updated: 2025-07-09; Datestamp: 2025-07-09

The Little Red Dots (LRDs) are high-redshift galaxies uncovered by JWST, characterized by small effective radii ($R_{\rm eff} \sim 80-300$ pc), number densities that are intermediate between those of typical galaxies and QUASARs, and a redshift distribution peaked at $z \sim 5$. We present a theoretical model in which the LRDs descend from DARK MATTER halos in the extreme low-spin tail of the angular momentum distribution. Within this framework, we explain their three key observational signatures: (i) abundance, (ii) compactness, and (iii) redshift distribution. Our model focuses on observed, not modeled, properties; it is thus independent of whether they are powered primarily by a BLACK HOLE or stars. We find that the assumption that the prototypical LRD at $z\sim5$ originates from halos in the lowest $\sim 1\%$ of the spin distribution is sufficient to reproduce both their observed number densities and physical sizes. The redshift evolution of their observability is driven by the interplay between the evolving compact disk fraction and cosmological surface brightness dimming. This effect leads to a well-defined "LRDs Era" at $48$, they are common but faint. Finally, we test the predicted redshift trend against observational data, finding excellent agreement. Additional observational support comes from their excess small-scale clustering and spectral signatures of extreme core densities, both of which are expected outcomes of galaxy formation in low-spin halos. These findings suggest that the LRDs are not a fundamentally distinct population but the natural manifestation of galaxies forming in the rarest, lowest angular momentum environments.

[abstract 12 / 28] (score: 3)
arXiv:2507.05342 [pdf, ps, other]

Title: A new Bowen Fluorescence Flare and Extreme Coronal Line Emitter discovered by SRG/eROSITA

Authors: Pietro Baldini, Arne Rau, Riccardo Arcodia, Taeho Ryu, Zhu Liu, Paula Sánchez-Sáez, Iuliia Grotova, Andrea Merloni, Stefano Ciroi, Adelle J. Goodwin, Mariusz Gromadzki, Adela Kawka, Megan Masterson, Dusán Tubín-Arenas, David A. H. Buckley, Francesco Di Mille, Gemma E. Anderson, Sabina Bahic, David Homan, Mirko Krumpe, James C. A. Miller-Jones, Kirpal Nandra,

Comments: Accepted for publication in A&A

Subjects: astro-ph.HE astro-ph.GA

Created: 2025-07-07; Updated: 2025-07-09; Datestamp: 2025-07-09

The nuclear transient eRASSt J012026.5-292727 (J012026 hereafter) was discovered in the second SRG/eROSITA all-sky survey (eRASS2). The source appeared more than one order of magnitude brighter than the eRASS1 upper limits (peak eRASS2 0.2-2.3 keV flux of 1.14 x 10^-12 erg cm^-2 s^-1), and with a soft X-ray spectrum (photon index Gamma = 4.3). Over the following months, the X-ray flux started decaying, with significant flaring activity on both hour- and year-timescales. By inspecting the multiwavelength light curves of time-domain wide-field facilities, we detected a strong mid-infrared flare, evolving over 2 years, and a weaker optical counterpart. Follow-up optical spectroscopy revealed transient features, including redshifted Balmer lines (FWHM ~1500 km/s), strong Fe II emission, He II and Bowen lines, and high-ionization iron coronal lines. One spectrum showed a triple-peaked H-beta line, consistent with emission from a face-on elliptical disk. The spectroscopic features and the slow evolution of the event place J012026 within the classifications of Bowen fluorescence flares (BFFs) and extreme coronal line emitters (ECLEs). BFFs have been associated with rejuvenated accreting SMBHs, although the mechanism triggering the onset of the new accretion flow is still unclear, while ECLEs have been linked to the disruption of stars in gas-rich environments. The association of J012026 to both classes, combined with the multi-wavelength information, suggests that BFFs could be, at least in some cases, due to tidal disruption events (TDEs). The observed X-ray variability, uncommon in standard TDEs, adds complexity to these families of nuclear transients. These results highlight the diverse phenomenology of nuclear accretion events and demonstrate the value of systematic X-ray surveys, such as eROSITA and Einstein Probe, for uncovering such transients and characterizing their physical origin.

[abstract 13 / 28] (score: 3)
arXiv:2507.05354 [pdf, ps, other]

Title: JWST MIRI/MRS observations of hot molecular gas in an AGN host galaxy at Cosmic Noon

Authors: D. Kakkad, V. Mainieri, Takumi S. Tanaka, John D. Silverman, D. Law, Rogemar A. Riffel, C. Circosta, E. Bertola, M. Bianchin, M. Bischetti, G. Calistro Rivera, S. Carniani, C. Cicone, G. Cresci, T. Costa, C. M. Harrison, I. Lamperti, B. Kalita, Anton M. Koekemoer, A. Marconi, M. Perna, E. Piconcelli, A. Puglisi, Gabriele S. Ilha, G. Tozzi, G. Vietri, C. Vignali, S. Ward, G. Zamorani, L. Zappacosta,

Comments: Accepted for publication in MNRAS, 11 figures, 2 tables

Subjects: astro-ph.GA astro-ph.HE

Created: 2025-07-07; Updated: 2025-07-09; Datestamp: 2025-07-09

Active Galactic Nuclei (AGN) are believed to play a central role in quenching STAR FORMATION by removing or destroying molecular gas from host galaxies via radiation-pressure driven outflows and/or radio JETs. Some studies of cold molecular gas in galaxies at Cosmic Noon ($z\sim2$) show that AGN have less cold gas ($<$100 K) compared to mass-matched star-forming galaxies. However, cold gas could also be shock-heated to warmer phases, detectable via H$_{2}$ transitions in the rest-frame near- and mid-infrared spectra. The Medium Resolution Spectrograph (MRS) of the Mid-infrared Instrument (MIRI) aboard JWST has opened a unique window to observe these emission lines in galaxies at Cosmic Noon. We present the first detection of hot molecular gas in cid_346, an X-ray AGN at $z\sim2.2$, via the H$_{2}$ ro-vibrational transition at 2.12 $μ$m. We measure a hot molecular gas mass of $\sim 8.0 \times 10^{5}$ M$_{\odot}$, which is $\sim 10^{5}-10^{6}$ times lower than the cold molecular gas mass. cid_346 is located in an environment with extended gas structures and satellite galaxies. This is supported by detection of hot and cold molecular gas out to distances $>$10 kpc in MIRI/MRS and ALMA data, respectively and ancillary NIRCam imaging that reveals two satellite galaxies at distances of $\sim$0.4 arcsec (3.3 kpc) and $\sim$0.9 arcsec (7.4 kpc) from the AGN. Our results tentatively indicate that while the CO(3-2)-based cold gas phase dominates the molecular gas mass at Cosmic Noon, H$_{2}$ ro-vibrational transitions are effective in tracing hot molecular gas locally in regions that may lack CO emission.

[abstract 14 / 28] (score: 3)
arXiv:2507.05652 [pdf, ps, other]

Title: Influence of Conical Wire Array Geometry on Flow and Temperature Profiles Measured via Thomson Scattering and Optical Techniques

Authors: Luisa Izquierdo, Felipe Veloso, Miguel Escalona, Vicente Valenzuela-Villaseca, Gonzalo Avaria, Julio Valenzuela,

Comments:

Subjects: physics.plasm-ph

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

Conical wire arrays with different opening angles are used as load of a 400kA, 1kA/ns generator. The differences in opening angle allow the study of the influence of the array geometry on the JET properties. The characterization of the JETs is performed using a combination of advanced diagnostic techniques, including moiré schlieren deflectometry, visible self-emission spectroscopy, and optical Thomson scattering. The results reveal that, under the experimental conditions, the plasma JETs exhibit electron temperatures ranging from $8$ to $17$ eV, increasing along the axial direction. In contrast, the ion temperature decreases from approximately $35$ eV near the base of the JET to about $20$ eV at higher axial positions. The electron density profile peaks at $\sim 4 \times 10^{18}$ cm$^{-3}$ in the central lower region of the JET and decreases with height exponentially with a characteristic lenght $L_n = $2.86 mm. This behavior is reproducible and independent of the conical array geometry. However, the cone opening angle significantly affect the JET propagation velocity, with larger opening angles producing higher axial velocities ($V_{ϕ=40^\circ} \approx 125\pm3$ km/s, $V_{ϕ=20^\circ} \approx 98\pm5$ km/s), demonstrating that the cone geometry provides effective control over the JET propagation velocity.

[abstract 15 / 28] (score: 3)
arXiv:2507.05739 [pdf, ps, other]

Title: A New Search Pipeline for Short Gamma Ray Bursts in FERMI/GBM Data -- A 50% Increase in the Number of Detections

Authors: Ariel Perera, Barak Zackay, Tejaswi Venumadhav,

Comments:

Subjects: astro-ph.HE astro-ph.IM

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

In this paper, we present the development and the results of a new search pipeline for short GAMMA-RAY BURSTs (sGRBs) in the publicly available data from the Gamma-Ray Burst Monitor (GBM) on board the FERMI satellite. This pipeline uses rigorous statistical methods that are designed to maximize the information extracted from the FERMI/GBM detectors. Our approach differs substantially from existing search efforts in several aspects: The pipeline includes the construction of template banks, Poisson matched filtering, background estimation, background misestimation correction, automatic routines to filter contaminants, statistical estimation of the signal location and a quantitative estimator of the signal probability to be of a cosmological, terrestrial, or solar origin. Our analysis also includes operating the pipeline on "time-slided" copies of the data, which allows exact significance assessment and $p_{\text{astro}}$ computation, akin to the state-of-the-art gravitational waves (GW) data analysis pipelines. Depending on the spectral properties of the bursts, our pipeline achieves a signal-to-noise ratio (SNR) improvement by a factor of 2 to 15 over the onboard GBM triggering algorithm. This enhancement increases the detectable volume for sGRBs and results in an approximate 50% increase in sGRB detections in the 2014 GBM dataset. As a further consequence of the sensitivity increase, we detect hundreds of soft gamma-ray flares of galactic origin. This improved sensitivity enhances the chances of detecting fainter, off-axis GRBs that would likely fall below the standard triggering thresholds. Applying this pipeline to the full GBM archive is expected to expand further the joint sGRB-GW detection volume.

[abstract 16 / 28] (score: 3)
arXiv:2507.05841 [pdf, ps, other]

Title: Cosmic-Ray Physics in the PeV to EeV Energy Range with the IceCube-Gen2 Surface Array (ICRC 2025)

Authors: Frank G. Schröder,

Comments: Presented at the 39th International Cosmic Ray Conference (ICRC2025)

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

IceCube-Gen2 is a proposed neutrino observatory at the South Pole that will build on the success of IceCube and will also serve as a unique detector for cosmic-ray air showers. Analogous to the IceTop surface array over IceCube's deep optical detector, IceCube-Gen2 will also feature a surface array above the optical array deep in the ice. As improvement over IceTop, the IceCube-Gen2 surface array will be comprised of elevated detectors to avoid snow coverage, and will combine two types of detectors: scintillation panels that measure air-shower particles on ground and enable a low detection threshold, which is important to serve as a veto for selecting downgoing neutrino candidates, and radio antennas which increase the measurement accuracy for air showers by providing a calorimetric measurement of the electroMAGNETic shower component and its depth of maximum, $X_\mathrm{max}$. As another major advantage, the eight times larger surface area combined with a larger field of view will provide a 30-fold increase for the aperture of surface-deep coincident events. With these improvements in statistics and measurement accuracy, IceCube-Gen2 will thus make unique contributions to the particle physics and astrophysics of Galactic COSMIC RAYs in the PeV to EeV energy range, including the search for PeV photon sources. This proceeding summarizes the technical design and science case enabled by the IceCube-Gen2 Surface Array.

[abstract 17 / 28] (score: 3)
arXiv:2507.06163 [pdf, ps, other]

Title: Reconstructing PTA measurements via early seeding of supermassive BLACK HOLEs

Authors: Sohan Ghodla, Cosmin Ilie,

Comments: 13 Pages, 6 Figures. Comments welcome

Subjects: astro-ph.CO astro-ph.GA astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

The growing evidence of supermassive BLACK HOLEs (SMBHs) being present in the early Universe poses challenges to their traditional formation pathways. Separately, studies suggest that merging SMBH binaries with total masses $\gtrsim 10^9 M_\odot$ could be the primary sources of the nanohertz gravitational wave background detected by the Pulsar Timing Arrays (PTAs). Owing to their extreme masses, these SMBHs have a higher probability of forming earlier than their lower-mass counterparts. In this work, we provide a formalism to calculate the implications of early seeded SMBHs for the PTA signal. As an application, we explore the two most prominent scenarios of high-$z$ SMBHs seeding mechanisms: direct collapse BLACK HOLEs (DCBHs) and collapse of supermassive dark stars (SMDSs). We show that SMDS-seeded SMBHs, with comoving seed number density of $\mathcal{O}(10^{-3}) \, {\rm Mpc}^{-3}$ can be the dominant contributor to the PTA signal, with mass $> 10^9 M_\odot$ binaries acquiring a peak merger rate at $z< 1$. By contrast, SMBHs seeded via the DCBH channel may contribute only sub-dominantly unless produced with a much larger number density than implied by numerical simulations. Our analysis further suggests that the seed number density should be $< \mathcal{O}(10^{-1}) \, {\rm Mpc}^{-3}$ in order to not over-predict the expected PTA signal.

[abstract 18 / 28] (score: 2)
arXiv:2501.08527 [pdf, ps, other]

Title: Cold Gas and Star Formation in the Phoenix Cluster with JWST

Authors: Michael Reefe, Michael McDonald, Marios Chatzikos, Jerome Seebeck, Richard Mushotzky, Sylvain Veilleux, Steven Allen, Matthew Bayliss, Michael Calzadilla, Rebecca Canning, Megan Donahue, Benjamin Floyd, Massimo Gaspari, Julie Hlavacek-Larrondo, Brian McNamara, Helen Russell, Arnab Sarkar, Keren Sharon, Taweewat Somboonpanyakul,

Comments: 25 pages, 18 figures, 2 tables. Accepted for publication in ApJ

Subjects: astro-ph.GA

Created: 2025-07-07; Updated: 2025-07-09; Datestamp: 2025-07-09

We present integral field unit observations of the Phoenix Cluster with the JWST Mid-infrared Instrument's Medium Resolution Spectrometer (MIRI/MRS). We focus this study on the molecular gas, dust, and STAR FORMATION in the brightest cluster galaxy (BCG). We use precise spectral modeling to produce maps of the silicate dust, molecular gas, and polycyclic aromatic hydrocarbons (PAHs) in the inner $\sim$50 kpc of the cluster. We measure the optical depth from silicates by comparing the observed H$_2$ line ratios to those predicted by excitation models. We provide updated measurements of the total molecular gas mass of $1.9^{+0.5}_{-0.4} \times 10^{10}$ $M_{\odot}$ which agrees with CO-based estimates, providing an estimate of the CO-to-H$_2$ conversion factor of $α_{\rm CO} = 0.8 \pm 0.2\,M_{\odot}\,{\rm pc}^{-2}\,({\rm K}\,{\rm km}\,{\rm s}^{-1})^{-1}$; an updated stellar mass of $M_* = 2.6 \pm 0.5 \times 10^{10}$ $M_\odot$; and STAR FORMATION rates averaged over 10 and 100 Myr of $\langle{\rm SFR}\rangle_{\rm 10} = 1340 \pm 100$ $M_\odot\,{\rm yr}^{-1}$, and $\langle{\rm SFR}\rangle_{\rm 100} = 740 \pm 80$ $M_\odot\,{\rm yr}^{-1}$, respectively. The H$_2$ emission seems to be powered predominantly by shocks and STAR FORMATION within the central $\sim 20$ kpc, induced by stellar feedback and radio JETs from the ACTIVE GALACTIC NUCLEus. Additionally, we find nearly an order of magnitude drop in the STAR FORMATION rates estimated by PAH fluxes in cool core BCGs compared to field galaxies, suggesting that hot particles from the intracluster medium are destroying PAH grains even in the centralmost 10s of kpc.

[abstract 19 / 28] (score: 2)
arXiv:2506.17138 [pdf, ps, other]

Title: SRG/eROSITA No. 5: Discovery of quasi-periodic eruptions every ~3.7 days from a galaxy at z>0.1

Authors: R. Arcodia, P. Baldini, A. Merloni, A. Rau, K. Nandra, J. Chakraborty, A. J. Goodwin, M. J. Page, J. Buchner, M. Masterson, I. Monageng, Z. Arzoumanian, D. Buckley, E. Kara, G. Ponti, M. E. Ramos-Ceja, M. Salvato, K. Gendreau, I. Grotova, M. Krumpe,

Comments: Accepted in ApJ

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

Quasi-periodic eruptions (QPEs) are repeating soft X-ray bursts from the nuclei of galaxies, tantalizingly proposed to be extreme mass ratio inspirals. Here, we report the discovery of a new galaxy showing X-ray QPEs, the fifth found through a dedicated blind search in the \emph{SRG}/eROSITA all-sky survey data, hereafter named eRO-QPE5. Its QPE duration ($t_{\rm dur}\sim0.6$\,d), recurrence time ($t_{\rm recur}\sim3.7\,$d), integrated energy per eruption ($\sim3.4 \times 10^{47}\,$erg), and BLACK HOLE mass ($M_{\rm BH}=2.9^{+5.4}_{-2.2}\times10^7\,M_{\astrosun}$) sit at the high end of the known population. Like other eROSITA or X-ray-discovered QPEs, no previous or concurrent optical-IR transient is found in archival photometric datasets, and the optical spectrum looks almost featureless. With a spectroscopic redshift of $0.1155$, eRO-QPE5 is the most distant QPE source discovered to date. Given the number of recent discoveries, we test for possible correlations and confirm a connection between $t_{\rm dur}$ and $t_{\rm recur}$, while we do not find any significant correlation involving either $M_{\rm BH}$ or the QPE temperature. The slope of the $t_{\rm dur}-t_{\rm recur}$ relation ($1.14\pm0.16$) is roughly consistent with predictions from star-disk collision models, with a preference for those that suggest that QPEs are powered by stellar debris streams around the orbiter. Considering this and previous discoveries, eROSITA has proved extremely successful in finding many QPE candidates given its grasp, namely its sensitivity and large field of view, and scanning capabilities over the full sky. We advocate the need of sensitive wide-area and time-domain oriented surveys from future-generation soft X-ray missions.

[abstract 20 / 28] (score: 2)
arXiv:2507.03119 [pdf, ps, other]

Title: Neural-Network solver of ideal MHD equilibria

Authors: Timo Thun, Andrea Merlo, Rory Conlin, Dario Panici, Daniel Böckenhoff,

Comments: To be submitted to Nuclear Fusion, 16 pages, 8 figures

Subjects: cs.LG cs.AI physics.plasm-ph

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

We present a novel approach to compute three-dimensional Magnetohydrodynamic equilibria by parametrizing Fourier modes with artificial neural networks and compare it to equilibria computed by conventional solvers. The full nonlinear global force residual across the volume in real space is then minimized with first order optimizers. Already,we observe competitive computational cost to arrive at the same minimum residuals computed by existing codes. With increased computational cost,lower minima of the residual are achieved by the neural networks,establishing a new lower bound for the force residual. We use minimally complex neural networks,and we expect significant improvements for solving not only single equilibria with neural networks,but also for computing neural network models valid over continuous distributions of equilibria.

[abstract 21 / 28] (score: 2)
arXiv:2507.05381 [pdf, ps, other]

Title: Escape fractions from unattenuated Ly$α$ emitters around luminous $z>6$ QUASARs

Authors: Minghao Yue, Anna-Christina Eilers, Jorryt Matthee, Rohan P. Naidu, Rongmon Bordoloi, Frederick B. Davies, Joseph F. Hennawi, Daichi Kashino, Ruari Mackenzie, Robert A. Simcoe,

Comments: Submitted to AAS journals

Subjects: astro-ph.GA

Created: 2025-07-07; Updated: 2025-07-09; Datestamp: 2025-07-09

Ionized proximity zones around luminous QUASARs provide a unique laboratory to characterize the Ly$α$ emission lines from $z>6$ galaxies without significant attenuation from the intergalactic medium (IGM). However, Ly$α$ line measurements for galaxies within high-redshift QUASARs' proximity zones have been rare so far. Here we present deep spectroscopic observations obtained with the NIRSpec/MSA instrument on the James Webb Space Telescope (JWST) of galaxies in two $z>6$ QUASAR fields. We measure the Ly$α$ line fluxes for 50 galaxies at $6QUASARs, i.e. within $Δv<2500\rm\,km\,s^{-1}$. We find that galaxies near the QUASARs show significant flux bluewards of the systemic Ly$α$ wavelength, and have higher Ly$α$ equivalent width compared to galaxies at similar redshifts that are not located within the QUASARs' environment. Our result indicates little or no redshift evolution for the Ly$α$-emitter fraction from $z\sim6.4$ to $z\sim5$. Leveraging the low IGM opacity in the QUASARs' vicinity, we evaluate the Ly$α$ escape fraction ($f_\text{esc}^{\text{Ly}α}$) of high-redshift galaxies. Our analysis suggests that galaxies at $\langle z\rangle\approx6.4$ have an average $f_\text{esc}^{\text{Ly}α}=0.14\pm0.04$. This value is consistent with reionization models where the Lyman continuum escape fraction is low $(f_\text{esc}^\text{LyC}\lesssim0.1)$ for luminous galaxies, and where the most luminous galaxies have only a minor contribution to the total ionizing photon budget.

[abstract 22 / 28] (score: 2)
arXiv:2507.05456 [pdf, ps, other]

Title: Absolute constraints on the MAGNETic field evolution in tokamak power plants

Authors: Allen H Boozer,

Comments:

Subjects: physics.plasm-ph

Created: 2025-07-07; Updated: 2025-07-09; Datestamp: 2025-07-09

Issues of tokamak power plants, such as maximum possible length of a pulse of fusion power, the required time between fusion pulses, and the evolution of the current profile towards disruptive states, are tightly constrained by a simple evolution equation for the MAGNETic field. This equation follows from Faraday's Law and the mathematical relation between the MAGNETic and the electric fields. The validity of detailed simulations is tested by consistency with Faraday's Law, not the other way around. The evolution equation suggests methods of avoiding the limitations of these constraints. Commonwealth Fusion Systems (CFS) is proceeding on a fast timescale to operate a fusion power plant -- even writing contracts on the power to be produced by their ARC tokamak. This makes it important to determine the issues that should be studied by SPARC, which is the tokamak that CFS is building to address issues before ARC is built. The STEP prototype of a spherical tokamak power plant of Tokamak Energy is on a similar fast timescale. Feasible simulations from startup to shutdown for prototype plasmas could greatly clarify these constraints and the feasibility of their avoidance.

[abstract 23 / 28] (score: 2)
arXiv:2507.05589 [pdf, ps, other]

Title: Quantum Machine Learning for Identifying Transient Events in X-ray Light Curves

Authors: Taiki Kawamuro, Shinya Yamada, Shigehiro Nagataki, Shunji Matsuura, Yusuke Sakai, Satoshi Yamada,

Comments: 35 pages, 18 figures, 2 tables, accepted for publication in ApJ

Subjects: astro-ph.HE quant-ph

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

We investigate whether a novel method of quantum machine learning (QML) can identify anomalous events in X-ray light curves as transient events and apply it to detect such events from the XMM-Newton 4XMM-DR14 catalog. The architecture we adopt is a quantum version of the long-short term memory (LSTM) where some fully connected layers are replaced with quantum circuits. The LSTM, making predictions based on preceding data, allows identification of anomalies by comparing predicted and actual time-series data. The necessary training data are generated by simulating ACTIVE GALACTIC NUCLEus-like light curves as the species would be a significant population in the XMM-Newton catalog. Additional anomaly data used to assess trained quantum LSTM (QLSTM) models are produced by adding flares like quasi-periodic eruptions to the training data. Comparing various aspects of the performances of the quantum and classical LSTM models, we find that QLSTM models incorporating quantum superposition and entanglement slightly outperform the classical LSTM (CLSTM) model in expressive power, accuracy, and true-positive rate. The highest-performance QLSTM model is then used to identify transient events in 4XMM-DR14. Out of 40154 light curves in the 0.2--12 keV band, we detect 113 light curves with anomalies, or transient event candidates. This number is $\approx$ 1.3 times that of anomalies detectable with the CLSTM model. By utilizing SIMBAD and four wide-field survey catalogs made by ROSAT, SkyMapper, Pan-STARRS, and WISE, no possible counterparts are found for 12 detected anomalies.

[abstract 24 / 28] (score: 2)
arXiv:2507.05596 [pdf, ps, other]

Title: Investigating the transverse-momentum- and pseudorapidity-dependent flow vector decorrelation in p--Pb collisions with a Multi-Phase Transport model

Authors: Siyu Tang, Zuman Zhang, Chao Zhang, Liang Zheng, Renzhuo Wan,

Comments: accepted by Chinese Physics C

Subjects: hep-ph

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

The event-by-event fluctuations in the initial energy density of the nuclear collisions lead to the decorrelation of second order flow vector, as known as its transverse-momentum ($p_{\mathrm{T}}$) and pseudorapidity ($η$) dependence as observed in high-energy heavy-ion collisions. Existing measurements at the CERN Large Hadron Collider shown that these decorrelations are also observed in small collision systems. In this work, a systematic study of the transverse-momentum- and pseudorapidity-dependent flow vector decorrelation is performed in p--Pb collisions at the 5.02 TeV with A Multi-Phase Transport (AMPT) model using different tunings of the initial conditions, partonic and hadronic interactions. It is found that the string-melting version of the AMPT model provides a reasonable description of the measured flow vector decorrelation as a function of $p_{\mathrm{T}}$ and $η$. We demonstrate that the hadronic scatterings do not have significant impact on decorrelation in p--Pb collisions for different centrality selections, while both initial conditions and partonic interactions influence the magnitude of the decorrelations. In addition, we found that the subtraction of the nonflow, especially the long-range JET correlation, is crucial for the accurate extraction of the flow vector decorrelation in small collision systems. The comparison of data and model presented in this paper provide further insights in understanding the fluctuations of the flow vector with $p_{\mathrm{T}}$ and $η$ in small collision systems and has referential value for future measurements.

[abstract 25 / 28] (score: 2)
arXiv:2507.05982 [pdf, ps, other]

Title: Localisation and host galaxy identification of new Fast Radio Bursts with MeerKA

Authors: Inés Pastor-Marazuela, Alexa C. Gordon, Ben Stappers, Ilya S. Khrykin, Nicolas Tejos, Kaustubh Rajwade, Manisha Caleb, Mayuresh P. Surnis, Laura N. Driessen, Sunil Simha, Jun Tian, J. Xavier Prochaska, Ewan Barr, Wen-Fai Fong, Fabian Jankowski, Lordrick Kahinga, Charles D. Kilpatrick, Michael Kramer, Lluis Mas-Ribas,

Comments: 25 pages, including 6 of appendix, 18 figures, 4 tables. Submitted to MNRAS

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

Accurately localising fast radio bursts (FRBs) is essential for understanding their birth environments and for their use as cosmological probes. Recent advances in radio interferometry, particularly with MeerKAT, have enabled the localisation of individual bursts with arcsecond precision. In this work, we present the localisation of 15 apparently non-repeating FRBs detected with MeerKAT. Two of the FRBs, discovered in 2022, were localised in 8 second images from the projects which MeerTRAP was commensal to, while eight were localised using the transient buffer pipeline, and another one through SeeKAT, all with arcsecond precision. Four additional FRBs lacked TB triggers and sufficient signal, limiting their localisation only to arcminute precision. For nine of the FRBs in our sample, we identify host galaxies with greater than 90% confidence, while two FRBs have ambiguous associations with two host galaxy candidates. We measured spectroscopic redshifts for six host galaxies, ranging from 0.33 to 0.85, demonstrating MeerKAT's sensitivity to high redshift FRBs. For galaxies with sufficient photometric coverage, we performed spectral energy those of known FRB hosts. This work represents one of the largest uniform samples of well-localised distant FRBs to date, laying the groundwork for using MeerKAT FRBs as cosmological probes and understand how FRB hosts evolve at high redshift.

[abstract 26 / 28] (score: 2)
arXiv:2507.06002 [pdf, ps, other]

Title: Measurement of the Diffuse Astrophysical Neutrino Spectrum above a TeV with All Flavor Starting Events in IceCube

Authors: Vedant Basu, Aswathi Balagopal V., Albrecht Karle,

Comments: Presented at the 39th International Cosmic Ray Conference (ICRC2025)

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

The IceCube Neutrino Observatory utilizes the Cherenkov radiation emitted by charged secondary particles produced in interactions of neutrinos with ice nucleons to detect neutrino events. "Starting events", where this interaction vertex is contained inside the detector volume, can be used to distinguish neutrinos from the dominant background of atmospheric through-going muons. We present the Medium Energy Starting Events (MESE) selection, which employs a series of vetoes to obtain a neutrino-pure sample to measure the flux of diffuse extragalactic neutrinos from 1 TeV to 10 PeV from the entire sky. In this talk we will present a measurement of the spectrum of the diffuse flux of neutrinos, which demonstrates strong evidence for structure in the spectrum beyond a single power law, with a significance of $4.2\,σ$.

[abstract 27 / 28] (score: 2)
arXiv:2507.06089 [pdf, ps, other]

Title: Combining IceCube Muon Tracks and Cascades to measure the Galactic Diffuse Neutrino Flux

Authors: Jonas Hellrung, Julia Becker Tjus, Wolfgang Rhode,

Comments: Presented at the 39th International Cosmic Ray Conference (ICRC2025)

Subjects: astro-ph.HE

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

The diffuse Galactic neutrino flux is produced by COSMIC RAYs interacting with the interstellar medium. The measurement of this flux can help to understand the distribution of COSMIC RAYs in the Galaxy. The first observation of this neutrino flux was published in 2023 by the IceCube Collaboration. Here, plans for a new analysis combining different event topologies are presented. IceCube measures events in two main topologies. Tracks, originating in charged current $ν_μ$ interactions, provide a better angular resolution. In contrast, cascades, from most other possible interactions, provide a better energy resolution and are able to observe the Southern sky (and therefore the Galactic Center) despite the huge background of atmospheric muons. Combining both event topologies in one analysis exploits all these advantages. Sensitivities and model discrimination power of a combined measurement using a forward folding binned likelihood fit are discussed here.

[abstract 28 / 28] (score: 2)
arXiv:2507.06151 [pdf, ps, other]

Title: Observation of Broadband In-ice Radiation from Impacting High-Energy Cosmic Rays

Authors: Philipp Windischhofer, Nathaniel Alden,

Comments: Submitted to ICRC 2025

Subjects: astro-ph.HE astro-ph.IM

Created: 2025-07-08; Updated: 2025-07-09; Datestamp: 2025-07-09

We present the first experimental evidence for in-ice radiofrequency emission from high-energy particle cascades developing in the Antarctic ice sheet. In 208 days of data recorded with the phased-array trigger of the Askaryan Radio Array, we detect 13 events with impulsive radiofrequency pulses originating from below the ice surface. Considering only the arrival angles and timing properties, this rate is inconsistent with an a-posteriori background expectation for thermal noise events and on-surface events at the level of 3.5$\,σ$, which rises to 5.1$\,σ$ when additionally considering impulsivity. The observed event geometry, event rate, signal shape, spectral content, and electric field POLARIZATION are consistent with Askaryan radiation from COSMIC RAY air shower cores impacting the ice sheet. For the brightest events, the angular radiation pattern independently favors an extended cascade-like emitter over a pointlike source.