MARELLI, MARTINOMARTINOMARELLIPizzocaro, DanieleDanielePizzocaroDE LUCA, AndreaAndreaDE LUCAGASTALDELLO, FABIOFABIOGASTALDELLOCARAVEO, PATRIZIAPATRIZIACARAVEOSaz Parkinson, PabloPabloSaz Parkinson2020-05-222020-05-2220160004-637Xhttp://hdl.handle.net/20.500.12386/25066We analyzed a deep XMM-Newton observation of the radio-quiet γ-ray PSR J2055+2539. The spectrum of the X-ray counterpart is nonthermal, with a photon index of Γ = 2.36 ± 0.14 (1σ confidence). We detected X-ray pulsations with a pulsed fraction of 25% ± 3% and a sinusoidal shape. Taking into account considerations on the γ-ray efficiency of the pulsar and on its X-ray spectrum, we can infer a pulsar distance ranging from 450 to 750 pc. We found two different nebular features associated with PSR J2055+2539 and protruding from it. The angle between the two nebular main axes is ∼162.°8 ± 0.°7. The main, brighter feature is 12′ long and <20″ thick, characterized by an asymmetry with respect to the main axis that evolves with the distance from the pulsar, possibly forming a helical pattern. The secondary feature is 250″ × 30″. Both nebulae present an almost flat brightness profile with a sudden decrease at the end. The nebulae can be fitted by either a power-law model or a thermal bremsstrahlung model. A plausible interpretation of the brighter nebula is in terms of a collimated ballistic jet. The secondary nebula is most likely a classical synchrotron-emitting tail.STAMPAenArticle10.3847/0004-637X/819/1/402-s2.0-84960951549000372303400040https://iopscience.iop.org/article/10.3847/0004-637X/819/1/40https://arxiv.org/pdf/1509.05833.pdf2016ApJ...819...40MFIS/05 - ASTRONOMIA E ASTROFISICA