Transient Radio-source PSR J1928+15 proposed as SETI Candidate

Article: J Benford, D Benford "HOW CAN WE DISTINGUISH TRANSIENT PULSARS FROM SETI BEACONS? " (2010) 

Article: JS Deneva, JM Cordes, MA McLaughlin "Arecibo pulsar survey using ALFA: Probing radio pulsar intermittency and transients" (2009) 

EXCERPT: "PSR J1928+15 was discovered in 2005 by detection of what looked like a single bright pulse at DM = 245 pc cm−3 in a 120 s observation. More detailed analysis revealed that the event was in fact composed of 3 separate pulses occurring at intervals of 0.403 s, with the middle pulse being brighter by an order of magnitude than the other two. The dispersion of the brightest pulse by ionized interstellar gas is shown in the time-frequency plane, evidence of the non-terrestrial origin of the pulses.  A fit to the pulse signal in the time-frequency plane resulted in a refined estimate of DM = 242 pc cm−3.                                        Despite multiple follow-up observations, the source has not been detected again. Given the DM of this source, 242 pc cm−3, it is unlikely that the non-detection can be attributed to diffractive scintillation. Since the three pulses are equally spaced they can be interpreted as a single event seen in succes sive rotations of a neutron star. This signature might be accounted for by an object that is dormant or not generally beamed toward the Earth and whose magnetosphere is perturbed sporadically by accretion of material from an asteroid belt"