Current date: 2025-09-18

Setting default datestamp limit: 0

Datestamp limit: 2025-09-18 (0 days ago)

Created/updated limit: 2025-09-11 (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=2025-09-18&until=2025-09-18&set=physics&metadataPrefix=arXiv

Scoring abstracts

Number of records retrieved: 563

Keyword score statistics

score 8 -- 1 abstracts

score 7 -- 2 abstracts

score 6 -- 2 abstracts

score 5 -- 1 abstracts

score 4 -- 5 abstracts

score 3 -- 8 abstracts

score 2 -- 9 abstracts

in total -- 28 abstracts

Articles that appeared on 2025-09-18

[abstract 1 / 28] Wow! (score: 8)
arXiv:2311.00432 [pdf, ps, other]

Title: Misaligned MAGNETized accretion flows onto spinning BLACK HOLEs: Magneto-spin alignment, outflow power, and intermittent JETs

Authors: Koushik Chatterjee, Nicholas Kaaz, Matthew Liska, Alexander Tchekhovskoy, Sera Markoff,

Comments: Accepted version. One youtube link for a movie of the T90 model: https://www.youtube.com/watch?v=mTLbZgd5CtY&ab_channel=KoushikChatterjee

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

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

Magnetic fields regulate BLACK HOLE (BH) accretion, governing both inflow and outflow dynamics. When a BH accumulates substantial vertical MAGNETic flux, it enters the MAGNETically arrested disk (MAD) state, where dynamically important fields power JETs and trigger disk eruptions. We investigate MAD evolution when the BH spin and disk angular momentum are misaligned, a likely scenario in many BH systems. Using numerical simulations, we show that JETs from rapidly spinning, prograde BHs realign the inner disk via the MAGNETo-spin alignment mechanism for initial tilts up to $T \lesssim 60^\circ$. Larger tilts lead to intermittent JETs that disrupt the disk out to $r\gtrsim100$ gravitational radii, creating hot cavities and MAGNETized filaments. These episodic JETs form a mini$-$feedback loop and may explain quasiperiodic X-ray and radio flares observed in low-luminosity active galaxies. We also find that (i) BH spin and disk tilt influence the amount of MAGNETic flux accumulated at the horizon, and (ii) large-scale, thick, misaligned accretion flows do not exhibit sustained Lense$-$Thirring (LT) precession. This suggests that slowly accreting BHs ($\dot{M} \ll 10^{-3} \dot{M}_{\rm Edd}$) are unlikely to show lightcurve quasiperiodic oscillations from LT precession, consistent with observations. Instead, MAGNETic flux eruptions drive JET wobbling and lateral motion, offering an alternative explanation for phenomena such as the M87 JET's apparent precession and rapid swings in BLAZAR JET orientation.

[abstract 2 / 28] Wow! (score: 7)
arXiv:2509.13411 [pdf, ps, other]

Title: The Broadband View of the Bare Seyfert PG 1426+015: Relativistic Reflection, the Soft Excess and the Importance of Oxygen

Authors: D. J. Walton, A. Madathil-Pottayil, P. Kosec, J. Jiang, J. Garcia, A. C. Fabian, C. Pinto, D. J. K. Buisson, M. L. Parker, W. N. Alston, C. S. Reynolds,

Comments: 17 pages, 13 figures, accepted for publication in MNRAS

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

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

We present results from a deep, coordinated $XMM$-$Newton$ + $NUSTAR$ observation of the type 1 Seyfert PG 1426+015, a source of particular interest as the most massive reverberation-mapped BLACK HOLE to date ($\log [M_{\rm{BH}}/M_{\odot}]$ = $9.01^{+0.11}_{-0.16}$). The high-resolution RGS data confirm the 'bare' nature of the source, showing no evidence for absorption beyond the Galactic column, while the broadband spectrum unambiguously reveals the presence of RELATIVISTIC reflection from the innermost accretion disc (in the form of a RELATIVISTICally broadened iron emission and associated Compton reflection hump) as well as confirming the presence of the strong soft excess reported previously. We explore whether RELATIVISTIC reflection can successfully account for the soft excess along with the higher-energy reflection features, utilizing the two most-commonly used reflection codes (REFLIONX, XILLVER). Ultimately we find that both models are able to successfully reproduce the soft excess, though in the case of the XILLVER model this is contingent on reducing the strength of the O VIII line included in the model, as otherwise this feature prevents the model from reproducing the data. The reflection models that successfully reproduce the broadband data imply a relatively high density for the accretion disc of $\log [n_{\rm{e}} / \rm{cm}^{-3}] \sim 18$, consistent with the loose anti-correlation seen from other AGN in the $\log [n_{\rm{e}} / \rm{cm}^{-3}]$ vs $\log[m_{\rm{BH}} \dot{m}^2]$ plane, as well as a moderate-to-high BLACK HOLE spin of $a^* \gtrsim 0.7$. This preliminary spin constraint is strongly dependent on the assumption that the soft excess is dominated by RELATIVISTIC reflection.

[abstract 3 / 28] Wow! (score: 7)
arXiv:2509.14013 [pdf, ps, other]

Title: Extensive Analysis of gamma-Ray Periodicity in Jetted AGN from the 4FGL Catalog Using FERMI-LAT Observations

Authors: P. Peñil, A. Domínguez, S. Buson, M. Ajello, S. Adhikari, A. Rico,

Comments: 29 pages, 7 figures, 1 table

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

The quest to uncover periodic patterns within the $γ$-ray emissions of JETted ACTIVE GALACTIC NUCLEi (AGN) has recently emerged as a focal point in astrophysics. One of the primary challenges has been the necessity for prolonged exposures in the $γ$-ray energy band. In our investigation, we leverage 12 years' worth of observations from the \textit{FERMI}-LAT to systematically explore periodicity across 1492 JETted AGN cataloged in 4FGL, representing the largest sample analyzed to date. Our analysis involves a robust pipeline employing nine distinct techniques designed to detect potential periodic emissions within their $γ$ rays. We note that 24 objects with previous hints of periodicity are deliberately excluded in the present work since they were reanalyzed in a dedicated paper using a similar methodology. Using this thorough approach, we do not find any evidence for periodic signals in the 1492 JETted AGN $γ$-ray light curves analyzed here.

[abstract 4 / 28] Yes (score: 6)
arXiv:2410.11753 [pdf, ps, other]

Title: Identification and modelling of optically thin inverse Compton scattering in the prompt emission of GRB131014A

Authors: Pragyan Pratim Bordoloi, Shabnam Iyyani,

Comments: Accepted for publication in The Astrophysical Journal

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

The mechanism responsible for the prompt gamma-ray emission of a GAMMA-RAY BURST continues to remain an enigma. The detailed analysis of the spectrum of GRB 131014A observed by the $FERMI$ gamma ray burst monitor and Large Area Telescope has revealed an unconventional spectral shape that significantly deviates from the typical Band function. The spectrum exhibits three distinctive breaks and an extended power law at higher energies. Furthermore, the lower end of the spectrum aligns with power-law indices greater than -0.5, and in the brightest region of the burst, these values approach +1. The lowest spectral break is thereby found to be consistent with a blackbody. These observed spectral characteristics strongly suggest the radiation process to be inverse Compton scattering in an optically thin region. Applying the empirical fit parameters for physical modeling, we find that the kinetic energy of the GRB JET of bulk Lorentz factor, $Γ\sim 400$, gets dissipated just above the photosphere, approximately at a radius of $\sim 10^{14}$ cm. The electrons involved in this process are accelerated to a power-law index of $δ= -1.5$, and the minimum electron Lorentz factor, $γ_{min}$, is approximately $3$. In summary, this study provides a comprehensive identification and detailed modeling of optically thin inverse Compton scattering in the prompt emission of GRB 131014A.

[abstract 5 / 28] Yes (score: 6)
arXiv:2508.04387 [pdf, ps, other]

Title: Probing chromospheric fine structures with a Hα proxy using MURaM-ChE

Authors: Sanghita Chandra, Robert Cameron, Damien Przybylski, Sami K. Solanki, Patrick Ondratschek, Sanja Danilovic,

Comments: 16 pages, 15 figures. Accepted for publication in A&A

Subjects: astro-ph.SR

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

H$α$ observations of the solar chromosphere reveal dynamic small-scale structures known as spicules at the limb and rapid blue and red shifted excursions (RBEs/RREs) on-disk. We want to understand what drives these dynamic features, their MAGNETohydrodynamic (MHD) properties and their role in energy and heat transport to the upper solar atmosphere. To do this, we aim to develop a proxy for synthetic H$α$ observations in radiative-MHD simulations to help identify these features. We use the chromospheric extension to the MURaM code (MURaM-ChE) to simulate an enhanced network region. We develop a proxy for H$α$ based on a photon escape probability. This is a Doppler-shifted proxy that we use to identify fine structures in the line wings. We study on-disk features in 3D, obtaining their 3D structure from the absorption coefficient. We validate the H$α$ proxy by comparing it against features detected in the wings of H$α$ synthesized using MULTI3D. We detect numerous small-scale structures rooted at the network patches, similar to observations in H$α$. The dynamics of an example feature (RBE) at a Doppler shift of 37 km/s show that flux emergence and consequent RECONNECTion drive the formation of this feature. Pressure gradient forces build up to drive a flow along the field line carrying the feature, making it a JET. There is strong viscous and resistive heating at the first appearance of the feature associated with the flux emergence. At the same time and location, a heating front appears and propagates along the field lines at speeds comparable to the Alfven velocity. We show that a synthetic observable based on an escape probability is able to reliably identify features observed with the H$α$ spectral line. We demonstrate its applicability by studying the formation, dynamics and properties of an RBE.

[abstract 6 / 28] Yes (score: 5)
arXiv:2508.06688 [pdf, ps, other]

Title: A Multi-Wavelength Survey of Transient Lensing Opportunities for Primordial Black Hole Searches

Authors: Stefano Profumo,

Comments: 24 pages, 2 tables, 2 figures; accepted for publication in JCAP

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

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

Gravitational lensing of short astrophysical transients provides a uniquely direct avenue for searching for primordial BLACK HOLEs (PBHs) across a vast range of masses. While past search efforts have focused on particular source classes-such as fast radio bursts (FRBs) and GAMMA-RAY BURST spikes-no systematic, multi-wavelength assessment has compared their relative potential for PBH discovery. We present here a broad assessment of transient lensing search opportunities, spanning more than twenty decades in photon frequency and over twelve orders of magnitude in PBH mass. For each class, we determine the accessible PBH mass window by accounting for wave-optics suppression and time-delay resolution limits, and we estimate potential sensitivities to the PBH abundance using representative event rates, distances, and optical depths. Our survey includes low-frequency radio events (FRBs, pulsar giant pulses, planetary cyclotron bursts), optical/infrared signals, and high-energy phenomena (GAMMA-RAY BURST spikes, fast X-ray transients, TeV BLAZAR flares). We synthesize these results in a unified mass-abundance diagram and comprehensive tables summarizing both physical reach and observational requirements. This work serves as a roadmap for optimizing future multi-wavelength lensing searches, guiding the design of instruments and strategies to explore the PBH DARK MATTER hypothesis across its remaining viable parameter space.

[abstract 7 / 28] Yes (score: 4)
arXiv:2206.14837 [pdf, ps, other]

Title: New physics above 50 TeV: probing its phenomenology through UHECR air-shower simulations

Authors: S. Romanopoulos, V. Pavlidou, T. Tomaras,

Comments: 10 pages, 10 figures

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

Ground based observations appear to indicate that Ultra High Energy Cosmic Rays (UHECR) of the highest energies (>10^{18.7} eV) consist of heavy particles -- shower depth and muon production data both pointing towards this conclusion. On the other hand, cosmic-ray arrival directions at energies >10^{18.9} eV exhibit a dipole anisotropy, which disfavors heavy composition, since higher-Z nuclei are strongly deflected by the Galactic MAGNETic field, suppressing anisotropy. This is the composition problem of UHECR. One solution could be the existence of yet-unknown effects in proton interactions at center-of-mass (CM) energies 50 TeV, which would alter the interaction cross section and the multiplicity of interaction products, mimicking heavy primaries. We study the impact of such changes on cosmic-ray observables using simulations of Extensive Air-Shower (EAS), in order to place constrains on the phenomenology of any new effects for high energy proton interactions that could be probed by \sqrt{s}>50 TeV collisions. We simulate showers of primaries with energies in the range 10^{17} - 10^{20} eV using the CORSIKA code, modified to implement a possible increase in cross-section and multiplicity in hadronic collisions exceeding a CM energy threshold of 50 TeV. We study the composition-sensitive shower observables (shower depth, muons) as a function of cross-section, multiplicity, and primary energy. We find that in order to match the Auger shower depth measurements by means of new hadronic collision effects alone (if extragalactic UHECR are all protons even at the highest energies), the cross-section of proton-air interactions has to be 800 mb at 140 TeV CM energy, accompanied by an increase of a factor of 2-3 in secondary particles. We also study the muon production of the showers in the same scenario.

[abstract 8 / 28] Yes (score: 4)
arXiv:2505.23889 [pdf, ps, other]

Title: Gas meets Kozai: the influence of a gas-rich accretion disc on hierarchical triples undergoing von Zeipel-Lidov-Kozai oscillations

Authors: Yubo Su, Connar Rowan, Mor Rozner,

Comments: 15 pages, 8 figures. Accepted to MNRAS

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

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

Active galactic nuclei (AGNs) consist of a central supermassive BLACK HOLE (SMBH) embedded in a region with both high gas and stellar densities: the gas is present as a thin accretion disc that fuels the central SMBH, while the stars form a dense, roughly isotropic nuclear star cluster. The binaries present in such a cluster could be considered naturally as triples, with the SMBH as a third object, and their dynamics also depend on the interaction with the gas-rich disc. In this paper, we study the evolution of such a binary on an inclined orbit with respect to the disc. The binary experiences both eccentricity excitation via the von Zeipel-Lidov-Kozai (ZLK) effect and drag forces from each time it penetrates the disc. We find that, as the outer orbital inclination decreases, the evolution of inner orbital separation can transition from a regime of gradual hardening to a regime of rapid softening. As such binaries grow wider, their minimum pericentre distances (during ZLK oscillations) decrease. We show that a simple geometric condition, modulated by the complex ZLK evolution, dictates whether a binary expands or contracts due to the interactions with the AGN disc. Our results suggest that the interaction with gas-rich accretion disc could enhance the rate of stellar mergers and formation of gravitational wave sources, as well as other transients. The treatment introduced here is general and could apply, with the proper modifications, to hierarchical triples in other gas-rich systems.

[abstract 9 / 28] Yes (score: 4)
arXiv:2509.13419 [pdf, ps, other]

Title: Origin of Pulsed Radio Emission from Magnetars

Authors: Shuzhe Zeng, Alexander Philippov, James Juno, Andrei M. Beloborodov, Elena Popova,

Comments: 17 pages, 8 figures

Subjects: astro-ph.HE

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

Extended periods of radio pulsations have been observed for six MAGNETars, displaying characteristics different from those of ordinary pulsars. In this Letter, we argue that radio emission is generated in a closed, twisted MAGNETic flux bundle originating near the MAGNETic pole and extending beyond 100 km from the MAGNETar. The electron-positron flow in the twisted bundle has to carry electric current and, at the same time, experiences a strong drag by the radiation field of the MAGNETar. This combination forces the plasma into a ``radiatively locked'' state with a sustained two-stream instability, generating radio emission. We demonstrate this mechanism using novel first-principles simulations that follow the plasma behavior by solving the RELATIVISTIC Vlasov equation with the discontinuous Galerkin method. First, using one-dimensional simulations, we demonstrate how radiative drag induces the two-stream instability, sustaining turbulent electric fields. When extended to two dimensions, the system produces electroMAGNETic waves, including superluminal modes capable of escaping the MAGNETosphere. We measure their frequency and emitted power, and incorporate the local simulation results into a global MAGNETospheric model. The model explains key features of observed radio emission from MAGNETars: its appearance after an X-ray outburst, wide pulse profiles, luminosities $\sim 10^{30}{\rm{erg/s}}$, and a broad range of frequencies extending up to $\sim 100\, \mathrm{GHz}$.

[abstract 10 / 28] Yes (score: 4)
arXiv:2509.13812 [pdf, ps, other]

Title: FERMI-LAT Detected Gamma-ray Emission Likely Associated with SNR Kes 78

Authors: Yun-Zhi Shen, Yang Chen, Xiao Zhang, Chen Huang,

Comments: To appear in the Astrophysical Journal. 12 pages, 5 figures

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

We have analyzed the GeV gamma-ray emission in the region of the SUPERNOVA remnant (SNR) Kes 78 using $\sim$16.7 years of FERMI-LAT observations and found that the catalog sources 4FGL J1852.4+0037e and 4FGL J1851.8$-$0007c are better represented as two extended sources modeled as `2Ext'. One of them, designated as E2, is located at R.A.$=282.86^\circ$, Dec.$=-0.11^\circ$ with the 68\% containment radius $R_{68} = 0.31^\circ$, and is detected with a significance of 15.2$σ$ in the 0.2--500 GeV energy range. The gamma-ray emission of source E2 is well described by a log-parabola (LogP) spectral model with spectral index $Γ$ = 1.2 and curvature $β$ = 0.3. The fitting with electron-proton number ratio $K_{\rm ep}=0.01$ indicates that the GeV emission of source E2 is dominated by hadronic emission. Given the dense molecular environment surrounding the middle-aged SNR Kes 78, the hadronic scenario provides a natural explanation for the observed GeV emission. The extended source E2 can also be replaced with two point sources. One of them, designated as PTS1, is coincident with the newly discovered PSR J1852$-$0002g within the 68\% positional uncertainty circle, indicating a possible gamma-ray contribution from this PSR. The gamma-ray spectrum of source PTS1 can be well described by a LogP spectral shape. The synchro-curvature radiation model provides a satisfactory spectral fit for source PTS1, suggesting that some of the GeV emission from the Kes 78 region might possibly originate from the MAGNETosphere of PSR J1852$-$0002g.

[abstract 11 / 28] Yes (score: 4)
arXiv:2509.14202 [pdf, ps, other]

Title: Mass Transport, Turbulent Mixing, and Inflow in Black Hole Accretion

Authors: George N. Wong, Lia Medeiros, James M. Stone,

Comments: 24 pages, 19 figures. submitted

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

We investigate mass transport, mixing, and disk evolution in non-radiative BLACK HOLE accretion flows using Lagrangian tracer particles embedded in general RELATIVISTIC MAGNETohydrodynamics simulations. Our simulation suite spans MAGNETically arrested disk (MAD) and standard and normal evolution (SANE) states across a range of BLACK HOLE spins. By tracking tracer trajectories, we directly measure both advective inflow and stochastic spreading of fluid elements. The tracer distributions are well described by a combination of coherent inward drift and Gaussian-like broadening, consistent with an advection-diffusion picture. MADs exhibit systematically faster inflow than SANEs, with retrograde flows showing the most rapid infall; the innermost stable circular orbit leaves little imprint in MADs but remains more visible in SANEs. Turbulent fluctuations drive strong radial dispersion in all cases, with a superdiffusive scaling of sigma ~ t^0.95 in MADs and sigma ~ t^0.75 in SANEs for high-spin prograde disks. Mixing times decrease toward the event horizon and are consistently shorter in MADs and retrograde configurations. Tracers also reveal how accretion sources shift over time: turbulence draws inflow from a broad range of initial radii, with rapid torus depletion in MADs driving the mean source radius outward as r ~ t^(2/3), while SANEs evolve more gradually with r ~ t^(1/2). We show that the finite mass of the initial torus has a strong influence on late-time behavior, especially in MADs, where imprints of differently sized initial conditions may be accessible as early as t ~ 10000 GM/c^3.

[abstract 12 / 28] (score: 3)
arXiv:2501.09748 [pdf, ps, other]

Title: PyPLUTO: a data analysis Python package for the PLUTO code

Authors: Giancarlo Mattia, Daniele Crocco, David Melon Fuksman, Matteo Bugli, Vittoria Berta, Eleonora Puzzoni, Andrea Mignone, Bhargav Vaidya,

Comments: 7 pages, 3 figures. Accepted for publication in JOSS

Subjects: astro-ph.IM

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

In recent years, numerical simulations have become indispensable for addressing complex astrophysical problems. The MagnetoHydroDynamics (MHD) framework represents a key tool for investigating the dynamical evolution of astrophysical plasmas, which are described as a set of partial differential equations that enforce the conservation of mass, momentum, and energy, along with Maxwell's equations for the evolution of the electroMAGNETic fields. Due to the high nonlinearity of the MHD equations (regardless of their specifications, e.g., classical/RELATIVISTIC or ideal/resistive), a general analytical solution is precluded, making the numerical approach crucial. Numerical simulations usually end up producing large sets of data files, and their scientific analysis leans on dedicated software designed for data visualization. However, in order to encompass all of the code output features, specialized tools focusing on the numerical code may represent a more versatile and built-in tool. Here, we present PyPLUTO, a Python package tailored for efficient loading, manipulation, and visualization of outputs produced with the PLUTO code (Mignone et al., 2007; Mignone et al., 2012). PyPLUTO uses memory mapping to optimize data loading and provides general routines for data manipulation and visualization. PyPLUTO also supports the particle modules of the PLUTO code, enabling users to load and visualize particles, such as COSMIC RAYs (Mignone et al., 2018), Lagrangian (Vaidya et al., 2018), or dust (Mignone et al., 2019) particles, from hybrid simulations. A dedicated Graphical User Interface simplifies the generation of single-subplot figures, making PyPLUTO a powerful yet user-friendly toolkit for astrophysical data analysis.

[abstract 13 / 28] (score: 3)
arXiv:2503.07549 [pdf, ps, other]

Title: Beyond first light: Global monitoring for high-energy neutrino astronomy

Authors: Lisa Johanna Schumacher, Mauricio Bustamante, Matteo Agostini, Foteini Oikonomou, Elisa Resconi,

Comments: Accepted for publication in PRD

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

Decades of progress have culminated in first light for high-energy neutrino astronomy: the identification of the first astrophysical sources of TeV-PeV neutrinos by the IceCube neutrino telescope, the ACTIVE GALACTIC NUCLEi NGC 1068 and TXS 0506+056. Today, the prospect of going beyond first light to build high-energy neutrino astronomy in earnest by discovering many more neutrino sources is hampered by the relatively low rate of neutrino detection and the limited view of the sky afforded by IceCube, the single cubic-kilometer-scale neutrino telescope in operation. Yet, this will not stand for much longer. Already today, and over the next 10-20 years, the combined observations of new neutrino telescopes, larger and distributed around the world, will have the potential for transformative progress. Together, they will increase the global rate of neutrino detection by up to 30 times and continuously monitor the entire sky. Within a new joint analysis network - the Planetary Neutrino Monitoring network (PLEnuM) - we make detailed forecasts for the discovery of steady-state astrophysical sources of high-energy neutrinos. We show that a combined analysis of global data will expedite source discovery - in some cases, by decades - and enable the detection of fainter sources anywhere in the sky, discovering up to tens of new neutrino sources.

[abstract 14 / 28] (score: 3)
arXiv:2505.22567 [pdf, ps, other]

Title: A BLACK HOLE in a near-pristine galaxy 700 million years after the Big Bang

Authors: Roberto Maiolino, Hannah Uebler, Francesco D'Eugenio, Jan Scholtz, Ignas Juodzbalis, Xihan Ji, Michele Perna, Volker Bromm, Pratika Dayal, Sophie Koudmani, Boyuan Liu, Raffaella Schneider, Debora Sijacki, Rosa Valiante, Alessandro Trinca, Saiyang Zhang, Marta Volonteri, Kohei Inayoshi, Stefano Carniani, Kimihiko Nakajima, Yuki Isobe, Joris Witstok, Gareth C. Jones, Sandro Tacchella, Santiago Arribas, Andrew Bunker, Elisa Cataldi, Stephane Charlot, Giovanni Cresci, Mirko Curti, Andrew C. Fabian, Harley Katz, Nimisha Kumari, Nicolas Laporte, Giovanni Mazzolari, Brant Robertson, Fengwu Sun, Bruno Rodriguez Del Pino, Giacomo Venturi,

Comments: Replaced with updated figures and references and expanded discussion, 17 pages, 10 figures, 2 tables

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

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

The recent discovery of a large number of massive BLACK HOLEs within the first two billion years after the Big Bang, as well as their peculiar properties, have been largely unexpected based on the extrapolation of the properties of luminous QUASARs. These findings have prompted the development of several theoretical models for the early formation and growth of BLACK HOLEs, which are, however, difficult to differentiate. We report the metallicity measurement around a gravitationally lensed massive BLACK HOLE at redshift 7.04 (classified as a Little Red Dot), hosted in a galaxy with very low dynamical mass. The weakness of the [OIII]5007 emission line relative to the narrow H$β$ emission indicates extremely low metallicity, less than $10^{-2}$ solar. We argue that such properties cannot be uncommon among accreting BLACK HOLEs around this early cosmic epoch. Explaining such a low chemical enrichment in a system that has developed a massive BLACK HOLE is challenging for most theories. Models assuming heavy BLACK HOLE seeds (such as Direct Collapse Black Holes) or super-Eddington accretion scenarios struggle to explain the observations, although they can potentially reproduce the observed properties in some cases. Models invoking "primordial BLACK HOLEs" (i.e. putative BLACK HOLEs formed shortly after the Big Bang) may potentially explain the low chemical enrichment associated with this BLACK HOLE, although this class of models also requires further developments for proper testing.

[abstract 15 / 28] (score: 3)
arXiv:2509.13455 [pdf, ps, other]

Title: Oakridge PPU Magnets: Results and Measurements

Authors: J. DiMarco, D. Harding, V. Kashikhin, O. Kiemschies, M. Kifarkis, A. Makulski, J. Nogiec, S. Stoynev, T. Strauss, M. Tartaglia, P. Thompson,

Comments: 2025 International Conference on Magnet Technology (MT29)

Subjects: physics.acc-ph

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) is being upgraded from 1.0 GeV to 1.3 GeV (or 1.4 to 2.8 MW). Several water-cooled MAGNETs have been upgraded to transport 30% higher beam energy. FERMIlab contributed the MAGNET design for the new chicane MAGNETs and injection/extraction septum. Designing the MAGNETs was a challenging task because the new MAGNETs required good combined integrated field quality and needed to occupy the old MAGNETs space but with about 20% greater integrated MAGNETic field. Additional strong requirements applied to the MAGNETs fringe field so as not to disturb the circulating beam. After fabrication of the MAGNETs, an extensive measurement campaign was developed and performed at FERMIlab's Magnet Test Facility. The measurements needed to assess MAGNET performance and provide comparison to design calculations. These included verification of field strength and harmonics along an 8 m length and 200 mm good field diameter for the chicane dipoles, end-field Hall probe mapping of these MAGNETs, and measurements along two differently curved trajectories within the ~3 m septum gradient MAGNET. Details of the measurements and systems are presented along with results and comparison to field models.

[abstract 16 / 28] (score: 3)
arXiv:2509.13465 [pdf, ps, other]

Title: Magnetic measurements of FERMIlab rapid-cycling Booster gradient MAGNETs

Authors: J. DiMarco, D. Assell, T. Cummings, D. Johnson, V. Kashikhin, M. Kifarkis, J. Kuharik, J. Larson, M. Mubarak, S. Poopathi, K. Triplett,

Comments: 2025 International Conference on Magnet Technology (MT29)

Subjects: physics.acc-ph

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

FERMIlab is upgrading its Booster SYNCHROTRON to increase ramp rate and intensity. This is part of the Proton Improvement Plan (PIP-II) that will allow the Main Injector to achieve proton beam power of 1.2 MW within the next few years. This upgrade includes running the 55-year-old Booster MAGNETs at 20 Hz instead of the usual 15 Hz, and construction of some shorter and wider aperture versions of these combined-function gradient MAGNETs. Magnetic measurements were performed to characterize the present 15 Hz AC performance, and then again with 20 Hz ramp cycle to ensure performance and compatibility in this new operating regime. A 3 m-long curved flat-coil was developed for these measurements using Printed Circuit Board (PCB) technology. The probe also has a separate 0.5 m-long body-field probe, allowing integral, body, and end fields to be measured across 100 mm of the MAGNET aperture. The sampling rate for these measurements during the AC cycle was 200 kHz, and field resolution was better than 0.01%. Details of the probe, measurements, and results are presented.

[abstract 17 / 28] (score: 3)
arXiv:2509.13732 [pdf, ps, other]

Title: Polar Mounds on Strangeon Stars: the Neutrino Emission from Ultraluminous X-ray Pulsars

Authors: Hong-Bo Li, Shi-Jie Gao, Xiang-Dong Li, Ren-Xin Xu,

Comments: 12 pages, 5 figures, 2 tables

Subjects: astro-ph.HE gr-qc

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

Ultraluminous X-ray pulsars (ULXPs) serve as unique astrophysical laboratories, offering critical insights into accretion physics under extreme conditions, such as strong MAGNETic fields and super-Eddington accretion rates. Additionally, the nature of pulsars, i.e., the equation of state of supranuclear matter, is still a matter of intense debate, basing on either conventional neutron stars or strange stars in the litterateurs. In this work, we investigate accretion columns of ULXPs based on the strangeon-star model, focusing on the thermal mound at the column base. Accounting for Coulomb and strangeness barriers of the strangeon stars, we find that the mound can reach $0.7-0.95\,\rm km$ in height with temperatures above $10^9\, \rm K$, enabling substantial neutrino emission via electron-positron annihilation. Heat transport along the strangeon star surface contributes a luminosity of $10^{36} \, \rm erg\, s^{-1} $, independent of the accretion rate. At low accretion rates ($< 10^{20}\, \rm g\,s^{-1}$), photons dominate the luminosity, while at higher rates ($> 10^{21}\, \rm g\, s^{-1}$), photon trapping makes neutrino emission the main cooling channel, with total luminosity exceeding photon emission, which saturates near $10^{41}\, \rm erg\,s^{-1}$. Estimating neutrino fluxes at Earth, we find that only the nearest ULXP, SWIFT J0243.6$+$6124, could produce a marginally detectable signal, while most extragalactic sources remain well below background levels. These results emphasize the key role of the thermal mound and strangeon star properties in determining accretion luminosities and neutrino emission, offering insights for future modeling and observations of ULXPs.

[abstract 18 / 28] (score: 3)
arXiv:2509.13911 [pdf, ps, other]

Title: Spatially resolved broad line region in a QUASAR at z=4: Dynamical BLACK HOLE mass and prominent outflow

Authors: GRAVITY+ Collaboration, K. Abd El Dayem, N. Aimar, A. Berdeu, J. -P. Berger, G. Bourdarot, P. Bourget, W. Brandner, Y. Cao, C. Correia, S. Cuevas Cardona, R. Davies, D. Defrère, A. Drescher, A. Eckart, F. Eisenhauer, M. Fabricius, A. Farah, H. Feuchtgruber, N. M. Förster Schreiber, A. Foschi, P. Garcia, R. Garcia Lopez, R. Genzel, S. Gillessen, T. Gomes, F. Gonté, V. Gopinath, J. Graf, M. Hartl, X. Haubois, F. Haußmann, L. C. Ho, S. Hönig, M. Houllé, S. Joharle, C. Keiman, P. Kervella, J. Kolb, L. Kreidberg, A. Labdon, S. Lacour, O. Lai, S. Lai, R. Laugier, J. -B. Le Bouquin, J. Leftley, R. Li, B. Lopez, D. Lutz, F. Mang, A. Mérand, F. Millour, M. Montargès, N. More, N. Morujão, H. Nowacki, M. Nowak, S. Oberti, C. Onken, J. Osorno, T. Ott, T. Paumard, K. Perraut, G. Perrin, R. Petrov, P. -O. Petrucci, N. Pourré, S. Rabien, C. Rau, D. Ribeiro, S. Robbe-Dubois, M. Sadun Bordoni, M. Salman, J. Sanchez-Bermudez, D. Santos, J. Sauter, M. Scialpi, J. Scigliuto, J. Shangguan, P. Shchekaturov, T. Shimizu, F. Soulez, C. Straubmeier, E. Sturm, M. Subroweit, C. Sykes, L. J. Tacconi, H. Übler, G. Ulbricht, F. Vincent, R. Webster, E. Wieprecht, J. Woillez, C. Wolf,

Comments: submitted to A&A (15 pages, 10 figures)

Subjects: astro-ph.GA

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

We present the first near-infrared interferometric data of a QSO at z=4. The K-band observations were performed with GRAVITY+ on the VLTI using all 4 UTs, detecting a differential phase signal that traces the spatially resolved kinematics for both the H$β$ and H$γ$ lines in the broad line region. We fit the two lines simultaneously with an updated model that includes distinct rotating and conical outflowing components. We find that more than 80\% of the HI line emission from the BLR originates in an outflow with a velocity up to $10^4$ km s$^{-1}$. This is oriented so that our line of sight is along an edge of the conical structure, which produces the prominent blue wing on the line profile. A combination of anisotropic line emission and mid-plane opacity lead to the single-sided phase signal. The model is able to qualitatively match both the outflowing CIV line profile and the systemic OI fluorescent emission. The derived BLACK HOLE mass of $8\times10^8$ M$_\odot$ is the highest redshift BLACK HOLE mass measurement to date obtained directly from BLR dynamics. It is an order of magnitude lower than that inferred from various single epoch scaling relations, and implies that the accretion is highly super-Eddington. With reference to recent simulations, the data suggest that this QSO is emitting close to its radiative limit in a regime where strong outflows are expected around a polar conical region.

[abstract 19 / 28] (score: 3)
arXiv:2509.14043 [pdf, ps, other]

Title: Searching for radio emission from radio quiet MAGNETars with MeerKAT

Authors: Marlon L. Bause, Kamalpreet Kaur, Isabella Rammala-Zitha, Laura G. Spitler,

Comments: 13 pages, 8 figures, submitted to A&A

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

Magnetars occupy the neutron star population, with MAGNETic field strengths of more than 10e12 G. They have been proposed as one of the most likely progenitor models for the phenomenon of energetic, ms-duration, extragalactic radio bursts (FRBs) intensively since FRB-like bursts emitted from the galactic Magnetar SGR 1935+2154. Only a low fraction of the MAGNETars (six in total) has been detected in the radio regime and most MAGNETars are radio quiet. We conducted regular observations of 13 radio quiet MAGNETars to probe the long term radio quietness using MeerKAT. These provide deep constraints on the radio emission of MAGNETars, relevant for the progenitor models of FRBs Given that MeerKAT is an interferometer, we probe the MAGNETars for radio emission in both imaging and time domain. We search in the time domain in a DM range of 20 pc/cm^3 to 10000 pc/cm^3 for single pulses using a TransientX based search pipeline (FRB perspective) as well as from a pulsar perspective by folding the data using the X-ray ephemeris. We use the imaging domain to search for radio emission in Stokes I and V as well as to create light curves using snapshot imaging having the long transient perspective as well. We find no radio emission in the time domain for any of the observed MAGNETars but provide deep limits of the mean flux density 60 uJy and the single pulse fluence of 39 mJy. From the image domain, we provide upper limits on the persistent radio radio emission and the light curve for the 13 MAGNETars. Additionally, an ULPT and an additional MAGNETar were observed in the images. We provide an extensive series of deep upper limits in the time domain but also as a novelty limits from the imaging domain for the MAGNETars. We encourage monitoring of radio quiet MAGNETars independent of their X-ray flux with high cadence for further insights in their potential for emitting in the radio regime.

[abstract 20 / 28] (score: 2)
arXiv:2507.00578 [pdf, ps, other]

Title: A comprehensive study of time delay between optical/near-infrared and X-ray emissions in BLACK HOLE X-ray binaries

Authors: Dizhan Du, Bei You, Zhen Yan, Xinwu Cao, Jean-Marie Hameury, Yue Wu,

Comments: 25 pages, 24 figures, accepted by MNRAS

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

We conducted a comprehensive study of daily delays using multi-wavelength data from a sample of well-studied BLACK HOLE X-ray binaries, specifically focusing on the sources GX 339-4, 4U 1543-47, and XTE J1550-564. The Interpolated Cross-Correlation Function method was employed to investigate the temporal relationship between the X-ray (Compton component) and optical-infrared (OIR) emissions. Our results show that during the rising hard state, the Compton emission consistently lags behind OIR emission for several days. In contrast, during the decaying hard state, the OIR emission lags behind the Compton emission by approximately 6 to 35 days. This measurement can potentially be used in models of accretion physics and disk instability. We explore the underlying mechanisms responsible for these time delays, highlighting the critical role of viscous heating in the accretion disk in generating OIR luminosity for these sources. The observed time delays during both the rising and decaying hard states are well explained by the disk instability model.

[abstract 21 / 28] (score: 2)
arXiv:2507.13453 [pdf, ps, other]

Title: ASKAP J144834-685644: a newly discovered long period radio transient detected from radio to X-rays

Authors: Akash Anumarlapudi, David L. Kaplan, Nanda Rea, Nicolas Erasmus, Daniel Kelson, Stella Koch Ocker, Emil Lenc, Dougal Dobie, Natasha Hurley-Walker, Gregory Sivakoff, David A. H. Buckley, Tara Murphy, Joshua Pritchard, Laura Driessen, Kovi Rose, Andrew Zic,

Comments: Accepted for publication in the Monthly Notices of the Royal Astronomical Society; minor change (additions to Acknowledgements) in v2

Subjects: astro-ph.HE

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

Long-period radio transients (LPTs) are an emerging group of radio transients that show periodic polarized radio bursts with periods varying from a few minutes to a few hours. Fewer than a dozen LPTs have been detected so far, and their origin (source and emission mechanism) remains unclear. Here, we report the discovery of a 1.5 h LPT, ASKAP J144834-685644, adding to the current sample of sources. ASKAP J144834-685644 is one of the very few LPTs that has been detected from X-rays to radio. It shows a steep radio spectrum and polarized radio bursts, which resemble the radio emission in known LPTs. In addition, it also shows highly structured and periodic narrow-band radio emission. Multiwavelength properties suggest that the spectral energy distribution (SED) peaks at near ultraviolet wavelengths, indicating the presence of a hot MAGNETic source. Combining multiwavelength information, we infer that ASKAP J144834-685644 may be a near edge-on MAGNETic white dwarf binary (MWD), although we cannot fully rule out ASKAP J144834-685644 being an isolated white dwarf pulsar or even a transitional millisecond pulsar (despite the lack of radio pulsations). If ASKAP J144834-685644 is a MWD binary, the observed broad-band SED can be explained by emission from an accretion disc. This hints that some fraction of optically bright LPTs may be accreting binaries with the radio period being the orbital period. It might further suggest a connection between optically bright synchronized WD binaries, such as polars, and non-accreting asynchronous WD pulsars, such as AR Sco and J1912-4410.

[abstract 22 / 28] (score: 2)
arXiv:2508.08234 [pdf, ps, other]

Title: Gravitational Waves from Strongly Magnetized Eccentric Neutron Star Binaries

Authors: R. Prasad, Anushka Doke, Prayush Kumar,

Comments:

Subjects: astro-ph.HE gr-qc

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

We study the imprint of MAGNETic fields on gravitational waves emitted during the inspiral phase of eccentric binary neutron star systems. While observations indicate that neutron stars typically exhibit strong MAGNETic fields in the range of $10^{14}$-$10^{15}\,\mathrm{G}$, theoretical models allow for fields as high as $ \sim 10^{17-18}\,\mathrm{G}$. In binaries, the fate of these fields depends on the formation pathway: in systems formed through isolated evolution, MAGNETic fields may decay over long inspiral timescales. In contrast, binaries formed via dynamical capture can retain substantial eccentricity and strong fields until merger, potentially altering the gravitational waveform. We consider two MAGNETic effects: MAGNETic interaction between the neutron stars and electroMAGNETic radiation from the system's effective dipole, and identify regimes where each dominates. Using a perturbative framework, we compute the associated energy loss and gravitational wave phase evolution. We find that for binaries with strong and comparable MAGNETic fields, $10^{14}\,\mathrm{G}$ fields may be detectable up to $\sim 10 \, \mathrm{Mpc}$ with DECIGO and the Einstein Telescope, while $10^{15}\,\mathrm{G}$ fields extend the reach to several hundred Mpc. For extreme fields of $10^{16}\,\mathrm{G}$, third-generation detectors could be sensitive out to Gpc scales. In contrast, LIGO (O5) is limited to galactic distances: $10^{15}\,\mathrm{G}$ fields are detectable only within $\sim 1\,\mathrm{Mpc}$, and only ultrastrong fields ($\sim 10^{16}$-$10^{17}\,\mathrm{G}$) are potentially observable to 700 Mpc. In highly asymmetric systems, where dipole radiation dominates, the gravitational wave dephasing is significantly suppressed, reducing the detection horizon. These findings suggest that current and future gravitational wave observatories may be capable of identifying MAGNETic effects in binaries.

[abstract 23 / 28] (score: 2)
arXiv:2509.13418 [pdf, ps, other]

Title: Modeling Cosmological Evolution of Jetted Seyfert Galaxies for z<10

Authors: Julianne Goddard, Isaac Shlosman, Emilio Romano-Diaz,

Comments: Accepted by ApJ. Figure 9 includes an animation in the publisher's version, it is not included here. 26 pages and 20 figures

Subjects: astro-ph.GA

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

We use high-resolution cosmological zoom-in simulations to model mechanical and thermal feedback from AGN onto the evolution of Seyfert-type galaxies, studying the morphology of central galaxies growing within DARK MATTER (DM) halos with masses logM/Mo ~11.8 at z=0. In Paper I, we focused on the end products at z=0, here we analyze evolution for z<10. Black holes (SMBHs) of ~10^6 Mo were seeded at z~9.1 and z~3.7, producing JETs along their spin axes. Obtained SMBH accretion rates vary in the range ~0.3-10^(-4) of the Eddington rate. We compared the basic properties of galaxies, such as STAR FORMATION rate, masses, gas and stellar fractions, bulge-to-disk mass ratios, SMBH masses, etc., over the range of redshifts. Our results indicate that JETs and associated over-pressured bubbles have substantial effects on Seyfert galaxy evolution, including properties of the interstellar and circumgalactic medium (ISM and CGM), and even beyond. This feedback can suppress and even quench STAR FORMATION, reduce stellar mass and gas fraction, modify the bulge-to-disk ratios, drive outflows from galaxies and host DM halos, and metal-enrich the CGM. The JETs are largely but not exclusively contained within galaxies. However, over-pressured bubbles cross and modify the composition of the CGM and IGM, their thermodynamic and dynamic state, and generate vorticity. The CGM emerges as a complex region, where action of galactic outflows and JET-formed bubbles combines with the influx from cosmological filaments and diffuse accretion. Ultimately, the above processes affect the gas balance within the galaxy, its morphology, and gas supply to the SMBH, limiting its growth.

[abstract 24 / 28] (score: 2)
arXiv:2509.13472 [pdf, ps, other]

Title: The effect of parameter drift in the transport of MAGNETized plasma particles

Authors: P. Haerter, R. L. Viana,

Comments:

Subjects: nlin.CD physics.plasm-ph

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

We investigate how time dependent modulations of drift wave amplitudes affect particle transport and chaos in a MAGNETized plasma. Using the Horton model, we apply a sawtooth ramp to a primary wave's amplitude and periodic rectangular kicks to secondary waves, simulating a driven system. Particle transport is quantified by the Mean Square Displacement (MSD) exponent, $α$, and chaos by the Maximum Lyapunov Exponent (MLE). Our primary finding is a strong negative correlation between the system's average chaoticity and its transport efficiency. We show that rapid sawtooth ramping (short period $τ$) produces highly efficient, superdiffusive transport ($α> 1$). In contrast, slower ramping increases the system's chaos but suppresses transport, driving it towards normal diffusion ($α\to 1$). This counter intuitive result demonstrates that heightened chaos destroys the coherent, streamer like structures necessary for superdiffusive flights. Our findings indicate that the coherence of the turbulent field, rather than its raw chaoticity, is the key determinant of transport efficiency, offering a new perspective on plasma control.

[abstract 25 / 28] (score: 2)
arXiv:2509.13530 [pdf, ps, other]

Title: Deep Extragalactic VIsible Legacy Survey (DEVILS): Galaxy group catalogue for the D10-COSMOS field with 90% spectroscopic redshift completeness

Authors: Matías Bravo, Luke J. M. Davies, Aaron S. G. Robotham, Claudia del P. Lagos, Sabine Bellstedt, Joss Bland-Hawthorn, Malgorzata Siudek, Trystan S. Lambert, Chris Power,

Comments: Submitted to ApJ. 15 pages, 9 figures. Comments are welcome!

Subjects: astro-ph.GA

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

Large-scale galaxy redshift surveys conducted over the last couple of decades have proven crucial in deepening our understanding of structure growth in the Universe and galaxy evolution. While there have been several such surveys, until now those that achieve the high completeness and precision necessary to probe the low-mass end of galaxy groups have been limited to relatively low redshifts ($z\lesssim0.3$), with surveys exploring the more distant Universe being constrained by small sample sizes and/or low redshift completeness. The recent Deep Extragalactic VIsible Legacy Survey (DEVILS) aims to explore galaxy environment over the last $\sim6$ Gyr with a completeness level comparable to the most complete local Universe surveys ($>85\%$). In this work, we present the galaxy group catalogue for the D10-COSMOS field from DEVILS, which achieves a redshift completeness of $90\%$ for galaxies with $Y<21.2$ mag. We showcase the science potential by exploring the impact of environment on the fraction and power of ACTIVE GALACTIC NUCLEi (AGN), finding that satellites in galaxy groups show no evidence of altered AGN properties, while satellites in clusters exhibit increased AGN fractions but decreased AGN luminosities.

[abstract 26 / 28] (score: 2)
arXiv:2509.13540 [pdf, ps, other]

Title: Dark matter annihilation signals from the Large Magellanic Cloud and its impact on the Milky Way

Authors: Evan Vienneau, Evan Batteas, Addy J. Evans, Odelia V. Hartl, Nassim Bozorgnia, Louis E. Strigari,

Comments:

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

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

We study the DARK MATTER (DM) annihilation signals from the Large Magellanic Cloud (LMC) and the impact of the LMC on the DM annihilation signals from the Milky Way (MW) halo, using a MW-LMC analogue from the Auriga MAGNETo-hydrodynamical simulations. We find that the gamma-ray signals from DM annihilation from the LMC rises above the MW foreground by a factor of greater than 100 for the s-wave velocity-independent annihilation model, as well as for the Sommerfeld, p-wave, and d-wave velocity-dependent models. We derive upper limits on the annihilation cross section of DM particles in the LMC using FERMI-LAT data for all velocity-dependent cross section models. Bounds for d-wave annihilation are more stringent by $\sim 4-6$ orders of magnitude relative to previous bounds from dwarf galaxies, and for p-wave emission our bounds are $\sim 2-3$ orders of magnitude more stringent. We also demonstrate that the impact of the LMC on the DM annihilation signals from the MW halo is greatest for the p-wave and d-wave models towards the outer MW halo, while the impact is minimal for Sommerfeld and s-wave models. The LMC boosts the DM density and velocity distribution in the outer MW halo, both by bringing in high-speed DM particles and by accelerating the DM particles of the MW, affecting the DM annihilation signals from the MW for the p-wave and d-wave models.

[abstract 27 / 28] (score: 2)
arXiv:2509.13593 [pdf, ps, other]

Title: DESI DR1 Ly$α$ 1D power spectrum: Validation of estimators

Authors: N. G. Karaçaylı, C. Ravoux, P. Martini, J. M. Le Goff, E. Armengaud, M. Abdul-Karim, J. Aguilar, S. Ahlen, A. Anand, S. BenZvi, D. Bianchi, D. Brooks, T. Claybaugh, A. Cuceu, A. de la Macorra, Biprateep Dey, P. Doel, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, G. Gutierrez, H. K. Herrera-Alcantar, K. Honscheid, M. Ishak, J. Jimenez, R. Joyce, D. Kirkby, T. Kisner, A. Kremin, O. Lahav, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, S. Nadathur, G. Niz, N. Palanque-Delabrouille, W. J. Percival, C. Poppett, F. Prada, I. Pérez-Ràfols, G. Rossi, E. Sanchez, D. Schlegel, M. Schubnell, H. Seo, J. Silber, D. Sprayberry, T. Tan, G. Tarlé, M. Walther, B. A. Weaver, H. Zou,

Comments: 30 pages, 12 figures

Subjects: astro-ph.CO

Created: 2025-09-16; Updated: 2025-09-18; Datestamp: 2025-09-18

The Data Release 1 (DR1) of the Dark Energy Spectroscopic Instrument (DESI) is the largest sample to date for small-scale Ly$α$ forest cosmology, accessed through its one-dimensional power spectrum ($P_{\mathrm{1D}}$). The Ly$α$ forest $P_{\mathrm{1D}}$ is extracted from QUASAR spectra that are highly inhomogeneous (both in wavelength and between QUASARs) in noise properties due to intrinsic properties of the QUASAR, atmospheric and astrophysical contamination, and also sensitive to low-level details of the spectral extraction pipeline. We employ two estimators in DR1 analysis to measure $P_{\mathrm{1D}}$: the optimal estimator and the fast Fourier transform (FFT) estimator. To ensure robustness of our DR1 measurements, we validate these two power spectrum and covariance matrix estimation methodologies against the challenging aspects of the data. First, using a set of 20 synthetic 1D realizations of DR1, we derive the masking bias corrections needed for the FFT estimator and the continuum fitting bias needed for both estimators. We demonstrate that both estimators, including their covariances, are unbiased with these corrections using the Kolmogorov-Smirnov test. Second, we substantially extend our previous suite of CCD image simulations to include 675,000 QUASARs, allowing us to accurately quantify the pipeline's performance. This set of simulations reveals biases at the highest $k$ values, corresponding to a resolution error of a few percent. We base the resolution systematics error budget of DR1 $P_{\mathrm{1D}}$ on these values, but do not derive corrections from them since the simulation fidelity is insufficient for precise corrections.

[abstract 28 / 28] (score: 2)
arXiv:2509.14214 [pdf, ps, other]

Title: Time-of-flight Energy Measurements with BPMs

Authors: A. Shemyakin, J. Kuharik, R. Sharankova,

Comments: 2025 North American Particle Accelerator Conference

Subjects: physics.acc-ph

Created: 2025-09-17; Updated: 2025-09-18; Datestamp: 2025-09-18

The energy of a bunched non-RELATIVISTIC ion beam can be deduced from measuring the beam phases in neighbouring Beam Position Monitors (BPMs). This report discusses implementation of such a procedure at the PIP-II H- linac being constructed at FERMIlab. The case when the flight time between BPMs is longer than the period of BPM frequency is considered in more detail. When absolute BPM phase calibration is not available, the BPM phase information can be used to track deviations of the beam energy from the de-sired value. Such "energy deviation" parameter is operationally implemented at the transfer line between 400 MeV Linac and the Booster, and its analog is expected to be used in the transfer line from PIP-II as well.