 Using the telescope XMM-Newton, Caraveo has contributed to the first direct measurement of the magnetic field of an isolated neutron star, thanks to the discovery of cyclotron absorption lines in the data source 1E1207-59, a neutron star at the center of a supernova with no radio counterpart.The high sensitivity of XMM-Newton has also resulted in two major findings on Geminga.The star, as it moves with supersonic speed in the interstellar medium, generates a shock wave that produces a train of X-rays.