Daily Image
19-04-2010
The Galaxy comes into focus
| Submitter: | Stefan Wijnholds |
| Description: | The map shown in the top panel was LOFAR's first all-sky map. This image was made in 2004 using the Initial Test Station using all RFI free 9.77 kHz channels between 29.5 and 30.5 MHz in 86 snapshots with 6.7 s integration time captured during a two-week monitoring campaign. After ITS was built, the LOFAR team had to focus on stuff with a much lower PR value like developing a real-time station backend for the next prototype, core station 10. The ITS map has more than served its purpose to fill the resulting PR gap. Meanwhile, the station calibration and imaging routines were developed further using a model based approach adopted from the array signal processing community. In view of imaging, the implicit deconvolution is one of the attractive features of this approach (see this daily image daily image). All of this has been scrambled to produce the map in the bottom panel from all RFI free 195 kHz subbands between 40 and 70 MHz from a three-day observing run with CS10. The resolution provided by CS10 is similar to that of ITS, but owing to the more advanced data processing, the result differs dramatically. Especially the more subtle features like loop III stand out much clearer. Reference: Stefan J. Wijnholds, "Fish-Eye Observing with Phased Array Radio Telescopes", Ph.D. thesis, Delft University of Technology, Delft, The Netherlands, 2 March 2010 |
| Copyright: | ASTRON / LOFAR |
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