5 papers
A new Chandra look at the globular cluster NGC 6540 and its peculiar X-ray flaring source
A. Sacchi, S. Mereghetti, R. Di Stefano +4
We report the results of a deep ( ks) Chandra exposure of the globular cluster NGC 6540, obtained by combining three observations carried out in 2023-2024 to investigate…
The long quest for vacuum birefringence in magnetars: 1E 1547.0-5408 and the elusive smoking gun
Roberto Taverna, Roberto Turolla, Lorenzo Marra +7
Magnetars are now known to be among the most strongly polarized celestial sources in X-rays. Here we report on the observation of the magnetar 1E 1547.0-5408 per…
Classification of Unidentified Extended LHAASO Sources based on their Gamma-Ray Morphology: Prospects for Future IACTs
Alberto Bonollo, Paolo Esposito, Andrea Giulisni +4
While Supernova Remnants (SNRs) are widely considered the primary accelerators of cosmic rays (CRs) up to hundreds of TeV, they struggle to account for the CR flux at PeV energies,…
Morphology of Young Massive Stellar Clusters with Next-Generation IACTs
Alberto Bonollo, Paolo Esposito, Andrea Giuliani +5
The term PeVatron designates astrophysical objects capable of accelerating particles to PeV energies. Their nature and particle acceleration mechanisms are uncertain, but ultra-hig…
Unveiling TeV halos among unidentified extended TeV sources
Michela Rigoselli, Sarah Recchia, Alberto Bonollo +4
In recent years, the number of known sources emitting very- and ultra-high-energy gamma-rays has increased significantly thanks to facilities such as LHAASO and HAWC. Many of the o…