Recent work has exploited pulsar survey data to identify temporally isolated , millisecond-duration radio bursts with large dispersion measures ( DMs ) .
These bursts have been interpreted as arising from a population of extragalactic sources , in which case they would provide unprecedented opportunities for probing the intergalactic medium ; they may also be linked to new source classes .
Until now , however , all so-called fast radio bursts ( FRBs ) have been detected with the Parkes radio telescope and its 13-beam receiver , casting some concern about the astrophysical nature of these signals .
Here we present FRB 121102 , the first FRB discovery from a geographic location other than Parkes .
FRB 121102 was found in the Galactic anti-center region in the 1.4-GHz Pulsar ALFA survey with the Arecibo Observatory with a DM = 557.4 \pm 3 \mbox { pc cm } ^ { -3 } , pulse width of 3 \pm 0.5 ms , and no evidence of interstellar scattering .
The observed delay of the signal arrival time with frequency agrees precisely with the expectation of dispersion through an ionized medium .
Despite its low Galactic latitude ( b = -0.2 ^ { \circ } ) , the burst has three times the maximum Galactic DM expected along this particular line-of-sight , suggesting an extragalactic origin .
A peculiar aspect of the signal is an inverted spectrum ; we interpret this as a consequence of being detected in a sidelobe of the ALFA receiver .
FRB 121102 ’ s brightness , duration , and the inferred event rate are all consistent with the properties of the previously detected Parkes bursts .