We report on simultaneous wideband observations of Crab giant pulses with the Parkes radio telescope and the Murchison Widefield Array ( MWA ) .
The observations were conducted simultaneously at 732 and 3100 MHz with Parkes , and at 120.96 , 165.76 and 210.56 MHz with the MWA .
Flux density calibration of the MWA data was accomplished using a novel technique based on tied-array beam simulations .
We detected between 90–648 giant pulses in the 120.96–210.56 MHz MWA subbands above a 5.5 \sigma threshold while in the Parkes subbands we detected 6344 and 231 giant pulses above a threshold of 6 \sigma at 732 and 3100 MHz , respectively .
We show , for the first time over a wide frequency range , that the average spectrum of Crab giant pulses exhibits a significant flattening at low frequencies .
The spectral index , \alpha , for giant pulses evolves from a steep , narrow distribution with a mean \alpha = -2.6 and width \sigma _ { \alpha } = 0.5 between 732 and 3100 MHz , to a wide , flat distribution of spectral indices with a mean \alpha = -0.7 and width \sigma _ { \alpha } = 1.4 between 120.96 and 165.76 MHz .
We also comment on the plausibility of giant pulse models for Fast Radio Bursts based on this spectral information .