Crab Pulsar
Understanding the Pulse Shape & Giant Pulses vs. Frequency
(Bhat, Cordes, Hankins, Kern, McLaughlin)
Jan/Feb 2002
Composite of Average Profiles and GP Histograms vs. Pulse Phase
0.43 -> 8.7 GHz
(gzipped postscript 38kB)
The largest 430 MHz pulse in one hour (January 2002 data):
430 MHz S/N = 10,0000 S_peak = 160kJy (gzipped postscript 68kB)
Legend:
Top panel = Standard Profile
Bottom panel = Histogram of Giant Pulse counts vs. pulse phase
(red histogram if shown = blown up version)
P-band: 430 MHz
Plot of thresholded hits vs. time and frequency.
Note aliasing of the strong giant pulse at the band edges.
Histogram of Adjacent GP TOA Differences (L-band: 1180 MHz)
Histogram shows peaks at
-
multiples of the pulse period (~335 samples)
-
at the MP->IP separation (140 deg ~ 134 samples)
-
at the IP->MP separation (220 deg ~ 201 samples)
-
at the "GP Precursor"->MP separation (60 deg ~ 56 samples)
Some of these peaks are expected if GPs are occurring randomly and independently.
The GP Precursor->MP peak is larger than the MP->IP and IP->MP peaks and would
to imply that there is a correlation between the GP Precursor and the MP.
last updated: 03 Dec 2002 by Jim Cordes
cordes@astro.cornell.edu