Observations of the Galactic bulge revealed an excess of short-timescale gravitational microlensing events that are generally attributed to a large population of free-floating or wide-orbit exoplanets. However, in recent years, some authors suggested that planetary-mass primordial black holes (PBHs) comprising a substantial fraction (1%–10%) of the dark matter in the milky Way may be responsible for

The extinction curve of interstellar dust in the dense molecular cloud cores is crucial for understanding dust properties, particularly size distribution and composition. We investigate the infrared extinction law in four nearby isolated molecular cloud cores—L429, L483, L673, and L1165—across the 1.2–8.0 μm wavelength range, using deep near-infrared and mid-infrared photometric data from UKIRT Infrared

We report the discovery of a rare isolated group of five dwarf galaxies located at z = 0.0086 (D = 36 Mpc). All member galaxies are star forming, blue, and gas rich, with g − r indices ranging from 0.2 to 0.6 mag, and two of them show signs of ongoing mutual interaction. The most massive member of the group has a stellar mass that is half of the Small Magellanic Cloud stellar mass, and the median stellar

The recent observations by the James Webb Space Telescope (JWST) have revealed a larger number of bright galaxies at z ≳ 10 than was expected. The origin of this excess is still under debate, although several possibilities have been presented. We propose that gamma-ray bursts (GRBs) are a powerful probe to explore the origin of the excess and, hence, the star and galaxy formation histories in the early

Relativistic jets from a Kerr black hole (BH) following the core collapse of a massive star (“collapsar”) is a leading model for gamma-ray bursts (GRBs). However, the two key ingredients for a Blandford–Znajek-powered jet—rapid rotation and a strong magnetic field—seem mutually exclusive. Strong fields in the progenitor star’s core transport angular momentum outward more quickly, slowing down the core

The mass–metallicity relation provides crucial insights into the baryon cycle in galaxies and strong constraints on galaxy formation models. We use JWST NIRSpec observations from the UNCOVER program to measure the gas-phase metallicity in a sample of eight galaxies during the epoch of reionization at z = 6–8. Thanks to the strong lensing of the galaxy cluster Abell 2744, we are able to probe extremely

We present constraints on the shape of Kepler-51d, which is a superpuff with a mass ∼6 M⊕ and a radius ∼9 R⊕, based on detailed modeling of the transit light curve from James Webb Space Telescope (JWST) NIRSpec. The projected shape of this extremely low-density planet is consistent with being spherical, and a projected oblateness f⊥ > 0.2 can be excluded regardless of the spin obliquity angles. If

On 2024 May 10–11, the strongest geomagnetic storm since 2003 November occurred, with a peak Dst index of −412 nT. The storm was caused by NOAA active region (AR) 13664, which was the source of a large number of coronal mass ejections and flares, including 12 X-class flares. Starting from about May 7, AR 13664 showed a steep increase in its size and (free) magnetic energy, along with increased flare

We present updated constraints on cosmological parameters in a 12-parameter model, extending the standard six-parameter ΛCDM by including dynamical dark energy (DE; w0, wa), the sum of neutrino masses (∑mν), the effective number of non-photon radiation species (Neff), the lensing amplitude scaling (Alens), and the running of the scalar spectral index (αs). For cosmic wave background (CMB) data, we

Some, if not all, binary neutron star (BNS) coalescences, and a fraction of neutron star–black hole (NSBH) mergers, are thought to produce sufficient mass ejection to power gamma-ray bursts (GRBs). However, this fraction, as well as the distribution of beaming angles of BNS-associated GRBs, is poorly constrained from observation. Recent work applied machine learning tools to analyze GRB light curves

We report on the discovery of a very prominent mid-infrared (18–25 μm) excess associated with the trans-Neptunian dwarf planet (136472) Makemake. The excess, detected by the Mid-Infrared Instrument of the James Webb Space Telescope, along with previous measurements from the Spitzer and Herschel space telescopes, indicates the occurrence of temperatures of ∼150 K, much higher than what solid surfaces

A crucial yet challenging task in galaxy evolution studies is the identification of distant merging galaxies, a task that suffers from a variety of issues ranging from telescope sensitivities and limitations to the inherently chaotic morphologies of young galaxies. In this paper, we use random forests and convolutional neural networks to identify high-redshift JWST Cosmic Evolution Early Release Science

In this study, we present the first-ever direct measurements of synchrotron-emitting heliospheric traveling shocks, intercepted by the Parker Solar Probe (PSP) during its close encounters. Given that much of our understanding of powerful astrophysical shocks is derived from synchrotron radiation, these observations by PSP provide an unprecedented opportunity to explore how shocks accelerate relativistic

We report on the onset of a coronal mass ejection (CME) using spectroscopic observations in the 5303 Å coronal emission line with the Visible Emission Line Coronagraph (VELC) onboard ADITYA-L1, the recently launched first Indian space solar mission. The CME was observed on 2024 July 16 in association with an X1.9 class soft X-ray flare from heliographic location S05W85. The VELC observations were near

The accretion luminosity of an FU Ori disk is a fundamental system parameter, but a challenging one to estimate for all but the most well-studied systems. FU Ori objects are dynamically evolving accretion disks, especially close in time to the outburst epoch. They have a complex multitemperature disk structure that results in distinctly shaped, broad spectral energy distributions (SEDs). Detailed spectroscopic

JWST observations of the young Galactic supernova remnant Cassiopeia A revealed an unexpected structure seen as a green emission feature in colored composite MIRI F1130W and F1280W images—hence dubbed the Green Monster—that stretches across the central parts of the remnant in projection. Combining the kinematic information from NIRSpec and the MIRI Medium Resolution Spectrograph with the multiwavelength

In this study, we employ the combined charged particle measurements from Integrated Science Investigation of the Sun on board the Parker Solar Probe (PSP) and Energetic Particle Detector on board the Solar Orbiter (SolO) to study the composition variation of the solar energetic particle (SEP) event occurring on 2023 May 16. During the event, SolO and PSP were located at a similar radial distance of

Solar active regions (ARs) provide the required magnetic energy and the topology configuration for flares. Apart from conventional static magnetic parameters, the evolution of AR magnetic flux systems should have nonnegligible effects on magnetic energy store and the trigger mechanism of eruptions, which would promote the prediction for the flare using photospheric observations conveniently. Here we

Several long-standing theories postulate that turbulent dissipation can heat solar wind protons in situ. Turbulent dissipation can occur via current sheets, which are small-scale structures embedded in the solar wind magnetic field. This study examines the role that switchbacks—intermediate-scale reversals in the interplanetary magnetic field—may play in heating the solar wind by generating current

The nearby radio galaxy M87 is a very high-energy (VHE) gamma-ray emitter established by observations with ground-based gamma-ray detectors. Here we report the long-term monitoring of M87 from 2021 to 2024 with the Large High Altitude Air Shower Observatory (LHAASO). M87 has been detected by LHAASO with a statistical significance ∼ 9σ. The observed energy spectrum extends to 20 TeV, with a possible

We observed the ultrahot Jupiter WASP-33b with the SpectroPolarimètre InfraRouge on the Canada–France–Hawaii Telescope. Previous observations of the dayside of WASP-33b show evidence of CO and Fe emission indicative of a thermal inversion. We observed its nightside over five Earth nights to search for spectral signatures of CO in the planet’s thermal emission. Our three pretransit observations and

Solar energetic particles (SEPs) are a major source of space radiation, especially within the inner heliosphere. These particles, originating from solar flares and coronal mass ejections (CMEs), propagate primarily along interplanetary magnetic fields. The energy spectra of SEP events are crucial for assessing radiation effects and understanding the acceleration and propagation mechanisms in their

Light passing near a black hole can follow multiple paths from an emission source to an observer due to strong gravitational lensing. Photons following different paths take different amounts of time to reach the observer, which produces an echo signature in the image. The characteristic echo delay is determined primarily by the mass of the black hole, but it is also influenced by the black hole spin

Particle accelerators abound in space plasmas, saturating the cosmos with fully stripped nuclei and gamma rays, with energies surpassing the capabilities of human-made accelerators by orders of magnitude. Upon reaching Earth’s atmosphere, these particles trigger extensive air showers (EASs), generating millions of secondary cosmic rays of lower energies. Free electrons from EASs developing in the atmosphere

The acceleration of the young solar wind is studied using the first 17 encounters of the Parker Solar Probe. We identify wind intervals from different source regions: coronal hole (CH) interiors, streamers, and low-Mach-number boundary layers (LMBLs), i.e., the inner boundaries of coronal holes. We present their statistical trends in the acceleration process. Most of the observations can be reproduced

We develop analytical tools and perform three-body simulations to investigate the orbital evolution and dynamical stability of binary planets within star clusters. Our analytical results show that the orbital stability of a planetary-mass binary against passing stars is mainly related to its orbital period. Critical flybys, defined as stellar encounters with energy kicks comparable to the binary binding

Based on the observations by the Parker Solar Probe (PSP) during its encounter phases of approaching the Sun, I. C. Jebaraj et al. found that fundamental–harmonic (F-H) pairs constitute a majority of interplanetary (IP) type III radio bursts. In the present Letter, spectral characteristics of the IP F-H pairs are identified and analyzed further. The observations were made with the Radio Frequency Spectrometer

The recent observation of high-energy neutrinos from the Galactic plane implies an abundant population of hadronic cosmic-ray sources in the Milky Way. We explore the role of the coronae of accreting stellar-mass black holes as such astroparticle emitters. We show that the particle acceleration and interaction timescales in the coronal region are tied to the compactness of the X-ray source. Thus, neutrino

Discrepancy between the measurements of Hubble constant H 0 from the cosmic microwave background and the local distance ladder is the most serious challenge to the standard ΛCDM model. Recent research has pointed out that it might be related with the violation of cosmological principle. Here, we investigate the impact of dipole–monopole correction on the constraints of H 0 utilizing the dipole-fitting

The Einstein Probe (EP) achieved its first detection and localization of a bright X-ray flare, EP240219a, on 2024 February 19, during its commissioning phase. Subsequent targeted searches triggered by the EP240219a alert identified a faint, untriggered gamma-ray burst (GRB) in the archived data of Fermi Gamma-ray Burst Monitor (GBM), Swift Burst Alert Telescope (BAT), and Insight-HXMT/HE. The EP Wide-field

To study the dust dynamics in the dust-trapping vortices in the protoplanetary disk around MWC 758, we analyzed the 1.3 mm continuum images of the MWC 758 disk obtained with the Atacama Large Millimeter/submillimeter Array in 2017 and 2021. We detect proper motions of 22 mas and 24 mas in the two dust clumps at radii of 0.″32 and 0.″54 in the disk on the plane of the sky, respectively. On the assumption

Nonradiative shocks accelerate particles and heat astrophysical plasmas. While supernova remnants are the most well-studied example, neutron star (NS) bow shocks are also nonradiative and Balmer dominated. NS bow shocks are likely ubiquitous in the interstellar medium due to their large speeds imparted at birth, and they are thought to be a discrete source population contributing to the Galactic cosmic-ray

Recent studies revealed viewing-angle-dependent color and spectral trends in brown dwarfs, as well as long-term photometric variability (∼100 hr). The origins of these trends are yet unexplained. Here, we propose that these seemingly unrelated sets of observations stem from the same phenomenon: the polar regions of brown dwarfs and directly imaged exoplanets are spectrally different from lower-latitude

We report our study of the field of the ≃0.2 PeV neutrino event IC-190619A. This neutrino belongs to Gold events, which more likely have an astrophysical origin. Among the two γ-ray sources within the neutrino’s positional uncertainty region, we find that one of them, the BL Lac–type blazar PKS 2254+074, had a γ-ray flare at the arrival time of the neutrino. The flare is determined to have lasted ∼2

Positive spectral lags are commonly observed in gamma-ray burst (GRB) prompt phase where soft photons lag behind hard ones in their spectral studies. In contrast to this pattern, a fraction of GRBs show a negative spectral lag where hard photons arrive later compared to soft photons. Similarly, recent Fermi-Large Area Telescope observations show a late onset of high-energy photons in most GRB observations

How black holes are formed remains an open and fundamental question in astrophysics. Despite theoretical predictions, it lacks observations to understand whether the black hole formation experiences a supernova explosion. Here we report the discovery of an X-ray shell north of the Galactic microquasar SS 433 harboring a stellar-mass black hole spatially associated with radio continuum and polarization

Streaming instability (SI) in dust has long been thought to be a promising process in triggering planetesimal formation in the protoplanetary disks (PPDs). In this study, we present the first numerical investigation that models the SI in the vertically stratified disk together with the dust coagulation process. Our simulations reveal that, even with the initially small dust sizes, because dust coagulation

After over three decades of unsuccessful attempts, we report the first detection of molecular gas emission in Malin 1, the largest spiral galaxy observed to date, and one of the most iconic giant low surface brightness galaxies. Using Atacama Large Millimeter/submillimeter Array, we detect significant 12CO (J = 1–0) emission in the galaxy’s central region and tentatively identify CO emission across

The three successive coronal mass ejections (CMEs) that erupted from 2023 November 27–28, provide the first opportunity to shed light on the entire process of a shock propagating through, sequentially compressing, and modifying two preceding CMEs using in situ data from Solar Orbiter, Wind, and STEREO-A. We describe the interaction of the three CMEs as follows: CME-1 and CME-2 interacted with each

It is well known that almost all isolated dwarf galaxies are actively forming stars. We report the discovery of dw1322m2053 (nicknamed Hedgehog), an isolated quiescent dwarf galaxy at a distance of 2.40 ± 0.15 Mpc with a stellar mass of M ⋆ ≈ 105.8 M ⊙. The distance is measured using surface brightness fluctuations with both Legacy Surveys and deep Magellan/IMACS imaging data. Hedgehog is 1.7 Mpc from

A primary science goal for JWST is to detect and characterize the atmospheres of terrestrial planets orbiting M dwarfs (M-Earths). The existence of atmospheres on M-Earths is highly uncertain because their host stars’ extended history of high X-ray and ultraviolet irradiation may act to completely remove their atmospheres. We present two JWST secondary eclipse observations of the M-Earth Gl 486b (also

We calculate the arrival direction distribution of ultrahigh-energy cosmic rays (UHECRs) with a new suite of models of the Galactic magnetic field (GMF), assuming sources follow the large-scale structure of the Universe. Compared to previous GMF models, the amplitude of the dipole component of the UHECR arrival flux is significantly reduced. We find that the reduction is due to the accidentally coinciding

Massive stars mainly form in close binaries, where their mutual interactions can profoundly alter their evolutionary paths. Evolved binaries consisting of a massive OB-type main-sequence star with a stripped helium star or a compact companion represent a crucial stage in the evolution toward double compact objects, whose mergers are (potentially) detectable via gravitational waves. The recent detection

We introduce a new capability of the Neil Gehrels Swift Observatory, dubbed “continuous commanding,” that achieves 10 s latency response time on orbit to unscheduled target-of-opportunity requests received on the ground. We show that this will allow Swift to respond to premerger (early-warning) gravitational-wave (GW) detections, rapidly slewing the Burst Alert Telescope (BAT) across the sky to place

L 98-59 d is a Super-Earth planet orbiting an M-type star. We performed retrievals on the transmission spectrum of L 98-59 d obtained using NIRSpec G395H during a single transit, from JWST Cycle 1 GTO 1224. The wavelength range of this spectrum allows us to detect the presence of several atmospheric species. We found that the spectrum is consistent with a high mean molecular weight atmosphere. The

Detecting atmospheres around planets with a radius below 1.6 R ⊕, commonly referred to as rocky planets, has proven to be challenging. However, rocky planets orbiting M dwarfs are ideal candidates due to their favorable planet-to-star radius ratio. Here, we present one transit observation of the Super-Earth L98-59 d (1.58 R ⊕ and 2.31 M ⊕), at the limit of rocky/gas-rich, using the JWST NIRSpec G395H

The intensity of the extragalactic background (EBL), the accumulated optical and infrared emissions since the first stars, is the subject of a decades-long tension in the optical band. These photons form a target field that attenuates the γ-ray flux from extragalactic sources. This Letter reports the first γ-ray measurement of the EBL spectrum at z = 0 that is purely parametric and independent of EBL

Within the birth environment of a massive globular cluster, the combination of a luminous young stellar population and a high column density induces a state in which the thermal optical depth and radiation pressure are both appreciable. In this state, the sonic mass scale, which influences the peak of the stellar mass function, is tied to a fundamental scale composed of the Planck mass and the mass

Angrites originate from the early-formed differentiated angrite parent body. The pristine volcanic angrite D’Orbigny is devoid of brecciation, shock effects, or any evidence of secondary processes and is thus key for studying the early stages of planetary accretion and differentiation. However, chronometers used to establish the formation chronology of angrites (including D’Orbigny) yield discordant

Astrophysical explosions that contain dense and ram-pressure-dominated ejecta evolve through an interaction phase, during which a forward shock (FS), contact discontinuity (CD), and reverse shock (RS) form and expand with time. We describe new self-similar solutions that apply to this phase and are most accurate in the limit that the ejecta density is large compared to the ambient density. These solutions

The Schwarzschild radii of primordial black holes (PBHs) in the mass range of 6 × 1014–4 × 1019 g match the sizes of nuclei to atoms. I discuss the resulting quantum-mechanical suppression in the accretion of matter by PBHs in dense astrophysical environments, such as planets or stars.

Asteroseismology, the study of stellar vibration, has met with great success, shedding light on stellar interior structure, rotation, and magnetism. Prominently known as δ Scutis, the intermediate-mass main-sequence oscillators that often exhibit rapid rotation and possess complex internal stratification are important targets of asteroseismic study. δ Scuti pulsations are driven by the κ (opacity)

We present the radio afterglow of short gamma-ray burst (GRB) 230217A, which was detected less than 1 day after the gamma-ray prompt emission with the Australia Telescope Compact Array (ATCA) and the Karl G. Jansky Very Large Array. The ATCA rapid-response system automatically triggered an observation of GRB 230217A following its detection by the Neil Gehrels Swift Observatory and began observing the

For the first time in an extragalactic source, we detect linearly polarized H2O maser emission associated with the molecular accretion disk of NGC 1068. The position angles of the electric polarization vectors are perpendicular to the axes of filamentary structures in the molecular accretion disk. The inferred magnetic field threading the molecular disk must lie within ∼35° of the sky plane. The orientation

Based on astrometric measurements and spectral analysis from Gaia DR3, two quiescent black hole (BH) binaries, Gaia BH1 and BH2, have been identified. Their origins remain controversial, particularly for Gaia BH1. By considering a rapidly rotating (ω/ω crit = 0.8) and strongly magnetized (B 0 = 5000 G) merger product, we find that, at typical Galactic metallicity, the merger product can undergo efficient

The recently discovered Pa 30 nebula, the putative type Iax supernova remnant associated with the historical supernova of 1181 AD, shows puzzling characteristics that make it unique among known supernova remnants. In particular, Pa 30 exhibits a complex morphology, with a unique radial and filamentary structure, and it hosts a hot stellar remnant at its center, which displays oxygen-dominated, ultrafast

The ultra-high-energy (UHE) Galactic diffuse gamma-ray emission holds important information on the propagation of cosmic rays in the Galaxy. However, its measurements suffer from a contamination from unresolved sources whose contribution remains unclear. In this Letter, we propose a novel data-driven estimate of the contribution of unresolved pulsar wind nebulae and TeV halos based on the information

The coronal magnetic topology significantly affects the outcome of magnetic flux rope (MFR) eruptions. The recently reported nested double null magnetic system remains unclear as to how it affects MFR eruptions. Using observations from the New Vacuum Solar Telescope and the Solar Dynamics Observatory, we studied the formation and successful eruption of a hot channel MFR from NOAA active region AR 12173

Saturn has long been the only giant planet in our solar system without any known Trojan members. In this Letter, with serendipitous archival observations and refined orbit determination, we report that 2019 UO14 is a Trojan of the gas giant. However, the object is only a transient Trojan currently librating around the leading Lagrange point L 4 of the Sun–Saturn system in a period of ∼0.7 kyr. Our

JWST has revealed a ubiquitous population of “little red dots” (LRDs) at z ≳ 4, selected via their red rest-frame optical emission and compact morphologies. They are thought to be reddened by dust, whether in tori of active galactic nuclei (AGNs) or the interstellar medium, though none have direct dust detections to date. Informed by the average characteristics of 675 LRDs drawn from the literature