Peer Revenue Past citations are no guarantee of future returns

Papers

Fresh from arXiv, typeset properly. Highlighted words trade on the market.

Physics Astrophysics

astro-ph Watch Astrophysics

Thursday 18 December

Earth and Planetary Astrophysics

N-body interactions and collisions in circumstellar disks for planar and inclined binary star configurations

Maximilian Zimmermann and Elke Pilat-Lohinger

The discovery of exoplanets in binary star systems-now numbering about 850 of the nearly 4,600 known exoplanet systems-raises questions about whether observational bias or stellar companions inhibit planet formation. While most studies on terrestrial planet formation assume planar configurations, wide binaries likely feature random inclinations, potentially disrupting planet-forming disks. This study explores the evolution of embryo-planetesimal disks in S-type motion in misaligned binary systems, focusing on the stage after the gas phase when terrestrial planet formation begins and gravitational interactions dominate. Using our GPU-accelerated N-body code GANBISS, we simulate disks with 2,000 planetesimals and 25 planetary embryos, studying the influence of the planetesimals on the evolution of the embryos and tracking their growth through collisions. After the simulations, we analyse collision outcomes with an analytical model. Moreover, for certain inclined binary configurations, we compare dynamically excited (perturbed by the secondary star) with cold disks in inclined configurations, as the distribution after the gas phase in misaligned binaries remains unclear. Our simulations reveal two key outcomes: (i) embryos migrate slightly inward in misaligned systems, and (ii) The initial large oscillations in embryos' inclinations and nodes around the respective values of the secondary star dampen over time. Collision analysis shows distinct differences: planar systems favour accretive collisions, while inclined configurations exhibit more destructive events. These findings underscore the sensitivity of planet formation dynamics to binary star alignment and initial disk conditions.
Read the full abstract

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

On Non-Minimal Couplings to Gravity and Axion Isocurvature Bounds

Claire Rigouzzo and Sebastian Zell

For axions present during inflation, it has been shown that a non-minimal coupling $\xi_\sigma$ of the inflaton to gravity worsens isocurvature bounds, while a non-minimal coupling $\xi_\rho$ of the radial Peccei-Quinn field can alleviate them. We analyze the simultaneous presence of both couplings and determine when one effect dominates the other, in both the metric and Palatini formulations of gravity. The two tendencies interpolate smoothly, but introducing a non-minimal inflaton coupling reduces the viable interval of $\xi_\rho$ in which isocurvature bounds can be alleviated while avoiding backreaction on the inflationary dynamics. We illustrate our findings in Palatini Higgs inflation and Starobinsky inflation.
Read the full abstract

Instrumentation and Methods for Astrophysics

The WINTER Observatory: A One-Degree InGaAs Survey Camera to study the Transient Infrared Sky

Danielle Frostig, Nathan Lourie, Viraj Karambelkar et al. (+20 more)

The Wide-field Infrared Transient Explorer (WINTER) is a near-infrared time-domain survey instrument operating on a dedicated 1-meter robotic telescope at Palomar Observatory. The project takes advantage of recent technology advances in time-domain astronomy, robotic telescopes, large-format sensors, and rapid data reduction and alert software for timely follow up of events. Since June of 2023, WINTER robotically surveys the sky each night to a median depth of J_AB = 18.5 mag, balancing a variety of science programs including searching for kilonovae from gravitational-wave alerts, blind surveys to study galactic and extragalactic transients and variables, and building up reference images of the near-infrared sky. The project also serves as a technology demonstration for new large-format Indium Gallium Arsenide (InGaAs) sensors for wide-field science in the near infrared without cryogenically cooled optics or detectors. WINTER's custom camera combines six InGaAs sensors with a novel tiled fly's-eye optical design to cover a >1 deg^2 field of view with 1 arcsecond pixels in the Y-, J-, and shortened-H-band filters (0.9 - 1.7 micron). This paper presents the design, performance, and early on-sky science of the WINTER observatory.
Read the full abstract

All authors Danielle Frostig, Nathan Lourie, Viraj Karambelkar, Mansi M. Kasliwal, Andrew Malonis, Robert A. Simcoe, Robert Stein, John W. Baker, Kevin Burdge, Rick Burruss, Curt Corcoran, Kishalay De, Gabor Furesz, Nicolae Ganciu, Kari Haworth, Carolyn M. Heffner, Erik Hinrichsen, Jill Juneau, Geoffrey Mo, Josiah Purdum, Sam Rose, Cruz Soto, Jeffry Zolkower

Cosmology and Nongalactic Astrophysics

Probing the sensitivity of dark energy dynamics to equation of state parametrization flexibility

Md. Wali Hossain

Allowing for greater low redshift flexibility through parametrizations such as CPL can lead to apparent deviations from $\Lambda$CDM. This motivates an investigation into whether such deviations reflect genuine dynamical dark energy or arise from parametrization choices. We investigate several dark energy parametrizations, including two phenomenological power law type extensions proposed here, the power law and modified power law forms, which allow greater low redshift flexibility (around $z \sim 1$) than CPL. Parametrizations permitting stronger evolution of the equation of state can exhibit enhanced phantom like behaviour at intermediate redshifts, but this feature is sensitive to the assumed functional form and its extrapolation. The statistical preference for such behaviour is modest, depends on the supernova sample, and is consistent across parametrizations, in agreement with recent analyses. The likelihood-ratio significance of this preference is $2.2$–$3.9\sigma$. Owing to limited data at $z > 2$, this is primarily driven by the equation of state in the range $1 \leq z \leq 2$, where parametrizations with enhanced flexibility, such as power law type forms, mildly improve the fit. The Akaike Information Criterion favours the DDE parametrizations over $\Lambda$CDM for all three supernova samples. The Bayesian Information Criterion mildly favours them for $+$Union3 and $+$DESY5 but disfavours them for $+$PantheonPlus.
Read the full abstract

Astrophysics of Galaxies

A faint M$_{\rm UV} = -14.5$ Lyman-continuum leaker candidate in the epoch of reionization: Unprecedented Ly$\alpha$ properties at z=5.725

M. Messa, E. Vanzella, T. Morishita et al. (+10 more)

We report the unprecedented Ly$\alpha$ properties of AMORE6, an extremely metal-poor ($12+\log({\rm O/H}) < 6$), low-mass ($M_\star = 4.4\times10^{5}\,M_\odot$), and ultracompact (effective radius $\sim30$ pc) dwarf galaxy at $z=5.7253$, which is gravitationally lensed by the cluster A2744. A prominent, narrow, and nearly symmetric Ly$\alpha$ emission line is detected at the systemic redshift (the latter traced by H$\beta$, from JWST/NIRCam slitless spectroscopy), with a rest-frame equivalent width of $150 \pm 10$ Å, a full width at half maximum of $\rm 58\pm1$ km s$^{-1}$, and a slight asymmetry, resulting in a flux excess of $\rm \sim10\%$ in the red wing of the line. The negligible velocity offset from systemic ($dv = 4\pm67$ km s$^{-1}$, $3\sigma$ uncertainty), together with the sharpness and symmetry of the profile, indicates minimum radiative transfer effects, which implies a neutral hydrogen column density consistent with an optically thin medium that in turn is compatible with a nonzero ionizing photon escape fraction. If indirect spectral diagnostics calibrated at $z<4.5$ remain the only viable tools for identifying LyC leakers during reionization, then based on its strongest indicator (Ly$\alpha$), AMORE6 stands out as one of the most compelling LyC-leaking candidates yet discovered in the epoch of reionization.
Read the full abstract

All authors M. Messa, E. Vanzella, T. Morishita, M. Stiavelli, T. Treu, P. Bergamini, Z. Liu, A. Zanella, A. Bolamperti, A. Verhamme, T. Garel, C. Grillo, P. Rosati

High Energy Astrophysical Phenomena

A finite temperature framework for quark matter with color-superconducting phases

Hosein Gholami, Marco Hofmann, Débora Mroczek et al. (+1 more)

Current observations of neutron stars and measurements of gravitational waves only provide constraints on the zero temperature ($T=0$) equation of state (EoS) of dense matter. The detection of the post-merger gravitational-wave signal from a binary neutron star merger would additionally provide access to finite-temperature properties of the EoS which contain more information about the composition and the interactions of dense matter than the cold EoS alone. In particular deconfined quark matter may be probed by its characteristic finite temperature effects. This is especially the case for color-superconducting phases, in which the quasiparticle contribution to the thermal pressure is exponentially suppressed at low temperatures. Here we develop a new finite $T$ framework to model the thermal EoS for dense quark matter based on the cold quark matter EoS which is useful for numerical relativity simulations. We test the validity of the framework against a three-flavor NJL mean-field calculation, both with and without diquark pairing. We find that even for the complicated phase diagram of the NJL model including multiple different phases the framework is accurate to the few percent level for temperatures up to $T\sim 50\,$MeV.
Read the full abstract

All authors Hosein Gholami, Marco Hofmann, Débora Mroczek, Jacquelyn Noronha-Hostler

Earth and Planetary Astrophysics

Evidence of Possible Spectral Variability in the Patroclus-Menoetius Binary System

Ian Wong, William M. Grundy, Joshua P. Emery et al. (+5 more)

We present new visible-wavelength spectroscopic observations of the Patroclus-Menoetius binary system in the Jupiter Trojan population. Motivated by previously published spectra from different instruments that showed evidence of significant longitudinal variability, we obtained two spectra spanning 440-680 nm at near-opposite rotational phases with the Gemini Multi-Object Spectrograph on the Gemini South telescope during the late 2024 apparition. The same solar analog was used for both observations to remove one source of inconsistency. We measured spectral slopes of 2.51% $\pm$ 0.05%/100 nm and 8.13% $\pm$ 0.05%/100 nm at the two different rotational phases. The first of these measurements was serendipitously obtained during an occultation of Menoetius by Patroclus. Although the statistical significance of the spectral slope discrepancy persists even after considering possible systematic errors stemming from differences in slit position angles and air masses between the asteroid and solar analog exposures, we consider this report of variability to be tentative. We briefly explore several scenarios that could explain the measured spectral slope variability. Additional follow-up observations are necessary to definitively confirm and characterize any inhomogeneities across the surface, which will have major implications for the 2033 flyby of Patroclus-Menoetius by the Lucy spacecraft.
Read the full abstract

All authors Ian Wong, William M. Grundy, Joshua P. Emery, Richard P. Binzel, Oriel A. Humes, Simone Marchi, Pippa M. Molyneux, Keith S. Noll

High Energy Astrophysical Phenomena

Multiwavelength identification of millisecond pulsar candidates in the Galactic bulge

J. Berteaud, F. Calore, M. Clavel et al. (+4 more)

The existence of a population of millisecond pulsars in the Galactic bulge is supported, along with other evidence, by the Fermi GeV excess, an anomalous {\gamma}-ray emission detected almost 15 years ago in the direction of the Galactic center. However, radio surveys searching for pulsations have not yet revealed bulge millisecond pulsars. Identifying promising bulge millisecond pulsar candidates is key to motivating pointed radio pulsation searches. Candidates are often selected among steep-spectrum or polarized radio sources, but multiwavelength information can also be exploited: The aim of this work is to pinpoint strong candidates among the yet unidentified X-ray sources. We investigated the multiwavelength counterparts of sources detected by the Chandra X-ray observatory that have spectral properties expected for millisecond pulsars in the Galactic bulge. We considered that ultraviolet, optical, and strong infrared counterparts indicate that an X-ray source is not a bulge pulsar, while a radio or a faint infrared counterpart makes it a promising candidate. We identify a large population of more than a thousand X-ray sources without optical, ultraviolet, or strong infrared counterparts. Among them, five are seen for the first time in unpublished radio imaging data from the Very Large Array. We provide the list of promising candidates, for most of which follow-up pulsation searches are ongoing.
Read the full abstract

All authors J. Berteaud, F. Calore, M. Clavel, J. Marvil, S. Hyman, F. K. Schinzel, M. Kerr

Instrumentation and Methods for Astrophysics

Simulation-based inference with neural posterior estimation applied to X-ray spectral fitting – III Deriving exact posteriors with dimension reduction and importance sampling

Didier Barret and Simon Dupourqué

Simulation-based inference (SBI) with neural posterior estimation (NPE) provides rapid X-ray spectral fitting in both Gaussian and Poisson regimes by learning approximate parameter posteriors from simulations. We investigate auto-encoders for compressing high-resolution X-ray spectra, motivated by newAthena X-ray Integral Field Unit (X-IFU), and use likelihood-based importance sampling to refine NPE outputs. Our auto-encoder maps spectra to a low-dimensional latent space and is trained with a custom loss equal to the Cash statistic (C-stat) between simulated and reconstructed spectra. A neural density estimator is then trained on the latent representations. Both models are trained in multiple rounds: at each round, new simulations are drawn from a truncated proposal concentrated around the observation, improving efficiency as the proposal contracts. After NPE convergence, we apply likelihood-based importance sampling to correct the learned posterior. To assess information retention, we train a diagnostic network that predicts the original spectral parameters from the latent space, and we also train a network to learn the likelihood directly to accelerate importance sampling. On X-IFU-like simulations, the auto-encoder and multi-round NPE outperforms PCA and hand-crafted spectral summaries in accuracy and robustness. After importance sampling, the resulting posteriors are statistically indistinguishable from those obtained with nested sampling. On a standard laptop, the full pipeline (simulation, compression, inference, correction) delivers 10x speedups. We further demonstrate the approach on XRISM/Resolve and on lower-resolution NICER and XMM-Newton EPIC-pn data, confirming applicability across instruments and resolutions. Overall, NPE on compressed spectra paired with likelihood-based importance sampling offers an exact yet efficient alternative for Bayesian X-ray spectral fitting.
Read the full abstract

Astrophysics of Galaxies

On the Origin of Kinematic Structure in the Young Association Serpens OB2

Michael A. Kuhn, Robert A. Benjamin and Simran S. Singh

The Serpens OB2 association (l ~ 18.5 deg, b ~ 1.9 deg, d = 1950 +/- 30 pc) is a large star-forming complex ~65 pc above the Galactic midplane, with a clumpy, elongated structure extending ~50 pc parallel to the plane. We analyse probable association members, including OB stars and low-to-intermediate-mass young stellar objects (YSOs) from the SPICY catalogue. We use 13CO MWISP data to trace the molecular clouds. The OB stars are concentrated toward the centre of the association, coincident with a gap in the molecular clouds, and toward the side nearest the Galactic plane. The YSOs are distributed throughout the association, but cluster around molecular-cloud clumps. Using Gaia DR3 proper motions to probe the association's internal kinematics, we find aligned stellar velocities on length scales <2 pc, two-point statistics that show increasing velocity differences and predominantly divergent motions at larger separations, and distinct velocities for star clusters within the association. Finally, the association exhibits gradual but statistically significant global expansion perpendicular to the Galactic plane, with a spatial gradient of 0.10 +/- 0.02 km/s/pc. The clumpy stellar distribution, correlated velocities on small scales, and increasingly divergent motions on larger scales are consistent with an initial velocity field inherited from a turbulent molecular cloud modified by stellar feedback. The global vertical expansion may arise from large-scale turbulence or feedback-driven shell expansion, with the H II region Sh 2-54 preferentially pushing the molecular gas away from the Galactic plane. Ser OB2 demonstrates that the multi-scale expansion of an OB association can begin even while star formation is still ongoing throughout the complex.
Read the full abstract

High Energy Astrophysical Phenomena

Discovery of two new millisecond pulsars towards the Galactic bulge

J. Berteaud, F. Calore, M. Clavel et al. (+13 more)

The mysterious Galactic Center Excess of gamma rays could be explained by a large population of millisecond pulsars hiding in the Galactic bulge, too faint to be detected as individual high-energy point sources by the Fermi Large Area Telescope, as well as too fast and too dispersed to be detected in shallow radio pulsation surveys. Motivated by an innovative candidate selection method, we aim at detecting millisecond pulsars associated with the Galactic Center Excess by carrying deep radio pulsation searches towards promising candidates detected in the inner Galaxy, in X rays by Chandra, and in radio or gamma rays by the Very Large Array or Fermi. We conducted deep radio observation and follow-up campaigns with MeerKAT, the Murriyang and the Green Bank telescopes towards 9 X-ray candidate sources. We here report the detection of two new millisecond pulsars, including a black widow candidate, towards the Galactic bulge: PSRs J1740-2805 and J1740-28. These discoveries double the number of MSPs discovered within the innermost 2 degree from the Galactic center.
Read the full abstract

All authors J. Berteaud, F. Calore, M. Clavel, S. Dai, J.S. Deneva, S. Hyman, F.K. Schinzel, A. Ridolfi, S.M. Ransom, F. Abbate, C.J. Clark, M. Kramer, T. Thongmeearkom, B.W. Stappers, E.D. Barr, R.P. Breton

Earth and Planetary Astrophysics

Comparison of General Circulation Models of the Venus upper atmosphere

Antoine Martinez, Hiroki Karyu, Amanda Brecht et al. (+7 more)

In the context of future Venusian missions, it is crucial to improve our understanding of Venus upper atmosphere through 3D modeling, notably for spacecraft orbit computation. This study compares three General Circulation Models (GCMs) of the Venusian atmosphere up to the exosphere: the Venus Planetary Climate Model (Venus PCM), the Venus Thermospheric Global Model (VTGCM) and the Tohoku University GCM (TUGCM), focusing on their nominal simulations (e.g. composition, thermal structure and heating/cooling rates). Similarities and discrepancies among them are discussed in this paper, together with data-models comparison. The nominal simulations analyzed in this study fail to accurately reproduce the daytime observations of Pioneer Venus, notably overestimating the exospheric temperature. This is linked to an underestimation of the atomic oxygen (O) abundance in the three GCMs, and suggests the need of additional O production in the thermosphere. The selection of solar spectrum is also the main reason for the discrepancies between the models in terms of temperature dependence on solar activity. A list of recommendations is proposed aiming at improving the modeling of Venus' upper atmosphere, among them: 1. Standardize the EUV-UV solar spectrum input. 2. Update the near-infrared heating scheme with Venus Express-Era data. 3. Reassess Radiative cooling schemes. 4. Investigate the underestimated atomic Oxygen abundance.
Read the full abstract

All authors Antoine Martinez, Hiroki Karyu, Amanda Brecht, Gabriella Gilli, Sebastien Lebonnois, Takeshi Kuroda, Aurelien Stolzenbach, Francisco Gonzalez Galindo, Stephen Bougher, Hitoshi Fujiwara

High Energy Astrophysical Phenomena

Einstein Probe Discovery of an X-ray Flare from K-type Star PM J23221-0301

Guoying Zhao, WeiKang Zheng, Rong-Feng Shen et al. (+21 more)

Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily concentrated in the optical and X-ray bands, with the X-ray flux potentially increasing by tens or even hundreds of times. Einstein Probe (EP) detected a new X-ray transient EP J2322.1-0301 on 27 September 2024. Its spatial localization shows a high positional coincidence with the nearby high proper motion K-type star PM J23221-0301. Follow-up X-ray observations confirmed the flux enhancement of the source, while optical spectroscopic monitoring revealed time-variable features, particularly the disappearance of the H-alpha emission line. This X-ray flare is consistent with a characteristic fast-rise-exponential-decay (FRED) light curve, with a rise timescale of 1.4 ks, a decay timescale of 5.7 ks, and a total duration of about 7.1 ks. The peak luminosity in the 0.5-4.0 keV energy band reached about 1.3 x 10^31 erg s^-1, with a total energy release of about 9.1 x 10^34 erg, consistent with the empirical energy correlations observed in magnetic-reconnection-driven stellar flares, as inferred from the multitemperature plasma structure and H-alpha-X-ray energy correlation. This discovery underscores EP's capability in understanding stellar magnetic activity via observing stellar transients.
Read the full abstract

All authors Guoying Zhao, WeiKang Zheng, Rong-Feng Shen, Qingcang Shui, Dongyue Li, Chang Zhou, Tianci Zheng, Weimin Yuan, HeYang Liu, Chong Ge, Junfeng Wang, Alexei V. Filippenko, Thomas G. Brink, Jordan Forman, Mayra Gutierrez, Isabelle Jones, Ravjit Kaur, Naunet Leonhardes-Barboza, Petra Mengistu, Avi Patel, Andrew Skemer, Anavi Uppal, Nicole Wolff, Michele N. Woodland

Solar and Stellar Astrophysics

The Preliminary Mauve Science Programme: Science themes identified for the first year of operations

Mauve Science Collaboration - Year 1:, Marcel Agueros, Don Dixon et al. (+22 more)

Mauve is a low-cost small satellite developed and operated by Blue Skies Space Ltd. The payload features a 13 cm telescope connected with a fibre that feeds into a UV-Vis spectrometer. The detector covers the 200-700 nm range in a single shot, obtaining low resolution spectra at R~20-65. Mauve has launched on 28th November 2025, reaching a 510 km Low-Earth Sun-synchronous orbit. The satellite will enable UV and visible observations of a variety of stellar objects in our Galaxy, filling the gaps in the ultraviolet space-based data. The researchers that have already joined the mission have defined the science themes, observational strategy and targets that Mauve will observe in the first year of operations. To date 10 science themes have been developed by the Mauve science collaboration for year 1, with observational strategies that include both long duration monitoring and short cadence snapshots. Here, we describe these themes and the science that Mauve will undertake in its first year of operations.
Read the full abstract

All authors Mauve Science Collaboration - Year 1:, Marcel Agueros, Don Dixon, Chuanfei Dong, Girish M. Duvvuri, Patrick Flanagan, Christopher Johns-Krull, Hongpeng Lu, Hiroyuki Maehara, Kosuke Namekata, Alejandro Nunez, Elena Pancino, Sharmila Rani, Anusha Ravikumar, T. A. A. Sigut, Keivan Stassun, Jamie Stewart, Krisztián Vida, Emma Whelan, Benjamin Wilcock, Sharafina Razin, Arianna Saba, Giovanna Tinetti, Marcell Tessenyi, Jonathan Tennyson

High Energy Astrophysical Phenomena

Cygnus X-3: A variable petaelectronvolt gamma-ray source

The LHAASO Collaboration, Zhen Cao, F. Aharonian et al. (+328 more)

We report the discovery of variable $\gamma$-rays up to petaelectronvolt from Cygnus X-3, an iconic X-ray binary. The $\gamma$-ray signal was detected with a statistical significance of approximately 10 $\sigma$ by the Large High Altitude Air Shower Observatory (LHAASO). Its intrinsic spectral energy distribution (SED), extending from 0.06 to 3.7 PeV, shows a pronounced rise toward 1 PeV after accounting for absorption by the cosmic microwave background radiation. We find variability on month-long timescales at a significance of $8.6 \sigma$, coinciding with a high state of the GeV gamma-ray flux detected by the Fermi-LAT. This,together with a 3.2$\sigma$ evidence for orbital modulation, suggests that the PeV $\gamma$-rays originate within, or in close proximity to, the binary system itself. The observed energy spectrum and temporal modulation can be naturally explained by $\gamma$-ray production through photomeson processes in the innermost region of the relativistic jet, where protons need to be accelerated to tens of PeV energies.
Read the full abstract

All authors The LHAASO Collaboration, Zhen Cao, F. Aharonian, Y.X. Bai, Y.W. Bao, D. Bastieri, X.J. Bi, Y.J. Bi, W. Bian, J. Blunier, A.V. Bukevich, C.M. Cai, Y.Y. Cai, W.Y. Cao, Zhe Cao, J. Chang, J.F. Chang, E.S. Chen, G.H. Chen, H.K. Chen, L.F. Chen, Liang Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, X.B. Chen, X.J. Chen, X.P. Chen, Y. Chen, N. Cheng, Q.Y. Cheng, Y.D. Cheng, M.Y. Cui, S.W. Cui, X.H. Cui, Y.D. Cui, B.Z. Dai, H.L. Dai, Z.G. Dai, Danzengluobu, Y.X. Diao, A.J. Dong, X.Q. Dong, K.K. Duan, J.H. Fan, Y.Z. Fan, J. Fang, J.H. Fang, K. Fang, C.F. Feng, H. Feng, L. Feng, S.H. Feng, X.T. Feng, Y. Feng, Y.L. Feng, S. Gabici, B. Gao, Q. Gao, W. Gao, W.K. Gao, M.M. Ge, T.T. Ge, L.S. Geng, G. Giacinti, G.H. Gong, Q.B. Gou, M.H. Gu, F.L. Guo, J. Guo, K.J. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Guo, R.P. Han, O.A. Hannuksela, M. Hasan, H.H. He, H.N. He, J.Y. He, X.Y. He, Y. He, S. Hernández-Cadena, B.W. Hou, C. Hou, X. Hou, H.B. Hu, S.C. Hu, C. Huang, D.H. Huang, J.J. Huang, X.L. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Y.Y. Huang, A. Inventar, X.L. Ji, H.Y. Jia, K. Jia, H.B. Jiang, K. Jiang, X.W. Jiang, Z.J. Jiang, M. Jin, S. Kaci, M.M. Kang, I. Karpikov, D. Khangulyan, D. Kuleshov, K. Kurinov, Cheng Li, Cong Li, D. Li, F. Li, H.B. Li, H.C. Li, Jian Li, Jie Li, K. Li, L. Li, R.L. Li, S.D. Li, T.Y. Li, W.L. Li, X.R. Li, Xin Li, Y. Li, Zhe Li, Zhuo Li, E.W. Liang, Y.F. Liang, S.J. Lin, B. Liu, C. Liu, D. Liu, D.B. Liu, H. Liu, J. Liu, J.L. Liu, J.R. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, X. Liu, Y. Liu, Y. Liu, Y.N. Liu, Y.Q. Lou, Q. Luo, Y. Luo, H.K. Lv, B.Q. Ma, L.L. Ma, X.H. Ma, I.O. Maliy, J.R. Mao, Z. Min, W. Mitthumsiri, Y. Mizuno, G.B. Mou, A. Neronov, K.C.Y. Ng, M.Y. Ni, L. Nie, L.J. Ou, Z.W. Ou, P. Pattarakijwanich, Z.Y. Pei, D.Y. Peng, J.C. Qi, M.Y. Qi, J.J. Qin, D. Qu, A. Raza, C.Y. Ren, D. Ruffolo, A. Sáiz, D. Savchenko, D. Semikoz, L. Shao, O. Shchegolev, Y.Z. Shen, X.D. Sheng, Z.D. Shi, F.W. Shu, H.C. Song, Yu.V. Stenkin, V. Stepanov, Y. Su, D.X. Sun, H. Sun, J.X. Sun, Q.N. Sun, X.N. Sun, Z.B. Sun, N.H. Tabasam, J. Takata, P.H.T. Tam, H.B. Tan, Q.W. Tang, R. Tang, Z.B. Tang, W.W. Tian, C.N. Tong, L.H. Wan, C. Wang, D.H. Wang, G.W. Wang, H.G. Wang, J.C. Wang, K. Wang, Kai Wang, Kai Wang, L.P. Wang, L.Y. Wang, L.Y. Wang, R. Wang, W. Wang, X.G. Wang, X.J. Wang, X.Y. Wang, Y. Wang, Y.D. Wang, Z.H. Wang, Z.X. Wang, Zheng Wang, D.M. Wei, J.J. Wei, Y.J. Wei, T. Wen, S.S. Weng, C.Y. Wu, H.R. Wu, Q.W. Wu, S. Wu, X.F. Wu, Y.S. Wu, S.Q. Xi, J. Xia, J.J. Xia, G.M. Xiang, D.X. Xiao, G. Xiao, Y.F. Xiao, Y.L. Xin, H.D. Xing, Y. Xing, D.R. Xiong, B.N. Xu, C.Y. Xu, D.L. Xu, R.F. Xu, R.X. Xu, S.S. Xu, W.L. Xu, L. Xue, D.H. Yan, T. Yan, C.W. Yang, C.Y. Yang, F.F. Yang, L.L. Yang, M.J. Yang, R.Z. Yang, W.X. Yang, Z.H. Yang, Z.G. Yao, X.A. Ye, L.Q. Yin, N. Yin, X.H. You, Z.Y. You, Q. Yuan, H. Yue, H.D. Zeng, T.X. Zeng, W. Zeng, X.T. Zeng, M. Zha, B.B. Zhang, B.T. Zhang, C. Zhang, H. Zhang, H.M. Zhang, H.Y. Zhang, J.L. Zhang, J.Y. Zhang, Li Zhang, P.F. Zhang, R. Zhang, S.R. Zhang, S.S. Zhang, S.Y. Zhang, W. Zhang, W.Y. Zhang, X. Zhang, X.P. Zhang, Yi Zhang, Yong Zhang, Z.P. Zhang, J. Zhao, L. Zhao, L.Z. Zhao, S.P. Zhao, X.H. Zhao, Z.H. Zhao, F. Zheng, T.C. Zheng, B. Zhou, H. Zhou, J.N. Zhou, M. Zhou, P. Zhou, R. Zhou, X.X. Zhou, X.X. Zhou, B.Y. Zhu, C.G. Zhu, F.R. Zhu, H. Zhu, K.J. Zhu, Y.C. Zou, X. Zuo, J.S.Wang

High Energy Astrophysical Phenomena · Cross-listed from physics.plasm-ph

Photon Accelerator in Magnetized Electron-Ion Plasma

Sergei Bulanov, Stepan Bulanov, Timur Esirkepov et al. (+6 more)

Strong magnetic fields and plasmas are intrinsically linked in both terrestrial laboratory experiments and in space phenomena. One of the most profound consequences of that is the change in relationship between the frequency and the wave number of electromagnetic waves propagating in plasma in the presence of such magnetic fields when compared to the case without these fields. Furthermore, magnetic fields alter electromagnetic wave interaction with relativistic plasma waves, resulting in different outcomes for particle and radiation generation. For a relativistic plasma wave-based photon acceleration this leads to an increased frequency gain, and, thus, potentially to higher efficiency. The influence of a magnetic field leads to quantitative and qualitative change in the properties of photon acceleration, amplifying the increase in the electromagnetic wave frequency.
Read the full abstract

All authors Sergei Bulanov, Stepan Bulanov, Timur Esirkepov, Gianluca Gregori, Gabriele Grittani, Marcel Lamač, Brandon Russell, Alec Thomas, Petr Valenta

Astrophysics of Galaxies

The high-redshift radio galaxy 3C 294 at low frequencies: radio detection of the X-ray Ghost

Vijay H. Mahatma, Andrew C. Fabian and Leah K. Morabito

We report on the very first radio detection associated with the peculiar hourglass-morphology X-rays surrounding 3C 294 at z=1.8. Using International Low Frequency Array (LOFAR) data at 144 MHz and Chandra data at 0.3-6 keV, we find that the co-spatial diffuse radio and X-ray emission is well described by synchrotron and inverse-Compton processes by the same electron population. Through modelling of this rare low-energy plasma, we find that the most defining property of the electrons up-scattering CMB photons at this redshift is very low electron Lorentz factors ($\gamma_{\text{max}}\ll 10^{4}$ and $\gamma_{\text{break}}\lesssim 10^{3}$) in the lobe: deep low frequency (<150 MHz) observations are critical to the detection of radio lobes at high redshift. The physical conditions imply a total energy in the diffuse emission significantly greater than that implied by the temperature of the protocluster gas: 3C 294 is one of the most powerful known radio-loud systems in a dense protocluster environment. Through resolved spectral analysis of archival radio data up to 15 GHz, we find evidence that the inner hotspots are due to restarted activity, while the outer hotspots remain energetic, suggesting a rapid duty cycle while the jet precesses. This allowed the low-energy aged plasma driving the X-rays to remain spatially distinct from the high-energy plasma. Together, our results promise a revelation of AGN-related radio emission at high redshift using future low-frequency arrays such as SKA-LOW.
Read the full abstract

Earth and Planetary Astrophysics

Observing spatial and temporal variations in the atmospheric chemistry of rocky exoplanets: prospects for mid-infrared spectroscopy

Marrick Braam and Daniel Angerhausen

Future telescopes such as the Large Interferometer For Exoplanets (LIFE) will enable mid-infrared characterisation of the atmospheres of nearby rocky exoplanets. Whilst 4D spatial and temporal variations of Earth as an exoplanet are below spectroscopic detection limits, such variability is planet-specific. We investigate LIFE's ability to detect 4D variability in the atmospheres of tidally locked exoplanets. We create daily synthetic LIFE observations of Proxima Centauri b in a 1:1 and an eccentric 3:2 spin-orbit resonance (SOR), using LIFEsim on spectra from daily 3D climate-chemistry model output of an aquaplanet with Earth-like composition. Hemispheric distributions of temperature, clouds, and chemical species determine spectral signatures and variability with orbital phase angle. Such variability dictates the extent to which parameters can be reliably inferred from snapshot spectra at arbitrary viewing geometries. In the 1:1 SOR, MIR spectra vary significantly with viewing geometry and indirectly probe atmospheric circulation. Nightside temperature inversions generate O3, CO2, and H2O emission features, though these lie below LIFE's detection threshold, and instead O3 features disappear at certain phase angles. In contrast, the 3:2 SOR yields a more homogeneous atmosphere with weaker phase variability but enhanced bolometric flux due to eccentric heating. Phase-resolved LIFE observations confidently distinguish between the SORs and capture seasonal O3 variability for golden targets like Proxima Centauri b. In case of abiotic O2/O3 build-up, the O3 variability presents a potential false positive scenario. Hence, LIFE can disentangle different spin-orbit states and resolve 4D atmospheric variability, enabling daily characterisation of the 4D physical and chemical state of nearby terrestrial worlds. Importantly, this characterisation requires phase-resolved rather than snapshot spectra.
Read the full abstract

Earth and Planetary Astrophysics

Closed Form Expressions for the Potentials and Accelerations of Generalized Ring Models

Zachary Murray

We present several closed-form expressions of useful mass distributions. These include the potentials and accelerations of circular rings and arcs, the potentials of uniform density rings and arcs at arbitrary eccentricities, and the potentials and accelerations of rings and arcs when the mass is time-averaged over a Kepler orbit. We show that these expressions can be expressed, often simply, in terms of elliptic functions of complex arguments. We show that in a few limiting cases, the expressions are entirely real. We expect that these expressions will allow for more rapid modeling in many areas of celestial mechanics.
Read the full abstract

Cosmology and Nongalactic Astrophysics

An effective $\boldsymbol{\Lambda}$-Szekeres modelling of the local Universe with Cosmicflows-4

Marco Galoppo, Leonardo Giani, Morag Hills et al. (+1 more)

We develop an effective description of the local cosmic environment, namely, for redshift $z \lesssim 0.1$, to quantify the bias induced by local structure on cosmological observables. Our approach models the metric of the nearby Universe as a superposition of multi-structured $\Lambda$-Szekeres patches, calibrated against the HAMLET peculiar velocity and density field reconstructions of Cosmicflows-4. From this framework we compute the fully inhomogeneous and anisotropic quasilocal expansion field predicted by our model, and use it to assess the impact of local structure on estimates of $H_0$. For this purpose we analyse low-redshift Type Ia supernovae from the Pantheon+ catalogue. We find that accounting for the local structure increases the Hubble tension, yielding a shift in the best-fit value of the Hubble constant of order $\Delta H_0 \approx 0.5\ \mathrm{km\,s^{-1}Mpc^{-1}}$.
Read the full abstract

All authors Marco Galoppo, Leonardo Giani, Morag Hills, Aurélien Valade

Astrophysics of Galaxies

JWST MIRI color classification of mid-infrared selected galaxies: MIRI color classification toward cosmic noon

Ece Kilerci, Tomotsugu Goto, Matthew A. Malkan et al. (+7 more)

We investigated the James Webb Space Telescope photometric color classification of mid-infrared (MIR) selected galaxies at high redshifts, toward cosmic noon. The aim of the present work is to obtain a z-dependent mid-infrared (MIR) photometric galaxy classification tool based on broad spectral emission and absorption lines using the JWST Mid-Infrared Instrument (MIRI) and its broadband filters. We used the largest Spitzer MIR spectral database to obtain synthetic photometry in the JWST/MIRI filters. We formed MIRI filter combinations to trace the strong polycyclic aromatic hydrocarbon (PAH) emission features and the 9.7 micron silicate feature in seven redshift windows from z = 0.25-2.10. Results. We present z-dependent MIRI color-color plots that separate active galactic nuclei (AGN), star-forming galaxies (SFGs), and silicate absorption-dominated galaxies up to z$\sim$2. We applied the photometric MIR colors to the largest ($\sim$34 arcmin square) MIRI survey called the Systematic Mid-infrared Instrument Legacy Extragalactic Survey (SMILES), to identify AGN, SFGs, and Si-absorption dominated galaxies out to substantial redshifts. Our JWST/MIRI SFGs sample includes galaxies with total IR luminosities of $10^{9.2} \sim 10^{11.9} L_{\odot}$ at 0.9 $\leq$z < 1.57. The majority of them are consistent with the z$\sim$1 main sequence. We also identified the first examples of z$\sim$1 galaxies with deep silicate absorption.
Read the full abstract

All authors Ece Kilerci, Tomotsugu Goto, Matthew A. Malkan, Seong Jin Kim, Chih-Teng Ling, Cossas C.-K Wu, Tetsuya Hashimoto, Simon C.-C. Ho, Amos Y.-A. Chen, Ersin Gogus

Earth and Planetary Astrophysics

Probing thermal gradients of habitable-zone rocky planets as an anti-indicator of a global surface ocean using mid-infrared direct imaging

Yuka Fujii, Daniel Angerhausen, Taro Matsuo et al. (+1 more)

Future direct-imaging missions such as the Large Interferometer for Exoplanets (LIFE) aim to observe thermal emission from potentially habitable planets to characterize their surface environments and search for signs of life. Previous studies of directly imaged Earth-like planets have mainly examined the signatures of atmospheric composition, often using 1D models, while the effect of horizontal temperature gradients has received limited attention. Because a pronounced horizontal temperature gradient may signal the absence of a global ocean, we investigate its detectability through thermal-emission direct imaging. Adopting Teegarden's Star b (zero-albedo equilibrium temperature ~280 K) as a benchmark, we compute 3D atmospheric structures with and without a global ocean using the ROCKE-3D general circulation model and simulate geometry-dependent thermal emission spectra. We show that the temperature gradients that disfavor a global-ocean scenario manifest in both orbital phase variation and spectral shape of the snapshot spectra. The phase variation is more readily detectable: one-day integrations with LIFE at two orbital phases would reveal flux variations in no-ocean cases with 1-10 bar atmospheres, depending on background atmospheric composition. Shapshot spectra provide complementary diagnostics, including the running brightness temperature of the continuum and detailed absorption band shapes, but detecting these features requires longer integration times. These 3D effects, if neglected, can bias interpretations based on 1D models, and could also lead to misidentification of the H$_2$O band beyond 10 $\mu$m. We also assess the detectability of these 3D effects on other nearby planets. Our results highlight the need to incorporate 3D atmospheric structures when characterizing rocky exoplanets, both to constrain surface conditions and to avoid misinterpretation of spectral data.
Read the full abstract

All authors Yuka Fujii, Daniel Angerhausen, Taro Matsuo, Eric T. Wolf

High Energy Astrophysical Phenomena

A Tidal Disruption Event from an Intermediate-mass Black Hole Revealed by Comprehensive Multi-wavelength Observations

Jialai Wang, Mengqiu Huang, Yongquan Xue et al. (+12 more)

Tidal disruption events (TDEs) occur when a star crosses the tidal radius of a black hole (BH) and is ripped apart, providing a powerful way to probe dormant BHs over a wide mass range. In this study, we present our late-time observations and comprehensive multi-wavelength analyses of AT2018cqh, a TDE at the center of a dwarf galaxy that exhibited successive flares in the optical, X-ray, and radio bands. We discovered an unexpected high-state X-ray plateau phase following the peak until the present time. Along with its reported prolonged rise lasting at least 550 days, these unique characteristics are consistent with the scenario of a TDE caused by an intermediate-mass black hole (IMBH) with a mass of approximately $(1-6) \times 10^5$ solar masses. Furthermore, scaling relations derived from the host-galaxy properties indicated a similar BH mass in concert. This discovery highlights the invaluable role of TDEs in the search for elusive IMBHs.
Read the full abstract

All authors Jialai Wang, Mengqiu Huang, Yongquan Xue, Ning Jiang, Shifeng Huang, Yibo Wang, Jiazheng Zhu, Shifu Zhu, Lixin Dai, Chichuan Jin, Bin Luo, Xinwen Shu, Mouyuan Sun, Tinggui Wang, Fan Zou

High Energy Astrophysical Phenomena

Prompt Searches for Very-High-Energy {\gamma}-Ray Counterparts to IceCube Astrophysical Neutrino Alerts

J. Abhir, A. Biland, K. Brand et al. (+831 more)

The search for sources of high-energy astrophysical neutrinos can be significantly advanced through a multi-messenger approach, which seeks to detect the gamma rays that accompany neutrinos as they are produced at their sources. Multi-messenger observations have so far provided the first evidence for a neutrino source, illustrated by the joint detection of the flaring blazar TXS 0506+056 in highenergy (HE, E > 1 GeV) and very-high-energy (VHE, E > 100 GeV) gamma rays in coincidence with the high-energy neutrino IceCube-170922A, identified by IceCube. Imaging atmospheric Cherenkov telescopes (IACTs), namely FACT, H.E.S.S., MAGIC, and VERITAS, continue to conduct extensive neutrino target-of-opportunity follow-up programs. These programs have two components: followup observations of single astrophysical neutrino candidate events (such as IceCube-170922A), and observation of known gamma-ray sources after the identification of a cluster of neutrino events by IceCube. Here we present a comprehensive analysis of follow-up observations of high-energy neutrino events observed by the four IACTs between September 2017 (after the IceCube-170922A event) and January 2021. Our study found no associations between gamma-ray sources and the observed neutrino events. We provide a detailed overview of each neutrino event and its potential counterparts. Furthermore, a joint analysis of all IACT data is included, yielding combined upper limits on the VHE gamma-ray flux.
Read the full abstract

All authors J. Abhir, A. Biland, K. Brand, T. Bretz, D. Dorner, L. Eisenberger, D. Elsaesser, P. Günther, S. Hasan, D. Hildebrand, K. Mannheim, M. Linhoff, F. Pfeifle, W. Rhode, B. Schleicher, V. Sliusar, M. Vorbrugg, R. Walter, F. Aharonian, F. Ait Benkhali, J. Aschersleben, H. Ashkar, M. Backes, V. Barbosa Martins, R. Batzofin, Y. Becherini, D. Berge, M. Böttcher, C. Boisson, J. Bolmont, J. Borowska, R. Brose, A. Brown, F. Brun, B. Bruno, S. Casanova, J. Celic, M. Cerruti, A. Chen, M. Chernyakova, J. Chibueze, O. Chibueze, B. Cornejo, G. Cotter, G. Cozzolongo, J. Damascene Mbarubucyeye, J. de Assis Scarpin, A. Delgado Giles, A. Djannati-Ataï, J. Djuvsland, A. Dmytriiev, K. Egberts, K. Egg, S. Einecke, J.-P. Ernenwein, C. Escañ, K. Feijen, M. Filipovic, G. Fontaine, S. Funk, S. Gabici, J.F. Glicenstein, P. Goswami, G. Grolleron, B. Heß, J.A. Hinton, M. Holler, M. Jamrozy, F. Jankowsky, I. Jung-Richardt, E. Kasai, K. Katarzyń, H. Katjaita, D. Kerszberg, R. Khatoon, B. Khélifi, W. Kluź, Nu. Komin, R. Konno, K. Kosack, D. Kostunin, G. Kukec Mezek, R.G. Lang, A. Lemière, M. Lemoine-Goumard, J.-P. Lenain, A. Luashvili, J. Mackey, V. Marandon, G. Martí-Devesa, R. Marx, M. Mayer, A. Mehta, A. Mitchell, R. Moderski, M.O. Moghadam, L. Mohrmann, E. Moulin, M. de Naurois, J. Niemiec, E. de Ona Wilhelmi, S. Panny, M. Panter, R.D. Parsons, U. Pensec, P. Pichard, G. Pühlhofer, M. Punch, A. Quirrenbach, M. Regeard, O. Reimer, H. Ren, F. Rieger, G. Rowell, B. Rudak, K. Sabri, V. Sahakian, H. Salzmann, M. Sasaki, J. Schäfer, F. Schüssler, H.M. Schutte, M. Senniappan, J.N.S. Shapopi, A. Sharma, H. Sol, S. Spencer, Ł., R. Steenkamp, S. Steinmassl, C. Steppa, T. Takahashi, T. Tanaka, A.M. Taylor, M. Tsirou, C. van Eldik, M. Vecchi, C. Venter, J. Vink, T. Wach, S.J. Wagner, A. Wierzcholska, M. Zacharias, A.A. Zdziarski, A. Zech, N. Żywucka, S. Abe, J. Abhir, A. Abhishek, A. Aguasca-Cabot, I. Agudo, T. Aniello, S. Ansoldi, L. A. Antonelli, A. Arbet Engels, C. Arcaro, M. Artero, K. Asano, A. Babić, C. Bakshi, U. Barres de Almeida, J. A. Barrio, L. Barrios-Jiménez, I. Batković, J. Baxter, J. Becerra González, W. Bednarek, E. Bernardini, J. Bernete, A. Berti, J. Besenrieder, C. Bigongiari, A. Biland, O. Blanch, H. Bökenkamp, G. Bonnoli, Ž, E. Bronzini, I. Burelli, A. Campoy-Ordaz, A. Carosi, R. Carosi, M. Carretero-Castrillo, A. J. Castro-Tirado, D. Cerasole, G. Ceribella, Y. Chai, A. Chilingarian, A. Cifuentes, J. L. Contreras, J. Cortina, S. Covino, G. D'Amico, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, M. Delfino, C. Delgado Mendez, F. Di Pierro, R. Di Tria, L. Di Venere, A. Dinesh, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, L. Eisenberger, D. Elsaesser, J. Escudero, L. Fariña, A. Fattorini, L. Foffano, L. Font, S. Fröse, Y. Fukazawa, S. Gasparyan, M. Gaug, J. G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinović, T. Gradetzke, R. Grau, D. Green, J. G. Green, P. Günther, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, D. Hrupec, R. Imazawa, D. Israyelyan, I. Jiménez Martínez, J. Jiménez Quiles, J. Jormanainen, S. Kankkunen, T. Kayanoki, D. Kerszberg, J. Konrad, P. M. Kouch, H. Kubo, J. Kushida, M. Láinez, A. Lamastra, E. Lindfors, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, L. Lulić, E. Lyard, P. Majumdar, M. Makariev, M. Mallamaci, G. Maneva, M. Manganaro, S. Mangano, S. Marchesi, M. Mariotti, M. Martínez, P. Maruš, A. Mas-Aguilar, D. Mazin, S. Menchiari, J. Méndez Gallego, D. Miceli, J. M. Miranda, R. Mirzoyan, M. Molero González, E. Molina, H. A. Mondal, A. Moralejo, T. Nakamori, C. Nanci, V. Neustroev, M. Nievas Rosillo, C. Nigro, L. Nikolić, K. Nilsson, K. Nishijima, K. Noda, S. Nozaki, A. Okumura, J. Otero-Santos, S. Paiano, D. Paneque, J. M. Paredes, M. Peresano, M. Persic, M. Pihet, F. Podobnik, P. G. Prada Moroni, E. Prandini, M. Ribó, J. Rico, T. Saito, S. Sakurai, K. Satalecka, F. G. Saturni, K. Schmitz, F. Schmuckermaier, J. L. Schubert, A. Sciaccaluga, G. Silvestri, J. Sitarek, V. Sliusar, D. Sobczynska, A. Stamerra, J. Striš, D. Strom, M. Strzys, Y. Suda, H. Tajima, M. Takahashi, R. Takeishi, P. Temnikov, K. Terauchi, T. Terzić, A. Tutone, S. Ubach, J. van Scherpenberg, M. Vazquez Acosta, S. Ventura, G. Verna, I. Viale, A. Vigliano, C. F. Vigorito, E. Visentin, V. Vitale, I. Vovk, R. Walter, F. Wersig, M. Will, T. Yamamoto, P. K. H. Yeung, S. Yoo, A. Acharyya, A. Archer, P. Bangale, J. T. Bartkoske, W. Benbow, J. H. Buckley, Y. Chen, J. L. Christiansen, A. J. Chromey, M. Errando, S. Feldman, Q. Feng, S. Filbert, L. Fortson, A. Furniss, W. Hanlon, O. Hervet, C. E. Hinrichs, J. Holder, Z. Hughes, T. B. Humensky, W. Jin, M. N. Johnson, P. Kaaret, M. Kertzman, M. Kherlakian, D. Kieda, T. K. Kleiner, N. Korzoun, M. J. Lang, M. Lundy, G. Maier, M. J. Millard, J. Millis, P. Moriarty, R. Mukherjee, W. Ning, R. A. Ong, A. Pandey, M. Pohl, J. Quinn, P. L. Rabinowitz, K. Ragan, P. T. Reynolds, D. Ribeiro, E. Roache, I. Sadeh, A. C. Sadun, L. Saha, M. Santander, G. H. Sembroski, R. Shang, D. Tak, A. K. Talluri, J. V. Tucci, J. Valverde, V. V. Vassiliev, D. A. Williams, S. L. Wong, S. Buson, R. Abbasi, M. Ackermann, J. Adams, S. K. Agarwalla, J. A. Aguilar, M. Ahlers, J.M. Alameddine, S. Ali, N. M. Amin, K. Andeen, C. Argü, Y. Ashida, S. Athanasiadou, S. N. Axani, R. Babu, X. Bai, J. Baines-Holmes, A. Balagopal V., S. W. Barwick, S. Bash, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, P. Behrens, J. Beise, C. Bellenghi, B. Benkel, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, I. Bodo, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. Bö, O. Botner, J. Bö, J. Braun, B. Brinson, Z. Brisson-Tsavoussis, R. T. Burley, D. Butterfield, M. A. Campana, K. Carloni, J. Carpio, S. Chattopadhyay, N. Chau, Z. Chen, D. Chirkin, S. Choi, B. A. Clark, A. Coleman, P. Coleman, G. H. Collin, D. A. Coloma Borja, A. Connolly, J. M. Conrad, D. F. Cowen, C. De Clercq, J. J. DeLaunay, D. Delgado, T. Delmeulle, S. Deng, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, J. C. Dí, S. DiKerby, T. Ding, M. Dittmer, A. Domi, L. Draper, L. Dueser, D. Durnford, K. Dutta, M. A. DuVernois, T. Ehrhardt, L. Eidenschink, A. Eimer, P. Eller, E. Ellinger, D. Elsä, R. Engel, H. Erpenbeck, W. Esmail, S. Eulig, J. Evans, P. A. Evenson, K. L. Fan, K. Fang, K. Farrag, A. R. Fazely, A. Fedynitch, N. Feigl, C. Finley, L. Fischer, D. Fox, A. Franckowiak, S. Fukami, P. Fü, J. Gallagher, E. Ganster, A. Garcia, M. Garcia, G. Garg, E. Genton, L. Gerhardt, A. Ghadimi, C. Glaser, T. Glü, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, S. Griffin, S. Griswold, K. M. Groth, D. Guevel, C. Gü, P. Gutjahr, C. Ha, C. Haack, A. Hallgren, L. Halve, F. Halzen, L. Hamacher, M. Ha Minh, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. Hä, K. Helbing, J. Hellrung, B. Henke, L. Hennig, F. Henningsen, L. Heuermann, R. Hewett, N. Heyer, S. Hickford, A. Hidvegi, C. Hill, G. C. Hill, R. Hmaid, K. D. Hoffman, D. Hooper, S. Hori, K. Hoshina, M. Hostert, W. Hou, M. Hrywniak, T. Huber, K. Hultqvist, K. Hymon, A. Ishihara, W. Iwakiri, M. Jacquart, S. Jain, O. Janik, M. Jansson, M. Jeong, M. Jin, N. Kamp, D. Kang, W. Kang, X. Kang, A. Kappes, L. Kardum, T. Karg, M. Karl, A. Karle, A. Katil, M. Kauer, J. L. Kelley, M. Khanal, A. Khatee Zathul, A. Kheirandish, H. Kimku, J. Kiryluk, C. Klein, S. R. Klein, Y. Kobayashi, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. Kö, C. Kopper, D. J. Koskinen, P. Koundal, M. Kowalski, T. Kozynets, A. Kravka, N. Krieger, J. Krishnamoorthi, T. Krishnan, K. Kruiswijk, E. Krupczak, A. Kumar, E. Kun, N. Kurahashi, N. Lad, C. Lagunas Gualda, L. Lallement Arnaud, M. Lamoureux, M. J. Larson, F. Lauber, J. P. Lazar, K. Leonard DeHolton, A. Leszczyń, J. Liao, C. Lin, Y. T. Liu, M. Liubarska, C. Love, L. Lu, F. Lucarelli, W. Luszczak, Y. Lyu, M. Macdonald, J. Madsen, E. Magnus, Y. Makino, E. Manao, S. Mancina, A. Mand, I. C. Mariş, S. Marka, Z. Marka, L. Marten, I. Martinez-Soler, R. Maruyama, J. Mauro, F. Mayhew, F. McNally, J. V. Mead, K. Meagher, S. Mechbal, A. Medina, M. Meier, Y. Merckx, L. Merten, J. Mitchell, L. Molchany, S. Mondal, T. Montaruli, R. W. Moore, Y. Morii, A. Mosbrugger, M. Moulai, D. Mousadi, E. Moyaux, T. Mukherjee, R. Naab, M. Nakos, U. Naumann, J. Necker, L. Neste, M. Neumann, H. Niederhausen, M. U. Nisa, K. Noda, A. Noell, A. Novikov, A. Obertacke, V. O'Dell, A. Olivas, R. Orsoe, J. Osborn, E. O'Sullivan, V. Palusova, H. Pandya, A. Parenti, N. Park, V. Parrish, E. N. Paudel, L. Paul, C. Pé, T. Pernice, T. C. Petersen, J. Peterson, M. Plum, A. Ponté, V. Poojyam, Y. Popovych, M. Prado Rodriguez, B. Pries, R. Procter-Murphy, G. T. Przybylski, L. Pyras, C. Raab, J. Rack-Helleis, N. Rad, M. Ravn, K. Rawlins, Z. Rechav, A. Rehman, I. Reistroffer, E. Resconi, S. Reusch, C. D. Rho, W. Rhode, L. Ricca, B. Riedel, A. Rifaie, E. J. Roberts, M. Rongen, A. Rosted, C. Rott, T. Ruhe, L. Ruohan, D. Ryckbosch, J. Saffer, D. Salazar-Gallegos, P. Sampathkumar, A. Sandrock, G. Sanger-Johnson, M. Santander, S. Sarkar, J. Savelberg, M. Scarnera, P. Schaile, M. Schaufel, H. Schieler, S. Schindler, L. Schlickmann, B. Schlü, F. Schlü, N. Schmeisser, T. Schmidt, F. G. Schrö, L. Schumacher, S. Schwirn, S. Sclafani, D. Seckel, L. Seen, M. Seikh, S. Seunarine, P. A. Sevle Myhr, R. Shah, S. Shefali, N. Shimizu, B. Skrzypek, R. Snihur, J. Soedingrekso, A. Sø, D. Soldin, P. Soldin, G. Sommani, C. Spannfellner, G. M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, T. Stezelberger, T. Stü, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, A. Thakuri, M. Thiesmeyer, W. G. Thompson, J. Thwaites, S. Tilav, K. Tollefson, S. Toscano, D. Tosi, A. Trettin, A. K. Upadhyay, K. Upshaw, A. Vaidyanathan, N. Valtonen-Mattila, J. Valverde, J. Vandenbroucke, T. Van Eeden, N. van Eijndhoven, L. Van Rootselaar, J. van Santen, J. Vara, F. Varsi, M. Venugopal, M. Vereecken, S. Vergara Carrasco, S. Verpoest, D. Veske, A. Vijai, J. Villarreal, C. Walck, A. Wang, E. H. S. Warrick, C. Weaver, P. Weigel, A. Weindl, J. Weldert, A. Y. Wen, C. Wendt, J. Werthebach, M. Weyrauch, N. Whitehorn, C. H. Wiebusch, D. R. Williams, L. Witthaus, M. Wolf, G. Wrede, X. W. Xu, J. P. Yanez, Y. Yao, E. Yildizci, S. Yoshida, R. Young, F. Yu, S. Yu, T. Yuan, A. Zander Jurowitzki, A. Zegarelli, S. Zhang, Z. Zhang, P. Zhelnin, P. Zilberman, F. D'Ammando

High Energy Astrophysical Phenomena

Double shell structure in supernova 2024ggi

Kobi Shiran and Noam Soker

We built a simple toy model of a core-collapse supernova (CCSN) ejecta composed of two shells, an outer low-mass spherical shell and an inner elongated massive shell, and show that it can reproduce the evolution of the photospheric radius of SN 2024ggi, Rph(t). During the first week, the larger spherical shell, the S-shell, forms the photosphere. As the shell expands and becomes increasingly transparent, the photosphere moves inward along the mass coordinate, although it grows in size. When the photosphere reaches the long axis of the elongated inner shell, the E-shell begins to contribute to the photosphere, ultimately comprising the entire photosphere. The simple toy model explains the transition of Rph(t) from being concave (decreasing slope) to convex (increasing slope). A single-shell model predicts only concave behavior. The structure of a spherical shell with an inner elongated shell is motivated by the morphologies of several CCSN remnants whose structures have been attributed to multiple pairs of jets in the framework of the jittering jets explosion mechanism (JJEM). The deduced multiple-shell ejecta of SN 2024ggi in this study, and of SN 2023ixf in an earlier study, as well as studies of the polarization of SN 2024ggi, are better compatible with the JJEM than with the neutrino-driven mechanism. Our study supports the growing evidence that the JJEM is the primary explosion mechanism of CCSNe.
Read the full abstract

Cosmology and Nongalactic Astrophysics

Decoupling perturbations from background in $f(Q)$ gravity: the square-root correction and the impact on the $\sigma_8$ tension

Chunyu Li, Xin Ren, Yuhang Yang et al. (+2 more)

We investigate a perturbation-level modification of symmetric teleparallel gravity of the form $f(Q)=F(Q)+M\sqrt{Q}$ and assess its potential to ease the $\sigma_8$ tension. The square-root term leaves the background expansion unchanged at the level of FLRW cosmology, while modifying the effective gravitational coupling and thereby providing a decoupling between background evolution and structure-growth. Using the latest redshift-space distortion data, including DESI DR1 Full-Shape measurements, we constrain the model through its impact on the growth observable $f\sigma_8(z)$ across three representative backgrounds: $\Lambda$CDM, an $H_0$-tension-reducing model, and a DESI-motivated dynamical dark energy scenario. In all cases, the square-root correction suppresses the growth of structure and induces a degeneracy with $\sigma_8$, leading to weaker constraints from current data. This allows for a wider range of $\sigma_8$ values consistent with Planck, with the effect being most pronounced in the $H_0$-tension-oriented background model. However, because RSD data constrain $f\sigma_8$ rather than $\sigma_8$ directly, a residual degeneracy between $M$ and $\sigma_8$ remains, indicating that future multi-probe analyses combining lensing and full-shape clustering will be required to determine whether the $\sqrt{Q}$ term represents a genuine signal of modified gravity.
Read the full abstract

All authors Chunyu Li, Xin Ren, Yuhang Yang, Emmanuel N. Saridakis, Yi-Fu Cai

Earth and Planetary Astrophysics

Warm Jupiter Tidal Migration Can Spare Inner Planets; Hot Jupiter Tidal Migration May Not

Juliette Becker

In this work, we investigate the dynamical survival of short-period inner planets during the high-eccentricity tidal migration of companion exterior giant planets. Using a combination of analytic arguments and N-body simulations including equilibrium tides and general relativistic precession, we find the boundary in parameter space where an inner companion can remain dynamically stable. We find that survival requires a periastron separation exceeding roughly 14 mutual Hill radii at closest approach. Below this threshold, secular eccentricity exchange, orbit crossing, and/or tidal evolution can lead to the destruction of the inner planet. We apply our methodology to the current exoplanet sample and find that none of the known systems containing a short-period giant and an inner companion could have assembled via high-eccentricity tidal migration. However, warm Jupiters with larger periastron distances ($q_{\mathrm{out}} \sim 0.05-0.08$ AU, corresponding to final observed semi-major axis values $a_{\mathrm{out}} \sim 0.10-0.16$ AU) can allow the survival of short-period inner planets while potentially also circularizing on $\lesssim 1$ Gyr timescales. Our results provide a framework for distinguishing disk migration from tidal migration in observed multi-planet systems containing close-in gas giants.
Read the full abstract

Astrophysics of Galaxies

N-emitters as possible sign-posts of GC formation

D. Schaerer, R. Marques-Chaves, H. Atek et al. (+7 more)

Based on the finding of unusual chemical abundance ratios of N-emitters, which resemble those of globular cluster (GC) stars, their compactness, high ISM densities and other properties, it has been suggested that N-emitters could indicate the formation sites of globulars. A recent statistical study of the N-emitter population has quantified the frequency $f_N$ of these rare objects and their redshift evolution (Morel et al. 2025). Using these results we here test if N-emitters trace the formation of GCs and use the observed cosmic star-formation rate density evolution to predict the cosmological evolution of the GC population with time, their age distribution, and the total present-day stellar mass density formed in globulars. The predicted age distribution of GCs strongly resembles the typical asymmetric observed distributions in the Galaxy and ellipiticals, with a peak at $\sim 11.5-12$ Gyr and a longer tail extending to younger ages. We derive a total stellar mass density formed in N-emitters down to redshift zero of $(2-7) \times 10^5$ M$_{\odot}$ Mpc$^{-3}$, which matches within a factor $\sim 2$ the observed fraction of stellar mass found in the GC population at $z=0$. These results provide additional indirect arguments supporting the hypothesis that N-emitters could represent sign-posts of a short phase of GC formation.
Read the full abstract

All authors D. Schaerer, R. Marques-Chaves, H. Atek, N. Prantzos, C. Charbonnel, M. Talia, I. Morel, M. Dessauges-Zavadsky, Y.I. Izotov, N. Guseva

Astrophysics of Galaxies

Galaxy evolution in compact groups - III. Structural analysis of galaxies and dynamical state of non-isolated compact groups

Gissel P. Montaguth, Ana Laura O'Mill, Claudia Mendes de Oliveira et al. (+17 more)

Compact Groups (CGs) of galaxies are dense systems where projected separations are comparable to their optical diameters. A subset - non-isolated CGs - are embedded within major structures. Using multi-band S-PLUS data, we analyse galaxies in 122 non-isolated CGs within more massive systems such as larger groups and clusters. We compare them to galaxies in the host structures, hereafter surrounding group galaxies. Structural parameters were obtained with MorphoPLUS, a pipeline for multi-wavelength Sérsic profile fitting. Dividing galaxies into early (ETG), transition, or late types (LTG), we find: (1) Non-isolated CGs host higher quenched fractions and more ETGs, especially for stellar masses $\log(M/M_\odot) > 10.2$, than surrounding groups. (2) Sérsic indices increase with wavelength for all morphological types in both environments, whereas effective radii show a stronger morphology-dependent behaviour - ETGs become more compact towards redder bands, while LTGs exhibit flatter $Re(\lambda)$ trends. Environmental differences remain weak, with only a modest enhancement of the gradients for ETGs in non-isolated CGs. (3) Transition galaxies in CGs show a concentrated $R_e$-$n$ distribution and faint-end bimodality, consistent with ongoing morphological transformation absent in surrounding groups. (4) Phase-space analysis indicates that some CGs in clusters are projection artefacts, while others are genuine dense systems at various infall stages, from recent arrivals to ancient remnants. These results show that galaxies in non-isolated CGs follow distinct evolutionary paths compared to their surrounding groups galaxies, suggesting that the compact configuration plays a unique role beyond the influence of the larger-scale environment.
Read the full abstract

All authors Gissel P. Montaguth, Ana Laura O'Mill, Claudia Mendes de Oliveira, Ciria Lima-Dias, Sergio Torres-Flores, Antonela Monachesi, D. E. Olave-Rojas, Diego Pallero, Pedro K. Humire, Ricardo Demarco, Eduardo Telles, Paulo A. A. Lopes, Swayamtrupta Panda, Rodrigo F. Haack, Amanda R. Lopes, Alvaro Alvarez-Candal, Analia V. Smith Castelli, Antonio Kanaan, Tiago Ribeiro, William Schoenell

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

Chiral magnetic effect amplified baryogenesis at first-order phase transitions

Hui Liu and Ligong Bian

In this study, we show that, in the background of the primordial magnetic field, the chiral magnetic effect effect can significantly amplify the chiral chemical potential sourced by the CP violation near the bubble walls during the first-order electroweak phase transition. This effect can lift the generated baryon asymmetry by several orders, and make it possible to explain the baryon asymmetry of the Universe with a CPV in the fermion sector far beyond the limitation of the electron dipole moment.
Read the full abstract