Astrophysics of Galaxies
Studying Outflows with Synthetic Absorption Line Spectra from High Resolution Simulations
Jake Magee, Evan Schneider, Kate H. R. Rubin et al. (+2 more)
Down-the-barrel absorption line spectra are a powerful probe of the properties of multiphase galactic outflows. In this work, we demonstrate a method to generate realistic synthetic spectra using high resolution ($\Delta x=5-20 \ \mathrm{pc}$), 20-kiloparsec-scale outflow simulations from the next generation of the CGOLS project. Aiming to mimic modern observational surveys of nearby
star-forming
galaxies, we generate a suite of UV absorption lines, from which we measure common observables such as equivalent widths and velocity statistics, and compare them to observed values. The velocity statistics from the simulated data agree well with high-resolution, far-UV HST treasury data, but the equivalent widths (EWs) display more variability. Our fiducial EWs are systematically lower than the empirical predictions by $\sim50-97\%$, particularly in the lines with higher ionization potentials, though these values increase with inclination angle,
star formation rate, and time. We find a strong correlation between the measured outflow velocity and ionization potential, reminiscent of the known correlation between velocity and temperature from the simulations. We also study the effect of simulation resolution on our statistics, finding the EWs to be much more sensitive to the simulation resolution than the velocities. Overall, we find that we can generate realistic synthetic spectra from high-resolution hydrodynamic simulations that are qualitatively similar to observations. In future work, we will further improve the physical realism of our synthetic spectra by implementing a more accurate ionizing background spectrum, with the ultimate goal of improving constraints on derived outflow properties from observations.
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All authors Jake Magee, Evan Schneider, Kate H. R. Rubin, S. Alwin Mao, Cameron Hummels
Earth and Planetary Astrophysics
Constraining Tidal Migration with the Hot Jupiter Population
Linhao Ma, Yubo Su, Samuel W. Yee et al. (+3 more)
Hot Jupiters with orbital periods shorter than a few days have probably been affected by tidal orbital migration. We develop an analytical framework for constraining tidal migration from the present-day hot Jupiter period distribution, taking into account the uncertain rate and period distribution of hot Jupiters produced by mechanisms such as high-eccentricity migration or disk-driven migration. Assuming the tidal migration timescale is proportional to $P^{\chi_\tau}$, solutions with $\chi_\tau \simeq 3, 1.7,$ and 5.6 are all compatible with the present-day period distribution. The $\chi_\tau \simeq 3$ solution is consistent with
equilibrium tides with suppression of dissipation at short periods, and implies that newly circularized hot Jupiters have periods concentrated near $3-4$ days, as predicted in some high-eccentricity migration models. The $\chi_\tau \simeq 1.7$ solution is also compatible with the $3-4$ day peak but has no clear counterpart in existing tidal theories and is more finely tuned. The $\chi_\tau \simeq 5.6$ solution is compatible with enhanced short-period
equilibrium tidal dissipation or weakly nonlinear
gravity-wave dissipation, but requires circularization at unexpectedly short periods. Thus, we find the model with $\chi_\tau \simeq 3$ most appealing. Transit timing of individual systems and observational constraints on the rate of hot Jupiter engulfment provide additional constraints, which are presently inconclusive but should improve with future data. Improved measurements of the occurrence of short-period
planets as a function of
planet mass and system age could also help to sharpen the constraints on tidal migration.
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All authors Linhao Ma, Yubo Su, Samuel W. Yee, Caleb Lammers, Eliot Quataert, Joshua N. Winn
High Energy Astrophysical Phenomena
XRISM observations of the Perseus cluster along two arms: Chaotic ICM motions probed by resonant scattering
Annie Heinrich, Irina Zhuravleva, Congyao Zhang et al. (+13 more)
XRISM has mapped gas velocities across the core of the Perseus cluster, separating the kinematic effects of mergers and AGN feedback. The physical properties of these motions remain unclear: are they a superposition of bulk flows, predominantly random/turbulent motions, or a mixture of both? Without resolving this question, constraints on the nonthermal pressure fraction and heating rate remain uncertain, as both assume predominantly random motions. Unlike emission line broadening, resonant scattering is most sensitive to small-scale, random motions rather than coherent bulk flows. Taking advantage of the extensive XRISM coverage of the Perseus cluster, we detect the full effects of resonant scattering on the He{\alpha} w line for the first time. This includes flux suppression in the cluster center, enhancement in the outer regions, and non-Gaussianity in the emission line. We employ radiative transfer simulations to constrain the amplitude of small-scale ICM velocities in the inner 60 kpc of Perseus, finding them to be consistent with the line broadening measurements within the uncertainties. This indicates the observed velocity dispersion is primarily due to small-scale random motions in the central Perseus regions rather than coherent bulk flows. We further explore potential anisotropy of these motions, showing that they are consistent with isotropic or radial motions rather than tangential ones. Longer XRISM observations are required to improve these anisotropy constraints. Finally, we explore azimuthal variations between the two complete radial arms observed by XRISM.
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All authors Annie Heinrich, Irina Zhuravleva, Congyao Zhang, Anna Ogorzalek, Ayşegül Tümer, François Mernier, Phillip C. Stancil, Elena Bellomi, Lior Shefler, John ZuHone, Yutaka Fujita, Julie Hlavacek-Larrondo, Yuto Ichinohe, Kyoko Matsushita, Nhut Truong, Shutaro Ueda
Solar and Stellar Astrophysics
Frozen-composition effects on rotational failure of neutron-star crusts
Elia Giliberti
The elastic response of a
neutron-
star crust to rotational loading depends on whether weak interactions can restore chemical
equilibrium during the deformation. We quantify this effect using unified equations of state and compare chemically equilibrated and frozen-composition responses within the same Newtonian hydro-elastic framework. Frozen composition increases the effective bulk modulus and redistributes the strain throughout the inner crust rather than producing a simple global rescaling. For BSk24, the breaking frequency decreases from $0.4997\Omega_K$ to $0.3912\Omega_K$, a reduction of 21.7 per cent, while the location of first failure moves to higher density. Comparable reductions are obtained for BSk21, whereas SLy4 gives a smaller effect of 16.7 per cent. For BSk24 the relative reduction remains close to 21–22 per cent over the mass range $1.2$–$2.0,M_\odot$. A density-resolved perturbation analysis shows that the result is controlled by the radial overlap between the microphysical frozen-composition stiffening and the mechanical susceptibility of the crust, with most of the linear sensitivity in the BSk models arising from $0.01<n_B<0.03,{\rm fm}^{-3}$. These results show that chemical non-
equilibrium can substantially modify both the rotational failure threshold and the layer in which crustal failure begins.
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Instrumentation and Methods for Astrophysics
Magnetising the quokka code with fast, second-order accurate, error-correcting schemes for magnetohydrodynamics on GPUs
Neco Kriel, Elizabeth Cole-Kodikara, Benjamin Wibking et al. (+4 more)
We implement a second-order accurate constrained transport (CT) magnetohydrodynamics (MHD) module with first-order flux correction in the open-source, adaptive mesh refinement (AMR), GPU-accelerated code quokka, supporting both ideal and resistive (constant Ohmic) regimes. For computing and averaging the electromotive forces (EMFs) at
cell edges, the basis of any CT-MHD method, we experiment with a wide range of recent, state-of-the-art schemes, together with different reconstruction schemes. Alongside these, we develop a new EMF compute scheme that requires fewer reconstruction steps than existing approaches. We evaluate these scheme combinations on the basis of accuracy, stability, and GPU throughput, and demonstrate that our new scheme achieves accuracy comparable to the best-in-class existing methods, together with greater stability in reconnection-dominated flows and roughly 25–60% higher GPU throughput. Using this scheme, quokka achieves excellent results across a wide range of MHD flow regimes, reaching >50 million
cell updates per GPU per second, with >70% parallel efficiency out to >500 GPUs. Finally, we confirm that our CT implementation preserves divergence-free
magnetic fields (to machine precision) under AMR.
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All authors Neco Kriel, Elizabeth Cole-Kodikara, Benjamin Wibking, Mark R. Krumholz, Chong-Chong He, Anish Sarkar, Pak Shing Li
Earth and Planetary Astrophysics
Fast and Furious: Long-term orbit integrations with collocation integrator Lobbie
Dmitrii E. Vavilov, Siegfried Eggl and Sarah Greenstreet
Efficient and accurate numerical integration methods are fundamental to studying long-term solar system dynamics, where numerical errors can accumulate over billions of orbital periods. In this work, we investigate the performance of our modification of Lobbie, a Lobatto collocation integrator for long-term simulations of the Solar System. We compare Lobbie against the widely used WHFast symplectic integrator and the high-order adaptive collocation integrator IAS15 implementations in the Rebound package. The performance of the integrator is evaluated using five
benchmark problems: a circular two-body orbit integrated over 100 Myrs, two-body orbits with eccentricities up to 1-10^{-6} to test the adaptive step size control during repeated close encounters, the full eight-
planet Solar System integrated over 100 Myrs, the four giant
planets integrated over 10 Gyrs, and the eight-
planet Solar System together with 50 asteroids on Aten-like orbits integrated over 1Myr to test the integrator's consistency in a chaotic, close-encounter-rich environment. Across all tests, Lobbie demonstrates excellent long-term stability and competitive computational performance. For full Solar System integrations, Lobbie achieves relative energy conservation at the level of 10^{-14} while outperforming IAS15 in computational efficiency and approaching the speed of WHFast at comparable accuracy. In the Solar System plus asteroids test, Lobbie also keeps different realizations of Jupiter's orbit consistent with each other to within about 1.5 km after 1 Myr of integration, two orders of magnitude better than IAS15, being twice faster. Our results demonstrate that Lobbie provides a powerful universal alternative to traditional symplectic mappings or Gauss-Radau collocation methods for long-term dynamical simulations in celestial mechanics.
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Instrumentation and Methods for Astrophysics
Instrument-Level Validation of Upper Sideband Syntonization Concept
Volodymyr Kudriashov and Manuel Martin-Neira
Upper Sideband Syntonization (USBS) is a two-way frequency-transfer concept proposed by the European Space Agency for distributed space
radio interferometric systems. Previous investigations validated the concept primarily through frequency-stability and phase-transfer measurements. This work demonstrates the first end-to-end instrument-level validation of the USBS concept through coherent W-band cross-correlation measurements and image reconstruction. A P=2 USBS breadboard was integrated with a W-band
radio interferometer developed for this test. The synchronized local oscillators (LOs) were evaluated through long-term cross-correlation measurements and coherent imaging of a point-like noise source. The results were compared with those obtained using a conventional common LO as well as two independent free-running LOs. The USBS-derived LOs maintained coherence over 500 s of cumulative effective integration time acquired over approximately five days of elapsed time and preserved inter-session phase stability over measurements spanning 40 days. The reconstructed image is nearly indistinguishable from that obtained with a common LO, whereas independent free-running LOs lead to severe coherence degradation, image distortion, and approximately 38 dB loss of peak response. The results demonstrate that USBS preserves the interferometric coherence required for W-band imaging and present the first end-to-end instrument-level validation of the USBS syntonization concept for future distributed space
radio interferometric missions
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Astrophysics of Galaxies
The THRILS Factor: Investigating the properties of Little Red Dots (LRDs) at 3<z<6 with JWST/NIRSpec
Ananya Ganapathy, Rebecca L. Larson, Erini Lambrides et al. (+20 more)
JWST has uncovered a class of objects called LRDs, whose nature is still widely debated. In this work, we present a comprehensive spectroscopic analysis of nine LRDs in the Extended Groth Strip (EGS) field studied as part of THRILS and C3PO, both JWST Cycle 3 programs. These targets, photometrically selected based on their compact red appearance, are observed with deep spectroscopic exposures ($\geq8$ hours), enabling robust detections of broad Balmer lines, He I emission, and other spectral features characteristic of AGN activity. Using the [SII] $\lambda\lambda6716,6731$ doublet, we find electron densities ($n_e$) between $2.33 < \log (n_e) < 2.97 \ \mathrm{cm^{-3}}$, comparable to those in narrow line regions (NLR) of local AGN and high-$z$
galaxies. The spectroscopic depth further enables detailed characterization of broad Balmer line profiles. We fit both Gaussian and convolved exponential models to each source and find that five LRDs are statistically better described by the latter model. We measure optical depths $\tau_{\rm sc} = 0.56-0.91$, scattering fractions $f_{\rm SC} = 0.40-0.82$ which correspond to column densities log(N$_e$) $\sim$ 23.93-24.14 cm$^{-2}$, and covering fractions $c_f = 0.43-0.59$. These results indicate a clumpier broad line region (BLR) geometry that deviates from conventional LRD models, which predict covering fractions close to unity. Furthermore, these Compton-thick gas columns may explain the X-ray weakness of LRDs. We also find that THRILS LRDs are narrow-line dominated compared to literature AGN-dominated LRDs, and show that exponential profile fitting corrects for systematic overestimation of black hole masses from Gaussian-based measurements.
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All authors Ananya Ganapathy, Rebecca L. Larson, Erini Lambrides, Guillermo Barro, Taylor A. Hutchison, Pablo Arrabal Haro, Anthony J. Taylor, Dale Kocevski, Casey Papovich, Steven L. Finkelstein, Anton M. Koekemoer, Jonathan R. Trump, Pablo G. Pérez-González, Weida Hu, Volker Bromm, Dan Coe, Kelcey Davis, Michaela Hirschmann, Nikko J. Cleri, Ray A. Lucas, Stephan R. McCandliss, L. Y. Aaron Yung, Jorge A. Zavala
Cosmology and Nongalactic Astrophysics
$w_0w_a$ or $bc$: DESI constraints on relative baryon-CDM perturbations
Ananda F. Smith, Mikhail M. Ivanov, Roger de Belsunce et al. (+3 more)
We carry out a search for the relative baryon-cold dark matter (CDM) density and velocity modes in the DESI full-shape (FS) data, and investigate whether DESI's preference for evolving dark energy can be affected by these relative perturbations, which are a known contaminant of the baryon acoustic oscillations. For the first time, we use a holistic effective field theory (EFT) treatment of the power spectrum and bispectrum both for the standard terms (without relative perturbations), modeled in EFT to one-loop order, and for the relative perturbations. For the latter we implement an efficient computation of the one-loop power spectrum that allows us to scan over different cosmologies. We obtain robust constraints on the relative density and velocity bias parameters $b_{\delta_{bc}}$, and $b_{v^2_{bc}}$ for all the DESI DR1 tracers, finding e.g. $b_{\delta_{bc}}=5 \pm 6$, $b_{v^2_{bc}}=-0.031\pm 0.023$ (at 68% CL) for the LRG2 sample in a DESI FS-only analysis within $\Lambda$CDM, supplemented by CMB priors on the baryon density and spectral tilt. Assuming instead a $w_0w_a$CDM cosmological model, and combining DESI FS with the CMB primary anisotropies, CMB
lensing, and Pantheon+
supernovae, our LRG2 constraints read $b_{\delta_{bc}}=2 \pm 5$, $b_{v^2_{bc}}=-0.032\pm 0.022$. Adding the relative velocity divergence biases we find $b_{\delta_{bc}}=-17_{-17}^{+19}$, $b_{\theta_{bc}}=-760_{-680}^{+700}$, $b_{v^2_{bc}}=-0.032\pm 0.024$ for the same sample. The constraints on the dark energy equation of state parameters are virtually unchanged when marginalizing over the baryon-CDM modes. We conclude that DESI's preference for evolving dark energy is robust with respect to the baryon-CDM relative perturbations.
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All authors Ananda F. Smith, Mikhail M. Ivanov, Roger de Belsunce, Shi-Fan Chen, Anton Chudaykin, Oliver H. E. Philcox
Solar and Stellar Astrophysics
UX Men: Detached Eclipsing Binary as a Benchmark Candidate
Ganesh N. Pawar, Krzysztof G. Hełminiak, Nicola J. Miller et al. (+5 more)
We present ultra-precise fundamental parameters for the detached eclipsing binary UX Men based on 31 TESS sectors ($\sim$882 d) and radial velocities from HARPS, FEROS, CORALIE, and UCLES. The light curves were detrended for spot-induced variability and modelled independently with JKTEBOP and ALLESFITTER, while radial velocities were extracted via TODCOR and fitted with a Keplerian orbit. Spectral disentangling yielded individual component spectra analysed with iSpec to determine $T_{\rm eff}$ and $\mathrm{[M/H]}$. Multi-band photometry was used to determine the fluxes, flux ratios and ultimately to measure photometric $T_{\rm eff}$. We obtain the masses $M_{\rm A}$ = $1.2300 \pm{0.0012}$ M$_{\odot}$, $M_{\rm B}$ = $1.1946\pm{0.0012}$ M$_{\odot}$ and radii $R_{\rm A}$ = $1.3605\pm{0.0031}$ R$_{\odot}$, $R_{\rm B}$ = $1.2801\pm{0.0069}$ R$_{\odot}$ with sub-percent precision. Uncertainties were found to be dominated by systematic effects coming from (weak) stellar activity. $T_{\rm eff,A}$ = $6302\pm{77}$, $T_{\rm eff,B}$ = $6292\pm65$ &
Metallicity estimates are $[M/H]_{\rm A} = 0.02\pm{0.13}$ dex and $[M/H]_{\rm B}= 0.07\pm{0.10}$ dex. Isochrone fitting yields a consistent age of $\tau$ = $2.75\pm{0.13}$ Gyr. The system exhibits a $\sim$ 673-day periodicity in eclipse-timing variations, likely due to stellar activity, with no evidence for a third body. Results are independent of the modelling code used, but without proper treatment of activity-induced systematics the uncertainties would be underestimated. UX Men is a high-precision
benchmark binary providing stringent tests of stellar models and a robust calibration source for PLATO. Expanding the sample of well-characterised detached eclipsing binaries will strengthen the empirical foundations for stellar physics and the calibration of future photometric missions
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All authors Ganesh N. Pawar, Krzysztof G. Hełminiak, Nicola J. Miller, Frédéric Marcadon, Ayush Moharana, Tilaksingh B. Pawar, Anish Kalsi, Maciej Konacki
High Energy Astrophysical Phenomena
Low-Mass Magnetic Monopoles in the Galaxy: Simulations and Comparison with Ultra-High-Energy Cosmic-Ray Data
Ala'a AL-Zetoun, Igor Ostrovskiy, Peiwen Mi et al. (+1 more)
Origin and composition of ultra-high energy
cosmic rays are still uncertain, particularly the rare events exceeding the Greisen-Zatsepin-Kuzmin cutoff and whose apparent arrival directions point to the Local Void. This work is an in-depth investigation of the possibility that such
cosmic rays contain low-mass
magnetic monopoles predicted in several recent theoretical models. Using a custom extension to CRPropa, a state-of-the-art code for modeling
cosmic ray propagation, monopoles are tracked in the galactic environment under realistic assumptions on mass,
magnetic charge, and initial phase-space distributions. Our simulations demonstrate that relic MMs follow filamentary “Galactic
magnetic funnels”, producing anisotropic arrival directions at Earth. The expected arrival directions are concentrated in a small region of the sky, which has significant implications for the design and interpretation of future searches. A comparison of the simulated arrival directions with the Pierre Auger Observatory
dataset shows that the null hypothesis - no monopole contribution - is statistically preferred for the majority of cases. Using a profile-likelihood analysis that incorporates both directional and energy information, we set 90% C.L. upper limits on the integral MM flux of $< 2.1\times10^{-23}$ $\mathrm{cm^{-2}s^{-1}sr^{-1}}$.
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All authors Ala'a AL-Zetoun, Igor Ostrovskiy, Peiwen Mi, Daniele Perri
Astrophysics of Galaxies
A Novel Approach to 3D Dust Mapping of the Central Molecular Zone
Arianna Vasini, Mattia C. Sormani, Jason L. Sanders et al. (+12 more)
The 3D distribution of dust and gas in the Milky Way's Central Molecular Zone (CMZ) is key to understanding gas inflows toward the Galactic Centre (GC), the process of
star formation in this extreme environment, and the propagation of energetic
cosmic rays originating from Sgr A*. However, while recent efforts have combined
datasets in a
Bayesian framework to estimate the near/far positions of individual molecular clouds in the CMZ, conflicts between different methodologies still remain and we are still lacking a comprehensive, model-independent map of all of the gas and dust in the CMZ, which is critical to address key science questions. Here we develop a new methodology to infer the 3D dust distribution of the CMZ. The key idea of the method is to use stellar proper motions to get probabilistic information about the unknown stellar distances through a model of the distribution of
star positions and velocities of the nuclear stellar disc (NSD), co-spatial to the CMZ. Taking stellar proper motions and extinctions as input, the latter adopted as a proxy of the dust column density, the method returns the 3D dust distribution. It is non parametric, makes no a-priori assumption on the dust distribution, and is fundamentally distinct and largely independent of all existing methods. We show that the method can robustly and effectively reconstruct the mock 3D CMZ structure by testing it on a range of mock dust distributions, both analytically generated and taken from hydrodynamical simulations. Finally, we discuss the prospects for applying the method to real data.
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All authors Arianna Vasini, Mattia C. Sormani, Jason L. Sanders, Adam Ginsburg, Cara Battersby, Francisco Nogueras-Lara, Rainer Schödel, Eva Deliporanidou, Marco Donati, Zi-Xuan Feng, Karl Fiteni, Savannah Gramze, Xingchen Li, Dani R. Lipman, Perry H. Hatchfield
Solar and Stellar Astrophysics
Solar Flare Prediction Using a Hybrid Convolutional Neural Network and Transformer Model
Mason Cao and Junwei Zhao
Solar
flares are intense bursts of electromagnetic radiation that occur when stored
magnetic energy in the Sun's atmosphere is suddenly released. They are categorized into five classes – from least to most powerful: A, B, C, M, and X – with each successive class representing a ten-fold increase in energy output. The electromagnetic radiation emitted by the stronger classes (C, M, and X) is capable of causing significant disruptions to communication systems, satellites, and power grids on Earth. Accurate prediction of solar
flares is crucial for mitigating their adverse effects and ensuring the functionality of critical infrastructure. This research introduces a novel model named ResNet-
Transformer, which combines a convolutional neural network (CNN), ResNet50, with a standard
Transformer architecture. The hybrid model effectively processes both spatial and time-series data derived from solar images to predict the occurrence, class (C, M, and X), and probability of solar
flares within 24-hour, 36-hour, and 72-hour windows. This hybrid deep learning model represents the first of its kind in the domain of image-based, multiclass solar
flare prediction. We evaluated the model's performance using a comprehensive set of metrics, including weighted precision, recall, and F1 score, together with balanced accuracy, the Matthews correlation coefficient (MCC), Cohen's kappa, and the area under the receiver operating characteristic curve (ROC-AUC). Results show that ResNet-
Transformer surpasses traditional machine learning methods, such as support vector machines (SVMs) and standalone CNN models, across all evaluated metrics. This study highlights the potential of integrating convolutional neural networks with
Transformers to enhance predictive capabilities in solar physics, paving the way for more reliable and timely solar
flare forecasting.
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Instrumentation and Methods for Astrophysics · Cross-listed from physics.optics
New Method for Path-length Equalization of Long Single-mode Fibers for Interferometry
M.Anderson, J. D. Monnier, K. Ozdowy et al. (+2 more)
The ability to use single mode (SM) fibers for beam transport in optical interferometry offers practical advantages over conventional long
vacuum pipes. One challenge facing fiber transport is maintaining constant differential path length in an environment where environmental thermal variations can lead to cm-level variations from day to night. We have fabricated three composite cables of length 470 m, each containing 4 copper wires and 3 SM fibers that operate at the astronomical H band (1500-1800 nm). Multiple fibers allow us to test performance of a circular core fiber (SMF28), a panda-style polarization-maintaining (PM) fiber, and a lastly a specialty dispersion-compensated PM fiber. We will present experimental results using precision electrical resistance measurements of the of a composite cable beam transport system. We find that the application of 1200 W over a 470 m cable causes the optical path difference in air to change by 75 mm (+/- 2 mm) and the resistance to change from 5.36 to 5.50 {\Omega}. Additionally, we show control of the dispersion of 470 m of fiber in a single polarization using white light interference fringes ({\lambda}c=1575 nm, {\Delta}{\lambda}=75 nm) using our method.
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All authors M.Anderson, J. D. Monnier, K. Ozdowy, J. Woillez, G. Perrin
Solar and Stellar Astrophysics
Hbeta Spicules, Small-scale Jets, and Hbeta Microflashes: Sub-arcsecond Dynamic Events and their Magnetic Origins in the Lower Solar Chromosphere Observed by DKIST
Navdeep K. Panesar, V. Aparna, Sanjiv K. Tiwari et al. (+3 more)
We examine an on-disk solar quiet region of enhanced
magnetic network using Hbeta images from Daniel K. Inouye Solar
Telescopes (DKISTs) Visible Broadband Imager (VBI) and line-of-sight magnetograms from DKISTs Visible Spectro-Polarimeter (ViSP). We also compare the ViSP magnetograms with co-aligned co-temporal line-of-sight magnetograms from the Solar Dynamics Observatory (SDO)/Helioseismic and
Magnetic Imager (HMI). We find:(i) Two types of chromospheric jet-like features: Hbeta spicules, and small-scale jets. Both are rooted near edges of
magnetic network lanes. Several sit close to ViSP-detected tiny islands of either minority-polarity flux or dips in majority-polarity flux. Hence, those several plausibly stem from mixed-polarity
magnetic flux, and are caused by chromospheric
magnetic reconnection. For He̱ta} spicules, the average width, length, lifetimes, and speeds are 420$\pm$400 km, 2600$\pm$1600 km, 4.3$\pm$0.25 min, and 12$\pm$4.7 kms. For small-scale jets, those are 385$\pm$100 km, 620$\pm$40 km, 5$\pm$3min, and 4.4$\pm$1.5 kms. (ii) H$\beta$ microflashes sit in evidently unipolar flux. Their widths, lengths, lifetimes, and speeds are 180$\pm$65 km, 365$\pm$100 km, 4.3$\pm$2.6 min, and 3.1$\pm$0.2 kms. (iii) At the base of a coronal plume, due to its higher spatial resolution than HMI, ViSP shows both some very strong (>800 G) majority-polarity flux not shown by HMI and some sub-arc-second minority-polarity-flux inclusions not shown by HMI. These sub-arcsecond chromospheric transients carry sufficient energy (10^{24}erg) to transiently heat the local chromosphere and corona and potentially contribute to solar-wind acceleration. They may represent the small-scale end of a continuum of
magnetic-reconnection-driven activity, highlighting the importance of DKIST's high-resolution
magnetic-field measurements for understanding small-scale chromospheric dynamics.
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All authors Navdeep K. Panesar, V. Aparna, Sanjiv K. Tiwari, Alphonse C. Sterling, Ronald L. Moore, J. M. da Silva Santos
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Binary-black hole spin population results may be driven by prior degeneracies
Noah E. Wolfe, Asad Hussain, Jack Heinzel et al. (+1 more)
Gravitational waves carry information on the
spins of merging binary-black holes. The orientations of their
spins relative to their orbits ("tilts")—while challenging to measure—differentiate the astrophysical formation mechanisms by which merging black hole binaries may form. Multiple analyses have reported tentative evidence that black hole
spins are preferentially oriented in the plane of the binary orbit. We show that these results are likely extrapolated from more easily measurable "effective
spin" parameters which characterize the gravitational-wave inspiral of black hole binaries but may not uniquely constrain their astrophysical formation. In particular, we reproduce a peak in the
spin tilt distribution with information about the marginal effective
spin distributions alone. We propose a
geometric picture to compare constraints on effective
spins to standard population modeling assumptions, suggesting that current inferences of a preferred
spin orientation are spurious.
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All authors Noah E. Wolfe, Asad Hussain, Jack Heinzel, Salvatore Vitale
High Energy Astrophysical Phenomena
Teglon: A Pixel-Level Pipeline for Galaxy-Informed Gravitational-Wave Follow-up Planning and Efficiency Analysis
D. A. Coulter, P. Darc, C. D. Kilpatrick et al. (+4 more)
We describe Teglon, an open-source database and analysis pipeline engineered to optimize the search for electromagnetic (EM) counterparts to gravitational wave (GW) sources. Teglon constructs a 3D
galaxy completeness metric from an input
galaxy catalog and convolves it with the 3D localization volume of a GW event, producing an updated posterior map informed by known
galaxy distributions. Using Teglon, users can ingest arbitrary instrument footprints — or download them directly from the Treasure Map — to generate dynamic observation plans that seamlessly interpolate between targeted
galaxy pointing and region tiling. By focusing efforts on high-probability volumes, Teglon significantly reduces the predicted search area to find EM counterparts and increases observational efficiency, especially for small field-of-view (<= 1 deg^2) instruments like the Nancy Grace Roman Space
Telescope. Furthermore, Teglon integrates with Redback to calculate pixel-level model detection efficiencies, enabling custom, event-specific observing strategies or retrospective detection efficiencies on an arbitrary grid of EM transient models. Teglon also supports custom science cases, such as prioritizing Active Galactic
Nuclei searches for EM counterparts to binary black hole mergers. Having supported
Gravity Collective and related programs from the LIGO-Virgo-KAGRA third observing run (O3) through O4, Teglon is being continuously developed to support O5 and beyond. We document the public repository lineage and packaging, and provide Version 2.0 as an open-source tool for the community.
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All authors D. A. Coulter, P. Darc, C. D. Kilpatrick, R. J. Foley, P. McGill, S. D. Wyatt, R. Hausen
Earth and Planetary Astrophysics
WASP-43b TESS Phase Curve Mapping: Evidence for a Hot Interior
Maura Lally, Ryan C. Challener, Elspeth Lee et al. (+1 more)
Phase-curve mapping probes various atmospheric properties depending on wavelength: thermal phase curves are dominated by atmospheric emission, while visible and near-infrared phase curves include reflected light. The measured planetary phase curve offset–the longitudinal offset of the hemisphere of peak brightness from the substellar point–is therefore sensitive to differing atmospheric processes in emission-dominated vs. reflection-dominated bands. In particular,
planets with partial western-dayside reflective cloud coverage show a westward reflected-light phase-curve offset relative to the thermal wavelengths. In this work, we analyze five sectors of TESS phase curve observations of the hot Jupiter WASP-43b and compare to previous published multi-band analyses to investigate dayside cloud coverage. We measure a mid-eclipse depth of 130 $\pm$ 34 ppm, indicating excess TESS planetary brightness above expectations based on observed and modeled thermal emission. Attributing this excess flux to reflection, we estimate a low
geometric albedo of $A_g$ $\approx$ 0.05 - 0.10. These findings support previous conclusions that WASP-43b lacks any significant cloud coverage on its dayside. Phase-curve mapping reveals a large eastward phase curve offset of 44 $\pm$ 18 degrees, significantly eastward of offsets measured at longer wavelengths with JWST, providing evidence for a cloud-free dayside. Both the detection of excess emission in the TESS band and the large measured eastward phase-curve offset support the conclusion that WASP-43b has a hot deep atmosphere that is probed at short wavelengths.
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All authors Maura Lally, Ryan C. Challener, Elspeth Lee, Nikole Lewis
Cosmology and Nongalactic Astrophysics
BINDing the lightcone: A suite of astrophysical ray-traced weak lensing and SZ maps
Max E. Lee, Shy Genel, Zoltan Haiman et al. (+2 more)
Recent multiwavelength observations of
galaxy group and cluster gas suggest stronger baryonic feedback than our best-calibrated hydrodynamical simulations produce, while modeling this feedback remains a primary source of uncertainty in Stage-IV weak-
lensing (WL) analyses. We present a suite of ray-traced maps generated with BIND (Baryonic INpainting with Deep learning), a conditional flow-matching model that paints baryonic mass and gas thermodynamics onto the
halos of dark-matter-only simulations, and which was developed in a companion paper. Applied to IllustrisTNG300-Dark and ray-traced, we generate convergence, optical depth, and Compton-$y$ maps at five source
redshifts, each with $1000$ pseudo-independent realizations. We build lightcones across a 256-node Sobol sequence spanning the thirty-dimensional IllustrisTNG
galaxy formation prior, with individual parameter variations and at the fiducial model. In validation, the maps match those built from the IllustrisTNG300
halos to within LSST-Y10-like precision for a range of WL statistics. Across the prior, the response to feedback exceeds Stage-IV statistical precision by more than an order of magnitude on small scales, and different statistics respond to different model sectors: galactic winds control the WL power spectrum and gas auto- and cross-spectra, while the stellar initial mass function slope and AGN parameters shape the morphological statistics (PDF, peaks, minima, and Minkowski functionals). Finally, we find that the response of statistics can be compressed into seven
halo properties which linearly predict a range of WL and SZ statistics. We publicly release the maps, statistics, and model tables.
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All authors Max E. Lee, Shy Genel, Zoltan Haiman, Greg L. Bryan, Boryana Hadzhiyska
Astrophysics of Galaxies
BIND (Baryonic INpainting with Deep learning): A Field-level Emulator for Galaxy Groups and Clusters
Max E. Lee, Shy Genel, Zoltan Haiman et al. (+3 more)
Baryonic feedback is a dominant source of systematic uncertainty for upcoming weak-
lensing surveys, but current tools for modeling its effect rely on spherical approximations and density profiles calibrated almost entirely on two-point statistics. We introduce BIND (Baryonic INpainting with Deep learning), a conditional flow-matching model that learns a field-level mapping from dark-matter-only
halos to their hydrodynamical counterparts. BIND is trained on
halos from the 1024 paired hydrodynamical and dark-matter-only simulations of the CAMELS $50\,h^{-1}\,\mathrm{Mpc}$ SB35 suite and samples dark matter, gas, and stellar mass fields over
redshift across the full 35-dimensional $\Lambda$CDM and IllustrisTNG
galaxy formation parameter space. BIND recovers dark matter, gas, and stellar masses at the percent level, reproduces azimuthally averaged profiles to $\lesssim10\%$ at all radii, and matches
halo shape distributions with high fidelity. The learned parameter dependence captures the rank correlations between the generated fields and the subgrid parameters, and the field-level response to individual parameter variations is recovered in both sign and morphology.
Halo mass is never supplied as conditioning, yet the baryon fraction, stellar-to-
halo mass relation, inter-component scaling relations, and the joint covariance of their residuals are all reproduced. We finally show that, applied
halo-by-
halo to a $(50\,h^{-1}\,\mathrm{Mpc})^3$ $N$-body volume with $512^3$ particles, BIND reproduces the projected matter power spectrum suppression to the accuracy ceiling set by pasting in the hydrodynamical
halos themselves, in minutes on one GPU. We release the trained BIND models and all generated
halos as open-source tools. A companion paper extends BIND to thermodynamic fields and non-Gaussian weak-
lensing statistics.
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All authors Max E. Lee, Shy Genel, Zoltan Haiman, Greg L. Bryan, Christopher C. Lovell, Boryana Hadzhiyska
Astrophysics of Galaxies
Predictions for astrometric microlensing in Gaia
Zofia Kaczmarek, David Sweeney, Łukasz Wyrzykowski et al. (+1 more)
ESA's astrometric space mission Gaia is uniquely positioned for microlensing studies thanks to its all-sky coverage and simultaneous astrometric and photometric observations. In Gaia Data Release 4 (DR4), astrometric time series will be published for the first time, providing a rich
dataset for isolated stellar remnant searches. In anticipation of DR4, we prepared tools for fitting photometric and 1D astrometric measurements. We tested the recovery of true event parameters and population distributions with Gaia-like observations. We created a mock survey of microlensing events mirroring Gaia DR4's design. The events were generated using dedicated Galactic simulations to provide realistic expectations on stellar and dark lens yields. For selected events, we simulated observations following Gaia's scanning law and precision, using the astromet package. Such simulations are needed to interpret forthcoming data; they also enable testing inference tools with known ground truth. We used nested sampling to infer full posterior distributions and compare them with the true lens parameters. Our simulation predicts $322 \pm 70$ microlensing events with astrometric signals above Gaia precision thresholds; $209 \pm 57$ of them have detectable photometric signals. Among those, $82 \pm 9$ and $49 \pm 7$, respectively, have remnant lenses. To assess Gaia's capabilities in constraining remnant mass distributions, we modelled $49$ events from this sample. We recovered the true Einstein times and radii for most events. Microlensing parallax measurements are consistent with true values but uncertain, limiting mass determination. We recommend focusing on events with bright sources or anomalous fits to optimize dark lens searches. We make available the mock Gaia time-series
dataset, as well as a toolkit repository for working with the data format, fitting models, and visualizing results.
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All authors Zofia Kaczmarek, David Sweeney, Łukasz Wyrzykowski, Ulrich Bastian
Astrophysics of Galaxies
Probing dynamics of extreme galaxies I. Dark matter content in ultra-diffuse galaxies
Filippo Bouchè, Chiara Buttitta, Saboura Zamani et al. (+6 more)
We investigate the internal structure of two
galaxies from the LEWIS sample: the ultra-diffuse
galaxy UDG-1 and the extended dwarf LSB-6. Both show coherent stellar rotation combined with a non-negligible fraction of random motion, with no signs of ongoing disturbance. This is the first attempt to constrain the dynamics and dark matter physics of rotation-supported UDGs through integral-field stellar kinematics. We model the
galaxies as stellar spheroids with typical dwarf-like thickness embedded in spherical dark matter
halos, deriving two-dimensional velocity fields that we compare with the observations in a
Bayesian framework. Besides cold dark matter, we test fuzzy, self-interacting, and non-minimally coupled dark matter. The data prefer a cuspy
halo in UDG-1 and a cuspless one in LSB-6. All the alternative models remain viable, although current data cannot conclusively discriminate among them. For fuzzy dark matter we obtain mutually consistent
boson masses, $m_\alpha = 4.7^{+1.8}_{-1.1} \times 10^{-22}$ eV for UDG-1 and $m_\alpha = 6.3^{+0.4}_{-0.4} \times 10^{-22}$ eV for LSB-6. For self-interacting dark matter, LSB-6 yields a robust constraint on the velocity-weighted cross section, $\langle \sigma v\rangle/m = 14.3^{+2.0}_{-1.9}$ cm$^2$ km g$^{-1}$ s$^{-1}$. For non-minimally coupled dark matter we derive upper bounds on the coupling length, implying marginal deviations from $\Lambda$CDM. Regardless of the model, both
galaxies exhibit a dark matter content comparable with
halos of typical dwarf
galaxies with similar stellar masses. Together with stellar population analyses and globular cluster information, these results support a scenario in which UDG-1 and LSB-6 originate from puffed-up dwarfs. This work is the first in a series exploiting kinematic data of extremely low-surface-brightness
galaxies to test fundamental physics, from dark matter to modified theories of
gravity.
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All authors Filippo Bouchè, Chiara Buttitta, Saboura Zamani, Enrichetta Iodice, Salvatore Capozziello, Vincenzo Salzano, Marcello Miranda, Enrico Maria Corsini, Marco Mirabile
High Energy Astrophysical Phenomena
Detection of hard X-ray pulsations in non-ULX X-ray pulsar 3X J0042 in M31
Ketan Rikame and Biswajit Paul
We report the detection of hard X-ray pulsations from the M31 accreting non-ULX X-ray
pulsar 3X J0042 (3XMM J004232.1+411314) using archival NuSTAR observations. The source has a
spin period of ~3 s and an orbital period of ~4.15 hr, with coherent pulsations previously detected only in XMM-Newton observations. We reanalyse all five publicly available NuSTAR observations by correcting the
photon arrival times for binary motion and optimizing the orbital epoch and projected semi-major axis. Coherent pulsations are detected in all five observations. The broad-band pulse profiles show similar morphology across the five observations spanning ~2.3 yr, with no significant long-term
evolution. The pulse profile also shows energy dependence, with structured, non-sinusoidal profiles below ~20 keV and a less structured profile at higher energies. The pulse periods show an overall decrease over the ~2.3 yr NuSTAR baseline, continuing the long-term
spin-up trend observed in the ~16 yr of XMM-Newton observations, but with a faster average
spin-up rate of ~-1.1e-10 s/s compared to the earlier reported ~-6e-11 s/s. The short orbital period and inferred low-mass companion
star shows it to be a low-mass X-ray binary containing a magnetized
neutron star, with systems such as Her X-1, 3A 1822-371, and XMM J174457-2850.3 providing closer Galactic comparisons. This work represents the first detection of hard X-ray pulsations from a non-ULX extragalactic accreting
pulsar.
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Cosmology and Nongalactic Astrophysics
PBH runaway during reheating
Md Riajul Haque, Mathieu Gross, Mathieu Houlier et al. (+1 more)
The growth of primordial black holes through the absorption of the surrounding
plasma has recently been shown to exhibit a critical behavior during radiation domination. We extend this analysis to the reheating era and derive analytical solutions for general reheating histories. We show that reheating modifies the critical condition for runaway absorption, making it dependent on both the reheating dynamics and the black-hole formation time. We identify two distinct regimes: runaway growth occurring during reheating, or being triggered after the onset of radiation domination by the mass accumulated during reheating. More generally, we derive a simple composition law describing how independent mass- growth mechanisms combine across successive cosmological eras. Applying it to radiation absorption and inflaton
accretion, we obtain analytical results in excellent agreement with the full numerical
evolution.
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All authors Md Riajul Haque, Mathieu Gross, Mathieu Houlier, Yann Mambrini
Earth and Planetary Astrophysics
Sorting a mess I: Addressing velocity-axis correlation of cross-correlation functions. A census of atomic and ionised species in KELT-9b's atmosphere
Nicholas W. Borsato, Brian Thorsbro, Jens Hoeijmakers et al. (+3 more)
Ultra-hot Jupiters (UHJs) are the most extreme class of close-in gas giants. We combine 13 transit observations of KELT-9b from six high-resolution spectrographs spanning 316-960 nm to conduct a census of atomic and ionised species in its atmosphere using cross-correlation. We introduce an agnostic strategy to mitigate velocity-axis correlation bias in parameter uncertainties. A forward model of the cross-correlation function (CCF) and a Monte Carlo bootstrap of flux uncertainties measure the CCF-derived velocity profiles of individual species and assess their time dependence. The stellar reference frame is determined, yielding Vsys = -17.99 +/- 0.04 km s^-1 and v sin i = 110.54 +/- 0.05 km s^-1. All previously reported species are recovered except Tb II; the combined analysis detects 29 species, including C I, Si I, K I, V II, Co I, Zr II, La II, Pr II, and Nd II. All 29 recovered species exceed the conventional 5 sigma threshold in the bootstrap Mahalanobis significance test. The collective Doppler shifts show a blueshift of Delta Voffset = -8.02 +/- 0.17 km s^-1 relative to the stellar rest frame, indicating a net day-to-night wind, with no explicit time dependence when all species are homogenised. These results provide a catalogue of detections and retrieved Doppler parameters for a companion study of KELT-9b.
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All authors Nicholas W. Borsato, Brian Thorsbro, Jens Hoeijmakers, Daniel B. Zucker, Stefan Pelletier, Bibiana Prinoth
High Energy Astrophysical Phenomena
Strong Black Hole Natal Kicks in Magnetized Accretion-Powered Explosions
Sean E. Li, Ore Gottlieb and Brian D. Metzger
Asymmetric stellar explosions impart an impulse, or natal kick, to their compact remnants by linear momentum conservation. Black hole (BH) natal kicks are often assumed to be weaker than
neutron star kicks because of greater mass
accretion, and they are harder to constrain observationally because isolated BHs are electromagnetically faint. Using 3D general-relativistic magnetohydrodynamic simulations lasting up to ~30 s, we show that BHs formed from the collapse of rapidly rotating massive
stars (collapsars) threaded by strong large-scale
magnetic fields can acquire large natal kicks 10^2–10^3 km/s. Asymmetric electromagnetic outflows,
magnetic-flux eruptions, and the gravitational pull of aspherical ejecta shape the kick magnitude, and their relative contributions depend on the progenitor structure,
magnetic-flux history, and BH
spin. More rapidly spinning BHs receive stronger, more nearly
spin-aligned kicks, primarily through the gravitational pull of asymmetric jet-driven ejecta. Delayed transitions to the magnetically arrested state produce more asymmetric outflows and can generate even stronger recoils. Because the large-scale
magnetic flux required in our models is also a key ingredient of relativistic gamma-ray burst jets and their associated energetic, jet-driven
supernovae, natal kicks may be a natural consequence of magnetized collapsars. Such kicks could substantially alter BH retention in dense stellar environments, binary survival,
spin-orbit misalignment, and the viability of magnetized collapsars in producing highly spinning BHs within the pair-instability mass gap.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
EFT Approaches to Sommerfeld Enhancement and Bound States in Singular Potentials
Arindam Bhattacharya, Rashmish K. Mishra and Tracy R. Slatyer
The Sommerfeld enhancement (SE) from long-range interactions, and the related bound state formation rate, can be important non-perturbative inputs to dark matter (DM) annihilation signals. In the presence of singular interaction potentials, the conventional boundary conditions of the Schrödinger equation fail, obfuscating the computation of SE, its physical origin, and its relation to bound states in such potentials. In this work, we clarify the origin of SE in singular potentials in a two-fold manner: using the framework of velocity power counting in non-relativistic effective field theory (NREFT), and via position-space regularization of singular potentials at short distances to compute SE and bound states. We illustrate our findings through the case of pseudoscalar mediators interacting with massive Dirac DM. We find that when such a system arises from a UV-complete theory at weak coupling, no SE is generated. However, in the case of a derivatively coupled pseudoscalar, where the interaction is described by a higher-dimension operator in an effective theory, SE (and bound states) can occur for weak couplings if there is a large hierarchy between the cutoff scale of the effective theory and the dark matter mass. This SE is sensitive to the choice of the UV completion of the potential at short distances, but a non-negligible SE can persist even when the UV physics alone would not generate any SE; we elucidate the interplay of UV and IR physics in this case.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Wave optical imaging of an oscillating electric dipole orbiting a black hole
Filipe Nazaré, João S. Santos, Vitor Cardoso et al. (+1 more)
We study the electromagnetic radiation and wave-optical imaging of an oscillating electric dipole orbiting a Kerr black hole. We derive the effective 4-current associated with a pointlike oscillating electric dipole in curved spacetime, and use black hole perturbation theory to compute the resulting radiation field at future null infinity, from first principles. We then develop a wave-optical imaging framework for a moving electromagnetic source in curved spacetime. We obtain images of an orbiting electric dipole, displaying relativistic beaming, gravitational
lensing, and Einstein rings. We study polarization-dependent scattering by comparing the images produced by spinning dipoles with opposite helicities, finding a displacement that roughly decreases with the inverse of the radiation frequency, as expected for a beyond-
geometric-optics effect. Our results provide a first-principles
benchmark for beyond-
geometric-optics descriptions of electromagnetic radiation in Kerr spacetime.
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All authors Filipe Nazaré, João S. Santos, Vitor Cardoso, José Natário
Earth and Planetary Astrophysics
Energy deposition in planetary and exoplanetary atmospheres induced by cosmic rays
Jesse Polman and Ingo Leya
Cosmic rays can significantly alter the abundances of certain species in the upper layers of planetary atmospheres, especially in terms of their biosignatures. To fully understand the extent of this effect, it is essential to accurately model the interactions of
cosmic rays with planetary
magnetic fields. We used the CosmicTransmutation code to study the effect of a planetary
magnetic field on the flux of galactic
cosmic rays and stellar energetic particles. We found that both particle sources are significantly affected by
magnetic fields, even though the effects are different due to the varying energy ranges that characterize each source. The stellar energetic particle energy flux is significantly higher for an Earth-like
planet with no
magnetic field, but with a
magnetic field of 30\,$\mu$T or higher, the energy flux of the two sources becomes comparable. We find that the atmospheric pressures the
cosmic rays reach are significantly lower than those found in previous studies using simpler models and that the effect of the atmospheric composition on this outcome is small. We found similar results using the model for the
exoplanet K2-18b, even though the radius is significantly larger than Earth's. Because the two
cosmic ray sources cover different energy ranges and are affected by the
magnetic field in different ways as a result, both sources should be considered. Future studies should focus on combining an accurate modelling procedure of the interaction between
cosmic rays and planetary
magnetic fields with atmospheric chemistry models. This will require general circulation models to capture the latitudinal and longitudinal dependencies in full.
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Instrumentation and Methods for Astrophysics
The CHIME/FRB Outriggers: Commissioning the Hat Creek Outrigger and an Updated Calibration Scheme for Mitigating RFI
Mattias Lazda, Nina V. Gusinskaia, Gurman Sachdeva et al. (+25 more)
This work presents commissioning of the Hat Creek Outrigger (HCO), a dual-polarization 256-element
radio interferometer that is part of the Canadian Hydrogen Intensity Mapping Experiment Fast
Radio Burst (CHIME/FRB) Outrigger project. Driven by a complex
radio-frequency interference (RFI) environment that consistently contaminates $\sim40\%$ of HCO's usable bandwidth, we implement an improved calibration scheme using Gaussian Process Regression to recover complex gain solutions over RFI contaminated channels. To validate our method, we test the performance of the array using known transients and continuum sources over relevant timescales used for fast-transient research ($\lesssim$ seconds). We find that our updated calibration scheme results in a $\sim1.69\times~\mathrm{to}~1.87\times$ improvement in the array's point-source sensitivity, while simultaneously maintaining noise properties consistent with thermal statistics. As a result, we find that the array performs consistently within theoretical expectations across $\gtrsim80\%$ of HCO's bandpass. We further observe an improvement in the interferometric performance after applying recently developed spatial filtering techniques for RFI mitigation, which rely on accurate calibration solutions for effective removal of unwanted interference. We conclude that our approach provides a valid framework for improving calibration solutions over RFI contaminated channels for large-$N$ interferometric arrays more broadly. Our work motivates future development of more sophisticated techniques to recover astrophysical information in RFI-contaminated channels, departing from the historical practice of discarding them outright.
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All authors Mattias Lazda, Nina V. Gusinskaia, Gurman Sachdeva, Shion Andrew, Juan Mena-Parra, Mandana Amiri, Bridget C. Andersen, Alyssa Atkinson, Kevin Bandura, Alice P. Curtin, Matt Dobbs, Ian Hendricksen, Jason W.T. Hessels, Danté M. Hewitt, Victoria M. Kaspi, Kholoud Khairy, Afrokk Khan, Ronniy C. Joseph, Adam E. Lanman, Calvin Leung, Kiyoshi W. Masui, Aaron B. Pearlman, Alexander W. Pollak, Vishwangi Shah, Kaitlyn Shin, Seth R. Siegel, Haochen Wang, Tarik J Zegmott