Astrophysics of Galaxies
How to Build an Empirical Speed Distribution for Dark Matter in the Solar Neighborhood
Tal Shpigel, Dylan Folsom, Mariangela Lisanti et al. (+3 more)
The dark matter flux in a direct detection experiment depends on its local speed distribution. This distribution has been inferred from simulations of Milky Way-like
galaxies, but such models serve only as proxies, given that no simulation directly captures the detailed
evolution of our own
Galaxy. This motivates alternative approaches that obtain this distribution directly from observations. In this work, we utilize 98 Milky Way analogues from the TNG50 simulation to develop and validate a procedure for inferring the dark matter speed distribution using the kinematics of nearby
stars. We find that the dark matter that originated from old mergers, plus that from recent nonluminous accretions, is well described by a Maxwell-Boltzmann speed distribution centered at the local standard-of-rest velocity. Meanwhile, recently accreted dark matter from massive mergers has speeds that can be traced from the associated
stellar debris of these events. The
stellar populations systematically underestimate the velocity dispersion of their dark matter counterparts, but a simple kinematic boost brings the two into good
alignment. Using the TNG50 host
galaxies, we demonstrate that combining these two contributions provides an accurate reconstruction of the local dark matter speeds. As an application of the procedure to our own
Galaxy, we utilize
stellar kinematic data from
Gaia to quantify how the dark matter remnants from the Milky Way's last major merger impact its speed distribution in the
solar neighborhood.
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All authors Tal Shpigel, Dylan Folsom, Mariangela Lisanti, Lina Necib, Mark Vogelsberger, Lars Hernquist
Cosmology and Nongalactic Astrophysics
Analytic Marginalization over Binary Variables in Physics Data
Marcus Högås and Edvard Mörtsell
In many data analyses, each measurement may come with a simple yes/no correction; for example, belonging to one of two populations or being contaminated or not. Ignoring such binary effects may bias the results, while accounting for them explicitly quickly becomes infeasible as each of the $N$ data points introduces an additional parameter, resulting in an exponentially growing number of possible configurations ($2^N$). We show that, under generic conditions, an exact treatment of these binary corrections leads to a mathematical form identical to the well-known Ising model from statistical physics. This connection opens up a powerful set of tools developed for the Ising model, enabling fast and accurate likelihood calculations. We present efficient approximation schemes with minimal computational cost and demonstrate their effectiveness in applications, including Type Ia
supernova calibration, where we show that the uncertainty in host-
galaxy mass classification has negligible impact on the inferred value of the Hubble constant.
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Earth and Planetary Astrophysics
Jean Schneider
This chapter reviews the definition of
exoplanets and of brown
dwarfs. Emphasis is given to the separation of these two populations. A traditional view is to declare {\guillemotleft}
planet {\guillemotright} objects with a mass < 13 M Jup and {\guillemotleft} brown
dwarf {\guillemotright} objects with a mass > 13 M Jup . By analogy with
Solar System
planets, a better definition is to call {\guillemotleft}
planets {\guillemotright} objects formed by
accretion of
dust and planetesimals in a disk. An by extension of the primitive introduction of the word {\guillemotleft} brown
dwarf {\guillemotright} for failed
stars by Jill Tarter, this term must be reserved to objects formed by gravitational collapse in a molecular gas cloud. The two definitions do not coincide since a {\guillemotleft} brown
dwarf {\guillemotright} can have a mass down to about 6 Jupiter mass. And there is no physical reason to assert that a 20 Jupiter mass object has not been formed by
accretion. From there, the difficulty is to decide if an object of say 20 Jupiter mass is formed by
dust accretion or by gravitational collapse. A future observational test to solve this difficulty is presented.
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High Energy Astrophysical Phenomena
From nuclear star clusters to Little Red Dots: black hole growth, mergers, and tidal disruptions
Konstantinos Kritos and Joseph Silk
Little Red Dots, discovered by the James Webb Space
Telescope, are hypothesized to be active
galactic nuclei containing a supermassive black hole, possibly surrounded by a dense
stellar cluster, large amounts of gas, and likely by a population of
stellar-mass black holes. We develop a simple
nuclear star cluster model to evolve the rapid mass growth of black hole seeds into the supermassive regime. The combined processes of
tidal disruption events, black hole captures, and gas
accretion are accounted for self-consistently in our model. Given the observed number density of Little Red Dots, and under reasonable assumptions, we predict at least a few tens of
tidal disruption events and at least a few black hole captures at z=4-6, with a
tidal disruption event rate an order of magnitude larger than the black hole capture rate. We also estimate the uncertainties in these estimates. Finally, we comment on the low x-ray luminosity of Little Red Dots.
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Astrophysics of Galaxies
A Unified Framework Connecting Chemical Enrichment to Resolved Star Formation Histories with Applications to Local Group Dwarf Irregulars
Christopher T. Garling, Alex M. Garcia, Niusha Ahvazi et al. (+4 more)
We present a new framework for modeling the chemical enrichment histories of
galaxies by integrating chemical
evolution with resolved
star formation histories (SFHs) derived from color-magnitude diagrams. This novel approach links the time
evolution of the
metallicity of the
star-forming ISM to the cumulative
stellar mass formed in the
galaxy, enabling a self-consistent description of chemical
evolution. We apply this methodology to four isolated, gas-rich Local Group
dwarf galaxies – WLM, Aquarius, Leo A, and Leo P – using deep HST and JWST imaging. For WLM, Aquarius, and Leo A, we independently validate our
metallicity evolution results against ages and
metallicities of individual red
giant stars with spectroscopic measurements. We quantify systematic uncertainties by repeating our analysis with multiple
stellar evolution and bolometric correction libraries. We compare the observed chemical enrichment histories to predictions from the TNG50 and FIREbox cosmological hydrodynamic simulations and the Galacticus semi-analytic model. Of our four
galaxies, only WLM is sufficiently massive to be reliably represented in these simulations; the remaining three fall below current resolution limits. We find that the enrichment history of WLM is best reproduced by FIREbox, while TNG50 and Galacticus predict higher
metallicities at early times, suggesting that differences in
stellar feedback and metal recycling prescriptions drive significant variation in predicted enrichment histories. This work demonstrates the power of combining resolved SFHs with physically motivated chemical
evolution models to constrain
galaxy formation physics and highlights the need for further observational and theoretical studies of metal retention and recycling in low-mass
dwarf galaxies.
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All authors Christopher T. Garling, Alex M. Garcia, Niusha Ahvazi, Nitya Kallivayalil, Kristen B. W. McQuinn, Robert Feldmann, Roger E. Cohen
Earth and Planetary Astrophysics
An H{\alpha} Transit of HD 189733b to Assess Stellar Activity Across the Transit Chord Close to JWST Observations
Kingsley E. Ehrich, Jason A. Dittmann, Samuel P. Halverson et al. (+1 more)
Transmission spectroscopy allows us to detect molecules in planetary atmospheres, but is subject to contamination from inhomogeneities on the
stellar surface. Quantifying the extent of this contamination is essential for accurate measurements of atmospheric composition, as
stellar activity can manifest as false atmospheric signals in planetary transmission spectra. We present a study of hot Jupiter HD 189733b, which has over 50 hours of JWST observations scheduled or taken, to measure the activity level of the host
star at the current epoch. We utilize high-resolution spectra of the H${\alpha}$ line from the MEGARA spectrograph on the 10-m GTC to examine the activity level of HD 189733 during a transit. We measure H${\alpha}$ becoming shallower mid-transit by an H${\alpha}$ index of ${\delta}$ = 0.00156 ${\pm}$ 0.00026, which suggests that HD 189733b crosses an active region as it transits. We posit this deviation is likely caused by a spot along the transit chord with an approximate radius of $R_{spot}$ = 3.47 ${\pm}$ 0.30R${\oplus}$ becoming occulted during transit. Including an approximation for unocculted spots, we estimate that this spot could result in transit depth variations of ${\sim}$17 ppm at the 4.3 micron CO2 feature. Since this is comparable to JWST NIRCam Grism mode's noise floor of ${\sim}$20 ppm, it could bias atmospheric studies by altering the inferred depths of the
planet's features. Thus, we suggest ground-based high-resolution monitoring of activity indicator species concurrently taken with JWST data when feasible to disentangle
stellar activity signals from planetary atmospheric signals during transit.
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All authors Kingsley E. Ehrich, Jason A. Dittmann, Samuel P. Halverson, Alejandro Camazón-Pinilla
Astrophysics of Galaxies
To Survive or to Shatter: The Impact of Cosmic Rays on the Fate of Stripped Cold Clouds
Manami Roy, Kung-Yi Su, Stephanie Tonnesen et al. (+3 more)
Does
cosmic ray (CR) pressure matter for the circumgalactic medium (CGM)? Despite growing interest, this remains a debated question, complicated by limited observational constraints and differing implementations of CR physics in simulations. While prior studies suggest that CRs influence the thermal and dynamical state of the CGM, their role in shaping cold gas structures remains underexplored. This paper investigates how CRs affect ram-pressure stripped cold gas clouds originating from satellite
galaxies in a Milky Way-like
halo. Using high-resolution simulations with varying CR energy densities, we find that CRs can significantly modify the size and survival of stripped clouds. Specifically, CR pressure puffs up the cold clouds, increasing their surface area and enabling more efficient mixing-layer cooling, allowing them to grow in mass. This enhanced growth results in higher cold gas inflow rates into the central
galaxy, leading to an increase in the
star formation rate compared to the no-CR case at a later time. Moreover, CRs can boost the total cold gas mass in the CGM by up to a factor of four. These effects are most pronounced in simulations where the CR energy density is in equipartition with the thermal gas. Our results demonstrate that CRs can play a critical role in regulating the cold phase of the CGM contributed by satellites and therefore their ability to feed
galaxies.
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All authors Manami Roy, Kung-Yi Su, Stephanie Tonnesen, Yue Samuel Lu, Cameron Hummels, Sam B. Ponnada
Cosmology and Nongalactic Astrophysics
HOLISMOKES XIX: SN 2025wny at $z=2$, the first strongly lensed superluminous supernova
Stefan Taubenberger, Ana Acebron, Raoul Cañameras et al. (+45 more)
We present imaging and spectroscopic observations of
supernova SN 2025wny, associated with the lens candidate PS1 J0716+3821. Photometric monitoring from the Lulin and Maidanak observatories confirms multiple point-like images, consistent with SN 2025wny being strongly lensed by two foreground
galaxies. Optical spectroscopy of the brightest image with the Nordic Optical
Telescope and the University of Hawaii 88-inch
Telescope allows us to determine the
redshift to be z_s = 2.008 +- 0.001, based on narrow absorption lines originating in the interstellar medium of the
supernova host
galaxy. At this
redshift, the spectra of SN 2025wny are consistent with those of superluminous
supernovae of Type I. We find a high ejecta temperature and depressed spectral lines compared to other similar objects. We also measure, for the first time, the
redshift of the fainter of the two lens
galaxies (the "perturber") to be z_p = 0.375 +- 0.001, fully consistent with the DESI spectroscopic
redshift of the main deflector at z_d = 0.3754. SN 2025wny thus represents the first confirmed
galaxy-scale strongly lensed
supernova with time delays likely in the range of days to weeks, as judged from the image separations. This makes SN 2025wny suitable for cosmography, offering a promising new system for independent measurements of the Hubble constant. Following a tradition in the field of strongly-lensed SNe, we give SN 2025wny the nickname SN Winny.
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All authors Stefan Taubenberger, Ana Acebron, Raoul Cañameras, Ting-Wan Chen, Aymeric Galan, Claudio Grillo, Alejandra Melo, Stefan Schuldt, Allan G. Schweinfurth, Sherry H. Suyu, Greg Aldering, Amar Aryan, Yu-Hsing Lee, Elias Mamuzic, Martin Millon, Thomas M. Reynolds, Alexey V. Sergeyev, Ildar M. Asfandiyarov, Stéphane Basa, Stéphane Blondin, Otabek A. Burkhonov, Lise Christensen, Frederic Courbin, Shuhrat A. Ehgamberdiev, Tom L. Killestein, Seppo Mattila, Asadulla M. Shaymanov, Yiping Shu, Dong Xu, Sheng Yang, Daniel Gruen, Justin D. R. Pierel, Christopher J. Storfer, Kim-Vy Tran, Kenneth C. Wong, Rosa L. Becerra, Damien Dornic, Jean-Grégoire Ducoin, Noémie Globus, Claudia P. Gutiérrez, Ji-an Jiang, Hanindyo Kuncarayakti, Diego López-Cámara, Peter Lundqvist, Francesco Magnani, Enrique Moreno Méndez, Benjamin Schneider, Christian Vogl
Earth and Planetary Astrophysics
Comparing the data reduction pipelines of FRIPON, DFN, WMPL, and AMOS: Geminids Case Study
P.M. Shober, J. Vaubaillon, S. Anghel et al. (+15 more)
Methods. We processed a
dataset of 584 Geminid fireballs observed by FRIPON between 2016 and 2023. The single-station astrometric data is converted into the Global Fireball Exchange (GFE) standard format for uniform processing. We assess variations in trajectory, velocity, radiant, and orbital element calculations across the pipelines and compare them to previously published Geminid measurements. Results. The radiant and velocity solutions provided by the four data reduction pipelines are all within the range of previously published values. However, there are some nuances. Particularly, the radiants estimated by WMPL, DFN, and AMOS are nearly identical. Whereas FRIPON reports a systematic shift in right ascension (-0.3 degrees), caused by improper handling of the precession. Additionally, the FRIPON data reduction pipeline also tends to overestimate the initial velocity (+0.3 km s-1) due to the deceleration model used as the velocity solver. The FRIPON velocity method relies on having a well-constrained deceleration profile; however, for the Geminids, many are low-deceleration events, leading to an overestimation of the initial velocity. On the other end of the spectrum, the DFN tends to predict lower velocities, particularly for poorly observed events. However, this velocity shift vanishes for the DFN when we only consider Geminids with at least three observations or more. The primary difference identified in the analysis concerns the velocity uncertainties. Despite all four pipelines achieving similar residuals between their trajectories and observations, their velocity uncertainties vary systematically, with WMPL outputting the smallest values, followed by AMOS, FRIPON, and DFN.
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All authors P.M. Shober, J. Vaubaillon, S. Anghel, H.A.R. Devillepoix, F. Hlobik, P. Matlovič, J. Tóth, D. Vida, E.K. Sansom, T. Jansen-Sturgeon, F. Colas, A. Malgoyre, L. Kornoš, F. Ďuriš, V. Pazderová, S. Bouley, B. Zanda, P. Vernazza
Earth and Planetary Astrophysics
Mechanisms of Superrotation in Slowly-Rotating and Tidally-Locked Planets
Quentin Nicolas and Geoffrey K. Vallis
Superrotation is a common feature of quickly rotating gas
giants, slowly rotating planetary bodies, and tidally-locked
planets. In this paper we compare and contrast the mechanisms of superrotation in slow rotators and tidally-locked
planets. We cover a wide range of planetary properties, varying in particular the thermal Rossby number Ro_T (controlled by planetary size, rotation rate, and instellation) and a radiative relaxation timescale T_rad (which parameterizes atmospheric optical thickness). We use a two-level model that contains the principal mechanisms for superrotation in both regimes yet remains analytically tractable. Linearizations of the model elucidate the behavior of superrotation-inducing eddies. In tidally-locked
planets a Matsuno-Gill-like structure organizes the eddy effects but of itself is insufficient to produce superrotation; baroclinicity and low-level drag are additional essential ingredients. Nonlinear integrations further explore the superrotating regimes and exhibit significant time variability even in statistical
equilibrium. Not all tidally-locked regimes superrotate: subrotation arises at high T_rad (optically thick atmospheres) and weak low-level drag. On axisymmetrically-forced slow rotators, superrotation is always linked to a previously identified Rossby-Kelvin instability. Perhaps surprisingly, the instability itself is also linked to the spinup of superrotation in some tidally-locked regimes. Finally, we explore the continuous transition in the mechanisms of superrotation from axisymmetrically-forced to tidally-locked
planets by applying a progressively stronger asymmetric equatorial forcing. The Matsuno-Gill pattern quickly dominates over traveling planetary Rossby-Kelvin waves in forcing superrotation, although both mechanisms can coexist. These results provide a unified view of superrotation mechanisms across a wide range of planetary bodies.
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Solar and Stellar Astrophysics
Predicted observational effects of rapid rotation for Be stars
Rina G. Rast, Carol E. Jones, Mark W. Suffak et al. (+6 more)
We conduct a systematic study on the effects of rapid rotation on predicted Be
star observables. We use the three-dimensional Monte Carlo radiative transfer code, hdust, to model a comprehensive range of Be
star subtypes at varying rotation rates. Using these models, we predict $V$ magnitude and photometric color, H$\alpha$ line profiles, and polarization at UV wavelengths as well as in the $V$-band for Be
stars from B0 to B8. For each spectral subtype, we investigate the effects of disk density on the produced observables. We find that reddening and brightening effects of
gravity darkening may cause rapidly-rotating
stars to appear more evolved than they truly are. Rotational effects on the H$\alpha$ line profile shape may reduce line intensity for Be
stars viewed at low inclinations and increase line intensity for those viewed at high inclinations. Additionally, rapid rotation can significantly impact the measured equivalent width of the line produced by a
star with a moderate to high density disk, especially at high inclinations. When the
star-disk system is viewed near edge-on,
gravity darkening can result in stronger H$\alpha$ emission than would otherwise be expected for a disk of a given density. We also find that the competing effects of rapid rotation and H\,i opacity cause the slope of the polarized continuum (the polarization color) to be very sensitive to changes in the
stellar rotation rate. This quantity offers a strong diagnostic for the rotation rate of Be
stars.
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All authors Rina G. Rast, Carol E. Jones, Mark W. Suffak, Jonathan Labadie-Bartz, Asif ud Doula, Alex C. Carciofi, Peter Quigley, Coralie Neiner, Jeremy J. Drake
Cosmology and Nongalactic Astrophysics
Exploring the Co-SIMP dark matter model using the 21-cm signal from the dark ages
Debarun Paul, Sourav Pal, Deepthi Moorkanat et al. (+3 more)
The redshifted 21-cm signal from the dark ages offers a powerful probe of cosmological models and the underlying dark matter (DM) microphysics. We investigate deviations from the standard $\Lambda$CDM prediction, an absorption trough of approximately $-40.6\,\mathrm{mK}$ at
redshift $z\simeq85.6$, in the context of co-SIMP (strongly interacting massive particle) DM. The co-SIMP interaction strength is encoded by the parameter $C_{\rm int}$, incorporating the masses of DM and standard model (SM) particles, the interaction cross-section, and the amount of heat exchange between the two sectors. Increasing $C_{\rm int}$ deepens the absorption feature and shifts the trough to higher
redshifts in the global signal. For $C_{\rm int}=1.0$, the minimum brightness temperature reaches $-50.6,\mathrm{mK}$ at $z\simeq86.2$. The 21-cm power spectrum increases with $C_{\rm int}$ in addition to the global signal. We assess the detectability of these signatures using signal-to-noise ratio (SNR) and Fisher forecasts. The maximum SNR reaches $\sim 15.7$ for $C_{\rm int}=1.0$ for the global signal. Fisher forecasts for $1,000$ hours of integration time show that this model can be distinguished from a null-signal at $4.3\sigma$ and a mild 1.6$\sigma$ from $\Lambda$CDM, improving by an order of magnitude for 100,000 hours. For the 21-cm power spectrum, a $5,\mathrm{km}^2$ array with 1,000 hours yields a $4.63\sigma$ detection and mildly separated from the standard scenario at $1.78\sigma$. These findings highlight the potential of the 21-cm cosmology to probe the properties of DM and demonstrate that upcoming dark ages experiments, particularly space-based and lunar observations, can offer a promising avenue to test co-SIMP models.
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All authors Debarun Paul, Sourav Pal, Deepthi Moorkanat, Antara Dey, Amit Dutta Banik, Rajesh Mondal
Astrophysics of Galaxies
Exploring the statistical properties of double radio relics in the TNG-Cluster and TNG300 simulations
Wonki Lee, Annalisa Pillepich, Dylan Nelson et al. (+4 more)
Double
radio relics, pairs of diffuse
radio features located on opposite sides of merging
galaxy clusters, are a rare subclass of
radio relics that are believed to trace merger shocks and provide valuable constraints on
plasma acceleration models and merger history. With the number of known double relics growing in recent and upcoming
radio surveys, statistical analyses of their properties are becoming feasible. In this study, we utilize the cosmological magnetohydrodynamics zoom-in simulations TNG-Cluster, in combination with TNG300-1, to examine the statistical properties of double
radio relics. The simulated double relic pairs exhibit a wide range of luminosity ratios, broadly consistent with the observations. We find that the two relics in a given double system often differ significantly in their shock properties and
magnetic field strengths. This diversity implies that the observed brightness asymmetry in the pair cannot be explained by a single factor alone, but instead reflects an interplay of multiple physical parameters. Nevertheless, double
radio relics tend to align with the collision axis within $\sim30^{\circ}$ and their separation ($d_{\rm drr}$) correlates tightly with the time since collision (TSC) as ${\rm TSC~[Gyr]} = 0.52 d_{\rm drr}/R_{500\rm c} - 0.24$, allowing it to be inferred with an accuracy of $\sim0.2~\rm Gyr$. With the statistical samples of simulated
radio relics, we predict that low-mass clusters will constitute the dominant population of double
radio relic systems detected with upcoming surveys such as SKA. These results demonstrate that double
radio relics can serve as robust probes of merger dynamics and
plasma acceleration, and that simulations provide critical guidance for interpreting the large samples expected from next-generation
radio surveys.
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All authors Wonki Lee, Annalisa Pillepich, Dylan Nelson, Myungkook James Jee, Daisuke Nagai, Kyle Finner, John ZuHone
Cosmology and Nongalactic Astrophysics
DESI constraints on two-field quintessence with exponential potentials
George Alestas, Marienza Caldarola, Indira Ocampo et al. (+2 more)
We investigate a quintessence model involving two scalar fields with double-exponential potentials. This configuration allows the system as a whole to emulate the dynamics of a single field with a shallower potential, enabling scalar fields that individually cannot drive
cosmic acceleration to collectively achieve and sustain it. We assess the viability of this model by performing a fully
Bayesian analysis and confronting its predictions with observational data, including the Planck 2018
cosmic microwave background (CMB) shift parameters, the newly released Dark Energy Spectroscopic Instrument (DESI) DR2
baryon acoustic oscillation (BAO) measurements, and the Dark Energy Survey Year 5 (DESY5) type Ia
supernova (SnIa) sample. Our analysis shows that the two-field quintessence model yields a log Bayes factor relative to the flat $\Lambda$ cold dark matter model of $\Delta \ln B \sim 4$, indicating moderate evidence against the latter. We also find that the central values of the two slopes of the exponential potentials are both close to 1, whereas the slope of an effective single-field system is constrained to be less than order unity. This property is theoretically desirable from the perspective of higher-dimensional theories. Thus, the two-field quintessence model with exponential potentials provides a physically motivated and compelling mechanism that is consistent with both observational and theoretical requirements.
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All authors George Alestas, Marienza Caldarola, Indira Ocampo, Savvas Nesseris, Shinji Tsujikawa
Solar and Stellar Astrophysics
Peakbagging the K2 KEYSTONE sample with PBjam: characterising the individual mode frequencies in solar-like oscillators
George T. Hookway, Martin B. Nielsen, Guy R. Davies et al. (+5 more)
The pattern of individual mode frequencies in
solar-like oscillators provides valuable insight into their properties and interior structures. The identification and characterisation of these modes requires high signal-to-noise and frequency resolution. The KEYSTONE project unlocks the asteroseismic potential of the K2 mission by providing individually reduced, high-quality time series data, global asteroseismic parameters, and spectroscopic analysis for 173
solar-like oscillators. In this work, we build on the KEYSTONE project and present the first analysis of the pattern of individual modes in the oscillation spectra for the K2 KEYSTONE
stars. We perform a robust identification and characterisation of the modes through peakbagging methods in the open-source analysis tool PBjam. We present over 6000 mode frequencies, widths, and heights for 168
stars in the sample, covering the HR diagram from FGK
dwarfs to sub-
giants and the lower red
giant branch, providing a significant increase in the number of individual mode frequency detections for main sequence and sub-
giant oscillators. This study also presents sample-wide trends of oscillation patterns as a function of the fundamental
stellar properties, and improves the precision of the global asteroseismic parameters. These measurements are part of the legacy of the K2 mission, and can be used to perform detailed modelling to improve the precision of fundamental properties of these
stars. The results of this analysis provides evidence for the validity of using PBjam to identify and characterise the modes resulting from the observations of the future PLATO mission.
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All authors George T. Hookway, Martin B. Nielsen, Guy R. Davies, Mikkel N. Lund, Rafael A. García, Savita Mathur, Victor See, Amalie Stokholm
Solar and Stellar Astrophysics
3D Synthetic Convective Velocity Fields to Initialise Core-Collapse Supernova Simulations from 1D Progenitors
Vishnu Varma, Bernhard Mueller and Raphael Hirschi
Core-collapse
supernovae (CCSNe) are among the most energetic and complex astrophysical phenomena, requiring threedimensional (3D) simulations to capture their intricate explosion mechanisms. One of the key ingredients for such simulations is the 3D pre-collapse structure, which can impact the development and geometry of the subsequent explosion. While
stellar convection simulations can provide such 3D initial conditions, these remain too expensive and demanding for widespread use. In this work, we present a method to generate synthetic 3D velocity fields for convective zones from 1D initial conditions, creating initial conditions for CCSN simulations using a vector spherical harmonics expansion without the need for expensive hydrodynamic progenitor simulations. The synthetic velocity field is designed to capture the typical scales and velocities of the convective flow as the most relevant parameters for the subsequent explosions. In addition, it respects relevant physical constraints such as the near-anelasticity of flow, vanishing radial vorticity, and zero net angular momentum in the convective zones. A Python implementation of this method is publicly available, offering the CCSN community a practical tool for generating synthetic velocity fields for multi-dimensional simulations to study the impact of 3D progenitor asymmetries on the CCSN mechanism.
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Solar and Stellar Astrophysics
An observational study of rotation and binarity of Galactic O-type runaway stars
M. Carretero-Castrillo, M. Ribó, J. M. Paredes et al. (+3 more)
Gaia DR3 data have revealed new massive runaway
stars, while spectroscopic surveys enable detailed characterization. The relative contributions of binary
supernova (BSS) and dynamical ejection (DES) scenarios to explain their runaway origin remain poorly constrained, particularly in the Milky Way. We aim to characterize the largest sample of
Galactic O-type runaway
stars ever investigated through their kinematics, rotation, and binarity to shed light into their origins. We use the GOSC-
Gaia DR3 catalog, and IACOB spectroscopic information to build a sample with 214 O-type
stars with projected rotational velocities ($v \sin{i}$), and a subsample of 168 O-type
stars with additional information about their likely single (LS) or single-lined (SB1) spectroscopic binary nature. We also consider an additional sample of 65 double-lined (SB2) spectroscopic binaries. We find that among our sample of
Galactic O-type runaways, most (74%) have $v \sin{i}<200$ km/s, whereas for normal
stars this fraction is slightly higher (82%). There are no fast-moving runaways being fast rotators, except for HD 124 979. Runaways show lower SB1 fractions than normal
stars, with no runaway SB1 fast-rotating systems; on average, runaways rotate faster than normal
stars; and their runaway fraction is higher among fast rotators (44%) vs. the slow rotators (34%). This is consistent with BSS dominance for fast rotators. We also found that SB2 systems hardly reach runaway velocities with a low runaway fraction (10%). Runaways with 2D velocities > 60 km/s are mostly single and interpreted as DES products, while runaways with 2D velocities > 85 km/s are also interpreted as two-step products. Three of 12 runaway SB1 systems are HMXBs. Our study reveals that most
Galactic O-type runaways are slow rotators, suggests a dominance of BSS among fast-rotating runaways, and of DES and two-step among the high-velocity ones. (Abridged)
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All authors M. Carretero-Castrillo, M. Ribó, J. M. Paredes, G. Holgado, C. Martínez-Sebastián, S. Simón-Díaz
Astrophysics of Galaxies · Cross-listed from gr-qc
Gravitational and kinematic redshifts of black holes in nonlinear electrodynamics
Marco A. A. de Paula and Mustapha Azreg-Aïnou
Spacetimes arising from nonlinear electrodynamics (NED) are a good laboratory for studying both the nature of regular black hole (RBH) solutions and the imprints of nonlinear electromagnetic fields within this context. Over the past few decades, NED-sourced black hole (BH) spacetimes have attracted considerable
attention, but electrically charged RBHs obtained in the so-called $F$ framework have been less addressed in the literature. We consider two electrically charged, fully regular members of the h-family that are solutions to general relativity minimally coupled to NED. Because of their potential astrophysical and astronomical applications, we mainly focus our investigation on the motion of
photons and its implications for the gravitational and kinematic
redshifts, as well as for the shadow radius, considering the effective geometry followed by
photons in NED. Moreover, we consider the observational data for Sagittarius A$^{\star}$ and Messier 87$^{\star}$ BHs to impose some constraints on the charge-to-mass ratio of the fully RBHs. We obtain the general equations that govern the gravitational and kinematic
redshifts of NED-sourced BH spacetimes. In particular, for fully RBHs with BH charge-to-mass ratios above some moderate value, we observe discrepancies in their physical and geometrical properties compared to those of the Reissner–Nordström (RN) BH. Therefore, our results indicate that it is possible to distinguish NED-based RBH solutions from RN BHs, from the perspective of gravitational and kinematic
redshifts, suggesting potential astrophysical relevance.
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Earth and Planetary Astrophysics
Irradiated Atmospheres IV: Effect of Mixing Heat Flux on Chemistry
Zhen-Tai Zhang, Wei Zhong, Wei Wang et al. (+5 more)
Vertical mixing disrupts the thermochemical
equilibrium and introduces additional heat flux that alters exoplanetary atmospheric temperatures. We investigate how this mixing-induced heat flux affects atmospheric chemistry. Temperature increase in the lower atmosphere by the mixing-induced heat flux alters species abundances there and modifies those in the upper atmosphere through vertical transport. In the lower atmosphere, most species follow thermodynamic
equilibrium with temperature changes. In the upper layers, species mixing ratios depend on the positions of quenching levels relative to the regions exhibiting significant mixing-induced temperature variations. When the quenching level resides within such region (e.g. CO, $\rm CH_4$, and $\rm H_2O$ with strong mixing), the mixing ratios in the upper atmosphere are modified due to changes in the quenched ratios affected by the temperature variation in the lower atmosphere. This alters the mixing ratio of other species (e.g. NO and $\rm CO_2$) through the chemical reaction network, whose quenching occurs in the region without much temperature change. The mixing ratios of $\rm CH_4$, $\rm H_2O$, and $\rm NH_3$ decrease in the lower atmosphere with increasing mixing heat flux, similarly reducing these ratios in the upper atmosphere. Conversely, the mixing ratios of CO, $\rm CO_2$, and NO rise in the lower atmosphere, with CO and $\rm CO_2$ also increasing in the upper levels, although NO decreases. Weaker host
star irradiation lowers the overall temperature of the
planet, allowing a smaller mixing to have a similar effect. We conclude that understanding the vertical mixing heat flux is essential for accurate atmospheric chemistry modeling and
retrieval.
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All authors Zhen-Tai Zhang, Wei Zhong, Wei Wang, Jianheng Guo, Xianyu Tan, Bo Ma, Ruyi Wei, Cong Yu
Instrumentation and Methods for Astrophysics · Cross-listed from physics.ins-det
TES Proton Irradiation Result Analysis for Future Space Applications
A. Besnard, V. Sauvage, S. L. Stever et al. (+8 more)
As observed on the signal of the Planck-HFI highly sensitive bolometers, the effect of
cosmic rays on detectors is a major concern for future similar space missions. Their instruments will have a larger detection surface, increased sensitivity, and more stringent requirements on the suppression of systematic effects. To study the impact of
cosmic rays on detector prototypes in operational conditions, IAS has designed a state-of-the-art cryogenic system to irradiate particles by coupling this facility to particle accelerators. An irradiation campaign has been carried out on LiteBIRD-HFT TES prototypes to study their response to particle hits. In this article, we present the results and the analysis of this first test campaign.
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All authors A. Besnard, V. Sauvage, S. L. Stever, B. Maffei, P. dal Bo, T. Lari, M. de Lucia, A. Tartari, G. Signorelli, J. Hubmayr, G. Jaehnig
High Energy Astrophysical Phenomena
Sco X-1 as a continuous gravitational waves source: modelling the secular evolution using MESA
Gianluca Pagliaro, Maria Alessandra Papa, Jing Ming et al. (+1 more)
We study the prospects for detecting continuous gravitational waves (GWs) from Sco X-1 and evaluate the most likely waveform and progenitor parameters. We model the
spin of the
neutron star by the
accretion torque and the gravitational-wave torque, considering two mechanisms for generating the non-axisymmetry responsible for the latter:
magnetic mountains and crustal breakage deformation. Both torques are intertwined with the binary
evolution, which we trace from the formation of the NS in a binary system with a main-sequence companion. We do this with MESA, starting from a set of initial binary configurations. At current sensitivity, a
magnetic ellipticity of $\varepsilon\gtrsim 10^{-6}$ is necessary for detection. The highest frequency at which we have detectable signals increases with the
accretion efficiency $\eta$, and it can be as high as 360Hz. At 3G (
Cosmic Explorer/Einstein
telescope) sensitivity, less deformed Sco X-1 NSs, with ellipticities as small as $6\cdot 10^{-9}$, are detectable, but the waveform highly depends on the binary system: the highest frequency of detectable signals spans the very broad range 600-1700Hz, strongly depending on $\eta$ and mass of the progenitor donor
star $M^d$. If $\eta\leq$30%, the crust does not break. For $\eta\in$[40%,60%] only progenitors with $M^d\geq[1.1,1.5]M_{\odot}$ present crustal breakage, while if $\eta\geq$70% all crusts break. In some systems, the crust breaks during their Sco X-1 phase. If Sco X-1 were one of those systems, it would be emitting a very loud GW signal sweeping from O(1000)Hz down to torque-balance frequencies in $\approx 150000[\varepsilon /10^{-5}]^{-2/5}$ years. We estimate the current detection probability for this signal to be under 1%; this probability increases substantially - to around 41% - with 3G detectors.
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All authors Gianluca Pagliaro, Maria Alessandra Papa, Jing Ming, Devina Misra
Cosmology and Nongalactic Astrophysics
Synergy between CSST and third-generation gravitational-wave detectors: Inferring cosmological parameters using cross-correlation of dark sirens and galaxies
Ya-Nan Du, Ji-Yu Song, Yichao Li et al. (+4 more)
Gravitational-wave (GW) events are generally believed to originate in
galaxies and can thus serve, like
galaxies, as tracers of the universe's large-scale structure. In GW observations, waveform analysis provides direct measurements of luminosity distances; however, without relying on a specific cosmological model, the
redshifts of GW sources cannot be determined due to the mass-
redshift degeneracy. By cross-correlating GW events with
galaxies, one can establish a correspondence between luminosity distance and
redshift shells, enabling cosmological inference. In this work, we explore the scientific potential of cross-correlating GW sources detected by third-generation (3G) ground-based GW detectors with the photometric
redshift survey of the China Space Station Survey
Telescope (CSST). We find that the constraint precisions of the Hubble constant and the matter density parameter can reach $1.04\%$ and $2.04\%$, respectively. Additionally, we have also constrained the precision of the GW clustering bias parameter. These results highlight the significant potential of the synergy between CSST and 3G ground-based GW detectors in constraining cosmological models and probing GW source formation channels using cross-correlation of dark sirens and
galaxies.
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All authors Ya-Nan Du, Ji-Yu Song, Yichao Li, Shang-Jie Jin, Ling-Feng Wang, Jing-Fei Zhang, Xin Zhang
Instrumentation and Methods for Astrophysics
LEO Satellite Track Correction for CSST Multi-Band Imaging Data
Huai-Jin Tang, Xiao-Lei Meng, Hu Zhan et al. (+5 more)
Low Earth Orbit satellite (LEOsat) mega-constellations are considered to be an unavoidable source of contamination for survey observations to be carried out by the China Space Station
Telescope (CSST) over the next decade. This study reconstructs satellite trail profiles based on simulated parameters, including brightness levels and orbital altitudes, in combination with multi-band simulated images. Compared to our previous work, the simulated images in this study more accurately replicate the realistic observational conditions of CSST and extend beyond single-band analysis. Variations in LEOsat trail brightness, source brightness, background noise, and source density across different bands result in differing levels of accuracy in trail reconstruction and subsequently affect the reliability of photometric measurements. The reconstructed trail profiles are subsequently applied to correct the contaminated regions. Simulation results reveal varying levels of contamination effects across different bands following LEOsat trail correction, including both reconstruction and subtraction. To evaluate the effectiveness of the correction, we quantified the fraction of affected sources using two metrics: (1) magnitude errors greater than 0.01 mag attributable to LEOsats, and (2) LEOsat-induced noise exceeding 10% of other noise contributions. Following trail repair, the analysis reveals a reduction of over 50% in the fraction of affected sources in the NUV band for both 550 km and 1200 km altitudes, assuming a maximum brightness of 7 in the V band. In the i band, the reduction exceeds 30%. The degree of improvement varies across spectral bands, and depends on both satellite altitude and the adopted brightness model.
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All authors Huai-Jin Tang, Xiao-Lei Meng, Hu Zhan, Guo-Liang Li, Cheng-Liang Wei, Xian-Min Meng, Xi-Yang Fu, You-Hua Xu
High Energy Astrophysical Phenomena
Multi-Messenger Search for Neutrino and Gravitational-Wave Emissions from Binary Black Holes Near Active Galactic Nuclei
Leonardo Ricca, Matthias Vereecken, Christoph Raab et al. (+3 more)
Binary black holes (BBHs) in the vicinity of Active
Galactic Nuclei (AGNs) are particularly interesting systems from both a cosmological and astrophysical point of view. Matter and radiation fields within the dense AGN environment could produce electromagnetic and
neutrino emission in addition to gravitational waves (GWs). Moreover, interactions between BBHs and AGN
accretion disks are expected to influence BBH formation channels and merger rates. Understanding these sources could help explain the unexpectedly high BBH masses observed through GWs by the LIGO-Virgo-KAGRA collaborations. We present a search for coincident gravitational-wave and
neutrino emission from AGNs. Our innovative approach combines information from gravitational-wave data,
neutrino observations, and AGN optical catalogs to increase the chances of identifying potential sources and studying their properties. We assess the sensitivity of the search using subthreshold gravitational-wave candidates from LIGO-Virgo-KAGRA data,
neutrino event candidates from public IceCube
Neutrino Observatory data and AGN candidates from the Quaia catalog. A confident detection of such an event would mark a breakthrough in multi-messenger astronomy.
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All authors Leonardo Ricca, Matthias Vereecken, Christoph Raab, Mathieu Lamoureux, Giacomo Bruno, Gwenhaël De Wasseige
Astrophysics of Galaxies
Discovery of a giant radio outburst of the narrow-line Seyfert 1 galaxy SDSS J110546.07+145202.4
K. É. Gabányi, S. Komossa, A. Kraus et al. (+2 more)
We have identified a high-amplitude
radio outburst in the course of a large-sample study of the
radio properties of narrow-line Seyfert 1 (NLS1)
galaxies. We have analysed previous
radio data and obtained new
radio observations with the Effelsberg 100 m
telescope, in order to measure the properties and understand the nature of the high-amplitude
radio variability. We have also searched for signs of variability in the infrared and optical bands using archival data. We report the discovery of a rare high-amplitude
radio outburst of a NLS1
galaxy, SDSS J110546.07+145202.4, with an amplitude of a factor of >20 at centimetre wavelengths within 18 yr, and remaining at high-state for at least 7.6 yr. Thus, the object transitioned to a
radio-loud state with a
radio-loudness parameter exceeding 150. The
radio spectrum measured at gigahertz frequencies during the 2020s is flat. We did not find indications of a similar increase in brightness in optical surveys or in the infrared measurements of the Wide-field Infrared Survey Explorer. The variability characteristics are inconsistent with
tidal disruption events, and hard to reconcile with blazar variability.
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All authors K. É. Gabányi, S. Komossa, A. Kraus, A. Mezősi, S. Frey
Solar and Stellar Astrophysics
Magnetic Field Configuration of a Quiescent Prominence Revealed by Large-amplitude Longitudinal Oscillations in End-view Observations
Jun Dai, Ayumi Asai, Dechao Song et al. (+2 more)
Prominence seismology, applied to the large-amplitude longitudinal oscillation, is used to indirectly diagnose the geometry and strength of the
magnetic fields inside the prominence. In this paper, combining imaging and spectroscopic data, the
magnetic field configuration of a quiescent prominence is revealed by large-amplitude longitudinal oscillations observed in end view on 2023 December 4. Particularly, the prominence oscillation involved blueshift velocities in Dopplergrams and horizontal motions in extreme-ultraviolet (EUV) images. Originally, the prominence oscillation was triggered by the collision and heating of an adjoining hot structure associated with two coronal jets. The oscillation involved two groups of signals with similar oscillatory parameters, a three-dimensional (3D) initial amplitude of 40 Mm and a 3D velocity amplitude of 48 km/s, both lasting for 4 cycles with a period of 77 minutes, with a phase difference of pi/4. While the angle between 3D velocities and the prominence axis ranges from 10 to 30. Two methods, utilizing time-distance diagrams and velocity fields, are employed to calculate the
curvature radius of
magnetic dips supporting the prominence materials. Both methods yield similar value ranges and trends from the bottom to the top of
magnetic dips, with the
curvature radius increasing from 90 Mm to 220 Mm, then decreasing to 10 Mm, with transverse
magnetic field strength 25 Gauss. From this, the realistic 3D geometry of the prominence
magnetic dips is determined to be sinusoidal. To the best of our knowledge, we present the first accurate calculation of the 3D
curvature radius and geometry of the prominence
magnetic dips based on longitudinal oscillatory motions.
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All authors Jun Dai, Ayumi Asai, Dechao Song, Ye Qiu, Zhe Xu
High Energy Astrophysical Phenomena
The population of Galactic young massive star clusters in the TeV range
Rowan Batzofin, Pierre Cristofari and Kathrin Egberts
Young massive
star clusters (YMSCs) can produce gamma rays in the very-high-energy (VHE, E>100 GeV) range and have been proposed as sources that can accelerate
cosmic rays up to PeV energies. Observations with current instruments have lead to the detection of only a few YMSCs but future instruments should significantly increase this number. However, the details of the production of the VHE emission are not well understood: What is the spectrum of accelerated particles? What is the efficiency of
cosmic-ray production? What fraction of the wind luminosity is converted into the turbulent
magnetic field? To address these questions, we simulate the population of YMSCs in the gamma-ray domain, by means of Monte Carlo methods, and apply the constraints based on the subsample of YMSCs currently detected at TeV energies. We confront our simulated populations with the catalogue of the H.E.S.S.
Galactic Plane Survey and the First LHAASO Catalogue of Gamma-Ray Sources, allowing us to investigate crucial aspects of particle acceleration at YMSCs.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Testing a cosmological teleparallel modified f(T) model with parametric H(z)
Adriel O. Aquino and J.E.G. Silva
We study the late-time cosmological expansion of a modified teleparallel
gravity model. This modified gravitational lagrangian yields a cosmological constant term along with power-law corrections to the Teleparallel Equivalent of General Relativity (TEGR) for small $\lambda$. By combining observational data from
cosmic chronometers, Type Ia
supernovae from the Pantheon+
dataset, and
Baryon Acoustic Oscillations (BAO) from DESI DR2, we constrain the parameters of the modified gravitational dynamics assuming a quadratically parameterized Hubble rate $H(z)$. The joint observational fit indicates a late-time accelerated expansion with a deceleration parameter of $q_0 = -0.388_{-0.038}^{+0.038}$. Furthermore, we analyze the effective energy density, pressure, and equation-of-state parameter $\omega$, showing that this modified
gravity theory naturally accommodates quintessence-like and phantom-like behavior. Finally, a linear scalar perturbation analysis confirms that the cosmological background is dynamically stable against homogeneous fluctuations.
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Instrumentation and Methods for Astrophysics
EBOP MAVEN: A machine learning model to estimate the input parameters for analytic fitting of detached eclipsing binary light curves
Stephen Overall and John Southworth
Detached eclipsing binary
stars (dEBs) are a key source of data on fundamental
stellar parameters. Within the light curve databases of survey missions such as Kepler and TESS are a wealth of new systems awaiting characterisation. We aim to improve the scalability of efforts to process these data by developing a Convolutional Neural Network (CNN) machine learning model to assist in the automation of their analysis. From a phase-folded and binned dEB light curve the model predicts system parameters relating to
stellar fractional radii, orbital inclination and eccentricity, and the
stellar brightness ratio, for use as input values in subsequent formal analysis with the established JKTEBOP analytic code. We find the model able to predict these parameters for a previously unseen test
dataset of 20000 synthetic dEB systems with a mean error of 14.1% when compared with the label values, improving to 8.6% against a subset representative of real systems. When tested with the TESS light curves of a set of real well-characterised systems, the model's predictions yield a mean error of $8.7\pm0.7\%$ when compared with label values derived from existing published analyses. Subsequent fitting of the TESS light curves with the JKTEBOP analytic code while using the model predictions as input values finds 27 of the 28 systems achieving a good fit. On the strength of these results, we plan to build a new characterisation pipeline based on the machine learning model and JKTEBOP code with the intention of producing a target catalogue of dEB systems for potential observation with the forthcoming PLATO mission.
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Solar and Stellar Astrophysics
Surface activity of a Rossby sequence of cool Hyades stars
K. G. Strassmeier, I. Ilyin, M. Steffen et al. (+1 more)
Aims. The Hyades cluster is key for the study of rotational, activity, and chemical
evolution of
solar-like low-mass
stars. Here we present quantitative surface-activity information for a sequence of 21 Hyades
dwarf stars. Conclusions. We conclude that the Rossby-number dependencies of the surface activity tracers A(Li), R(IRT), and B on our Hyades
dwarf sequence primarily originate from convective motions, expressed by its turnover time, and only to a smaller and sometimes inverse extent from surface rotation and its related extra mixing.
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All authors K. G. Strassmeier, I. Ilyin, M. Steffen, S. A. Barnes