Multifrequency Observations of Giant Radio Pulses from the Millisecond Pulsar B1937+21

Giant pulses are short, intense outbursts of radio emission with a power-law intensity distribution that have been observed from the Crab Pulsar and PSRB1937+21. We have undertaken a systematic study of giant pulses from PSRB1937+21 using the Arecibo telescope at 430, 1420, and 2380 MHz. At 430 MHz, interstellar scattering broadens giant pulses to durations of ∼ 50 μsecs, but at higher frequencies the pulses are very short, typically lasting only ∼ 1–2 μsecs. At each frequency, giant pulses are emitted only in narrow (∼< 10 μs) windows of pulse phase located ∼ 55–70 μsec after the main and interpulse peaks. Although some pulse-to-pulse jitter in arrival times is observed, the mean arrival phase appears stable; a timing analysis of the giant pulses yields precision competitive with the best average profile timing studies. We have measured the intensity distribution of the giant pulses, confirming a roughly power-law distribution with approximate index of −1.8, contributing ∼> 0.1% to the total flux at each frequency. We also find that the intensity of giant pulses falls off with a slightly steeper power of frequency than the ordinary radio emission. Subject headings: pulsars–pulsars: individual (PSRB1937+21, B0531+21)