Locally authored papers of the past 5 days

We investigated the nuclear structure of $^{31}$P near the proton threshold using Nuclear Resonance Fluorescence (NRF) to refine the properties of key resonances in the $^{30}$Si(p,$\gamma$)$^{31}$P reaction, which is critical for nucleosynthesis in stellar environments. Excitation energies and spin-parities were determined for several states, including two unobserved resonances at $E_r$ $=$ $18.7$~keV and $E_r$ $=$ $50.5$~keV. The angular correlation analysis enabled the first unambiguous determination of the orbital angular momentum transfer for these states. These results provide a significant update to the $^{30}$Si(p,$\gamma$)$^{31}$P thermonuclear reaction rate, with direct implications for models of nucleosynthesis in globular clusters and other astrophysical sites. The revised rate is substantially lower than previous estimates at temperatures below $200$~MK, affecting predictions for silicon isotopic abundances in stellar environments. Our work demonstrates the power of NRF in constraining nuclear properties, and provides a framework for future studies of low-energy resonances relevant to astrophysical reaction rates.

The physical nature of Little Red Dots (LRDs) - a population of compact, red galaxies revealed by JWST - remains unclear. Photometric samples are constructed from varying selection criteria with limited spectroscopic follow-up available to test intrinsic spectral shapes and prevalence of broad emission lines. We use the RUBIES survey, a large spectroscopic program with wide color-morphology coverage and homogeneous data quality, to systematically analyze the emission-line kinematics, spectral shapes, and morphologies of $\sim$1500 galaxies at $z > 3.1$. We identify broad Balmer lines via a novel fitting approach that simultaneously models NIRSpec/PRISM and G395M spectra, yielding 80 broad-line sources with 28 (35%) at $z > 6$. A large subpopulation naturally emerges from the broad Balmer line sources, with 36 exhibiting `v-shaped' UV-to-optical continua and a dominant point source component in the rest-optical; we define these as spectroscopic LRDs, constituting the largest such sample to date. Strikingly, the spectroscopic LRD population is largely recovered when either a broad line or rest-optical point source is required in combination with a v-shaped continuum, suggesting an inherent link between these three defining characteristics. We compare the spectroscopic LRD sample to published photometric searches. Although these selections have high accuracy, down to $\rm F444W<26.5$, only 50-62% of the RUBIES LRDs were previously identified. The remainder were missed due to a mixture of faint rest-UV photometry, comparatively blue rest-optical colors, or highly uncertain photometric redshifts. Our findings highlight that well-selected spectroscopic campaigns are essential for robust LRD identification, while photometric criteria require refinement to capture the full population.

We present the discovery of three sub-Neptune planets around TOI-1117, a Sun-like star with mass $0.97\pm0.02M_{\odot}$, radius $1.05\pm0.03R_{\odot}$, age $4.42\pm1.50$ Gyr and effective temperature $5635\pm62$ K. Light curves from TESS and LCOGT show a transiting sub-Neptune with a $2.23$ day period, mass $M_b=8.90_{-0.96}^{+0.95}M_{\oplus}$ and radius $R_b=2.46_{-0.12}^{+0.13}R_{\oplus}$. This is a rare 'hot Neptune' that falls within the parameter spaces known as the 'Neptunian Desert' and the 'Radius Valley'. Two more planetary signals are detected in HARPS radial velocities, revealing two non-transiting planets with minimum masses $M_c=7.46_{-1.62}^{+1.43}M_{\oplus}$ and $M_d=9.06_{-1.78}^{+2.07}M_{\oplus}$, and periods of $4.579\pm0.004$ and $8.67\pm0.01$ days. The eccentricities were poorly constrained by the HARPS data, with upper limits $e_b=0.11$, $e_c=0.29$, and $e_d=0.24$. However, dynamical simulations of the TOI-1117 system, suggest that the orbits must be nearly circular to be stable. The simulations also show that TOI-1117b and c are likely to be in a near 2:1 resonance. The multi-planet nature of TOI-1117 makes it a more complex case for formation theories of the Neptunian Desert and Radius Valley, as current theories such as high-eccentricity migration are too turbulent to produce a stable, non-eccentric, multi-planet system. Moreover, analysis of TOI-1117b's photoevaporation history found rocky core and H/He atmosphere models to be inconsistent with observations, whilst water-rich scenarios were favoured.

Current gravitational-wave data reveal structures in the mass function of binary compact objects. Properly modelling and deciphering such structures is the ultimate goal of gravitational-wave population analysis: in this context, non-parametric models are a powerful tool to infer the distribution of black holes from gravitational waves without committing to any specific functional form. Here, we aim to quantitatively corroborate the findings of non-parametric methods with parametrised models incorporating the features found in such analyses. We propose two modifications of the currently favoured PowerLaw+Peak model, inspired by non-parametric studies, and use them to analyse the third Gravitational Wave Transient Catalogue. Our analysis marginally supports the existence of two distinct, differently redshift-evolving subpopulations in the black hole primary mass function, and suggests that, to date, we are still unable to robustly assess the shape of the mass ratio distribution for symmetric ($q>0.7$) binaries.

Optical galaxy cluster identification algorithms such as redMaPPer promise to enable an array of astrophysical and cosmological studies, but suffer from biases whereby galaxies in front of and behind a galaxy cluster are mistakenly associated with the primary cluster halo. These projection effects caused by irreducible photometric uncertainty must be quantified to facilitate the use of optical cluster catalogues. We present measurements of galaxy cluster projection effects and velocity dispersion using spectroscopy from the Dark Energy Spectroscopic Instrument (DESI). Representative data from DESI enables characterizing these properties of clusters identified with the redMaPPer algorithm. Our findings are as follows: we confirm that the fraction of redMaPPer putative member galaxies mistakenly associated with cluster haloes is richness dependent, being more than twice as large at low richness than high richness; we present the first spectroscopic evidence of an increase in projection effects with increasing redshift, by as much as 25 per cent from $z\sim0.1$ to $z\sim0.2$; moreover, we find qualitative evidence for luminosity dependence in projection effects, with fainter galaxies being more commonly far behind clusters than their bright counterparts; finally we fit the scaling relation between measured mean spectroscopic richness and velocity dispersion, finding an implied linear scaling between spectroscopic richness and halo mass. We discuss further directions for the application of spectroscopic datasets to improve use of optically selected clusters to test cosmological models.

We discuss the model of astrophysical emission at millimeter wavelengths used to characterize foregrounds in the multi-frequency power spectra of the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6), expanding on Louis et al. (2025). We detail several tests to validate the capability of the DR6 parametric foreground model to describe current observations and complex simulations, and show that cosmological parameter constraints are robust against model extensions and variations. We demonstrate consistency of the model with pre-DR6 ACT data and observations from Planck and the South Pole Telescope. We evaluate the implications of using different foreground templates and extending the model with new components and/or free parameters. In all scenarios, the DR6 $\Lambda$CDM and $\Lambda$CDM+$N_{\rm eff}$ cosmological parameters shift by less than $0.5\sigma$ relative to the baseline constraints. Some foreground parameters shift more; we estimate their systematic uncertainties associated with modeling choices. From our constraint on the kinematic Sunyaev-Zel'dovich power, we obtain a conservative limit on the duration of reionization of $\Delta z_{\rm rei} < 4.4$, assuming a reionization midpoint consistent with optical depth measurements and a minimal low-redshift contribution, with varying assumptions for this component leading to tighter limits. Finally, we analyze realistic non-Gaussian, correlated microwave sky simulations containing Galactic and extragalactic foreground fields, built independently of the DR6 parametric foreground model. Processing these simulations through the DR6 power spectrum and likelihood pipeline, we recover the input cosmological parameters of the underlying cosmic microwave background field, a new demonstration for small-scale CMB analysis. These tests validate the robustness of the ACT DR6 foreground model and cosmological parameter constraints.

We report the discovery of a $z\sim3.9$ protocluster identified from Atacama Large Millimetre/sub-millimetre Array Band 3 spectral scans of a bright radio source selected from the GaLactic and Extra-galactic All-sky Murchison Widefield Array (GLEAM) survey. Extended CO(4-3) and [CI](1-0) line emission was detected in GLEAM J005332$-$325630 confirming it to be a $z=3.879$ powerful radio galaxy with luminosity, $L_{500 MHz}=1.3\times10^{28}$ ${W Hz}^{-1}$. This source is part of a sample of candidate high redshift radio galaxies with bright radio fluxes, $S_{150MHz}>0.1$ Jy, but host galaxies with $K_s({AB})\gtrsim23$ mag. The molecular gas associated with the radio galaxy host has two kinematically separate components, likely in-falling and indicative of a recent interaction or merger with another galaxy. One 100-GHz continuum source $\sim120$ pkpc away is found to have both CO(4-3) and [CI](1-0) emission lines and a further five protocluster members are identified from CO(4-3) emission alone, all at similar redshift ($\Delta v<700$ km s$^{-1}$) and within a radius of $1.1^{\prime}$. Using photometry from the High Acuity Widefield K-band Imager $K_s$-band and the Dark Energy Survey $g, r, i, z$ and $Y$ bands, we find this protocluster harbours a rare, optically-dark, very massive $M_*\sim10^{12}$ ${M}_\odot$ galaxy. Comparisons with the TNG300 cosmological simulation puts this galaxy in a dark matter halo of $M_{DM}\sim3\times10^{13}$ ${M}_\odot$ which will evolve into a Coma-like DM halo ($M_{DM}\sim10^{15}$ ${M}_\odot$) by the present day.

A major weakness in one-dimensional (1D) stellar structure and evolution modeling is the simplified treatment of convection, which leads to erroneous near-surface stratification and considerable uncertainties in predicted effective temperatures and luminosities of low-mass stars. In a series of preceding works, a novel method for coupling 1D stellar structural models with a grid of 3D surface convection simulations during stellar evolution was developed, at solar metallicity. This 1D-3D coupling method slightly shifts evolutionary tracks relative to standard calculations, meanwhile providing oscillation frequencies that agree more closely with asteroseismic observations. Here we extend this method to model metal-poor and metal-rich FGK-type stars, by implementing interpolations on-the-fly across metallicity ($\rm -3 < [Fe/H] < 0.5$) for mean 3D models during stellar evolution. We demonstrate quantitatively that the fundamental stellar parameters modeled within our framework are insensitive to the mixing-length parameter. A 20% change in the mixing-length parameter results in evolutionary tracks with a temperature shift of less than 30 K, compared to a difference of over 200 K in standard evolution calculations. Our extension is validated against eclipsing binary systems with extremely precise observational constraints as well as stars in binaries with asteroseismic data. Using a fixed mixing-length parameter that merely governs convective heat transport in the near-adiabatic layers, the 1D-3D coupling method successfully reproduces most observational constraints for all target stars. Coupling 1D stellar evolution models with 3D simulations greatly reduces uncertainties associated with the choice of atmosphere boundary conditions and mixing-length parameters, hence offering a powerful tool for characterizing stars with seismic measurements and determining ages for globular clusters.

The dispersion of fast radio bursts (FRBs) in conjunction with their redshifts can be used as powerful probes of the distribution of extragalactic plasma, and with a large enough sample, the free-electron--galaxy power spectrum $P_{eg}$ can be measured by cross-correlating FRB dispersions with galaxy positions. However, a precise measurement of $P_{eg}$ requires a careful investigation of the selection effects -- the fact that the probability of both observing the FRB dispersion measure and obtaining a host galaxy redshift depends on observed properties of the FRB and its host. We use ray tracing simulations with IllustrisTNG300-1 to investigate the impact of expected observational selection effects on FRB dispersion-galaxy angular cross-correlations with a sample of 3000 FRBs at redshift range of $0.3 \leq z \leq 0.4$ . Our results show that cross-correlations with such an FRB sample are robust to properties of the FRB host galaxy: this includes DM contributions from the FRB host and optical followup selection effects biased against FRBs with dim galaxy hosts. We also find that such cross-correlations are robust to DM dependent and scattering selection effects specific to the CHIME/FRB survey. However, a DM dependent selection effect that cuts off the 10\% most dispersed FRB at a fixed redshift shell can bias the amplitude of the cross-correlation signal by over 50\% at angular scales of $\sim 0.1^\circ$ (corresponding to Mpc physical scales). Our findings highlight the importance of both measuring and accounting for selection effects present in existing FRB surveys as well as mitigating DM dependent selection effects in the design of upcoming FRB surveys aiming to use FRBs as probes for large-scale structure.

Diverse searches for direct dark matter (DM) in effective electromagnetic and leptophilic interactions resulting from new physics, as well as Weakly Interacting Massive Particles (WIMPs) with unconventional electronic recoils, are intensively pursued. Low-energy backgrounds from radioactive $\gamma$ rays via Compton scattering and photon coherent scattering are unavoidable in terrestrial detectors. The interpretation of dark matter experimental data is dependent on a better knowledge of the background in the low-energy region. We provide a 2.3% measurement of atomic Compton scattering in the low momentum transfer range of 180 eV/c to 25 keV/c, using a 10-g germanium detector bombarded by a $^{137}\mathrm{Cs}$ source with a 7.2 m-Curie radioactivity and the scatter photon collected by a cylindrical NaI[Tl] detector. The ability to detect Compton scattering's doubly differential cross section (DDCS) gives a special test for clearly identifying the kinematic restraints in atomic many-body systems, notably the Livermore model. Additionally, a low-energy-background comparison is made between coherent photon scattering and Compton scattering replacing the scattering function of ${GEANT4}$@software, which uses a completely relativistic impulse approximation (RIA) together with Multi-Configuration Dirac-Fock (MCDF) wavefunctions. For the purpose of investigating sub-GeV mass and electronic-recoil dark matter theories, signatures including low energy backgrounds via high energy $\gamma$ rays in germanium targets are discussed.

Cosmic rays (CRs) are an integral part of the non-thermal pressure budget in the interstellar medium (ISM) and are the leading-order ionization mechanism in cold molecular clouds. We study the impacts that different microphysical CR diffusion coefficients and streaming speeds have on the evolution of isothermal, magnetized, turbulent plasmas, relevant to the cold ISM. We utilized a two-moment CR magnetohydrodynamic (CRMHD) model, allowing us to dynamically evolve both CR energy and flux densities with contributions from Alfvénic streaming and anisotropic diffusion. We identify $\textit{coupled}$ and $\textit{decoupled}$ regimes, and define dimensionless Prandtl numbers $\rm{Pm_c}$ and $\rm{Pm_s}$, which quantify whether the plasma falls within these two regimes. In the coupled regime -- characteristic of slow streaming ($\rm{Pm_s} < 1$) and low diffusion ($\rm{Pm_c} < 1$) -- the CR fluid imprints upon the plasma a mixed equation of state between $P_{\rm{c}} \propto \rho^{4/3}$ (relativistic fluid) and $P_{\rm{c}} \propto \rho^{2/3}$ (streaming), where $P_{\rm{c}}$ is the CR pressure, and $\rho$ is the plasma density. By modifying the sound speed, the coupling reduces the turbulent Mach number, and hence the amplitude of the density fluctuations, whilst supporting secular heating of the CR fluid. In contrast, in the decoupled regime ($\rm{Pm_s} > 1$ or $\rm{Pm_c} > 1$) the CR fluid and the plasma have negligible interactions. We further show that CR heating is enabled by coherent structures within the compressible velocity field, with no impact on the turbulence spectrum of incompressible modes.

High-redshift ($z>2$) massive quiescent galaxies are crucial tests of early galaxy formation and evolutionary mechanisms through their cosmic number densities and stellar mass functions (SMFs). We explore a sample of 745 massive ($\rm M_*> 10^{9.5}M_\odot$) quiescent galaxies from $z=2-7$ in over 800 arcmin$^2$ of NIRCam imaging from a compilation of public JWST fields (with a total area $>$ 5 $\times$ previous JWST studies). We compute and report their cosmic number densities, stellar mass functions, and cosmic stellar mass density. We confirm a significant overabundance of massive quiescent galaxies relative to a range of cosmological hydrodynamical simulations and semi-analytic models (SAMs). We find that one SAM, SHARK is able to reproduce our observed number density with the addition of mock observational errors, but that it is still unable to produce quiescent galaxies of the same masses. We find that no simulations or SAMs accurately reproduce the SMF for massive quiescent galaxies at any redshift within the interval $z=2-5$. This shows that none of these models' feedback prescriptions are fully capturing high-z galaxy quenching, challenging the standard formation scenarios. We find a greater abundance of lower-mass ($\rm M_*<10^{10}M_\odot$) quiescent galaxies than previously found, highlighting the importance of sSFR cuts rather than simple colour selection. We show the importance of this selection bias, alongside individual field-to-field variations caused by cosmic variance, in varying the observed quiescent galaxy SMF, especially at higher-z. We also find a steeper increase in the cosmic stellar mass density for massive quiescent galaxies than has been seen previously, with an increase of around a factor of 60 from $z=4.5$ to $z=2$, indicating the increasing importance of galaxy quenching within these epochs.

Pulsar glitches, sudden changes in a neutron star's rotation, offer a unique window into the extreme physics governing these celestial bodies. The post-glitch recovery phase, characterized by a gradual recovery, reveals insights into the superfluid dynamics within the star. The post-glitch recovery phase probes the coupling mechanisms between different stellar components, sheds light on the properties of neutron star matter at supra-nuclear densities and even allows us to predict the time to the next glitch. In this work, we present a detailed analysis of the Vela pulsar's rotational behavior using around 100 months of observational data spanning from September 2016 to January 2025, during which four glitches were identified. Here, we demonstrate the post-glitch recovery of these glitches within the framework of the vortex creep model, providing new insights into the Vela pulsar's internal structure. Notably, we present the first-ever investigation of vortex residuals (the discrepancy between observed values and those predicted by the vortex creep model) through the lens of the vortex bending model, marking a significant step forward in understanding neutron star physics through pulsar glitches.

Collisionless self-gravitating systems such as cold dark matter halos are known to harbor universal density profiles despite the intricate non-linear physics of hierarchical structure formation in the $\Lambda$CDM paradigm. The origin of these attractor states has been a persistent mystery, particularly because the physics of collisionless relaxation is not well understood. To solve this long-standing problem, we develop a self-consistent quasilinear theory in action-angle space for the collisionless relaxation of inhomogeneous, self-gravitating systems by perturbing the governing Vlasov-Poisson equations. We obtain a quasilinear diffusion equation that describes the secular evolution of the mean coarse-grained distribution function $f_0$ of accreted matter in the fluctuating force field of a halo. The diffusion coefficient not only depends on the fluctuation power spectrum but also on the evolving potential of the system, which reflects the self-consistency of the problem. Diffusive heating by an initially cored halo develops an $r^{-1}$ cusp in the density profile of the accreted material, with $r$ the halocentric radius. Subsequent accretion and relaxation around this $r^{-1}$ cusp develops an $r^{-3}$ fall-off, establishing the Navarro-Frenk-White (NFW) density profile, a quasi-steady state attractor of collisionless relaxation that is not particularly sensitive to initial conditions. Given enough time though, the halo tends to Maxwellianize and develop an isothermal sphere profile. We demonstrate for the first time that the universal NFW profile emerges as an attractor solution to a self-consistent theory for collisionless relaxation.

Noether's theorem connects symmetries to invariants in continuous systems, however its extension to discrete systems has remained elusive. Recognizing the lowest-order finite difference as the foundation of local continuity, a viable method for obtaining discrete conservation laws is developed by working in exact analogy to the continuous Noether's theorem. A detailed application is given to electromagnetism, where energy-momentum conservation laws are rapidly obtained in highly generalized forms that disrupt conventional notions regarding conservative algorithms. Field-matter couplings and energy-momentum tensors with optional deviations at the discreteness scale properly reduce in the continuous limit. Nonlocal symmetries give rise to an additional conservation channel for each spacetime displacement, permitting generalized nonlocal couplings. Prescriptions for conservative particle integrators emerge directly from field-matter coupling terms, enabling the development of fully explicit, energy-conserving particle-in-cell algorithms. The demonstration of exact conservation laws in discrete spacetime that preserve canonical structure has deep implications for numerical algorithms and fundamental physics.

We conduct a parameter survey of neutron star accretion column simulations by solving the relativistic radiation MHD equations with opacities that account for strong magnetic fields and pair production. We study how column properties depend on accretion rate, magnetic field strength, and accretion flow geometry. All the simulated accretion columns exhibit kHz oscillatory behavior, consistent with our previous findings. We show how the predicted oscillation properties depend on the column parameters. At higher accretion rates for fixed magnetic field, the column height increases, reducing the local field strength and leading to an anti-correlation between the observed cyclotron line energy and luminosity. We estimate the line energy from the simulations and find agreement with the observed trend. Downward scattering in the free-fall zone plays a key role in shaping sideways emission properties and column height. Strong downward scattering not only re-injects heat back into the column, increasing its height, but also compresses sideways emission, potentially smearing out shock oscillation signals. When the pair-production regime is reached at the base of the column, the system quickly readjusts to a force balance between gravity and radiative support. The high opacity in the pair-production region raises the radiation energy density, enhancing sideways emission through a large horizontal gradient. This shifts the sideways fan-beam radiation toward lower altitudes. In a hollow column geometry, both pencil- and fan-beam radiation emission occurs. Self-illumination across the hollow region increases the height and stabilizes the inner wall of the column, while shock oscillations persist in the outer regions.

We summarize results from a survey of radiation-dominated black hole accretion flows across a wide range of mass accretion rates, as well as two values of black hole spin and initial magnetic field geometry. These models apply an algorithm targeting direct solutions to the radiation transport equation in full general relativity and have been enabled by access to modern exascale computing systems. Super-Eddington accretion flows form geometrically thick radiation pressure supported disks that drive powerful equatorial outflows. A narrow funnel-shaped photosphere in the inner region results in very low radiative efficiencies in this regime. The structure of near- and sub-Eddington accretion depends on whether there is net vertical magnetic flux at the midplane of the disk. With net flux, the disk forms a thin, dense layer at the midplane surrounded by a magnetically-dominated corona, whereas without net flux the disk remains magnetically dominated everywhere. Although none of our models achieve the magnetically arrested disk (MAD) regime, those with net vertical flux and a rapidly spinning black hole still produce powerful relativistic jets. Our calculations adopt simple opacity models (with scalings appropriate to stellar-mass black hole accretion). We discuss the application of our results to observations of X-ray binaries and ultraluminous X-ray sources such as Cyg X-3 and SS433. We also speculate on the application of our super-Eddington models to the interpretation of little red dots (LRDs) recently discovered by JWST.

Exoplanetary and planetary environments are forced by stellar activity which manifest through variable radiation, particle and magnetic fluxes, stellar winds, flares and magnetic storms known as coronal mass ejections (CMEs). Recent studies have shown that (exo)planets with intrinsic magnetic fields and magnetospheres respond differently to this stellar forcing compared to planets which lack an intrinsic magnetism; this is borne out by observations in solar system planets. However, detailed investigations to uncover the subtle ways in which stellar magnetic storms impact exoplanets are still at a nascent stage. Here we utilize 3D magnetohydrodynamic simulations to investigate the impact of stellar CMEs on Earth-like planets with different magnetic fields. Our results show that planetary atmospheric mass loss rates are dependent on the relative orientation of stellar wind and planetary magnetic fields, with significantly higher losses when the CME and planetary magnetic fields are oppositely oriented -- favoring enhanced magnetic reconnections. In contrast, for unmagnetised planets, the mass loss rate do not strongly depend on stellar magnetic field orientation. More significantly, we find that stellar CME induced polarity reversals can distinguish between planets with and without intrinsic magnetism. In unmagnetised or weakly magnetised (exo)planets, the polarity of the externally imposed magnetosphere are prone to global polarity reversals forced by stellar magnetised storms. Our analysis of the magnetotail current density dynamics during polarity reversals aligns with observations of Venus. This distinction in magnetospheric response provides a new paradigm to differentiate between (exo)planets with or without significant (intrinsic) magnetic fields.

We present new or updated angular diameters, physical radii, and effective temperatures for 145 stars from the Navy Precision Optical Interferometer data archive. We used data from 1996 to late-2021, and we describe the differences between early and late data, which hinge upon an update of the beam combiner in 2002. We came across several sub-categories of stars of interest: 13 of our stars are promising targets for the Habitable World Observatory and therefore require as much study as possible, and 14 more are asteroseismic targets and have stellar masses after we combined our radii and effective temperatures with frequencies of maximum oscillation power values from the literature. In addition to this, many of the stars here show measurements to the first null in the visibility curve and beyond, which is the gateway to determining second-order effects such as direct measurements of limb-darkening. Finally, we consider the stars in the larger context of previous NPOI measurements and find the majority 75% of the angular diameters in the overall NPOI sample have uncertainties of 2% or less.

During the course of publishing angular diameters from the Navy Precision Optical Interferometer data archive, we found we had data on 17 confirmed exoplanet host stars and one exoplanet candidate (HD 20902/alpha Per). Here, we update our previously published stellar radii with more precise Gaia parallaxes when available, and use our radius and effective temperature measurements to fit each star's mass and age using MIST models. The mass changed by more than 10% for 9 of the 18 stars. Combining our updated masses, radii, and temperatures, we present refined planetary masses as well as habitable zone calculations.

The Euclid mission has the potential to understand the fundamental physical nature of late-time cosmic acceleration and, as such, of deviations from the standard cosmological model, LCDM. In this paper, we focus on model-independent methods to modify the evolution of scalar perturbations at linear scales. We consider two approaches: the first is based on the two phenomenological modified gravity (PMG) parameters, $\mu_{\rm mg}$ and $\Sigma_{\rm mg}$, which are phenomenologically connected to the clustering of matter and weak lensing, respectively; and the second is the effective field theory (EFT) of dark energy and modified gravity, which we use to parameterise the braiding function, $\alpha_{\rm B}$, which defines the mixing between the metric and the dark energy field. We discuss the predictions from spectroscopic and photometric primary probes by Euclid on the cosmological parameters and a given set of additional parameters featuring the PMG and EFT models. We use the Fisher matrix method applied to spectroscopic galaxy clustering (GCsp), weak lensing (WL), photometric galaxy clustering (GCph), and cross-correlation (XC) between GCph and WL. For the modelling of photometric predictions on nonlinear scales, we use the halo model to cover two limits for the screening mechanism: the unscreened (US) case, for which the screening mechanism is not present; and the super-screened (SS) case, which assumes strong screening. We also assume scale cuts to account for our uncertainties in the modelling of nonlinear perturbation evolution. We choose a time-dependent form for $\{\mu_{\rm mg},\Sigma_{\rm mg}\}$, with two fiducial sets of values for the corresponding model parameters at the present time, $\{\bar{\mu}_0,\bar{\Sigma}_0\}$, and two forms for $\alpha_{\rm B}$, with one fiducial set of values for each of the model parameters, $\alpha_{\rm B,0}$ and $\{\alpha_{\rm B,0},m\}$. (Abridged)

We perform 3D radiation-magnetohydrodynamic simulations of the evolution of the fallback debris after a tidal disruption event. We focus on studying the effects of magnetic fields on the formation and early evolution of the accretion flow. We find that large magnetic fields can increase the debris stream thickness, moderately reducing the efficiency of the radiative acceleration of outflows during the first self-intersecting collisions. As gas accumulates and the collisions happen instead between the infalling stream and the accretion flow, magnetized and nonmagnetized systems evolve similarly at these early times: radiation-driven outflows dominate early after the initial stream-stream collision and a few days later, the accretion rate exceeds the mass outflow rate. We find that the MRI does not play a significant role in angular momentum transport and dissipation. Nor do we find evidence of a magnetocentrifugal driven outflow. Instead, collisions continue to dissipate kinetic energy into radiation that launches outflows and powers TDE luminosities reaching $L\sim4-6\times10^{44}$ erg s$^{-1}$. Shock-driven outflows and inflows redistribute angular momentum throughout the extent ($\sim50 r_s$) of the forming eccentric disk. Even in the presence of magnetic stresses, the accretion flow remains mostly eccentric with $e\sim0.2-0.3$ for $r\lesssim8r_s$ and $e\sim0.4-0.5$ for $10\lesssim r\,(r_s)\lesssim50$. Lastly, we find a polar angle-dependent density structure compatible with the viewing-angle effect, along with an additional azimuthal angle dependence established by the collisions.

Hilda asteroids, which orbit in a 3:2 resonance with Jupiter, serve as key indicators of dynamical processes in the early solar system. Their spin rates, an important probe of these mechanisms, can constrain their density and collisional evolution, offering valuable insights into their origin. In this paper, we report on the identification of three fast-rotating Hilda asteroids with spin periods in the 3.2--3.7 h range using data from the Transiting Exoplanet Survey Satellite. These rotation periods are significantly shorter than the previous $\sim$5.0 h shortest rotation periods obtained from ground-based observations in the $\sim$10 km size range, and are comparable with the $\sim$3.0 h breakup limit of Hildas a few km in size, derived from the FOSSIL survey. These fast-rotating asteroids require either considerable cohesion (in the order of a few kPa), or densities $\rho$ $\gtrsim$1.5 $gm^{-3}$, in contrast to the typically assumed $\rho$ $\lesssim$1 $gm^{-3}$, to prevent rotational break-up. C-type asteroids, which are common in the outer main belt, have densities of $\rho$ $\approx$1.5 $gm^{-3}$ and are known to comprise a small but notable fraction of Hildas. The observed occurrence rate of the $\leq$4 h rotation periods may be explained by the 10-15% fraction of C-type asteroids, likely mixed into these populations from the outer main belt during giant planet dynamical interactions in the early solar system.

Context. The South Pole Telescope third-generation camera (SPT-3G) has observed over 10,000 square degrees of sky at 95, 150, and 220 GHz (3.3, 2.0, 1.4 mm, respectively) overlapping the ongoing 14,000 square-degree Euclid Wide Survey. The Euclid collaboration recently released Euclid Deep Field observations in the first quick data release (Q1). Aims. With the goal of releasing complementary millimeter-wave data and encouraging legacy science, we performed dedicated observations of a 57-square-degree field overlapping the Euclid Deep Field South (EDF-S). Methods. The observing time totaled 20 days and we reached noise depths of 4.3, 3.8, and 13.2 $\mu$K-arcmin at 95, 150, and 220 GHz, respectively. Results. In this work we present the temperature maps and two catalogs constructed from these data. The emissive source catalog contains 601 objects (334 inside EDF-S) with 54% synchrotron-dominated sources and 46% thermal dust emission-dominated sources. The 5$\sigma$ detection thresholds are 1.7, 2.0, and 6.5 mJy in the three bands. The cluster catalog contains 217 cluster candidates (121 inside EDF-S) with median mass $M_{500c}=2.12 \times 10^{14} M_{\odot}/h_{70}$ and median redshift $z$ = 0.70, corresponding to an order-of-magnitude improvement in cluster density over previous tSZ-selected catalogs in this region (3.81 clusters per square degree). Conclusions. The overlap between SPT and Euclid data will enable a range of multiwavelength studies of the aforementioned source populations. This work serves as the first step towards joint projects between SPT and Euclid and provides a rich dataset containing information on galaxies, clusters, and their environments.

A typical Bayesian inference on the values of some parameters of interest $q$ from some data $D$ involves running a Markov Chain (MC) to sample from the posterior $p(q,n | D) \propto \mathcal{L}(D | q,n) p(q) p(n),$ where $n$ are some nuisance parameters. In many cases, the nuisance parameters are high-dimensional, and their prior $p(n)$ is itself defined only by a set of samples that have been drawn from some other MC. Two problems arise: first, the MC for the posterior will typically require evaluation of $p(n)$ at arbitrary values of $n,$ \ie\ one needs to provide a density estimator over the full $n$ space from the provided samples. Second, the high dimensionality of $n$ hinders both the density estimation and the efficiency of the MC for the posterior. We describe a solution to this problem: a linear compression of the $n$ space into a much lower-dimensional space $u$ which projects away directions in $n$ space that cannot appreciably alter $\mathcal{L}.$ The algorithm for doing so is a slight modification to principal components analysis, and is less restrictive on $p(n)$ than other proposed solutions to this issue. We demonstrate this ``mode projection'' technique using the analysis of 2-point correlation functions of weak lensing fields and galaxy density in the \textit{Dark Energy Survey}, where $n$ is a binned representation of the redshift distribution $n(z)$ of the galaxies.

Previous X-ray and optical studies of the galaxy cluster pair Abell 222/223 suggested the possible presence of a filamentary structure connecting the two clusters, a result that appears to be supported by subsequent weak-lensing analyses. This filament has been reported to host a primordial warm-hot intergalactic medium (WHIM), which existed prior to being heated by the interactions of the clusters. In this study, we made an attempt to examine the reported emission feature with data from an archival Suzaku observation, taking advantage of its low detector background. Because the emission is expected to be very weak, we first carefully examined all potential sources of "contamination", and then modelled the residual emission. Due to large uncertainties, unfortunately, our results can neither confirm the presence of the reported emission feature nor rule it out. We discuss the sources of uncertainties.

We measured the angular diameters of six stars using the 6-element observing mode of the Navy Precision Optical Interferometer (NPOI) for the first time since the early 2000s. Four of the diameters ranged from 1.2 mas to 1.9 mas, while the two others were much smaller at approximately 0.5 mas to 0.7 mas, which are the two smallest angular diameters measured to date with the NPOI. There is a larger spread in the measurements than data obtained with 3- or 4- or 5-element modes, which can be attributed in part to the flux imbalance due to the combination of more than 2 siderostats in a single spectrograph, and also to cross talk between multiple baselines related to non-linearities in the fast delay line dither strokes. We plan to address this in the future by using the VISION beam combiner.