NGC 1052-DF2 and -DF4 are two ultradiffuse galaxies that have been reported as deficient in dark matter and associated with the same galaxy group. Recent findings suggest that DF2 and DF4 are part of a large linear substructure of dwarf galaxies that could have been formed from a high-velocity head-on encounter of two gas-rich galaxies, known as a “bullet dwarf” collision. Based on new observations

Multiplanet systems face significant challenges to detection. For example, farther-orbiting planets have a reduced signal-to-noise ratio in radial velocity detection methods, and small mutual inclinations between planets can prevent them from all transiting. One mechanism for exciting mutual inclination between planets is secular resonance, where the nodal precession frequencies of the planets align

Gigahertz peaked spectrum (GPS) and compact steep spectrum (CSS) sources are compact radio galaxies (RGs), with jets extending up to 20 kpc and ages <103 yr. They are considered to evolve to Fanaroff–Riley RGs, but the real scenario to explain the compact sources remains unsolved. The young compact jets make GPS/CSS ideal for studying feedback in the nuclear region of active galactic nuclei because

Stellar clusters are critical constituents within galaxies: They are the result of highest-density star formation, and through their spatially and temporally correlated feedback, they regulate their host galaxy evolution. We present a novel numerical method to model star clusters as individual units of star formation using sink particles. In our method, star clusters grow via gas accretion and via

Spatially resolved emission-line kinematics are invaluable for investigating fundamental galaxy properties and have become increasingly accessible for galaxies at z ≳0.5 through sensitive near-infrared imaging spectroscopy and millimeter interferometry. Kinematic modeling is at the core of the analysis and interpretation of such data sets, which at high z present challenges due to the lower signal-to-noise

We present a method that calibrates a semianalytic model to the Renaissance Simulations, a suite of cosmological hydrodynamical simulations with high-redshift galaxy formation. This approach combines the strengths of semianalytic techniques and hydrodynamical simulations, enabling the extension to larger volumes and lower redshifts that are inaccessible to simulations due to computational expense.

Low-mass X-ray binaries with a neutron star as the primary object show a complex array of phenomenology during outbursts. The observed variability in X-ray emission primarily arises from changes in the innermost regions of the accretion disk, neutron star surface, and corona. In this work, we present the results of a comprehensive X-ray spectral and timing analysis of the neutron star transient MAXI

In the leading theory of lunar formation, known as the giant impact hypothesis, a collision between two planet-sized objects resulted in a young Earth surrounded by a circumplanetary debris disk from which the Moon later accreted. The range of giant impacts that could conceivably explain the Earth–Moon system is limited by the set of known physical and geochemical constraints. However, while several

Quasiperiodic eruptions (QPEs) are high-amplitude, soft X-ray bursts recurring every few hours, associated with supermassive black holes. Many interpretations for QPEs were proposed since their recent discovery in 2019, including extreme mass ratio inspirals and accretion disk instabilities. But, as of today, their nature still remains debated. We perform the first high-resolution X-ray spectral study

Charge exchange is a predominant process in inelastic collisions in astronomical plasmas, influencing the charge state balance and leading to X-ray emissions when solar wind ions interact with neutral gas in astrophysical environments. Accurate analysis of these dynamic properties to diagnose the solar wind composition and velocities, as well as the spatial distribution of the heliospheric neutral

Radio halos of edge-on galaxies are crucial for investigating cosmic ray propagation and magnetic field structures in galactic environments. We present VLA C-configuration S-band (2–4 GHz) observations of the spiral galaxy NGC 3556, a target from the Continuum Halos in Nearby Galaxies—an EVLA Survey. We estimate the thermal contribution to the radio emission from a combination of the Hα and mid-IR

Observations have revealed unique temperature profiles in hot Jupiter atmospheres. We propose that the energy transport by vertical mixing could lead to such thermal features. In our new scenario, strong absorbers, TiO, and VO are not necessary. Vertical mixing could be naturally excited by atmospheric circulation or internal gravity wave breaking. We perform radiative transfer calculations by taking

We explore how the definition of a void influences the conclusions drawn about the impact of the void environment on galactic properties using two void-finding algorithms in the Void Analysis Software Toolkit: Voronoi Voids (V2), a Python implementation of ZOnes Bordering On Voidness (ZOBOV); and VoidFinder, an algorithm that grows and merges spherical void regions. Using the Sloan Digital Sky Survey

A high-resolution fourth-order Padé scheme is used to simulate locally isothermal 3D disk turbulence driven by the vertical shear instability (VSI) using 268.4 M points. In the early nonlinear period of axisymmetric VSI, angular momentum transport by vertical jets creates correlated N-shaped radial profiles of perturbation vertical and azimuthal velocity. This implies dominance of positive perturbation

Upon interaction, a pair of magnetic flux ropes can merge to form a new pair, each consisting of opposite helicity along their axis. Magnetic helicity along such new structures may annihilate and release the energy of the azimuthal magnetic field. In this study, we model the deformation dynamics of such structures within the solar wind at 1 au. The perturbation front of deformation propagates along

We report the discovery of three ultracompact binary white dwarf systems hosting accretion disks, with orbital periods of 7.95, 8.68, and 13.15 minutes. This significantly augments the population of mass-transferring binaries at the shortest periods, and provides the first evidence that accretors in ultracompacts can be dense enough to host accretion disks even below 10 minutes (where previously only

Screening mechanisms are a natural method for suppressing long-range forces in scalar-tensor theories as they link the local background density to their strength. Focusing on Brans-Dicke theories, those including a non-minimal coupling between a scalar degree of freedom and the Ricci scalar, we study the origin of these screening mechanisms from a field theory perspective, considering the influence

It is conceivable that a bosonic dark matter (DM) with non-gravitational interactions with SM particles will be accumulated at the center of a neutron star (NS) and can lead to black hole formation. In contrast to previous works with a fixed NS temperature, we dynamically determine the formation of Bose-Einstein condensate (BEC) for a given set of DM parameters, namely the DM-neutron scattering cross-section

We consider the effects of relaxing the assumption that gravitational waves composing the stochastic gravitational wave background (SGWB) are uncorrelated between frequencies in analyses of the data from Pulsar Timing Arrays (PTAs). While uncorrelated monochromatic plane waves are often a good approximation, a background composed of unresolved astrophysical sources cannot be exactly uncorrelated since

Recent outcomes by the DESI Collaboration have shed light on a possible slightly evolving dark energy, challenging the standard ΛCDM paradigm. To better understand dark energy nature, high-redshift observations like gamma-ray burst data become essential for mapping the universe expansion history, provided they are calibrated with other probes. To this aim, we calibrate the Ep - Eiso (or Amati) correlation

The reduced speed of light approximation (RSLA) has been employed to speed up radiative transfer simulations of reionization by a factor of ≳ 5-10. However, it has been shown to cause significant errors in the HI-ionizing background near reionization's end in simulations of representative cosmological volumes. We show that using the RSLA is, to a good approximation, equivalent to re-scaling the global

We describe a novel proposal for inflationary magnetogenesis by identifying the non-Abelian sector of Spectator Chromo Natural Inflation (SCNI) with the SU(2)L sector of the Standard Model. This mechanism relies on the recently discovered attractor of SCNI in the strong backreaction regime, where the gauge fields do not decay on super-horizon scales and their backreaction leads to a stable new trajectory

Gamma-ray bursts (GRBs) are usually classified into long/short categories according to their durations, but controversy still exists in this aspect. Here we reexamine the long/short classification of GRBs and further compare the cosmological distribution and evolution of each potential subclass. A large number of Swift Burst Alert Telescope (BAT) GRBs are analyzed in this study. The Gaussian mixture

Context. The identification of large numbers of localised transient extreme ultraviolet (EUV) brightenings, on very small spatial scales, in the quiet Sun corona has been one of the key early results from Solar Orbiter. However, there are still a great deal of unknowns about these events.Aims. In this work, we aim to better understand EUV brightenings by investigating their spatial distributions. Specifically

Context. Deuterium fractionation is a well-established evolutionary tracer in low-mass star formation, but its applicability to the high-mass regime remains an open question. In this context, the abundances and ratios of different deuterated species have often been proposed as reliable evolutionary indicators for different stages of the high-mass star formation process.Aims. In this study, we investigate

The search for accreted satellites in the Galactic disk is a challenging task, to which Gaia plays a crucial role in synergy with ground-based spectroscopic surveys. In 2021, P. Re Fiorentin et al. discovered five substructures with disk kinematics including Icarus. To gain more insight into the origin of Icarus as a remnant of a dwarf galaxy rather than a signature of secular processes of disk formation

We present images of the Vega planetary debris disk obtained at 15.5, 23, and 25.5 μm with the Mid-Infrared Instrument on JWST. The debris system is remarkably symmetric, smooth, and centered accurately on the star. There is a broad Kuiper-belt-analog ring at ∼80–170 au that coincides with the planetesimal belt detected with the Atacama Large Millimeter/submillimeter Array at 1.34 mm. The interior

The line-of-sight structure of the Galactic magnetic field (GMF) can be studied using Faraday rotation measure (RM) grids. We analyze how the choice of interpolation kernel can affect the accuracy and reliability of reconstructed RM maps. We test the following kernels: inverse distance weighting (IDW), natural neighbor interpolation (NNI), inverse multiquadric interpolation (IM), thin-plate spline

We present a detailed imaging analysis of 260 ks of subarcsecond resolution Chandra (ACIS-S) observations of the nearby Seyfert 2 galaxy NGC 5728. Our study focuses on the bright and diffuse soft X-ray emission within the galaxy's inner ∼1 kpc. By comparing the X-ray emission across different energy bands, we identify localized variations in the absorbing column and emission processes. We observe more

The circumgalactic medium (CGM) is responsive to kinetic disruptions generated by nearby astrophysical events. In this work, we study the saturation and dissipation of turbulent hydrodynamics within the CGM through an extensive array of 252 numerical simulations with proper cooling mechanisms and a large parameter space spanning average gas density, metallicity, and turbulence driving strength. A dichotomy

Fast radio bursts (FRBs) represent one of the most intriguing phenomena in modern astrophysics. However, their classification into repeaters and nonrepeaters is challenging. Here, we present the application of the graph theory minimum spanning tree (MST) methodology as an unsupervised classifier of repeater and nonrepeater FRBs. By constructing MSTs based on various combinations of variables, we identify

We present new radio images of the supernova remnant (SNR) CTA 1 at 1420 and 408 MHz, and in the 21 cm line of H i observed with the Dominion Radio Astrophysical Observatory Synthesis Telescope and at 1420 MHz observed with the Effelsberg 100 m telescope. We confirm previously described continuum features and elaborate further on filamentary features identified using the high-resolution (1′) maps from

We present a noteworthy transient AT 2021aeuk exhibiting three distinct optical flares between 2018 and 2023. It is hosted in a radio-loud narrow-line Seyfert 1 galaxy, with an optical image showing a minor tidal morphology and a red mid-infrared color (W1 − W2 = 1.1). Flares II and III exhibit rapid rises, and long-term decays (≳1000 days) with recurring after-peak bumps. The g − r color after subtracting

Investigating the angular momentum evolution of pre-main-sequence (PMS) stars provides important insight into the interactions between Sun-like stars and their protoplanetary disks, and the timescales that govern disk dissipation and planet formation. We present projected rotational velocities (v sin i values) of 254 T Tauri stars (TTSs) in the ∼3 Myr old open cluster NGC 2264, measured using high-dispersion

We present an analysis of the absorption-line system in the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph spectrum at a redshift of za = 3.1448 associated with the quasar SDSS J122040.23+092326.96, whose systematic redshift is ze = 3.1380 ± 0.0007, measured from the Hβ+[O iii] emission lines in our newly acquired NIR P200/TripleSpec data. This absorbing system, detected in numerous

In galactic centers, stars and binaries can be injected into low-angular-momentum orbits, resulting in close encounters with the central supermassive black hole (SMBH). Previous works have shown that under different conditions, such close encounters can lead to the breakup of the binary, disruptions of both stars, and collision between the stars. We use three-body scattering experiments to characterize

The Kelvin–Helmholtz instability (KHI) has been considered important in the energy transfer and momentum coupling between the solar wind and planetary magnetospheres. To explore this issue, we employ a two-dimensional magnetohydrodynamic simulation to study the nonlinear evolution of the KHI at Mercury’s magnetopause using the parameters derived from a global hybrid simulation of MESSENGER’s first

Secure methods for identifying the host galaxies of individual massive black hole (MBH) binaries and mergers detected by gravitational-wave experiments such as the Laser Interferometer Space Antenna and pulsar timing arrays are currently lacking, but will be critical to a variety of science goals. Recently, in Bardati et al., we used the Romulus25 cosmological simulation to show that MBH merger host

Switchbacks, defined as Alfvénic reversals in magnetic field polarity, can dissipate their magnetic energy with heliocentric distance. To further investigate this, two distinct solar wind parcels tracing back to a similar solar source region were examined during a radial alignment between Parker Solar Probe (@25.8RS) and Solar Orbiter (@152RS). The one caveat was that the two probes were located on

The role of internal and environmental factors in the star formation activity of galaxies is still a matter of debate, in particular at higher redshifts. Leveraging the most recent release of the COSMOS catalog, COSMOS2020, as well as density measurements from our previous study, we disentangle the impact of environment and stellar mass on the star formation rate (SFR) and specific SFR (sSFR) of a

The recent discovery of planetesimals orbiting white dwarfs has renewed interest in the final chapters of the evolution of planetary systems. Although observational and theoretical studies have examined the dynamical evolution of these systems, studies of their magnetic star–planet interactions, as powered by unipolar induction, have thus far only been assessed theoretically. This fifth paper of the

Electron cyclotron maser (ECM) emission is an important coherent emission mechanism for the direct amplification of electromagnetic waves by nonthermal electrons in a magnetized plasma. This paper will report on our recent study on ECM emission by fast electron beams with moderately relativistic energy. The results show that, similar to the spontaneous emission by the magnetic cyclotron motion of energetic

Several filament eruptions with pronounced writhing of the axis of the structure are analyzed. Initially, smooth arches of eruptive filaments are transformed into large-scale helical structures with at least one complete turn due to the development of kink instability. However, the initiation of the eruptions seems to be caused not by the kink instability but by catastrophic loss of equilibrium or

The nearby long gamma-ray burst (GRB) 190829A was observed using the Hubble Space Telescope/Wide Field Camera 3/infrared grisms about four weeks to 500 days after the burst. We find the spectral features of its associated supernova, SN 2019oyw, are redshifted by several thousand km s−1 compared to the redshift of the large spiral galaxy on which it is superposed. This velocity offset is seen in several

The magnetar SGR 1935+2154 is the only known Galactic source of fast radio bursts (FRBs). FRBs from SGR 1935+2154 were first detected by the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB and the Survey for Transient Astronomical Radio Emission 2 in 2020 April, after the conclusion of the LIGO, Virgo, and KAGRA Collaborations’ O3 observing run. Here, we analyze four periods of gravitational

We present photometric and spectroscopic observations of SN 2023fyq, a Type Ibn supernova (SN) in the nearby galaxy NGC 4388 (D ≃ 18 Mpc). In addition, we trace the 3 yr long precursor emission at the position of SN 2023fyq using data from DLT40, ATLAS, Zwicky Transient Facility, ASAS-SN, Swift, and amateur astronomer Koichi Itagaki. The double-peaked postexplosion light curve reaches a luminosity

Recent multiwavelength observations of gamma-ray burst afterglows observed in the TeV energy range challenge the simplest synchrotron self-Compton (SSC) interpretation of this emission and are consistent with a single power-law component spanning over 8 orders of magnitude in energy. To interpret this generic behavior in the single-zone approximation without adding further free parameters, we perform

The distribution of delay times between the formation of binary black hole (BBH) progenitors and their gravitational-wave (GW) merger provides important clues about their unknown formation histories. When inferring the delay time distribution, it is typically assumed that BBH progenitor formation traces the star formation rate (SFR). In this work, we consider the rate of long gamma-ray bursts (LGRBs)

One of the main obstacles for the signal extraction of the three point correlation function using photometric surveys, such as the Rubin Observatory Legacy Survey of Space and Time (LSST), will be the prohibitive computation time required for dealing with a vast quantity of sources. Brute force algorithms, which naively scales as 𝒪(N3) with the number of objects, can be further improved with tree

We develop a C++ package of the STOchastic LAttice Simulation (STOLAS) of cosmic inflation. It performs the numerical lattice simulation in the application of the stochastic-δ N formalism. STOLAS can directly compute the three-dimensional map of the observable curvature perturbation without estimating its statistical properties. In its application to two toy models of inflation, chaotic inflation and

We study spinoptics equations in the Schwarzschild spacetime. We demonstrate that using the explicit and hidden symmetries of this metric one can explicitly solve the equations for complex null tetrad associated with null rays representing photon's and graviton's motion. This allows one to integrate the spinoptics equations both for the electromagnetic and gravitational waves. It is shown that the

The ~5 Myr PDS 70 is the only known system with protoplanets residing in the cavity of the circumstellar disk from which they formed, ideal for studying exoplanet formation and evolution within its natal environment. Here, we report the first spin constraint and C/O measurement of PDS 70b from Keck/KPIC high-resolution spectroscopy. We detected CO (3.8σ) and H2O (3.5σ) molecules in the PDS 70b atmosphere

The coldest Y spectral type brown dwarfs are similar in mass and temperature to cool and warm (∼200–400 K) giant exoplanets. We can therefore use their atmospheres as proxies for planetary atmospheres, testing our understanding of physics and chemistry for these complex, cool worlds. At these cold temperatures, their atmospheres are cold enough for water clouds to form, and chemical timescales increase

A century or less separates the thermonuclear-powered eruptions of recurrent novae (RNe) in the hydrogen-rich envelopes of massive white dwarfs. The colliding ejecta of successive RN events are predicted to always generate very large (tens of parsecs) super-remnants; only two examples are currently known. T CrB offers an excellent opportunity to test this prediction. As it will almost certainly undergo

Context. (2060) Chiron is a large centaur that has been reported active on multiple occasions at relatively large heliocentric distances, including during aphelion passage. Studies of Chiron’s coma during active periods have resulted in the detection of C≡N and CO outgassing. Additionally, Chiron is surrounded by a disk of debris that varies with time. Significant work remains to be undertaken to comprehend

Context. Dust grains in circumstellar envelopes are likely to have a spread-out temperature distribution.Aims. We investigate how trends in the temperature distribution between small and large grains affect the hot-corino chemistry of complex organic molecules (COMs) and warm carbon-chain chemistry (WCCC).Methods. A multi-grain multi-layer astrochemical code with an advanced treatment of the surface

Context. The internal structure of Jupiter is constrained by the precise gravity field measurements by NASA’s Juno mission, atmospheric data from the Galileo entry probe, and Voyager radio occultations. Not only are these observations few compared to the possible interior setups and their multiple controlling parameters, but they remain challenging to reconcile. As a complex, multidimensional problem

HeH+ was the first heteronuclear molecule to form in the metal-free Universe after the Big Bang. The molecule gained significant attention following its first circumstellar detection in the young and dense planetary nebula NGC 7027. We target some hydride ions associated with the noble gases (HeH+, ArH+, and NeH+) to investigate their formation in harsh environments like the nova outburst region. We

Context. Compact hierarchical triple (CHT) systems, where a tertiary component orbits an inner binary, provide critical insights into stellar formation and evolution. Despite their importance, the detection of such systems, especially compact ones, remains challenging due to the complexity of their orbital dynamics and the limitations of traditional observational methods.Aims. This study aims to identify

Aims. It is quintessential for the analysis of the observed dust polarization signal to understand the rotational dynamics of interstellar dust grains. Additionally, high rotation velocities may rotationally disrupt the grains, which impacts the grain-size distribution. We aim to constrain the set of parameters for an accurate description of the rotational spin-up process of ballistic dust grain aggregates