High Energy Astrophysical Phenomena
Cross Calibration of Galaxy Cluster Temperatures Measured with NuSTAR, XMM-Newton, and Chandra
Fiona Lopez, Daniel R. Wik, Cicely Potter et al. (+10 more)
The use of
galaxy clusters to constrain cosmology is limited in part due to uncertainties in derived cluster masses, which often depend on the gas temperature. Unfortunately, there exists a longstanding discrepancy in temperature measurements of the same
galaxy clusters made by the two most sensitive X-ray observatories, Chandra and XMM-Newton. The NuSTAR X-ray Observatory's greater sensitivity to the exponential turnover in the bremsstrahlung continuum allows for more precise and potentially more accurate
galaxy cluster temperature estimates, especially given its unique ability to independently calibrate its optics in orbit. We present new NuSTAR spectra of 10 relaxed clusters ($5~\mathrm{keV} < kT < 10~\mathrm{keV}$), extracted from identical regions as previous spectra from Chandra and XMM-Newton. The 3–20~keV spectra are well fit by single temperature models, and fits done in narrower bandpasses provide no clear evidence in support of the existence of multi temperature gas. We find NuSTAR temperatures are typically $\sim 15\%$ higher than XMM-Newton temperatures. In contrast, good agreement is found between NuSTAR and Chandra temperatures for clusters with $kT \lesssim 7~\mathrm{keV}$, with Chandra measurements exceeding NuSTAR's in hotter systems. When more clusters are included, the trend is reinforced and can be extended to higher temperatures. A generic increase to Chandra's $E > 2~\mathrm{keV}$ effective area ($\sim 5\%$ at 5~keV) is found to explain the trend reasonably well. These results demonstrate the potential for NuSTAR data to address the two-decade-old temperature discrepancy between Chandra and XMM-Newton.
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All authors Fiona Lopez, Daniel R. Wik, Cicely Potter, Randall A. Rojas Bolivar, Ayşegül Tümer, Dominique Eckert, Fabio Gastaldello, Brian W Grefenstette, Kristin Madsen, Ben Maughan, Eric D. Miller, Gerrit Schellenberger, A. N. Wallbank
Instrumentation and Methods for Astrophysics
Alternative approach to time-delay interferometry with optical frequency comb
Kohei Yamamoto, Hannah Tomio, Charlotte Zehnder et al. (+2 more)
Spaceborne gravitational wave observatories, exemplified by the
Laser Interferometer Space
Antenna (LISA) mission, are designed to remove
laser noise and clock noise from interferometric phase measurements in postprocessing. The planned observatories will utilize electro-optic modulators (EOMs) to encode the onboard clock timing onto the beam phase. Recent research has demonstrated the advantage of introducing an optical frequency comb (OFC) in the metrology system with the modified framework of time-delay interferometry (TDI): the removal of the EOM and the simultaneous suppression of the
stochastic jitter of the
laser and the clock in the observation band. In this paper, we explore an alternative approach with the OFC-based metrology system. We report that after proper treatment, it is possible to use the measured carrier-carrier heterodyne frequencies to monitor the time derivative of the pseudoranges, which represent the physical light travel time and the clock difference. This approach does not require changing the existing TDI framework, as previous OFC based efforts did. Furthermore, this approach naturally captures not only
stochastic jitter but also clock offsets and slow drifts. We also present the experimental demonstration of our scheme using two separate systems to model two spacecraft. Using this novel approach, we synchronize the two independent phase measurement systems with an accuracy better than 0.47 ns, while the
stochastic jitter in the observation band is suppressed down to the setup sensitivity around the LISA performance levels at 15 pm/sqrt(Hz).
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All authors Kohei Yamamoto, Hannah Tomio, Charlotte Zehnder, Kenji Numata, Holly Leopardi
Instrumentation and Methods for Astrophysics · Cross-listed from nucl-ex
Latest results from CUORE and prospects for CUPID
K. Zhao
The search for neutrinoless double beta decay (0$\nu\beta\beta$) is fundamental for investigating
lepton-number violation, probing new physics beyond the Standard Model, and determining whether
neutrinos are Majorana particles. CUORE (Cryogenic Underground Observatory of Rare Events), a cryogenic bolometric experiment at LNGS, studies 0$\nu\beta\beta$ in $^{130}$Te using 988 TeO$_2$
crystals. It is a milestone of cryogenic detector arrays with a tonne-scale detector operated for more than 7~years below 15~mK. Since 2017, CUORE has accumulated over 2.9~tonne-years of exposure, achieving one of the leading 0$\nu\beta\beta$ limits and one of the most precise two-
neutrino double beta decay (2$\nu\beta\beta$) half-life measurements thanks to a detailed background reconstruction across a broad energy range. Building on CUORE's success, CUPID (CUORE Upgrade with Particle ID) aims to significantly enhance its 0$\nu\beta\beta$ discovery sensitivity to $10^{27}$ yr in $^{100}$Mo, covering the Inverted Hierarchy of
neutrino masses. It will employ lithium molybdate (Li$_2$MoO$_4$)
crystals enriched in $^{100}$Mo, alongside germanium light detectors with Neganov-Trofimov-Luke amplification, enabling simultaneous heat and light readout for enhanced background rejection. CUPID will reuse CUORE's cryostat and infrastructure. Current efforts focus on detector performance validation, sensitivity studies, and finalizing the experimental design to maximize physics reach. This work presents the latest CUORE results and outlines the key milestones toward CUPID's realization.
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Earth and Planetary Astrophysics
A Closed-Form Analytical Theory of Non-Isobaric Transmission Spectroscopy for Exoplanet Atmospheres
Leonardos Gkouvelis
Analytical models are essential for building physical intuition and guiding the interpretation of
exoplanet observations by clarifying the dependencies that shape atmospheric signatures. We present a generalization of the classical isothermal, isobaric transmission model by allowing the opacity to vary with pressure as a power law, $\kappa \propto P^{n}$, and explicitly defining the reference opacity $\kappa_{0}$ at a chosen pressure $P_{0}$. By treating the slant optical depth as an Abel transform of the radial absorption coefficient, we derive a closed-form expression for the effective transit radius in a hydrostatic, isothermal atmosphere with pressure-dependent opacity. The solution provides a compact framework for exploring non-isobaric effects and explicitly links the vertical opacity gradient to observable spectral features. We
benchmark the model against empirical transmission spectra of Earth and the hot Jupiter WASP-39b, finding a significantly improved fit relative to the isobaric formula. This generalized expression offers a physically interpretable foundation for analyzing high-precision spectra from JWST and upcoming ARIEL observations, and can serve as a basis for semi-analytical
retrieval approaches optimized for computational efficiency.
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High Energy Astrophysical Phenomena
First Results from the PanRadio Gamma-Ray Burst Collaboration: The 400-day Afterglow of GRB 230815A
James K. Leung, Gemma E. Anderson, Alexander J. van der Horst et al. (+26 more)
We introduce the PanRadio Gamma-ray Burst (GRB) program carried out on the Australia
Telescope Compact Array: a systematic, multi-year,
radio survey of all southern $\textit{Swift}$ GRB events, comprehensively following the multi-frequency
evolution of their afterglows from within an hour to years post-burst. We present the results of the 400-day observing campaign following the afterglow of the long-duration (collapsar) GRB 230815A, the first one detected through this program. Typically, GRB 230815A would not otherwise receive traditional
radio follow-up, given it has no known
redshift and lacks comprehensive multi-wavelength follow-up due to its high line-of-sight extinction with $A_V=2.3$. We found its early X-ray jet break at ${\sim}0.1$ days post-burst to be at odds with the
evolution of the multi-frequency
radio light curves that were traced over an unusually long duration of $400$ days. The
radio light curves approximately evolved (with minor deviations) according to the standard self-similar expansion for a relativistic blast wave in a homogeneous environment prior to the jet break, showing no evidence for evolutions of the microphysical parameters describing the electron acceleration processes. We reconcile these features by proposing a two-component jet: the early X-ray break originates from a narrow component with a half-opening angle ${\sim}2.1^{\circ}$, while the
evolution of the
radio afterglow stems from a wider component with a half-opening angle of $\gtrapprox 35^{\circ}$. The PanRadio GRB program will establish a sample of comprehensively followed GRBs, where a rigorous inspection of their microphysical and dynamical parameters can be performed, thereby revealing the diversity of features in their
outflows and environments.
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All authors James K. Leung, Gemma E. Anderson, Alexander J. van der Horst, Claire Morley, Benjamin Schneider, Fabio De Colle, Om Sharan Salafia, Giancarlo Ghirlanda, Sarah I. Chastain, Adelle J. Goodwin, Ashna Gulati, Lauren Rhodes, Stuart D. Ryder, Ashley A. Chrimes, Valerio D'Elia, Mathieu de Bony de Lavergne, Massimiliano De Pasquale, Antonio de Ugarte Postigo, Dieter H. Hartmann, Benjamin P. Gompertz, Andrew J. Levan, Tara Murphy, Gavin P. Rowell, Thomas D. Russell, Fabian Schüssler, Rhaana L. C. Starling, Nial R. Tanvir, Susanna D. Vergani, Ralph A.M.J. Wijers
High Energy Astrophysical Phenomena
Blazar PKS 0446+11 – Neutrino connection study using a lepto-hadronic model
Rukaiya Khatoon, Markus Boettcher and Joshua Robinson
We present a multi-wavelength study of a blazar PKS 0446+11, motivated by its spatial association with the
neutrino event IC240105A detected by the IceCube
Neutrino Observatory on 2024 January 5. The source is located 0.4 degrees from the best-fit
neutrino direction and satisfies selection criteria for VLBI-selected,
radio-bright AGN that have been identified as highly probable
neutrino associations. PKS 0446+11 exhibited a major gamma-ray
flare in November 2023, reaching approximately 18x its 4FGL-DR4 catalog average. Around the
neutrino epoch, PKS 0446+11 remained in an elevated state, with the gamma-ray flux more than six times above its catalog level, the X-ray flux an order of magnitude above the archival measurements, and the optical-UV emission also enhanced. We used
Fermi-LAT, Swift-XRT/UVOT, and archival multi-wavelength data to construct multi-wavelength light curves and spectral energy distributions (SEDs). SED modeling shows that the emission is best described by a leptonic scenario, with synchrotron emission at low energies and external Compton scattering of broad-line region and dusty
torus photons dominating the X-ray - gamma-ray output. A lepto-hadronic model fails to adequately reproduce the observed SED, although hadronic cascades can broadly account for the X-ray and gamma-ray spectral coverage at lower flux levels. We compute the expected
neutrino flux for the hadronic scenario and compare it to the IceCube 90% upper limit. Our results highlight the importance of continued multi-wavelength and
neutrino monitoring to better understand the physical conditions under which this blazar may serve as
neutrino source.
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Earth and Planetary Astrophysics
Searching for Exoplanets Born Outside the Milky Way: VOYAGERS Survey Design
Robert Aloisi, Andrew Vanderburg, Melinda Soares-Furtado et al. (+44 more)
Observations over the past few decades have found that
planets are common around nearby
stars in our
Galaxy, but little is known about
planets that formed outside the Milky Way. We describe the design and early implementation of a survey to test whether
planets also exist orbiting the remnant
stars of ancient
dwarf galaxies that merged with the Milky Way, and if so, how they differ from their Milky Way counterparts. VOYAGERS (Views Of Yore - Ancient
Gaia-enceladus
Exoplanet Revealing Survey) is a radial velocity (RV) search using precision spectrographs to discover
exoplanets orbiting very low
metallicity ($-2.8 < [\mathrm{Fe/H}] \leq -0.8$)
stars born in the
dwarf galaxy Enceladus, which merged with the Milky Way
galaxy about 10 Gyr ago. A sample of 22 candidates have been screened from a catalog of
Gaia-Enceladus-Sausage (GES) members using a combination of
stellar properties and reconnaissance observations from the TRES spectrograph. Precision RV measurements have been initiated using the NEID, HARPS-N, and CARMENES spectrographs. We plan to focus most upcoming observations on 10 main sequence targets. Data collection is well underway, with 778 observations on 22 candidates (385 of which are 10 focus targets), but far from complete. This survey is designed to be sensitive to sub-Neptune mass
planets with periods up to hundreds of days. We note that the RV analysis gives mass multiplied by $\sin (inclination)$ or the minimum mass for
exoplanets. The expected survey yield is three
planets, assuming that occurrence rates are similar to those in the Milky Way and taking into account the degeneracy with inclination in our yield models. Our survey is designed to detect at least one
exoplanet if occurrence rates are similar to known Milky Way
exoplanets or, if no
exoplanets are discovered, to rule out a Milky Way-like
planet population in GES with 95% confidence level.
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All authors Robert Aloisi, Andrew Vanderburg, Melinda Soares-Furtado, Phillip Cargile, Ke Zhang, Lina Necib, David W. Latham, Sam Quinn, Emily Pass, Anne Dattilo, Giacomo Mantovan, Francesco Amadori, Mariona Badenas-Agusti, Perry Berlind, Francesco Borsa, Walter Boschin, Lorenzo Cabona, Michael L. Calkins, Hans J. Deeg, Xavier Dumusque, Gilbert A. Esquerdo, Yoshi Nike Emilia Eschen, S. Filomeno, S. Geraldía-González, Natalia Guerrero, Sydney Jenkins, Gaia Lacedelli, Mercedes López-Morales, Paula Manuela Leguizamon-Pineda, Emilio Molinari, Juan Carlos Morales, Annelies Mortier, Rohan Naidu, Domenico Nardiello, Belinda Nicholson, Isabella Pagano, Enric Palle, Marco Pedani, Matteo Pinamonti, Jesus Maldonado, Monica Rainer, Ignasi Ribas, Ken Rice, Gu{\dh}mundur Kári Stefánsson, Daisy Turner, Thomas G. Wilson, Mathias Zechmeister
Solar and Stellar Astrophysics
Reassessing the Relationship Between Stellar X-ray Luminosity and Age with eROSITA Data Release 1
Nadja Aldarondo Quiñones, Sydney Jenkins, Andrew Vanderburg et al. (+2 more)
Accurate
stellar dating provides crucial information about the formation and development of planetary systems. Existing age-dating techniques are limited in terms of both the spectral type and age range they can accurately probe, and many are unreliable for
stars older than 1 Gyr. Recent studies have suggested that a
star's X-ray luminosity correlates strongly with
stellar age and shows a steep fall-off at ages older than 1 Gyr. In this work, we present X-ray luminosity relationship values from eROSITA for four previously unassessed
stars. Additionally, we reassess the X-ray luminosity/age relationship present in 24 main-sequence
stars older than a gigayear. We confirm that a correlation does appear to exist between
stellar age and X-ray luminosity at ages older than 1 Gyr. However, we measure a shallower slope with age than previous research for older
stars, similar to what was found for younger
stars. We also find evidence for significant astrophysical variability in a
star's X-ray luminosity, which will likely limit the precision with which X-ray measurements can yield age estimates. We also find weak evidence for mass dependence in the X-ray luminosity/age relationship. These results suggest that although X-ray luminosity correlates with
stellar age, it may not serve as a reliable standalone age indicator and is better used as part of a broader suite of age-dating methods.
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All authors Nadja Aldarondo Quiñones, Sydney Jenkins, Andrew Vanderburg, Melinda Soares-Furtado, Michael A. McDonald
Astrophysics of Galaxies
J-PLUS Reconstructing the Milky Way Disc's star formation history with twelve-filter photometry
J. A. Alzate-Trujillo, A. del Pino, C. López-Sanjuan et al. (+23 more)
Wide-field, multi-filter photometric surveys enable the reconstruction of the Milky Way's
star formation history (SFH) on
Galactic scales and offer new insights into disc assembly. The twelve-filter system of the Javalambre Photometric Local Universe Survey (J-PLUS) is particularly suitable, as its colours trace
stellar chemical abundances and help alleviate the age-
metallicity degeneracy in colour-magnitude diagram fitting. We aim to recover the SFH of the
Galactic disc and separate its chemically distinct components by combining J-PLUS DR3 photometry with
Gaia astrometry. We also evaluate the potential of isochrone fitting to estimate
stellar ages and
metallicities as proxies for evolutionary trends. We fit magnitudes and parallaxes of $1.38\times10^{6}$
stars using a
Bayesian multiple isochrone method. The bright region of the colour-absolute-magnitude diagram ($M_{r}\leq4.2$ mag) constrains ages, while the faint region provides an empirical
metallicity prior mitigating the age-
metallicity degeneracy. Both PARSEC and BaSTI isochrones, in
solar-scaled and $\alpha$-enhanced forms, are adopted. The recovered SFH reveals two sequences: an $\alpha$-enhanced population forming rapidly between $12.5$ and $8$ Gyr ago, enriching from [M/H]$\sim-0.6$ to $0.1$ dex; and a
solar-scaled sequence emerging $\sim8$ Gyr ago, dominating after $\sim7$ Gyr with slower enrichment reaching
solar metallicity by $3$ Gyr. Metal-rich ([M/H]$\gtrsim0$)
stars are confined to $\vert z_{GC}\vert\lesssim1$ kpc, whereas metal-poor ([M/H]$\lesssim-0.5$)
stars reach $\vert z_{GC}\vert\sim2$ kpc. Simultaneous fitting of both isochrone families reveals distinct formation epochs for the thin and thick discs. J-PLUS multi-filter photometry, combined with
Gaia parallaxes, mitigates age-
metallicity degeneracies and enables detailed mapping of the Milky Way's temporal and chemical
evolution.
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All authors J. A. Alzate-Trujillo, A. del Pino, C. López-Sanjuan, A. Hidalgo, S. Turrado-Prieto, Vinicius Placco, Paula Coelho, Haibo Yuan, Luis Lomelí-Núñez, Gustavo Bruzual, F. Jiménez-Esteban, Eduardo Telles, Borja Anguiano, Alvaro Alvarez-Candal, A. J. Cenarro, D. Cristóbal-Hornillos, C. Hernández-Monteagudo, A. Marín-Franch, M. Moles, J. Varela, H. Vázquez Ramió, J. Alcaniz, R. A. Dupke, A. Ederoclite, L. Sodré Jr., R. E. Angulo
Earth and Planetary Astrophysics
Dust Recycling and Icy Volatile Enhancement (DRIVE): A Novel Method of Volatile Enrichment in Cold Giant Planets
Eric R. Van Clepper, Felipe Alarcón, Edwin Bergin et al. (+1 more)
Giant planet atmospheres are thought to reflect the gas phase composition of the disk when and where they formed. However, these atmospheres may also be polluted via solid
accretion or ice sublimation in the disk. Here, we propose a novel mechanism for enriching the atmospheres of these
giant planets with volatiles via pebble drift, fragmentation, and ice sublimation. We use a combination of 3D hydrodynamic simulations, radiative transfer, and particle tracking to follow the trajectories and resulting temperatures of solids in a disk containing an embedded
planet forming outside the CO snowline. We show that small
dust can become entrained in the meridional flows created by the
giant planet and advected above the disk midplane where temperatures are well above the sublimation temperature of CO. This transport of small grains occurs over 10 kyr timescales, with individual micron-sized grains cycling between the midplane and surface of the disk multiple times throughout the planetary
accretion stage. We find that this stirring of
dust results in sublimation of CO gas above the snow surface in the
dust trap created exterior to the
giant planet, leading to super-
solar CO abundances in the pressure bump. This mechanism of
Dust Recycling and Icy Volatile Enhancement in cold
giant planets, which we call the DRIVE effect, may explain enhanced
metallicities of both wide separation
exoplanets as well as Jupiter in our own
Solar System.
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All authors Eric R. Van Clepper, Felipe Alarcón, Edwin Bergin, Fred J. Ciesla
Astrophysics of Galaxies
From Feedback-Free Star Clusters to Little Red Dots via Compaction
Avishai Dekel, Dhruba Dutta Chowdhury, Sharon Lapiner et al. (+6 more)
We address the origin of the Little Red Dots (LRDs) seen by JWST at
cosmic morning ($z \!=\! 4 \!-\! 8$) as compact
stellar systems with over-massive black holes (BHs). We propose that LRDs form naturally after feedback-free starbursts (FFB) in thousands of
star clusters and following wet compaction. Analytically, we show how the clusters enable efficient dry migration of
stars and BHs to the
galaxy center by two-body segregation and dynamical friction against the disk. The clusters merge to form compact central
stellar systems as observed. Mutual
tidal stripping does not qualitatively affect the analysis. The young, rotating clusters are natural sites for the formation of BH seeds via rapid core collapse. The migrating clusters carry the BH seeds, which merge into central super-massive BHs (SMBHs). Compactions are required to deepen the potential wells such that the SMBHs are retained after post-merger gravitational-wave
recoils, locked to the
galaxy centers. Using cosmological simulations at different epochs, with different codes and physical recipes, we evaluate the additional growth of LRD-matching compact central
stellar systems by global compaction events. Adding to the dry growth by cluster mergers, the compactions can increase the escape velocities to retain the SMBHs. The LRDs appear at $z \!\sim\! 8$, after the formation of FFB clusters, and disappear after $z \!\sim\! 4$ when the
stellar mass is above $10^9 M_\odot$ by growing post-compaction blue disks around the
nuclear LRDs. The LRD abundance is expected to be $\sim\! 10^{-5} \!-\! 10^{-4}\,{\rm Mpc}^{-3}$, increasing from $z \!\sim\! 4$ to $z\!\sim\! 8$.
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All authors Avishai Dekel, Dhruba Dutta Chowdhury, Sharon Lapiner, Zhiyuan Yao, Shmuel Gilbaum, Daniel Ceverino, Joel Primack, Rachel Somerville, Romain Teyssier
Earth and Planetary Astrophysics
Resolving the large exoKuiper belt of the HD 126062 debris disc and extended gas emission in its vicinity
James M. Miley, Grant M. Kennedy, Alvaro Ribas et al. (+8 more)
Intermediate-mass
stars (1-3 Msun) host some of the brightest and best-studied debris discs. This
stellar class is also the most frequent host of molecular gas in systems older than typical protoplanetary disc lifetimes, and the most likely to host detected
giant planets in radial-velocity surveys. The debris discs of intermediate-mass
stars have therefore become fertile ground for studying disc-
planet interactions. In this work, we present the first ALMA observations toward the A-type
star HD 126062, located in Upper Centaurus Lupus / Lower Centaurus Crux, with the aim of characterising its debris disc. We probed the thermal continuum emission using observations at 1.3 mm, analysed through image reconstruction under different visibility-weighting regimes and parametric model fitting to the observed visibilities. The setup also covered the frequency of the 12CO(2-1) line, allowing imaging of gas near the system. We detected
dust continuum emission from an exo-Kuiper belt around HD 126062. Modelled as a Gaussian ring, the visibilities are consistent with a radial separation R = 2.01” (+0.04, -0.05), equivalent to ~270 (+5, -4) au, and a full width at half maximum DeltaR = 0.71” +- 0.09 (95 +- 12 au). The continuum emission appears nearly face-on, with inclination <=17 deg. 12CO(2-1) emission is detected in the vicinity of the debris disc, with most of it located external to the exo-Kuiper belt. The exo-Kuiper belt characterised here is among the largest yet detected and agrees with previous predictions of the
dust distribution based on spectral energy distribution fitting. The morphology and velocity offset relative to the systemic velocity suggest that the gas is not associated with the
star or disc, but likely originates from a diffuse cloud in the nearby
galaxy.
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All authors James M. Miley, Grant M. Kennedy, Alvaro Ribas, Enrique Macias, John Carpenter, Miguel Vioque, Kevin Luhman, Thomas Haworth, Philipp Weber, Sebastian Perez, Alice Zurlo
High Energy Astrophysical Phenomena
Dark Matter Heating in Evolving Proto-Neutron Stars: A Two-Fluid Approach
Adamu Issifu, Prashant Thakur, Davood Rafiei Karkevandi et al. (+4 more)
Neutron stars (NSs) provide a unique laboratory to probe dark matter (DM) through its gravitational imprint on
stellar evolution. We use a two-fluid framework with non-annihilating, asymmetric DM, both fermionic and bosonic, that interacts with ordinary matter (OM) solely through
gravity. Within this framework, we track protoneutron
stars (PNSs) across their thermal and compositional
evolution via quasi-static modeling over the Kelvin–Helmholtz cooling timescale. We uncover a distinct thermal signature: DM cores deepen the gravitational potential, compressing and heating the baryonic matter, while extended DM
halos provide external support, leading to cooling of the
stellar matter. In contrast, hyperons and other exotic
baryons soften the equation of state similarly to DM cores but reduce, rather than increase, the temperature. DM thus alters both temperature and particle distribution profiles in ways that provide a clear diagnostic of its presence. DM cores also enhance compactness and shift hyperon onset, with the strongest effects during deleptonization and
neutrino-transparent phases due to reduced
neutrino pressure contributions. Consequently, this early thermal
evolution, observable through
supernova neutrino light curves and young
pulsar cooling curves, offers a direct, testable probe of DM in NSs.
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All authors Adamu Issifu, Prashant Thakur, Davood Rafiei Karkevandi, Franciele M. da Silva, Débora P. Menezes, Y. Lim, Tobias Frederico
Astrophysics of Galaxies
Effect of molecular hydrogen self-shielding modeling on early Reionization Era galaxies in radiative hydrodynamic cosmological simulations
Thinh Huu Nguyen, Kirk S. S. Barrow, Susie Byrom et al. (+1 more)
Accurately modeling molecular hydrogen ($\text{H}_{2}$) is an important task in cosmological simulations because it regulates
star formation. One fundamental property of $\text{H}_{2}$ is the ability to self-shield, a phenomenon in which the $\text{H}_{2}$ in the outer layer of a molecular cloud absorbs the photodissociating Lyman-Werner UV radiation and shields the inner $\text{H}_{2}$. Historically, numerical approximations have been utilized to avoid intensive ray-tracing calculations. This paper evaluates the use of the Sobolev-like density-gradient approximation in $\text{H}_{2}$ self-shielding modeling and tests its agreement with a more rigorous adaptive ray-tracing method in cosmological simulations. We ran four high-resolution zoom-in cosmological simulations to investigate the models' effects in the early Reionization Era ($z \geq 12$). We find that the approximation model returns a higher $\text{H}_{2}$ photodissociation rate in low gas density environments but a lower rate when gas density is high, resulting in low-mass
halos having less $\text{H}_{2}$ while high-mass
halos having more $\text{H}_{2}$. The approximation also hinders
star formation in small
halos, but it less affects the
stellar mass of larger
halos. Inside a
halo, the discrepancies between the two models regarding $\text{H}_{2}$ fraction, temperature, and
stellar mass are radially dependent. On a large scale, the simulations using the approximation have less $\text{H}_{2}$ in the intergalactic medium and may experience a slower reionization process. These results show that the Sobolev-like approximation alters properties of
galaxies and the large-scale universe when compared to the ray-tracing treatment, emphasizing a need for caution when interpreting results from these two techniques in cosmological simulations.
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All authors Thinh Huu Nguyen, Kirk S. S. Barrow, Susie Byrom, Varun Satish
Instrumentation and Methods for Astrophysics
General Implicit Runge-Kutta Integrators for Multifluid Gas-Dust Aerodynamic Drag
Giovanni Tedeschi-Prades, Til Birnstiel, Klaus Dolag et al. (+2 more)
The integration of aerodynamic drag is a fundamental step in simulating
dust dynamics in hydrodynamical simulations. We propose a novel integration scheme, designed to be compatible with Strang splitting techniques, which allows for the straightforward integration of external forces and hydrodynamic fluxes in general-purpose hydrodynamic simulation codes. Moreover, this solver leverages an analytical solution to the problem of drag acceleration, ensuring linear complexity even in cases with multiple
dust grain sizes, as opposed to the cubic scaling of methods that require a
matrix inversion step. This new General Implicit Runge-Kutta integrator (GIRK) is evaluated using standard
benchmarks for
dust dynamics such as DUSTYBOX, DUSTYWAVE, and DUSTYSHOCK. The results demonstrate not only the accuracy of the method but also the expected scalings in terms of accuracy, convergence to
equilibrium, and execution time. GIRK can be easily implemented in hydrodynamical simulations alongside hydrodynamical steps and external forces, and is especially useful in simulations with a large number of
dust grain sizes.
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All authors Giovanni Tedeschi-Prades, Til Birnstiel, Klaus Dolag, Barbara Ercolano, Mark Hutchison
Earth and Planetary Astrophysics
JWST/NIRCam observations of HD~92945 debris disk: An asymmetric disk with a gap
C. Lazzoni, R. Bendahan-West, S. Marino et al. (+9 more)
We present the first observations of the HD92945 debris disk obtained with JWST, targeting this nearby K0V
star located at 21.54 pc from the Sun. High-contrast coronagraphic imaging was performed using JWST/NIRCam in the F200W and F444W filters. After subtracting the disk contribution through forward modeling by means of synthetic PSFs and MCMC optimizations, the residuals were analyzed to identify candidate point sources. From these, we derived contrast curves and constructed detection probability maps for substellar companions. The disk is clearly detected in both NIRCam filters and reveals a broad, inclined structure with a gap, consistent with previous scattered-light and ALMA observations. The modeling confirms the presence of a gap at ~80 au and shows a scale height and scattering properties compatible with a dynamically active disk. A significant brightness asymmetry is observed in the southwestern inner ring at both 2 and 4.4 {\mu}m, consistent with previous ALMA results. Observing this feature across different wavelengths and epochs strongly supports a scenario where one or more unseen planetary companions are perturbing the disk. No comoving sources are detected, and all candidate objects in the field are consistent with background
stars or
galaxies. The derived detection limits exclude
planets more massive than ~0.4-0.5 MJ beyond 100 au and more massive than ~1 MJ beyond 20-40 au. This, in turn, rules out the possibility of a single
planet placed beyond ~20 au as responsible for the astrometric signal observed by
Gaia. These results, combined with the observed disk features, support a scenario in which a single or multiple sub-Jupiter
planets dynamically shape the system through mechanisms such as secular apsidal resonances, providing a coherent explanation for the gap, the asymmetric brightness distribution and the astrometric signal.
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All authors C. Lazzoni, R. Bendahan-West, S. Marino, K. D. Lawson, A. Carter, V. Squicciarini, G. Strampelli, S. Hinkley, G. Kennedy, A. D. James, J. Milli, S. Ray
Solar and Stellar Astrophysics
Characterizing TESS-Identified Quadruple and Higher Order Eclipsing Binaries: I. Speckle Imaging with DSSI and HRCam
Steven R. Majewski, James W. Davidson Jr., Robert F. Wilson et al. (+9 more)
NASA's TESS mission has unveiled a plethora of eclipsing binaries (EBs), among them hundreds of triples and higher order, hierarchical systems. These complex targets require follow-up observations to enable full characterization of system architectures and identify the most compact multiples expected to undergo the most dramatic dynamical
evolution. We report first results from a long-term effort to perform such follow-up, focusing here on multi-band speckle imaging of a majority, 57, of the sample of 97 quadruple and higher order eclipsing binaries (Q+EBs) identified via TESS light curves by V. B. Kostov et al. (2022). Diffraction-limited imaging with the Differential Speckle Survey Instrument (DSSI) on the ARC 3.5-meter
telescope and HRCam on the SOAR 4.1-m
telescope reveals nearly 60% of the 57 to resolve into two sources separated by $\geq$ 0.03 arcseconds. For these partly resolved systems, we report derived characteristics (e.g., relative position angle, angular separation, and magnitude differences in multiple passbands) from the speckle imaging. We find those Q+EBs partly resolved with 4-m class
telescopes to have significantly inflated
Gaia parallax errors and large
Gaia RUWE, particularly for systems with separations comparable to
Gaia's resolution limit (~0.6 arcseconds). For unresolved systems we report upper limits on angular and linear projected separations. We find two partly resolved Q+EBs with wide linear separations having eclipse timing variations that are therefore candidates of higher than quadruple multiplicity. Finally, we demonstrate how speckle imaging of resolved Q+EBs during an eclipse can clarify which speckle-resolved Q+EB subsystem is associated with a particular set of TESS eclipses.
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All authors Steven R. Majewski, James W. Davidson Jr., Robert F. Wilson, Elliott P. Horch, Paul M. McKee, Evan Fagan, Gabriel N. Hartwell, Veselin B. Kostov, Cassiopeia N. Adams, Torrie Sutherland, Andrei Tokovinin, John C. Wilson
Cosmology and Nongalactic Astrophysics
The impact of precession and higher-order multipoles for gravitational wave cosmological inference
Charlie Hoy and Konstantin Leyde
Gravitational-wave astronomy presents an exciting opportunity to provide an independent measurement of the expansion rate of the Universe. By combining inferences for the binary component masses and luminosity distances from individual observations, it is possible to infer $H_0$ without direct electromagnetic counterparts or
galaxy catalogs. However, this relies on theoretical gravitational-wave models, which are known to be incomplete descriptions of the full predictions of general relativity. Although the accuracy of our models are improving, they are also becoming increasingly expensive as additional phenomena are incorporated. In this work, we demonstrate that there is no significant advantage in including
spin-precession and higher-order multipole moments when inferring $H_0$ via the mass spectrum method for current and near-future gravitational-wave event numbers. Even when simulating a population of highly precessing and preferentially asymmetric-mass-ratio binaries, we show that the inferred $H_0$ posterior changes minimally. Using a simpler, less accurate model, achieves comparable $H_0$ estimates with six times less computational cost (on average). Using computationally cheaper models for single event inference may become crucial as thousands of gravitational-wave observations are expected to be detected in the near future.
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Astrophysics of Galaxies
Chemical dissection of merger-induced $m=1$ lopsidedness in Milky Way-like galaxies
Soumavo Ghosh, Paola Di Matteo, Chanda J. Jog et al. (+1 more)
The Milky Way harbours a prominent m=1 lopsided distortion in both
stellar and neutral gas distributions. On the other hand, chemo-dynamical studies have been proven to be effective in grasping the overall
evolution of
galaxies. Here, we investigate systematically the excitation and
evolution of a merger-driven $m=1$ lopsidedness in a Milky Way (MW)-like host
galaxy, as a function of chemical distribution of
stars. Using seven dissipationless, high-resolution $N$-body simulations of minor mergers (between a MW-like host and a satellite) under varying orbital configurations (prograde/retrograde and different orientation of the satellite orbital plane), we first show that a
tidal interaction excites a prominent $m=1$ lopsidedness in the
stellar density and velocity distribution of the MW-like host. Assigning, a posteriori,
metallicities to
stellar particles of the MW-like host based on the current observational constraints, we sub-divide the
stars into metal-rich ([Fe/H] > 0), metal-intermediate (-0.5 < [Fe/H] <0), and metal-poor (- 0.5 < [Fe/H]) populations. We demonstrate that metal-rich population always show a much stronger $m=1$ lopsidedness in both density and velocity distributions when compared to other two populations. This trend holds true for all minor merger model considered here, regardless of their orbital configurations. Furthermore, minor merger also triggers a transient off-centred
stellar disc-dark matter
halo configuration, with metal-rich population showing the highest degree of disc-
halo offset. We show that the metal-rich population which is kinematically colder (i.e. lower velocity dispersion) by construction, is more susceptible to external perturbations. Lastly, using a catalogue of photometry and metalicity for the LMC, we show that the strength of the $m=1$ distortion (predominantly in the form of an one-arm spiral) in
stars increases with
metallicity as well.
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All authors Soumavo Ghosh, Paola Di Matteo, Chanda J. Jog, Neige Frankel
Astrophysics of Galaxies
A Timescale-Resolved Analysis of the Breathing Effect in Quasar Broad Line Regions
C.-Z. Jiang, J.-X. Wang, H. Sou et al. (+1 more)
The single-epoch virial method is a fundamental tool for estimating supermassive black hole (SMBH) masses in large samples of AGNs and has been extensively employed in studies of SMBH-
galaxy co-
evolution across
cosmic time. However, since this method is calibrated using reverberation-mapped AGNs, its validity across the entire AGN population remains uncertain. We aim to examine the breathing effect-the variability of emission line widths with continuum luminosity-beyond reverberation-mapped AGNs, to assess the validity and estimate potential systematic uncertainties of single-epoch virial black hole mass estimates. We construct an unprecedentedly large multi-epoch spectroscopic
dataset of
quasars from SDSS DR16, focusing on four key broad emission lines (Ha, Hb, MgII, and CIV). We assess how breathing behavior evolves with the rest-frame time interval between observations. We detect no significant breathing signal in Ha, Hb, or MgII at any observed timescale. In contrast, CIV exhibits a statistically significant anti-breathing trend, most prominent at intermediate timescales. Notably, for Hb, which has shown breathing in previous reverberation-mapped samples, we recover the effect only in the small subset of
quasars with clearly detected BLR lags and only during the epochs when such lags are measurable-suggesting that both the lag and breathing signals are intermittent, possibly due to a weak correlation between optical and ionizing continua. These results highlight the complex, variable, and timescale-dependent nature of line profile variability and underscore its implications for single-epoch black hole mass estimates.
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All authors C.-Z. Jiang, J.-X. Wang, H. Sou, W.-K. Ren
Earth and Planetary Astrophysics
General Circulation Models of Hycean Worlds
Edouard Barrier and Nikku Madhusudhan
Sub-Neptunes represent the current frontier of
exoplanet atmospheric characterisation. A proposed subset, Hycean
planets, would have
liquid water oceans and be potentially habitable, but there are many unanswered questions about their atmospheric dynamics and 3D
climate states. To explore such climates in detail, we report a General Circulation Model (GCM) for Hycean worlds, building on a modified version of the ExoCAM GCM. Considering the temperate sub-Neptune K2-18 b as a Hycean candidate, we implement GCMs with different surface pressures and albedos. We find dynamical structures similar to those of tidally-locked terrestrial
planets as `slow rotators' with either one equatorial or twin mid-latitude zonal jets. We see moist convective inhibition that matches high resolution models, although in hotter cases the inhibited zone is subsaturated. When imposing a top-of-the-atmosphere (TOA) Bond albedo ($A_b$) by modifying the incident
stellar flux, we find that the threshold for K2-18~b to not enter a runaway greenhouse state is $A_b \geq 0.55$ for a 1 bar atmosphere, consistent with previous studies, and $A_b \geq 0.8$ for a 5 bar atmosphere. However, a more realistic treatment of the albedo, by modelling scattering within the atmosphere using an enhanced Rayleigh parametrisation, leads to lower lapse rates and stronger thermal inversions. We find that 1 bar atmospheres are stable for an albedo of $A_b \geq 0.27$, 5 bar atmospheres for $A_b \geq 0.35$, and 10 bar atmospheres for $A_b \geq 0.48$. Moderate albedos such as these are typical of the
solar system
planets and the required scattering is consistent with observational constraints for K2-18~b, supporting its plausibility as a Hycean world.
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Astrophysics of Galaxies
Warm and cold molecular gas in the cluster center of MACS 1931-26 with JWST and ALMA
L. Ghodsi, L. Kuhn, A. W. S. Man et al. (+9 more)
We perform one of the first spatially resolved studies of warm ($>$100 K) and cold (10-100 K) molecular gas in the circumgalactic medium (CGM), focusing on the brightest cluster
galaxy (BCG) of a cool-core
galaxy cluster, MACS1931-26 at z=0.35. This
galaxy has a massive H$_2$ reservoir and a
radio-loud active
galactic nucleus (AGN) and is undergoing a starburst event. We present new JWST observations of this system, revealing warm H$_2$ gas that is co-spatial with the cold molecular gas traced by CO, extending over 30 kpc around the BCG in a tail-like structure reaching into the circumgalactic medium of this
galaxy. Analysis of the mid-infrared pure H$_2$ rotational lines H$_2$S(1), H$_2$S(5), and H$_2$S(9) indicate warm gas temperatures of $515.6 \pm 0.8$ K and $535.2\pm 1.9$ K in the BCG and tail regions, respectively. We compare cold gas, traced by the CO(3-2) observed with ALMA, to the warm gas traced by JWST. The warm-to-cold molecular gas fraction is comparable in the BCG ($1.4\%\pm0.2\%$) and the CGM tail ($1.9\%\pm0.3\%$). Our analysis suggests that the dissipation of the kinetic energy of the H$_2$-emitting gas is sufficient to lead to the formation of the CO gas. This observation provides new insights into the molecular gas distribution and its potential role in the interplay between the central
galaxy and its circumgalactic environment.
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All authors L. Ghodsi, L. Kuhn, A. W. S. Man, P. Andreani, C. De Breuck, A. Togi, K. Dasyra, M. Lehnert, I. García-Bernete, D. Donevski, T. G. Bisbas, Y. Miyamoto
Astrophysics of Galaxies
Effect of ionizing photon escape fraction in faint galaxies on modeling reionization history of the universe
Zewei Wu, Andrey Kravtsov and Harley Katz
We present model calculations of the reionization history of hydrogen using
star formation histories, computed with a
galaxy formation model which reproduces properties of local
dwarf galaxies and UV luminosity functions of
galaxies at $z=5-16$. We use the ionizing
photon density functions predicted by the model along with different models for the escape fraction of ionizing
photons, $f_{\rm esc}$, to study the effects of ionizing
photons from faint
galaxies and different assumptions about $f_{\rm esc}$ on the
evolution of hydrogen ionized fraction with
redshift, $Q_{\rm HII}(z)$. We show that accounting for the contribution of faint
galaxies with UV luminosities $M_{1500}>-13$, and with a constant ionizing
photon escape fraction of $f_{\rm esc}=0.1$ results in the hydrogen reionization history consistent with all current observational constraints. Comparing results of the $f_{\rm esc}=0.1$ model and two alternative models shows that the model with a strong luminosity dependence of $f_{\rm esc}$, which assigns high $f_{\rm esc}$ to faint
galaxies, results in early reionization inconsistent with observational constraints. However, the model in which $f_{\rm esc}$ follows a universal
redshift-independent correlation with the recent maximum specific
star formation rate, motivated by the results of the SPHINX
galaxy formation simulation, results in the reionization history in good agreement with existing observational constraints, even though this model produces a sizeable ionized hydrogen fraction of $Q_{\rm HII}\approx 0.15-0.2$ at
redshifts $z=8-12$. Our results show that the relative contribution of faint
dwarf galaxies to reionization depends sensitively on assumptions about the escape fraction for
galaxies of different luminosities, and that this is the main source of uncertainty in modeling hydrogen reionization.
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Astrophysics of Galaxies
JWST's GLIMPSE: an overview of the deepest probe of early galaxy formation and cosmic reionization
Hakim Atek, John Chisholm, Vasily Kokorev et al. (+44 more)
We present an overview of the JWST GLIMPSE program, highlighting its survey design, primary science goals, gravitational
lensing models, and first results. GLIMPSE provides ultra-deep JWST/NIRCam imaging across seven broadband filters (F090W, F115W, F200W, F277W, F356W, F444W) and two medium-band filters (F410M, F480M), with exposure times ranging from 20 to 40 hours per filter. This yields a 5$\sigma$ limiting magnitude of 30.9 AB (measured in a 0.2 arcsec diameter aperture). The field is supported by extensive ancillary data, including deep HST imaging from the Hubble Frontier Fields program, VLT/MUSE spectroscopy, and deep JWST/NIRSpec medium-resolution multi-object spectroscopy. Exploiting the strong gravitational
lensing of the
galaxy cluster Abell S1063, GLIMPSE probes intrinsic depths beyond 33 AB magnitudes and covers an effective source-plane area of approximately 4.4 arcmin$^2$ at $z \sim 6$. The program's central aim is to constrain the abundance of the faintest
galaxies from $z \sim 6$ up to the highest
redshifts, providing crucial
benchmarks for
galaxy formation models, which have so far been tested primarily on relatively bright systems. We present an initial sample of $\sim 540$
galaxy candidates identified at $6 < z < 16$, with intrinsic UV magnitudes spanning $M_{\mathrm UV}$ = $-$20 to $-$12. This enables unprecedented constraints on the extreme faint end of the UV luminosity function at these epochs. In addition, GLIMPSE opens new windows for spatially resolved studies of
star clusters in early
galaxies and the detection and characterization of faint high-$z$ active
galactic nuclei. This paper accompanies the first public data release, which includes reduced JWST and HST mosaics, photometric catalogs, and gravitational
lensing models.
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All authors Hakim Atek, John Chisholm, Vasily Kokorev, Ryan Endsley, Richard Pan, Lukas Furtak, Iryna Chemerynska, Johan Richard, Adélaïde Claeyssens, Pascal Oesch, Seiji Fujimoto, Rohan Naidu, Damien Korber, Daniel Schaerer, Jeremy Blaizot, Joki Rosdahl, Angela Adamo, Yoshihisa Asada, Arghyadeep Basu, Benjamin Beauchesne, Danielle Berg, Rachel Bezanson, Rychard Bouwens, Gabriel Brammer, Miroslava Dessauges-Zavadsky, Amaël Ellien, Meriam Ezziati, Qinyue Fei, Ilias Goovaerts, Sylvain Heurtier, Tiger Yu-Yang Hsiao, Michelle Jecmen, Gourav Khullar, Jean-Paul Kneib, Ivo Labbé, Floriane Leclercq, Rui Marques-Chaves, Charlotte Mason, Kristen B.W. McQuinn, Julian B. Muñoz, Priyamvada Natarajan, Alberto Saldana-Lopez, Mabel G. Stephenson, Maxime Trebitsch, Marta Volonteri, Andrea Weibel, Adi Zitrin
High Energy Astrophysical Phenomena
Emission line models for the lowest mass core-collapse supernovae – II. 3D NLTE radiative transfer modelling of a $9.0\,M_\odot$ neutrino-driven explosion
Bart F.A. van Baal, Anders Jerkstrand, Daniel Kresse et al. (+1 more)
The nebular phase of a
supernova (SN) occurs several months to years after the explosion, with asymmetries created by the explosion encoded into the line profiles of the emission lines. To make accurate predictions for these line profiles, Non-Local Thermodynamic
Equilibrium (NLTE) radiative transfer calculations need to be carried out. In this work, we use $\texttt{ExTraSS}$ (EXplosive TRAnsient Spectral Simulator) – which was recently upgraded into a full 3D NLTE radiative transfer code (including photoionization and line-by-line transfer effects) – to perform such calculations. $\texttt{ExTraSS}$ is applied to a 3D explosion model of a $9.0\,M_\odot$ H-rich progenitor, evolved into the homologous phase. Synthetic spectra are computed and lines from different elements are studied for varying viewing angles. Line profile properties strongly correlate with a primary Ni plume in the ejecta. The model spectra are compared against observations of SN 1997D and SN 2016bkv. The model can create good line profile matches for both SNe, and reasonable luminosity matches for He, C, O, and Mg lines for SN 1997D – however H$\alpha$ and Fe I lines are too strong. Key diagnostic lines of low-mass core-collapse SNe (CCSNe), e.g. differentiating Fe CCSNe from electron capture SNe, are upheld from 1D to 3D. However, both line profiles and line luminosities differ in 3D across viewing angles, enabling the possibility of detailed comparisons to observed spectra to infer asymmetries imprinted by the explosion. We show that even the fastest $^{56}$Ni is traceable in nebular phase line profiles.
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All authors Bart F.A. van Baal, Anders Jerkstrand, Daniel Kresse, Hans-Thomas Janka