Astrophysics Research
Protostellar Jets as Regulators of Star Formation Efficiency in Young Clusters
Protostellar jets reduce star formation efficiency in centrally concentrated molecular clouds from 19-33% down to 12-16%, operating as an underappreciated early feedback mechanism that reshapes cluster structure. Beyond efficiency suppression, jets introduce temporal burstiness to star formation and…
Quasi-star model fits some Little Red Dot spectra but fails on helium and dust, exposing deep model degeneracy
This paper tests whether the 'quasi-star' model—where an accreting supermassive black hole seed (~10^5–10^6 M☉) is enshrouded by a convective envelope and dense gas shell—can explain the observed spectral properties of JWST's Little Red Dots (LRDs). Using Cloudy radiative transfer, the authors show …
A Choked-Jet Shock Breakout Bridges the Gap Between X-Ray Transients and Low-Luminosity GRBs
EP260321a is the faintest shock breakout X-ray transient yet associated with a broad-lined Type Ic supernova (SN 2026gzf) at z=0.0344, detected by the Einstein Probe. Its thermal X-ray emission (kT=160 eV, peak luminosity 2.2×10⁴⁴ erg/s) is consistent with shock breakout, yet deep Chandra observatio…
SN 2026gzf: First Direct Evidence Linking Pre-Explosion Eruptive Mass Loss to Circumstellar Interaction in a Stripped-Envelope Supernova
SN 2026gzf, a broad-lined Type Ic supernova, was observed just 1.25 hours post-detection by Einstein Probe, revealing a luminous blue first-day excess inconsistent with standard radioactive decay models. This excess is explained by ejecta interaction with ~0.02 M☉ of circumstellar material (CSM), li…
GW190521 and GW231123 Are Consistent with Cosmic Domain Walls, But BBH Remains Favored — With a Critical Degeneracy
Two anomalous gravitational-wave events, GW190521 and GW231123, whose extreme masses and spins strain standard binary black hole (BBH) stellar evolution models, are tested against a topological dark matter (TDM) interpretation using cosmic domain wall waveform templates fit to LIGO strain data. Whil…
Fastest UV-Detected Quasar Outflow Reaches 0.3c, Approaching Galaxy-Scale Feedback Threshold
Seaton et al. report the fastest quasar outflow ever first detected in the ultraviolet, observed in radio-quiet quasar SDSS J2318+2439 via variable C IV and Si IV absorption at velocities between −77,000 and at least −90,000 km/s (~0.3c). The outflow strengthened monotonically over ~2.2 rest-frame y…
HST Deep UV Survey Proposed to Pin Down the Ionizing Photon Escape Fraction Near Reionization
The dominant uncertainty in models of cosmic reionization — the escape fraction of ionizing photons from early galaxies — remains poorly constrained observationally. This paper proposes a dedicated HST/WFC3-UVIS deep UV imaging survey across 20 fields targeting galaxies at 2 < z < 4, where ionizing …
The Sloan Great Wall Anchors the Largest Known Basin of Gravitational Attraction in the Local Universe
Using Hamiltonian Monte Carlo forward reconstruction constrained by the Cosmicflows-4 galaxy distance and velocity dataset, researchers mapped the gravitational basins of attraction in the local cosmic volume. The Sloan Great Wall emerges not only as a prominent large-scale structure in redshift sur…
JWST Catches a Rare Ibn/Icn Supernova Building Substantial Dust Reservoirs Within Its First Year
SN 2023xgo, a Type Ibn/Icn supernova observed out to +377 days post-explosion, provides one of the most detailed IR characterizations of dust formation in this rare SN subclass. JWST (NIRSpec + MIRI) reveals a large dust mass (≥3×10⁻² M☉ in cool silicate dust) co-located near the shock radius, along…
First GeV Detection of a Superluminous Supernova Points to Magnetar Central Engine Over CSM Interaction
Fermi-LAT's systematic 16-year survey of nearby Type I and Type II superluminous supernovae yielded a single GeV detection: SN 2017egm, with >5σ significance (TS = 26–33). The gamma-ray signal — emerging 50–160 days post-explosion with a power-law spectrum (Γ = 2.17 ± 0.23) — is consistent with magn…
First Ab Initio DDT Mechanism Explains Why Type Ia Supernovae Are Standard Candles
This paper presents the first globally self-consistent, laboratory-validated mechanism for the deflagration-to-detonation transition (tDDT) in near-Chandrasekhar mass white dwarf Type Ia supernova progenitors, replacing decades of ad hoc detonation-initiation assumptions. Using 3D hydrodynamical sim…
X-ray Pulse Profile Modeling of a 448-Hz Accreting Millisecond Pulsar Yields Large Neutron Star Mass-Radius Constraints via NICER+IXPE Polarimetry
Combined NICER and IXPE observations of the newly discovered accreting millisecond pulsar SRGA J144459.2-604207 (spinning at 448 Hz) were analyzed using relativistic ray-tracing pulse profile modeling to constrain neutron star mass and radius. The best-fit model features two independent, geometrical…
IceCube Releases 14-Year Muon Track Dataset (IceTracks-DR2) for Open Neutrino Source Searches
The IceCube Collaboration has published IceTracks-DR2, its most comprehensive public muon track dataset to date, spanning 14 years of observations (2008–2022) and superseding the prior 10-year release. The dataset incorporates improved detector calibration for post-2010 data and includes binned inst…
EHT Brightness Asymmetry Data Marginally Rules Out Near-Zero Spin for M87*
Using three epochs of Event Horizon Telescope (EHT) observations, the EHT Collaboration compares the observed distribution of ring brightness asymmetry amplitudes in M87* against GRMHD simulation libraries spanning a range of black hole spins. For strongly magnetized (MAD) accretion models, the data…
Sgr A* Polarization Variability During 2018 EHT Campaign Challenges Standard Flare Models
ALMA full-polarization observations of Sagittarius A* during the 2018 EHT campaign reveal a striking asymmetry: total intensity variability is low (<10%), while linear and circular polarization variability reach ~30% and ~50%, respectively — implying polarized emission originates from a spatially an…
Sub-Solar Mass GW Candidate S251112cm: No Kilonova Found, But a Second Coincident Type IIb Supernova Hints at Superkilonova Formation Channel
The LVK collaboration's sub-solar mass gravitational wave candidate S251112cm triggered a rapid multi-facility EM follow-up campaign (DECam, ZTF, FTW) covering 56% of the localization region within 2.4 hours, yielding no kilonova counterpart — with FTW alone ruling out 92% of kilonova models. Howeve…
1:10 Satellite Encounters Produce Universal Dark Matter Halo Deformations: Evidence from the LMC-SMC System
Using basis function expansions applied to a high-resolution N-body simulation of the LMC-SMC system in isolation, this study quantifies the mutual dark matter halo distortions of the Magellanic Clouds prior to Milky Way infall. The SMC induces a ~20 kpc dynamical friction wake and dual overdensitie…
JWST Confirms Metal-Free HeII Emitter Near GN-z11 at z=10.6 — Strongest Evidence Yet for Population III Stars
Using JWST NIRSpec-IFU high-resolution spectroscopy, Maiolino et al. confirm a HeII λ1640 emitter at z=10.6, located just 3 physical kpc from the well-known galaxy GN-z11. The source shows no detectable metal lines and an exceptionally high HeII equivalent width (>20 Å), with the emission spectrally…