a2255 as seen by lofar roberto pizzo, annalisa bonafede, reinout van weeren, giulia macario
DESCRIPTION
A2255 as seen by LOFAR Roberto Pizzo, Annalisa Bonafede, Reinout van Weeren, Giulia Macario. At 25 cm. At 85 cm. Relic. Halo. Bridge. FWHM ~ 15’’ s ~ 11 m Jy/beam. FWHM ~ 1’ s ~ 0.1 mJy/beam. THE OBSERVATION. L2011_24627: 1-7 am of March 27 th 2011 - PowerPoint PPT PresentationTRANSCRIPT
A2255 as seen by LOFAR
Roberto Pizzo, Annalisa Bonafede, Reinout van Weeren, Giulia Macario
At 25 cmAt 85 cm
FWHM ~ 15’’Jy/beam
FWHM ~ 1’mJy/beam
Relic
HaloBridge
THE OBSERVATION
• L2011_24627: 1-7 am of March 27th 2011
• The observation was supposed to cover the frequency range between 210-250 MHz, but due to a problem during scheduling only the frequencies between 225-250 MHz (SB000-070) could be used for the data reduction.
• We performed a few tests to understand what approach to follow for the data reduction
Cas A & Cyg A: subtraction in BBS
• Data averaged by a factor of 6 in frequency
• Models for Cas and Cyg extractedfrom the 74 MHz maps
• Test done on SB000 (225 MHz)
Cas A & Cyg A: demixing
Data have not been averaged. Plots refer to SB000
WENSS model
• 230 components• Data averaged to 10 sec and 2 channels
SB064
Data clipped at 40 Jy
dynamic range ~ 350
Pizzo’s model
• 750 components• Data averaged to 10 sec and 2 channels
Clipping at 40 Jy after calibration
SB064
dynamic range ~ 330
Difference between Global solver and single-SB solver
No big difference is seen in the noise level but the image with the global calibration looks better (i.e., the huge head-tail to the south of the cluster center is better
visible).
The pipeline process
Courtesy of R. Pizzo, R. van Weeren, A. Bonafede & C. Ferraridynamic range ~ 2.500
SB00-025 excluded fromthe processing
Abell 2255 in HBA (225-250 MHz)
53 SBs, dynamic range ~ 2.500Courtesy of R. Pizzo, R. van Weeren,
A. Bonafede & C. Ferrari
Abell 2255 in HBA (225-250 MHz)
53 SBs, dynamic range ~ 2.500Courtesy of R. Pizzo, R. van Weeren,
A. Bonafede & C. Ferrari
Broad-band low-level RFI
SB000
Broad-band low-level RFI
SB010