Daily Image
24-06-2010
LOFAR 12-hr Simultaneous Imaging and Timing Observation of a Pulsar
| Submitter: | Anastasia Alexov |
| Description: | These data were taken on April 9, 2010 with 7 core and 3 remote LOFAR High Band Antenna (HBA) stations, 130-178 MHz. This 12-hour observation was the longest test to date of observing with LOFAR simultaneously using both the imaging and timing modes. All 248 subbands were used for both the imaging and timing data results. The imaging data were processed using the Standard Imaging Pipeline, using the three brightest sources in the field for calibration, excluding short baselines. Following pipeline processing an updated skymodel was derived from the imaged data and used for a second pass of calibration; the individual subband were processed separately but then combined before imaging into one large Measurement Set (MS), so that the deconvolution could be done properly. CASA was used for the imaging. The resultant combined image is shown on the left. The location of Pulsar B0329+54 is indicated by the arrow; the pulsar flux is ~1Jy. The entire 12-hour time series (also known as beam-formed) data set were processed using the Known Pulsar Pipeline. The results pinpoint all the pulses from Pulsar B0329+54 during the entire length of the observation, which repeat every 0.7 seconds. A small fraction of these repeated pulses are shown on the right hand side of the figure, in what's called a "Pulse Stack" plot. This observation was performed during LOFAR commissioning as a proof of concept of taking Beam-Formed data as a "piggy-back" mode of the LOFAR Million Source Shallow Survey (MSSS). The data rate is manageable for both Imaging and Timing data (one beam) to be taken simultaneously. The piggy back mode will be a key aspect to the Pulsar Search Survey, which can take data at the same time as imaging survey observations, for "free". This daily image is submitted on behalf of the Pulsar Working Group (PWG) with a special thank you to George Heald, John Swinbank and Evert Rol. |
| Copyright: | UvA/ASTRON/LOFAR |
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