Ponente
Descripción
Pulsar halos—extended regions of relativistic electrons surrounding middle-aged pulsars—offer critical insight into cosmic-ray acceleration and transport in the interstellar medium. These sources are often bright in the TeV gamma-ray band due to inverse Compton scattering by the most energetic electrons, which are also expected to emit synchrotron radiation in the X-ray band. A multiwavelength approach in the X-ray and TeV bands is therefore essential for probing the highest-energy electron populations. However, current-generation X-ray telescopes and imaging atmospheric Cherenkov telescopes face major challenges in detecting such faint, extended emission due to their limited fields of view.
To overcome these limitations, we employ novel analysis techniques and present the most detailed multiwavelength investigation to date of two systems: the archetypal Geminga halo and the unidentified gamma-ray source LHAASO J0621+3755. For Geminga, Manconi et al. exploit NuSTAR's stray light to probe diffuse X-ray emission over several degrees. For LHAASO J0621+3755, a candidate pulsar halo spatially coincident with the gamma-ray pulsar PSR J0622+3749, the VERITAS collaboration et al. analyze 40 hours of VERITAS data to look for extended TeV emission using a new technique that accurately models the background across the entire field of view. For both sources, we apply our theoretical model for the spatial and spectral distribution of pulsar halo emission to interpret our multiwavelength observations. These comparisons allow us to place stringent constraints on the magnetic field strength and the nature of cosmic-ray diffusion around the sources. We also report the first detection of X-ray emission and pulsation from PSR J0622+3749 using XMM-Newton. Finally, we discuss the prospects for future observations with the wide fields of view and high sensitivity of SRG/ART-XC, AXIS, and CTAO, which will play a key role in advancing our understanding of particle propagation near cosmic-ray accelerators.
