The X-ray emission of the highly magnetic RRAT J1819–1458

Abstract

We present the XMM–Newton discovery of X‐ray pulsations and a ∼1 keV spectral feature from RRAT J1819–1458, a Rotating Radio Transient source with an inferred surface dipole magnetic field of 5×1013 G and a 4.26 s spin period. We detect pulsations at the period predicted by the radio ephemeris, providing an unambiguous identification with the radio source and confirmation of its neutron star nature. The X‐ray pulse has a 0.3–5 keV pulsed fraction of 34% and is aligned with the radio pulse. On the other hand, the X‐ray spectrum is well fit by an absorbed blackbody with kT = 0.14 keV with the addition of a broad absorption feature at 1 keV The nature of this absorption feature is still not settled, it might be due to atomic transitions in the atmosphere or to resonant proton cyclotron scattering. No evidence for any X‐ray bursts or aperiodic variability has been found.