Absorption Features in the X-ray Spectrum of an Ordinary Radio Pulsar

The vast majority of known nonaccreting neutron stars (NSs) are rotation-powered radio and/or g-ray pulsars. So far, their multiwavelength spectra have all been described satisfactorily by thermal and nonthermal continuum models, with no spectral lines. Spectral features have, however, been found in a handful of exotic NSs and were thought to be a manifestation of their unique traits. Here, we report the detection of absorption features in the x-ray spectrum of an ordinary rotation-powered radio pulsar, J1740+1000. Our findings bridge the gap between the spectra of pulsars and other, more exotic, NSs, suggesting that the features are more common in the NS spectra than they have been thought so far. The study of neutron stars (NSs) offers anopportunity to understand physical pro-cesses under the most extreme conditions in the universe. These super-dense compact stars have extremely strong magnetic fields reaching up to a few hundred teragauss. Thanks to the strength of the magnetic field and rapid rotation, young NSs are capable of generating and main-taining huge electric potential drops (up to a fe