高能暂现源 · 每日文献综述

The origin of high-energy astrophysical neutrinos remains unresolved, and secure electromagnetic counterparts to individual events are rare despite rapid follow-up. Dusty star-forming galaxies (DSFGs) at cosmic noon (z ≈ 1-4) are natural cosmic-ray calorimeters, yet observational links between DSFGs and neutrinos have remained unknown. Here we report a compact-core DSFG within an IceCube localization, JCMT0402-0424, a quadruply lensed galaxy at z = 2.988 located inside the 90% containment region of the IceCube event IC 210922A. Atacama Large Millimeter/Submillimeter Array imaging and lens modelling resolve a highly magnified, compact starburst with no bright γ-ray or X-ray counterpart above current sensitivity limits. Considering the positional agreement, the low chance-coincidence probability (≲1%) for such an extreme submillimetre source, the absence of equally plausible alternatives in the field and the compact, gas-rich core revealed by Atacama Large Millimeter/Submillimeter Array, JCMT0402-0424 is the most plausible electromagnetic counterpart candidate within the IC 210922A localization. In a population context, compact-core starbursts at cosmic noon can provide a non-negligible population-level contribution to the diffuse high-energy neutrino background, even though the neutrino yield from any single DSFG is modest. This result connects high-energy neutrino production to the peak epoch of cosmic star formation, opening a new avenue to probe galaxy evolution and cosmic-ray acceleration across cosmic time.

We investigate the spectrum and polarization of radiation emerging from a subcritical X-ray pulsar using self-consistent radiation hydrodynamic simulations of an accretion channel in a strong magnetic field. The polarized radiative transfer in the channel above the hotspot is simulated for the two normal modes, taking into account resonant Compton scattering in a strongly magnetized plasma and the effects of vacuum polarization. We show that the deceleration of the accreting matter in the subcritical regime is mainly governed by resonant scattering. Our simulations provide the velocity profiles of the plasma flow and demonstrate that vacuum polarization dominates over plasma birefringence, enhancing both the cyclotron spectral feature and the radiative deceleration of the plasma. We also find that the energy of the cyclotron feature increases with accretion luminosity, indicating a positive correlation consistent with previous observational results and theoretical interpretation.