Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ex
Latin American HECAP Physics Briefing Book 2025
Mario A. Acero, Alexis A. Aguilar-Arevalo, Belén Andrada et al. (+24 more)
The first process for the Latin American Strategy Forum for Research Infrastructure for High Energy, Cosmology and Astroparticle Physics (LASF4RI-HECAP) came to a conclusion in October 2020, with a Physics Briefing Book (PBB) presented in (2104.06852). Here we present an updated PBB, the result of the first update of LASF4RI-HECAP. The update process began with a call for White Papers from the HECAP community. The submitted contributions were presented at the III LASF4RI for HECAP Symposium: Update of the Strategic Plan, held at ICTP-SAIFR in São Paulo in August 26-29, 2024, with the participation of the Preparatory Group, High Level Strategy Group, Funding Agencies and representatives of similar efforts from around the globe. This updated PBB was written by the Preparatory Group based mainly on 46 White Papers submitted by the community and is organized around seven working groups: Astronomy, Astrophysics and Astroparticle Physics; Cosmology; Dark Matter;
Neutrinos; Electroweak and Strong Interactions,
Higgs Physics, CP and Flavour Physics and BSM; Instrumentation and Computing; Advanced Training and Capacity Building. It is intended to provide the essential input for the creation of a long-term HECAP strategy in the region.
Read the full abstract ▾
All authors Mario A. Acero, Alexis A. Aguilar-Arevalo, Belén Andrada, Andrés Baquero Larriva, Mauro Cambiaso, Edgar Carrera, Melissa Cruz, Lucía Duarte, Juan Estrada, Alberto Gago, Esteban Jimenez, Diana López Nacir, José A. López, Marta Losada, Fernando Monticelli, Deywis Moreno, Martjin Mulders, Luis A. Núñez, Arturo S. Pineda, Juan Ponciano, Farinaldo Queiroz, Rogerio Rosenfeld, Sandro F. de Souza, Martin Alfonso Subieta Vasquez, Maria Elena Tejeda-Yeomans, Luis Ureña, Alfonso Zerwekh
Astrophysics of Galaxies
The trigonometric parallax of IRAS 23385+6053 and physical properties of molecular clouds based on the VLBI astrometry
Shota Hamada, Mikito Kohno, Toshihiro Omodaka et al. (+5 more)
We performed very long baseline interferometry (VLBI) observations to measure the trigonometric parallax of H$_2$O maser sources in the outer massive
star-forming region IRAS 23385+6053 using the VLBI Exploration of
Radio Astrometry (VERA) in Japan. The annual parallax is $\pi=0.460 \pm 0.086$~mas, which corresponds to a distance of $2.17^{+0.50}_{-0.34}$ kpc, roughly half the kinematic distance of 4.9 kpc reported in previous studies. The proper motion of IRAS 23385+6053 is obtained to be ($\mu_{\alpha}\cos{\delta}$,$\mu_{\delta}$)=($-3.73\pm0.53$, $-2.0{7}\pm0.73$) mas yr$^{-1}$. Based on VLBI astrometry result, we derived the physical properties of molecular clouds in which H$_2$O masers have been detected, including IRAS 23385+6053 in the Cepheus and Cassiopeia region. We discuss the line-of-sight structures of the
giant molecular clouds using the trigonometric distances obtained from the H$_{2}$O maser sources. Our results suggest that molecular clouds in the Perseus arm extend over approximately $2$ kpc at the Cepheus and Cassiopeia region.
Read the full abstract ▾
All authors Shota Hamada, Mikito Kohno, Toshihiro Omodaka, Nobuyuki Sakai, Riku Urago, Takumi Nagayama, Hideyuki Kobayashi, Yuji Ueno
Earth and Planetary Astrophysics
Vittorio Franzese
This paper investigates an autonomous
navigation method for spacecraft operating in the outer
solar system, up to 250 AU from the Sun, using the parallactic shifts of nearby
stars. These measurements enable estimation of the spacecraft trajectory while distant
stars provide attitude information through conventional
star-pattern matching.
Stellar observation models are developed, accounting for delta light-time, parallax, and aberration effects.
Navigation performance is assessed using two approaches: (1) a least-squares
estimator using simultaneous multi-
star measurements, and (2) a Kalman filter processing sequential single-
star observations along deep-space trajectories. Monte Carlo simulations on trajectories representative of Voyager 1, Voyager 2, Pioneer 10, Pioneer 11, and New Horizons missions show sub-AU position accuracies at 250 AU, and velocity accuracies better than 0.00004 AU/day, under realistic spacecraft and instrumentation uncertainties. These values correspond to relative errors below 0.4% in position and velocity with respect to the reference trajectories. Although less precise than radiometric tracking, this performance can support
navigation in the outer
solar system without reliance on Earth. When ground-based
navigation remains necessary, this approach can be employed during long cruising phases, lowering the number of ground contacts. The method additionally shows potential for future missions venturing farther from the Sun.
Read the full abstract ▾
High Energy Astrophysical Phenomena
The contribution to Galactic Centre {\gamma}-ray excess from cluster-born millisecond pulsars. Constraints from direct N-body simulations
M. Kalambay, M. Ishchenko, D. Kuvatova et al. (+2 more)
The
Galactic Centre {\gamma}-ray excess (GCE), observed by
Fermi-LAT around Sgr A*, exceeds expectations from standard
cosmic-ray models and is commonly attributed either to dark matter annihilation or to unresolved millisecond
pulsars (MSPs). We revisit the MSP scenario within a fully dynamical framework by tracking
neutron stars (NSs) formed in globular clusters (GCs) and deposited into the central kiloparsec. Using high-resolution direct N-body simulations of GCs evolving in a time-dependent Milky Way potential, we model both present-day clusters and an early population of disrupted systems. From the simulated NS distributions, we infer the MSP population via an empirically calibrated MSP-to-NS ratio and construct mock {\gamma}-ray flux profiles assuming representative
pulsar luminosities. MSPs associated with surviving clusters already produce a substantial {\gamma}-ray contribution, while disrupted clusters enhance both the amplitude and central concentration of the signal. Under reasonable assumptions, the combined MSP population reproduces the observed GCE properties, favouring an astrophysical origin over dark matter interpretations.
Read the full abstract ▾
All authors M. Kalambay, M. Ishchenko, D. Kuvatova, T. Panamarev, P. Berczik
Solar and Stellar Astrophysics
Fundamental properties of protoplanetary discs determined from simultaneous fits to thermal dust images and spectral energy distributions
Tim J. Harries
We present a novel machine learning method that is capable of rapidly and accurately producing
dust-continuum model images and spectral energy distributions from training sets created using a detailed radiative transfer code. We create a training set that encompasses the parameter space for protoplanetary discs, and then couple the trained machine learning method with a
Bayesian optimisation
algorithm. We then simultaneously fitted 1.3 mm ALMA ODISEA survey images of protostellar discs in the Ophiuchus Molecular Cloud, and their spectral energy distributions, in order to determine fundamental discs parameters such as
dust masses and radii. We find that good simultaneous fits may be found for the Class II objects in the survey, although the spectral fits are poorer for the Class I and flat spectrum sources. We find that the
dust mass distributions of discs is broader and shallower than that predicted from 1.3 mm flux
dust mass estimates, substantially increasing the numbers of objects with high-mass and low-mass discs. We show that this is due to a combination of optical depth and
dust temperature effects, which are strongly related to the disc size and inclination constraints provided by the imaging fits. We show that there is a significant decrease in disc scale height and disc flaring when moving from the the Class I objects, to the flat spectrum sources, and the Class II discs.
Read the full abstract ▾
Astrophysics of Galaxies
Mid-infrared Variability-based AGN Selection using the Multi-epoch Photometric Data from WISE
Shinyu Kim, Minjin Kim, Suyeon Son et al. (+1 more)
We assess the systematics and efficiency of an AGN selection method based on mid-infrared (MIR) variability. To this end, we utilize various types of active and inactive
galaxies from the Sloan Digital Sky Survey, matching them with multi-epoch photometric data from the NEOWISE mission. Using W1 and W2 band light curves with a $\sim10$-year baseline, we find that combining the likelihood of deviation from non-variability with the correlation coefficient between the W1 and W2 bands reliably identifies AGNs. Specifically, this MIR-based method recovers $\sim 28.2\%$ of optically selected AGNs. Applying the same technique to inactive
galaxies, we identify AGN candidates at fractions ranging from $0.4$ to $11.8\%$, indicating that MIR variability allows us to detect AGN candidates even in optically inactive hosts. While some variable sources exhibit transient-like light curves, possibly originating from
tidal disruption events or
supernovae, their contribution to the total variable population is less than a few percent, indicating a minimal impact on our results. Across all subsamples, the AGN fraction marginally increases with
star formation activity, implying coordinated
evolution between central black hole growth and
star formation. Finally, the AGN fraction inferred from our method drops dramatically in classical LINERs, consistent with their low
accretion rates and absence of a dusty
torus.
Read the full abstract ▾
All authors Shinyu Kim, Minjin Kim, Suyeon Son, Luis C. Ho
Astrophysics of Galaxies
Size measurements and characterization of the astrophysical properties of multiple-component radio-AGNs in the ROGUE I catalog
Arti Goyal, Arpita Misra, Subhrata Dey et al. (+6 more)
We present hand-curated size measurements for a sample of 2,002 multiple-component
radio AGNs in the
Radio sources associated with Optical
Galaxies and having Unresolved or Extended morphologies I (ROGUE I) catalog. The sources span total angular sizes of $\sim 5^{\prime\prime}$-1,100$^{\prime\prime}$ which translates to projected linear sizes $\sim$10 kpc- $\sim$2 Mpc across 0.01$\leq$z$\leq$0.54. About 10% of the sample are compact ($\leq$60 kpc) while $\sim$3% are
giant radio sources ($\geq$700 kpc). Roughly 34% are associated with
galaxy clusters, and 16% exhibit an arm-length asymmetry ratio $\geq$2. The cluster association fractions are comparable across Fanaroff-Riley (FR) I, II, and hybrid type morphological classes. Arm-length asymmetries occur at similar rates in FR I and hybrid classes but are about a factor of 2-4 less common in FR II, supporting the view that their jets are more stable and collimated, and thus less prone to disruption in dense cluster environments. In contrast, bent-angle sources (wide- and narrow-angle tails) show arm-length asymmetries about a factor of four less frequently than cluster-associated sources, suggesting that asymmetries are smoothed out by the local intracluster medium conditions. The mean
galaxy number densities of FR I, II, hybrid, wide-angle, narrow-angle, and head-tail sources are comparable, supporting the dominant role of local intra-cluster medium conditions in shaping bent morphologies.
Radio power-linear size tracks for FR IIs show that the population is dominated by AGNs with jet kinetic powers $\leq$10$^{38}$ erg/s, comprising both young (10 Myr) and old (100 Myr) AGNs. We also compare z, angular and linear sizes, core and total
radio luminosities, optical magnitudes, black hole, and
stellar masses across the morphological classes.
Read the full abstract ▾
All authors Arti Goyal, Arpita Misra, Subhrata Dey, Unnikrishnan Sureshkumar, Marion Soida, Anna Wojtowicz, Grazyna Stasinska, Natalia Vale Asari, Syed Naqvi
High Energy Astrophysical Phenomena
Search for Periodic Radio Signals from Double Neutron Star System Companions Using the Fast Folding Algorithm
Wenze Li, Zhichen Pan, Lei Qian et al. (+14 more)
As most of the companions in the double
neutron star systems should be normal
pulsars, the Fast Folding
Algorithm (FFA), which is suitable for finding these long
spin period
pulsars, was used to search their possible
radio signals. A time domain resampling code PYSOLATOR was used to maximize the available data length by removing the orbital modulation. We collected and processed 272.2 hours observational data taken by the Five-hundred-meter Aperture Spherical
radio Telescope (FAST) for the 13 double
neutron star systems in its sky. The signal-to-noise ratios of known
pulsar signals are obviously improved by this search method, including the detection of a faint
pulsar signal which only saw by folding the data. Unfortunately, no companion signals were found among all the 197962 candidates. Geodetic precession of the orbit could enhance detectability in future observations.
Read the full abstract ▾
All authors Wenze Li, Zhichen Pan, Lei Qian, Liyun Zhang, Yujie Chen, Dejiang Yin, Baoda Li, Yinfeng Dai, Yaowei Li, Dongyue Jiang, Qiaoli Hao, Menglin Huang, Xingyi Wang, Xianghua Niu, Minglei Guo, Jinyou Song, Shuangyuan Chen
High Energy Astrophysical Phenomena · Cross-listed from nucl-th
Inverse-mapped density-dependent relativistic mean-field inference of the neutron-star equation of state with multi-messenger constraints
Wen-Jie Xie and Cheng-Jun Xia
We perform a
Bayesian inference of the equation of state (EOS) of cold dense matter within a density-dependent relativistic mean-field (DD-RMF) model. An explicit inverse-mapping procedure reconstructs the density-dependent couplings from a physically interpretable ten-dimensional parameter set while enforcing thermodynamic consistency together with stability and causality conditions. The EOS is constrained by complementary multi-messenger data including
chiral effective field theory calculations at low density, heavy-ion collision flow information at intermediate densities, NICER mass-radius posteriors, and the existence of approximately two-
solar-mass
pulsars. The combined constraints strongly restrict both isoscalar and isovector sectors. In particular, the
chiral effective field theory band favors a relatively soft
symmetry-energy slope around 38 MeV, corresponding to a compact canonical
neutron-
star radius of about 11.6 km. To reconcile the intermediate-density softness suggested by heavy-ion data with the high-density stiffness required by massive
pulsars, the posterior prefers a moderately large Dirac effective mass at saturation together with correlated high-density limits of the scalar and vector couplings. The resulting sound-speed profile remains causal and shows significant stiffening above the conformal limit at several times
nuclear saturation density, indicating strongly interacting matter in
neutron-
star cores. Evidence diagnostics indicate strong compatibility among the adopted constraints within the present DD-RMF framework.
Read the full abstract ▾
Earth and Planetary Astrophysics
Global Abiotic Sulfur Cycling on Earth-like Terrestrial Planets
Rafael Rianço-Silva, Javed Akhter Mondal, Matthew A. Pasek et al. (+3 more)
Sulfur is a redox active element that may have helped mediate an electron flow that kickstarted life and which presently is an essential element for all life on Earth. Despite current uncertainties in global sulfur fluxes, modeling sulfur's abiotic cycling through Earth's deep history is important for understanding the impact of a
planet wide biosphere on sulfur geochemical cycling and availability and vice versa. We present here an open-source, dynamical box model for estimating global sulfur fluxes and concentrations among surface and deep Earth reservoirs over Earth history, allowing tracking and estimation of the sulfur distribution in planetary reservoirs over deep time in the absence of life. While the main model presented here does not take into account the abrupt
evolution of redox-shunting biosynthetic pathways such as oxygenic photosynthesis, we also modeled the abiotic sulfur cycle before and after a Great Oxidation Event-like transition on Earth-like
planets. Our results suggest a considerably distinct chemical makeup of sulfur content in marine sediments in the absence of life on an Earth-like
planet, leading to a marine sediment sulfate content two orders of magnitude larger than on present-day Earth and a marine sediment sulfide content 4 orders of magnitude lower than on present day Earth, attributable to the lack of microbial sulfur metabolism. This model could be useful for understanding sulfur cycling on potentially habitable
exoplanets.
Read the full abstract ▾
All authors Rafael Rianço-Silva, Javed Akhter Mondal, Matthew A. Pasek, Henry Jurney, Marcos Jusino-Maldonado, Henderson James Cleaves
High Energy Astrophysical Phenomena
Detection of quasi-periodic oscillations in the 37 GHz radio light curve of the blazar Ton 599 during 1990-2020
Alok C. Gupta, Alexandr E. Volvach, Shubham Kishore et al. (+6 more)
Blazars are a subclass of
radio-loud active
galactic nuclei (AGNs) that display strong multi-wavelength variability on diverse timescales ranging from years down to minutes. In the last 1.5 decades, there have been occasional detections of quasi-periodic oscillations in several blazars in their time series data. We search for quasi-periodic oscillations (QPOs) in the 37 GHz
radio band light curve of the flat-spectrum
radio quasar Ton~599 made at the RT-22
radio telescope in Simeiz, Crimea, from 1990 to 2020. To identify and quantify the QPO nature of this
radio light curve of Ton 599, we used the Lomb-Scargle periodogram (LSP), REDFIT, and weighted wavelet Z-transform (WWZ) analyses. We report the detection of a likely QPO of about 2.4 years in the 37 GHz
radio light curves of Ton 599. We briefly discuss possible emission models for
radio-loud active
galactic nuclei that could explain such QPOs with periods of a few years.
Read the full abstract ▾
All authors Alok C. Gupta, Alexandr E. Volvach, Shubham Kishore, Larisa N. Volvach, Paul J. Wiita, Lang Cui, Mauri J. Valtonen, Sandeep K. Mondal, Haritma Gaur
Astrophysics of Galaxies
Untangling dust emission and cosmic infrared background anisotropies with the scattering transform statistics
Srijita Sinha, Tuhin Ghosh, Erwan Allys et al. (+2 more)
The template-fit approach is often used to separate
Galactic dust emission from
cosmic infrared background (CIB) anisotropies in low $\text{HI}$ column density regions, under the assumption that gas and
dust are tightly correlated. However, this method fails in regions where additional
Galactic emission from molecular hydrogen, diffuse ionized gas, and dark gas is present. We develop and test a statistical component-separation method to extract the
dust signal from contaminated $\textit{Planck}$ $353\,\rm GHz$ observations using Scattering Covariance (SC) statistics. We first obtain a set of CIB maps over $25$ square patches, each covering an area of $222\,{\rm deg}^{2}$, using the linear correlation between
dust and
Galactic $21\,\rm cm$ $\text{HI}$ emission, which is valid in low $\text{HI}$ column density regions, through the template-fit approach. We then construct, from these $25$ maps, a generative model of the CIB using SC statistics. Finally, we rely on this contamination model to perform component separation of
dust and CIB in the $\textit{Planck}$ data for different sky regions. Applying our
algorithm to the $\textit{Planck}$ $353\,\rm GHz$ observations, we recover a
dust map for a test sky region that exhibits more structure than the corrected SFD map at $100\,\mu \rm m$. The differences observed at the map level can be explained by decomposing the recovered $\textit{Planck}$
dust map into two gas phases:
dust associated with $N_{\text{HI}}$ and
dust associated with $N_{\text{H}_{2}}$. This work provides a clear pathway for mapping
Galactic interstellar reddening over intermediate and high
Galactic latitudes.
Read the full abstract ▾
All authors Srijita Sinha, Tuhin Ghosh, Erwan Allys, François Boulanger, Jean-Marc Delouis
High Energy Astrophysical Phenomena
Accretion dynamics and coronal geometry in Mrk 530: Insights from 24 years of X-ray monitoring
Priyadarshee P. Dash, Prantik Nandi, Sachindra Naik et al. (+2 more)
We present a long-term broadband study of the Seyfert
galaxy Mrk~530 spanning $\sim$24 yr (2001–2024). The source remains largely stable across epochs, except in 2018, when a possible quasi-periodic oscillation is observed simultaneously in the UV and X-ray bands, with characteristic timescales of $\sim$90 and $\sim$60 days, characterized by low coherence. Time-resolved spectral analysis shows that this epoch is characterized by comparable coronal cooling and compressional heating timescales, a condition conducive to oscillatory behavior in the inner
accretion flow. Other epochs exhibit a clear mismatch between these timescales, and no such variability is observed. The X-ray spectral properties display significant long-term
evolution. The
photon index and luminosity vary systematically, while a soft excess is present only in early epochs (2001–2006) and weakens thereafter, consistent with an evolving warm corona. Physically motivated models indicate that changes in the
accretion rate regulate both the spectral slope and coronal geometry, with higher disc
accretion rates producing enhanced cooling, a more compact corona, and softer spectra, and lower rates yielding an expanded hot flow and harder emission. These results suggest that
accretion-driven coupling between the disc and corona governs both the long-term spectral
evolution and transient short-timescale variability in Mrk~530.
Read the full abstract ▾
All authors Priyadarshee P. Dash, Prantik Nandi, Sachindra Naik, Narendranath Layek, Sandip K. Chakrabarti
High Energy Astrophysical Phenomena
Variability Study and Searching for QPOs with day-like periods in the blazar S5 0716+714 with TESS
Shubham Kishore, Alok C. Gupta and Paul J. Wiita
Using an unprecedented cadence of 30 minutes provided by the Transiting
Exoplanet Survey Satellite (TESS), we have examined the optical light curves (LCs) of the blazar S5 0716+714 obtained from its Sectors 40, 47, and 53 over a period of about 75 days. This source exhibited flux variability in each of those sectors, reaching a maximum variability amplitude of 5.6%. The power spectral density (PSD) shapes were tested with a simple power law and two distinct bending power laws and were found to be better fit by bending power laws than simple power laws for all but one of the segments. To look for any periodicities in these LCs, we used weighted wavelet Z (WWZ) transform analysis and generalized Lomb-Scargle periodograms (LSPs). We identified one possible quasi-periodic oscillation (QPO) signature in a portion of sector 40 (period of ~6.5 h), having ~95% global significance. A statistical approach to assess the light curves involving continuous autoregressive moving average (CARMA) was implemented, and the light curves were found to follow more complex processes than the simplest and typical damped random walk process. We briefly discuss the statistical properties of the light curves along with the general variability features and physical processes that could cause these types of fluctuations.
Read the full abstract ▾
High Energy Astrophysical Phenomena
X-Ray Intraday Variability of the Blazar OJ 287 Observed with XMM-Newton
Tao Huang, Alok C. Gupta, Lang Cui et al. (+4 more)
We present X-ray intraday variability, cross-correlated variability, and power spectrum density analysis of the binary black hole blazar candidate OJ 287. The X-ray pointed observations of the source were carried out on eight occasions by the EPIC-pn camera on board the XMM-Newton satellite from November 2005 to November 2022. These good time intervals range between 3.6 hours and 24.1 hours. Three energy bands – 0.2-2 keV (soft), 2-10 keV (hard), and 0.2-10 keV (total) – have been used to estimate variability. Low amplitude variations are observed in 4, 5, and 6 light curves in soft, hard, and total energy bands, respectively. Only two observation IDs has shown variation in the all energy bands. The discrete correlation function of the light curves in soft and hard energy bands peaks at zero lag, suggesting that the emission in both bands was cospatial and came from the same population of
leptons. Red noise dominates the power spectral densities of variable light curves. According to our flux and spectrum investigations, both particle acceleration and synchrotron cooling mechanisms contribute significantly to the emission from this blazar.
Read the full abstract ▾
All authors Tao Huang, Alok C. Gupta, Lang Cui, Ashutosh Tripathi, Yongfeng Huang, P. U. Devanand, Xiang Liu
High Energy Astrophysical Phenomena
Investigating the Circumnuclear Medium of Tidal Disruption Events with Radio Observations
Chang Zhou, Wei-Hua Lei, Xiangli Lei et al. (+3 more)
Tidal disruption events (TDEs) are unique tools for investigating quiescent supermassive black hole (SMBH),
accretion physics, and circumnuclear medium (CNM) environments. The CNM density profile is of great astrophysical significance, since it provides key diagnostics for the
accretion history of dormant SMBH. TDEs can launch
outflows that produce
radio emission when propagating into the CNM. The synchrotron
radio flux density can be described by a series of power-law segments $F_\nu \propto t^{-\alpha} \nu^{-\beta}$. The closure relation (CR), i.e., the relation between the temporal indices $\alpha$ and the spectral indices $\beta$, are therefore monitoring the CNM density profile. In this work, we first collect 53 TDEs with
radio observations to date. We then obtain the predicted CR for arbitrary CNM and different dynamical phases of the
outflow, and apply to the
radio TDE sample. We constrain the CNM density profile for 26
radio TDEs with good data quality. The results are generally consistent with those estimated with equipatition method, suggesting that CR analysis is efficient in the study of CNM profile for a quiescent SMBH.
Read the full abstract ▾
All authors Chang Zhou, Wei-Hua Lei, Xiangli Lei, Po Ma, Shao-Yu Fu, Zi-Pei Zhu
Instrumentation and Methods for Astrophysics · Cross-listed from gr-qc
Accelerated Time-domain Analysis for Gravitational Wave Astronomy
Vaishak Prasad
Most current compact-binary searches and parameter-estimation pipelines evaluate the Gaussian-noise likelihood approximately using frequency-domain inner products with great success in analyzing gravitational-wave signals. This is historically motivated by (i) the approximate stationarity of detector noise on sufficiently long timescales, allowing a circulant approximation in the domain that diagonalizes the noise covariance in the
Fourier basis, and (ii) the efficiency of matched filtering via fast
Fourier transforms. However, the advantage of frequency-domain analysis comes with its own limitations. In this article, we develop a self-contained, end-to-end, fully time-domain formulation of gravitational-wave inference and present an implementation that makes the likelihood evaluation practical at scale by exploiting structured linear
algebra, software, and hardware acceleration. We validate the method using injections and demonstrate speedups for likelihood evaluation and on modern GPUs. We present tdanalysis, an accelerated implementation that handles gaps, sharp boundaries, and multiple disjoint segments, and supports GPUs. We demonstrate some of its applications in gravitational wave astronomy.
Read the full abstract ▾
Astrophysics of Galaxies
Indications of electron-to-proton mass ratio variations in the Galaxy. III. 0.6mm methanol lines toward SgrB2(N) and Orion-KL
J. S. Vorotyntseva and S. A. Levshakov
In this paper, we show that methanol (CH3OH) torsional-rotational transitions, which have increased sensitivity to small variations of mu - the electron-to-
proton mass ratio, are shifted relative to less sensitive transitions in the spectrum of the SgrB2(N) molecular cloud located at the
Galactic center. At the same time, an identical set of methanol lines in the spectrum of the Orion-KL molecular cloud, located far from the center, shows no shifts. Interpreting this behavior of molecular frequencies in terms of Delta mu/mu = (mu_obs - mu_lab)/mu_lab leads to the following weighted mean values: <Delta mu/mu> = (-3.4 +/- 0.4)*10^(-7) for SgrB2 and <Delta mu/mu> = (-1.1 +/- 0.8)*10^(-7) for Orion-KL (indicated are the total +/-1sigma errors of the weighted means <Delta mu/mu> including both statistical and systematic uncertainties). A possible correlation between <Delta mu/mu> values measured in various molecular clouds of the
Galactic disk and the distribution of dark matter along the
Galactic radius is discussed, which may suggest a hypothetical modulation of the
Higgs scalar field by dark matter, resulting in a change of mu.
Read the full abstract ▾
Astrophysics of Galaxies
The MeerKAT 1.3 GHz survey of the Large Magellanic Cloud: Point Source Catalogue
N. Rajabpour, M. D. Filipović, W. D. Cotton et al. (+6 more)
We present a point source catalogue of the Large Magellanic Cloud (LMC) using observations from the MeerKAT
radio telescope across a broad frequency band centred at 1295 MHz (L-band) with 12 sub-bands and an angular resolution of 8 arcsec x 8 arcsec. We investigate the source flux density distribution and spectral indices and compare these results with previous
radio catalogues, such as surveys conducted with the Australian Square Kilometre Array Pathfinder (ASKAP) at 888 MHz. This new MeerKAT survey reaches a lower average noise level of 11 microJy beam^-1, compared with the previous ASKAP level of 58 microJy beam^-1. The higher sensitivity and resolution enable the detection of a significantly larger number of faint sources. The catalogue contains 339,128 point sources, representing a substantial increase compared with the 54,612 sources detected in the ASKAP survey. This catalogue provides improved insight into the source population distribution, spectral properties, positional accuracy, and the overall improvement in source recovery and survey depth in the LMC region.
Read the full abstract ▾
All authors N. Rajabpour, M. D. Filipović, W. D. Cotton, Z. J. Smeaton, A. C. Bradley, E. J. Crawford, M. Ghavam, O. K. Khattab, J. Th. van Loon
Astrophysics of Galaxies
SwinYNet: A Transformer-based Multi-Task Model for Accurate and Efficient FRB Search
Yunchuan Chen, Shulei Ni, Chan Li et al. (+11 more)
In this study, we present a
transformer-based multi-task model for Fast
Radio Burst (FRB) detection, signal
segmentation, and parameter estimation directly from time-frequency data, without requiring computationally expensive de-dispersion preprocessing. To overcome the scarcity of labeled observational data, we develop an FRB simulator and a rule-based automatic annotation pipeline, enabling training exclusively on simulated data. Evaluations on the FAST-FREX
dataset show that our model achieves an F1 score of 97.8%, recall of 95.7%, and precision of 100%, outperforming both conventional tools (e.g., PRESTO, Heimdall) and recent AI-based baselines (e.g., RaSPDAM, DRAFTS) in both accuracy and inference speed. The model supports pixel-level signal
segmentation and yields reliable estimates for dispersion measure (DM) and time of arrival (ToA). Large-scale blind searches on CRAFTS data further demonstrate robustness, with an average false positive rate of 0.28% and minimal human verification required. This search has already led to the identification of two
pulsar candidates, both confirmed as known
pulsars. Processing
benchmarks indicate that the model enables real-time searches on a single consumer-grade GPU, making petabyte-scale blind searches feasible. The code is publicly available on GitHub, and the model can be easily integrated with existing tools to automate and streamline
radio data analysis beyond FRB or
pulsar searches.
Read the full abstract ▾
All authors Yunchuan Chen, Shulei Ni, Chan Li, Jianhua Fang, Dengke Zhou, Huaxi Chen, Yi Feng, Pei Wang, Chenwu Jin, Han Wang, Bijuan Huang, Xuerong Guo, Donghui Quan, Di Li
Astrophysics of Galaxies
Extremely Metal-Poor Galaxies in DESI DR1: Connections to Galaxies in the Early Universe
Jipeng Sui, Hu Zou, Dirk Scholte et al. (+43 more)
Extremely Metal-Poor
Galaxies (XMPGs), defined as having
metallicities below 10% of the
solar value, are considered possible local analogs to
primordial systems and offer a unique window into early
galaxy evolution. This study presents a large-scale search for XMPGs using data from the Dark Energy Spectroscopic Instrument DR1, systematically evaluating their resemblance to high-
redshift galaxies. From a parent sample of over 14 million
galaxies, we identify 656 (551 new) confirmed XMPGs and 767 (670 new) high-quality candidates via the direct $T_{\mathrm{e}}$ method. Results reveal that XMPGs follow a distinct
star-forming main sequence (SFMS) that is elevated and shallower than that of the comparing
star-forming
galaxies. Notably, at higher
stellar masses ($M_{\star} > 10^{7.5} M_{\odot}$), the XMPG SFMS converges with the sequence observed in high-
redshift galaxies by James Webb Space
Telescope (JWST), indicating that mature XMPGs sustain
star formation rates comparable to their
primordial counterparts. Furthermore, XMPGs consistently deviate below the local fundamental
metallicity relation, mirroring high-
redshift galaxy behavior. These findings demonstrate that XMPGs not only exhibit low
metallicities but also preserve scaling relations characteristic of the early Universe, confirming their potential value as local laboratories for studying early
galaxy formation processes.
Read the full abstract ▾
All authors Jipeng Sui, Hu Zou, Dirk Scholte, Amélie Saintonge, Mar Mezcua, Malgorzata Siudek, Wenxiong Li, Wei-Jian Guo, Shufei Liu, Yunao Xiao, Francisco Prada, Siwei Zou, Jessica Nicole Aguilar, Steven Ahlen, Carlos Allende Prieto, Davide Bianchi, David Brooks, Yu-Ling Chang, Todd Claybaugh, Andrei Cuceu, Axel de la Macorra, Peter Doel, Jaime E. Forero-Romero, Enrique Gaztañaga, Satya Gontcho A Gontcho, Gaston Gutierrez, ChangHoon Hahn, Dick Joyce, Robert Kehoe, Martin Landriau, Laurent Le Guillou, Yifei Luo, Aaron Meisner, Ramon Miquel, Seshadri Nadathur, Nathalie Palanque-Delabrouille, Will Percival, Ignasi Pérez-Ràfols, Graziano Rossi, Eusebio Sanchez, David Schlegel, Hee-Jong Seo, Joseph Harry Silber, David Sprayberry, Gregory Tarlé, Benjamin Alan Weaver
Astrophysics of Galaxies
Controlled Experiments on Dark-Matter Halo Structure and Galaxy Morphology I: What Sets Galaxy Sizes?
Guangze Sun, Fangzhou Jiang and Jing Wang
The properties of
galaxies are intricately linked to the characteristics of their host dark-matter
haloes. We use a suite of controlled simulations of isolated
galaxies to quantify how
halo spin, concentration, inner density profile, and
baryon fraction regulate
galaxy sizes, at fixed
halo mass of $M_{\rm{vir}}=10^{11} M_\odot$. We generate initial conditions of
haloes and inhabitant spherical gas distributions in
equilibrium, on a parameter grid spanned by these four
halo parameters, and evolve the systems with the $\texttt{GIZMO}$ code and the $\texttt{FIRE-3}$ physics. The resulting half-mass radii of
stars and cold
baryons depend systematically on
halo structure and
baryon content:
galaxy size increases with
halo spin, decreases with
halo concentration, is weakly sensitive to the inner density slope except in highly cuspy
haloes, and is strongly suppressed at high
baryon fractions. We evaluate the relative importance of the
halo parameters on
galaxy size using different metrics including the quadratic response-surface method and random-forest regression, and consistently find
halo concentration to be the most informative predictor of size. The
baryon fraction shows a subtle, non-monotonic impact on size, by modulating how
galaxy size depends on
halo spin. Our results clarify which secondary parameters of host dark-matter
haloes dominate the scatter in
galaxy sizes at the massive-
dwarf mass scale.
Read the full abstract ▾
High Energy Astrophysical Phenomena
CTAO Simulations for Potential PeVatron Candidates
P. Sharma, C. Dubos and S. R. Patel T. Suomijarvi
This paper reports on the capabilities of the Cherenkov
Telescope Array Observatory (CTAO) in detecting high-energy gamma-rays that show significant contributions of hadronic origin. We focus on four sources: RX J1713.7-3946, HESS J1731-347, Cassiopeia A, and HAWC J2227+610, which have been previously identified as PeVatron candidates, sources capable of accelerating
hadrons to PeV energies. In this study, we perform simulations using Gammapy for each source to obtain flux estimates for CTAO. In case of HAWC J2227+610, we also determined the maximum cut-off energy in the
proton distribution detectable by measuring gamma-rays with CTAO. To distinguish between fluxes with different
proton cut-off energies we used the Test Statistic (TS) method. Additionally, we used the PeVatron Test Statistic (PTS) metric to demonstrate whether CTAO could confirm or exclude SNRs as PeVatron candidates. Through this study, we found that a minimum of 100 hours of observation time is required to detect flux variations with different cut-offs, with the detection limit being around 600 TeV. Through the PTS study, SNRs Cassiopeia A, RX J1713.7-3946, and HESS J1731-347 were excluded as PeVatron sources, while HAWC J2227+610 remains inconclusive.
Read the full abstract ▾
Astrophysics of Galaxies
Confirmation and Refutation of Lyman Continuum Leakers at $z\sim3$ with JWST NIRSpec/IFU
Shengzhe Wang, Xin Wang, Hang Zhou et al. (+10 more)
Our understanding of the physical mechanisms and environments conducive to the escape of Lyman-continuum (LyC) radiation within the first 2 Gyr of
cosmic history remains limited. Here we present a detailed analysis of JWST/NIRSpec medium-resolution IFU observations of two LyC-leaker candidates, LACES-94460 and LACES-104037 at z = 3.1, selected from deep HST/WFC3 F336W imaging and supported by ground-based spectroscopy. We first rule out LACES-94460 as a genuine LyC leaker, demonstrating that its apparent F336W signal originates from a nearby low-
redshift interloper at z = 1.6, unambiguously identified through IFU spectroscopy. In contrast, for LACES-104037 we spectroscopically confirm bona fide LyC emission arising from a
tidal-tail structure during the early stage of a
galaxy merger, dubbed LACES104037-LyC. LACES104037-LyC exhibits extremely low rest-frame optical emission-line equivalent widths together with an exceptionally strong LyC flux. Within a picket-fence model framework, we reproduce its observed spectral and photometric properties with a young
stellar population of age $\sim5$ Myr and a LyC escape fraction of $f_{\mathrm{esc}} \sim 99\%$. Our identification and detailed modeling of LACES104037-LyC provide one of the first compelling observational demonstrations for merger-driven LyC escape, indicating that
galaxy mergers may represent an important and previously underappreciated contributor to the ionizing
photon budget relevant for
cosmic reionization. Furthermore, our analysis highlights the critical role of sub-kiloparsec resolution spectroscopy in securely identifying LyC leakers, removing contamination from closely projected low-
redshift interlopers, and pinpointing the physical regions responsible for LyC leakage.
Read the full abstract ▾
All authors Shengzhe Wang, Xin Wang, Hang Zhou, Yiming Yang, Zhiyuan Ji, Yuxuan Pang, Chao-Wei Tsai, Akio K. Inoue, Mengtao Tang, Themiya Nanayakkara, Karl Glazebrook, Hu Zhan, Pinjian Chen
Astrophysics of Galaxies
An updated model for the Perseus Spiral Arm from Trigonometric Parallax and 3-dimensional kinematic distances of distant massive stars
Lucas J. Hyland, Mark J. Reid, Simon P. Ellingsen et al. (+3 more)
We report trigonometric parallaxes and proper motions for three water masers and one methanol maser obtained with the VLBA as part of the BeSSeL Survey. Incorporating these parallaxes with 3-dimensional kinematic distances, we refine the position and pitch angle of the Perseus spiral arm in the 1$^\mathrm{st}$
Galactic quadrant. Extrapolating the Perseus and Sagittarius arm locations to beyond the
Galactic Center, we find that they intersect at an approximate Galactocentric azimuth of ${200^\circ}$ and radius of $5.6$~kpc.
Read the full abstract ▾
All authors Lucas J. Hyland, Mark J. Reid, Simon P. Ellingsen, Andreas Brunthaler, Xing-Wu Zheng, Karl M. Menten
High Energy Astrophysical Phenomena
Multiwavelength quasi-periodic variability of the blazar Ton 599
Yu. V. Sotnikova, T. V. Mufakharov, A. E. Volvach et al. (+34 more)
During the last 40-50 years, the TeV blazar Ton 599 has systematically experienced major outbursts detected in a wide wavelength range from
radio to $\gamma$-rays. In this work, we present an analysis of Ton 599 quasi-periodic variability across multiple wavelengths using an observing baseline from 1983 to 2025. The $\gamma$-ray, optical, and
radio emissions are found to be highly correlated with time lags $\sim0$-$360$ days, which indicates that they are triggered by the same population of particles. Using the Lomb-Scargle periodogram and the Weighted Wavelet Z-transform, we revealed several periodic components with characteristic periods of 1.4, 1.7, 2.3, 6.5, and 7.5 yrs. The result is consistent with the detection of periodic components in the 1997-2011 light curves, which means that we observe the same mechanism causing long-term periodic variability. A model of a binary supermassive black hole (SMBH) with a precessing jet, applied to the
radio light curves of Ton 599, yields frequency-dependent best-fitting parameters with orbital periods ranging from $\sim$1.2 to 1.7 yrs and precession periods from $\sim$5.8 to 7.7 yrs. This result implies the existence of an SMBH system modulating emission through both the orbiting and jet precession effects, with differing observed periods possibly reflecting frequency-dependent emission regions along a structured, stratified jet. Nonetheless, the short-term periodicity and exceptionally strong
flares likely arise from internal jet shocks, which aligns with typical blazar behavior. We suggest that the multiband quasi-periodicity of Ton 599 is reasonably described by a combination of
geometric effects (orbital motion and precession) and
stochastic processes.
Read the full abstract ▾
All authors Yu. V. Sotnikova, T. V. Mufakharov, A. E. Volvach, V. V. Vlasyuk, M. L. Khabibullina, A. G. Mikhailov, T. An, D. O. Kudryavtsev, Yu. A. Kovalev, Y. Y. Kovalev, A. V. Popkov, S. S. Savchenko, A. K. Erkenov, D. A. Morozova, T. A. Semenova, O. I. Spiridonova, M. A. Kharinov, I. A. Rakhimov, T. S. Andreeva, L. Cui, X. Wang, N. Chang, R. Yu. Udovitskiy, P. G. Zhekanis, G. A. Borman, T. S. Grishina, E. N. Kopatskaya, E. G. Larionova, I. S. Troitskiy, Yu. V. Troitskaya, A. A. Vasilyev, A. V. Zhovtan, D. V. Kratov, L. N. Volvach, E. V. Shishkina, A. I. Dmytrotsa, V. I. Zharov
Instrumentation and Methods for Astrophysics
Case study of a national-level academic conference organised in hybrid mode at low cost
Violet M. Harvey, Simon Lee, Bruce Dawson et al. (+2 more)
In July 2025, the University of Adelaide hosted the Astronomical Society of Australia's Annual Scientific Meeting on its North Terrace campus. We ran the conference in a hybrid mode, with options for in-person and online attendance. This report details the procedures that we used to enable the online mode of the conference at minimal cost and minimal inconvenience to the in-person attendees. We discuss our choices of hardware and software and how we integrated these systems together. We summarise our experience of organising a local AV team and the procedures that we set for running the AV in each session. We present statistics of the online attendance numbers and post-conference survey feedback, and discuss the lessons we feel other organisers may particularly be able to learn from.
Read the full abstract ▾
All authors Violet M. Harvey, Simon Lee, Bruce Dawson, Sabrina Einecke, Gavin Rowell
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Black Hole Vision: An Interactive iOS Application for Visualizing Black Holes
Roman Berens, Dominic O. Chang, Trevor Gravely et al. (+1 more)
The Black Hole Explorer (BHEX) is a proposed mission to launch a sub-millimeter
radio telescope into Earth orbit that will take the sharpest images in the history of astronomy and reveal novel horizon-scale features of supermassive black holes. Black Hole
Vision is an open-source application, freely available on the iOS App Store, that produces lensed images which highlight the key features expected to appear in the black hole images BHEX will capture. The app combines
video feeds from the front- and rear-facing iPhone cameras and uses the black hole
lensing equations to synthesize an onscreen image displaying the user's surroundings as if they were gravitationally lensed by a black hole within the cameras' field of view. Here, we describe how light rays are lensed by non-rotating (Schwarzschild) and rotating (Kerr) black holes, and we list the equations needed for computing black-hole-lensed images. We also describe their specific implementation within Black Hole
Vision.
Read the full abstract ▾
All authors Roman Berens, Dominic O. Chang, Trevor Gravely, Alexandru Lupsasca
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Searching for precessing binary systems with mode-by-mode filtering and marginalization
Zihan Zhou, Digvijay Wadekar, Javier Roulet et al. (+8 more)
Nearly all previous binary black hole searches in LIGO–Virgo–KAGRA (LVK) gravitational wave data have assumed that the component
spins are aligned with the orbital angular momentum, thereby neglecting
spin-precession effects in the waveform, which can lead to potentially missing interesting signals. Precessing searches are challenging, because the extra degrees of freedom due to misaligned
spins lead to: $(i)$ a much larger number of templates compared to the aligned-
spin configurations, $(ii)$ an increased rate of background triggers. To address this, we develop novel precessing signal template banks using mode-by-mode filtering and marginalization methods. We use the precession harmonic decomposition from Fairhurst et al. (2019) and filter each precessing harmonic separately with the data. We then marginalize over the SNRs from different harmonics in our detection statistic. We also use machine learning methods to improve our search efficiency: $(i)$ we use singular value decomposition together with random forest regressor to reduce redundancy in the dominant precessing-harmonic templates; $(ii)$ we use normalizing flows to generate optimal prior samples for harmonic SNRs for the marginalized statistic. We show that marginalizing (instead of maximizing) over the harmonic mode SNRs increases the search sensitive volume by $\sim 10\%$. Results from searching in LVK data using this framework will be reported in a companion paper.
Read the full abstract ▾
All authors Zihan Zhou, Digvijay Wadekar, Javier Roulet, Oryna Ivashtenko, Tejaswi Venumadhav, Tousif Islam, Ajit Kumar Mehta, Jonathan Mushkin, Mark Ho-Yeuk Cheung, Barak Zackay, Matias Zaldarriaga