| Description: | On the 14th June 2007 6 HBA tiles of the LOFAR CS1 station were pointed at the zenith as the radio pulsar B0329+54 passed overhead. The signals from the tiles were added incoherently and the source was observed for 15 minutes while it remained completely in the beam. A total of 48 subbands each of 0.15625 MHz wide, were collected in the frequency range 170-230 MHz. The left hand plot shows the frequency versus pulse phase, with the greyscale showing the pulse intensity. The pulsar is seen in almost all subbands and displays the expected change in arrival time due to dispersion in the interstellar medium. The total dispersion delay across this frequency range is about 1.8 seconds or 2.5 pulse periods. Only a couple of the subbands are affected by interference.
The right hand plot shows the sum of all subbands once the dispersion delay has been corrected for, and shows an excellent signal to noise. We note that this detection uses only 2.5% of a single station's collecting area! |
