RIGOSELLI, MICHELAMICHELARIGOSELLIMEREGHETTI, SandroSandroMEREGHETTI2020-11-132020-11-1320180004-6361http://hdl.handle.net/20.500.12386/28339We report on the X-ray properties of four rotation-powered pulsars with characteristic ages in the range 0.3-5 Myr, derived from the analysis of XMM-Newton archival observations. We found convincing evidence of thermal emission only in the phase-averaged spectrum of PSR B0114+58, which is well fitted by a blackbody with temperature kT = 0.17 ± 0.02 keV and emitting radius R = 405 [-90,+110] m, consistent with the size of its polar cap. The three other considered pulsars, PSR B0628-28, PSR B0919+06, and PSR B1133+16, have phase-averaged spectra that can be described well by single power laws with photon index Γ~3. The 3σ upper limits on the bolometric luminosity of a possible thermal component with temperatures in the range 0.05-2 keV are Lbol ≲ 3.2 × 10^28 erg/s and Lbol ≲ 2.4 × 10^29 erg/s, for PSR B0628-28 and PSR B0919+06, respectively. On the other hand, we found possible evidence that the pulsed emission of PSR B0628-28 is thermal. Two absorption lines at 0.22 keV and 0.44 keV are detected in the spectrum of PSR B1133+16. They are best interpreted as proton cyclotron features, implying the presence of multipolar components with a field of a few 10^13 G at the neutron star polar caps. We discuss our results in the context of high-energy emission models of old rotation-powered pulsars.STAMPAenArticle10.1051/0004-6361/2017324082-s2.0-85053067334000439002800005http://arxiv.org/abs/1802.09454v1https://www.aanda.org/articles/aa/abs/2018/07/aa32408-17/aa32408-17.html2018A&A...615A..73RFIS/05 - ASTRONOMIA E ASTROFISICA