Is the Bursting Radio-source Gcrt J1745-3009 a Double Neutron Star Binary ?

GCRT J1745-3009 is a peculiar transient radio-source in the direction of the Galactic Center. It was observed to emit a series of ∼ 1 Jy bursts at 0.33 GHz, with typical duration ∼ 10 min and at apparently regular intervals of ∼ 77 min. If the source is indeed at the distance of the Galactic Center as it seems likely, we show that its observational properties are compatible with those expected from a double neutron star binary, similar to the double pulsar system J0737-3039. In the picture we propose the (coherent) radio emission comes from the shock originating in the interaction of the wind of the more energetic pulsar with the magnetosphere of the companion. The observed modulation of the radio signal is the consequence of an eccentric orbit, along which the separation between the two stars varies. This cyclically drives the shock inside the light cylinder radius of the less energetic pulsar. 1. introduction Recently Hyman et al. (2005) announced the remarkable discovery of a powerful bursting radio-source located about 1 deg south of the Galactic Center (GC). GCRT J1745-3009 was detected in 2002 during a radio transient monitoring of the GC region at 0.33 GHz, and appears to emit a series of bursts of typical duration ∼ 10 min. The flux in a single burst is ∼ 1 Jy and no emission is detected between the events to an upper limit of 75 mJy. The bursts seem to follow a regular pattern, with a time separation of ∼ 77 min. The bursting source is unresolved and no counterparts are found thus far in other spectral bands. The quite high radio flux, combined with the limited spatial extent of the emitting region derived from the decay time of the bursts, implies a brightness temperature of T b ∼ 10 16 K placing the source at the GC distance. If this is the case, a coherent mechanism is required to power the observed radio emission (Hyman et al. 2005). A number of possible interpretations for the peculiar properties of GCRT J1745-3009 have been examined by Hyman et al. (2005). Their main conclusion is that, although the option that this is a close-by radio-source (a very cold dwarf, or an extrasolar planet) can not be dismissed , it appears much more likely that GCRT J1745-3009 is indeed located close to the GC. Along this line, they consider both a radio-pulsar and …