Observations of Giant Pulses from Pulsar B0950+08 Using LWA1
We report the detection of giant pulse (GP) emission from PSR B0950+08 in 24 hours of observations made at 39.4 MHz, with a bandwidth of 16 MHz, using the first station of the Long Wavelength Array. We detected 119 GPs from PSR B0950+08 (at its dispersion measure (DM)), which we define as having a signal-to-noise ratio at least 10 times larger than for the mean pulse in our data set. These 119 pulses are 0.035% of the total number of pulse periods in the 24 hours of observations. The rate of GPs is about 5.0 per hour. The cumulative distribution of pulse strength S is a steep power law, _N(>S) ∝ S^(-4.7), but much less steep than would be expected if we were observing the tail of a Gaussian distribution of normal pulses. We detected no other transient pulses in a DM range from 1 to 90 pc cm^(−3), in the beam tracking PSR B0950+08. The GPs have a narrower temporal width than the mean pulse (17.8 ms, on average, versus 30.5 ms). The pulse widths are consistent with a previously observed weak dependence on observing frequency, which may be indicative of a deviation from a Kolmogorov spectrum of electron density irregularities along the line of sight. The rate and strength of these GPs is less than has been observed at ~100 MHz. Additionally, the mean (normal) pulse flux density we observed is less than at ~100 MHz. These results suggest this pulsar is weaker and produces less frequent GPs at 39 MHz than at 100 MHz.
© 2015 American Astronomical Society. Received 2014 June 24; accepted 2014 November 30; published 2015 January 19. We acknowledge insightful discussions with S. W. Ellingson, T. J. W. Lazio, and P. S. Ray. Construction of the LWA has been supported by the Office of Naval Research under Contract N00014-07-C-0147. Support for operations and continuing development of the LWA1 is provided by the National Science Foundation under grant AST-1139974 and AST-1139963 of the University Radio Observatory program. Part of this research was performed while S. E. Cutchin held a NRC research appointment at NRL. Basic research in radio astronomy at NRL is supported by 6.1 base funding. P. S. and C. C. Y. have been supported by NSF grants PHY-1068549 and PHY-1404121. Facility: LWA
Submitted - 1502.01282v2.pdf
Published - 1538-3881_149_2_65.pdf