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Development and Commissioning of LOFAR for Astronomy (DCLA) Huub Röttgering Leiden Observatory
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13 Early July 2008
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15 September 2008
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March 2010
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10 International Station Rollout Effelsberg Tautenburg Potsdam
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p. 10 NL lofar: 20-25 core Stations & 20-25 outer stations E-lofar: 20-30 European stations?
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ASTRON LOFAR Surveys Meeting, 08 March 2010 12 2010: All LOFAR stations fully operational
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LOFAR opens up the last ‘unexplored’ part of the spectrum wavelength region Very Low Frequencies: 10-240 MHz Detection of extremely distant objects, new physics, serendipity High angular resolution: <1’’ at 200 MHz Morphologies, Identification of sources Nano second time resolution Cosmic rays Enormous Field of View Rare (transient) objects Sensitive polarization measurements Magnetic fields Low-Frequency Radio Spectroscopy Neutral gas in the early universe
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ExcellentData Quality (courtesy N. Jackson, J. Conway) 14 HBA stations (10 split core + 4 remote) Cygnus A
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Station beamforming Correlation of ~ Tbyte of station beams Removal Radio interference Calibration Removal ionospheric corruption Deconvolution Widefield imaging Status March 2010 3C196 field: 20 stations, 120-180 MHz, dynamic range of 10,000 (!), 960 sources
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Station beamforming Correlation of ~ Tbyte of station beams Removal Radio interference Calibration Removal ionospheric corruption Deconvolution Widefield imaging Status March 2010 3C196 field: 20 stations, 120-180 MHz, dynamic range of 10,000 (!), 960 sources Data stream and reduction pipeline: Station beamforming Correlation of ~ Tbyte/s datastream from station beams Removal radio frequence interference Calibration Removal ionospheric corruption Deconvolution Wide-field imaging All main elements in place, but need significant fine- tuning
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3C61.1 170 MHz, 10 arcsec
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NOVA and LOFAR Key-programs: driven the design Cosmic ray showers (Nijmegen) The epoch of reionization (Groningen) The bursting and transient Universe (Amsterdam) Surveying the low frequency universe: formation of AGN and galaxies (Leiden) Coordinated national program ASTRON: the instrument and standard software NOVA funded project ‘Development and Commissioning of LOFAR for Astronomy (DCLA)’ Testing and commissioning Specialized software pipelines Organization PM: Michael Wise Regular meetings on many levels Large international involvement
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Ultra High energy cosmic rays Where and how are they produced? What are they made off? Detection of Geosynchrotron emission from cosmic ray showers Team led by Falcke and Horandel (Nijmegen) DCLA: Detection and characterization
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Text CR detection works 5 ms all sky image with the LOFAR transient buffer boards
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Epoch of reionisation When and how did EOR occur? Detection EOR signal Team led by de Bruyn, Zaroubi, Koopmans, Brentjens Software: Calibration and removal foregrounds End-to-end simulation Implementation on Graphics Processor Units (GPU)
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EoR Simulation and reduction pipeline in place. Blue: Measured signal Dashed: Instr. Noise Red: True EoR Signal White/Gray: Extracted signal plus rms error Ingredients: simulated signal, foregrounds, ionosphere, beam forming, signal extraction
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Transients and pulsars Catalogue and characterize all transient radio sources (Gamma-ray bursts, jets, exo-planets, pulsars) Team led by Wijers, Fender and Stappers DCLA: write an pipeline for transient detection and characterization
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A simulated transient detected by the pipeline
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Surveying the low- frequency sky Goals Main: 100 z>6 radio galaxies, 100 radio clusters at z>0.6, 50 z>2 protoclusters Galaxies, clusters, physics of AGN and starbursts, the Galaxy, lensing, large scale structure, Team led by Huub Rottgering, Peter Barthel, Philip Best, Marcus Brüggen, Gianfranco Brunetti, Krzysztof Chyzy, John Conway, Matt Jarvis, Matt Lehnert, George Miley, Raffaella Morganti, Ignas Snellen DCLA: Source finding, characterization and cataloguing Ionospheric calibration
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Ionospheric model fitting 74 MHz VLA data Old new Source finding and characterization
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