Riccardo Ferrazzoli

Jun 17, 2024 | nature.com | Jeremy Heyl |Victor Doroshenko |Ilaria Caiazzo |Juri Poutanen |Sergey S Tsygankov |Matteo Bachetti | +62 more

AbstractIn an accreting X-ray pulsar, a neutron star accretes matter from a companion star through an accretion disk. The magnetic field of the rotating neutron star disrupts the inner edge of the disk, funnelling the gas to flow onto the poles on its surface. Hercules X-1 is a prototypical persistent X-ray pulsar about 7 kpc from Earth.

Jan 25, 2024 | inria.hal.science | Philip Kaaret |Riccardo Ferrazzoli |Stefano Silvestri |Michela Negro

X-Ray Polarization of the Eastern Lobe of SS 433 Mots clés High mass x-ray binary stars Jets High energy astrophysics Supernova remnants Astrophysical black holes Fichier principal Kaaret_2024_ApJL_961_L12.pdf (1.63 Mo) Télécharger le fichier Origine : Fichiers éditeurs autorisés sur une archive ouverte Licence : CC BY - Paternité

Jul 17, 2023 | nature.com | Steven R. Ehlert |Dawoon Kim |Immacolata Donnarumma |Ioannis Liodakis |Iván Agudo |Svetlana G. Jorstad | +71 more

AbstractThe magnetic-field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can track how the magnetic field changes in the flow of the radiating particles by observing rotations of the electric vector position angle Ψ. Here we report the discovery of a ΨX rotation in the X-ray band in the blazar Markarian 421 at an average flux state.

Apr 6, 2023 | nature.com | Niccolò Bucciantini |Riccardo Ferrazzoli |Matteo Bachetti |Niccolò Di Lalla |Carmelo Sgrò |Nicola Omodei | +51 more

AbstractThe Crab pulsar and its nebula are among the most studied astrophysical systems, and constitute one of the most promising environments where high-energy processes and particle acceleration can be investigated. They are the only objects for which significant X-ray polarization was detected in the past. Here we present the Imaging X-ray Polarimetry Explorer (IXPE) observation of the Crab pulsar and nebula. The total pulsar pulsed emission in the [2–8] keV energy range is unpolarized.