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F. Breitling, G. Mann, C. Vocks 3 nd Workshop of the Solar Key Science Project of LOFAR Astrophysikalisches Institut Potsdam 2010 July 05. Solar Data Analysis. Overview The three LOFAR data types. Dynamic spectra Single station imaging Standard imaging RCU: Receiver unit

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F. Breitling, G. Mann, C. Vocks

3nd Workshop

of the

Solar Key Science Project of LOFAR

Astrophysikalisches Institut Potsdam

2010 July 05

Solar Data Analysis

Solar Data Analysis F. Breitling

overview the three lofar data types
OverviewThe three LOFAR data types
  • Dynamic spectra
  • Single station imaging
  • Standard imaging

RCU: Receiver unit

RSP: Remote station processing board

TBB: Transient buffer boards

Solar Data Analysis F. Breitling

dynamic spectra data
Dynamic spectraData
  • Beam-formed data (currently)
    • Container format: Hirachical Data Format 5 (HDF5)
    • Specification: Interface Control Document 3

lofar-usg-icd-003.pdf

  • Dynamic spectrum data (maybe in future)
    • Container format: Hirachical Data Format 5 (HDF5)
    • Specification: Interface Control Document 6

lofar-usg-icd-006.pdf

=> both formats are currently under heavy development

Ref: http://usg.lofar.org/wiki/doku.php?id=documents:lofar_data_products

Solar Data Analysis F. Breitling

dynamic spectra software
Dynamic spectraSoftware
  • Dynspec package
  • developed by Solar KSP (Frank Breitling)
  • part of LOFAR User Software (http://usg.lofar.org)
  • build on Data Access Layer (DAL)
  • Python scripts
  • Components
    • specview.py (can read Fit and HDF5 files)
    • downsample.py (can also create Fit files)
    • rebin.py

Solar Data Analysis F. Breitling

dynamic spectra first solar observations
Dynamic spectraFirst solar observations

Date: 2009-09-11 10:08:52 (ID108)

2009-09-11 13:09:39 (ID109)

Duration: 1h

LOFAR stations: CS302-LBA

RS307-HBA

RS503-HBA

Measured param.: voltages of both polarizations

Subbands/station: 62

Down sampling: 128

Solar Data Analysis F. Breitling

dynamic spectra first results
Dynamic spectraFirst results

Solar Data Analysis F. Breitling

dynamic spectra identified problems
Dynamic spectraIdentified problems
  • stripe of high intensity in CS302, shifting from subband 30-40 for obs108 to subband 50-60 for obs109
  • intensity peaks and drops for subband 0-20 in obs109_CS302LBA
  • intensity gradient in obs109_RS503HBA

Solar Data Analysis F. Breitling

dynamic spectra next steps
Dynamic spectraNext steps
  • New versions of the beam-formed and dynamic spectra data format has to be finalized
  • Dynspec software can be adapted
  • Discussion with Michael Wise and Lars Bähren about their further development plans
  • Travel to ASTRON is already planed for July 12-16

Solar Data Analysis F. Breitling

single station imaging data
Single station imagingData
  • Visibilities from LCU correlator
    • 96 receiver units (RCUs) x 2 polarizations x 16 byte
    • Format: Binary
    • Specification:
      • Menno Norden <norden at astron.nl>
      • rspctl --help (running on LCU)

Reference: http://usg.lofar.org/forum/index.php?topic=202.0

Solar Data Analysis F. Breitling

single station imaging software
Single station imagingSoftware
  • acm2skyimage.m
  • developed by Stefan Wijnholds <wijnholds at astron.nl>
  • runs with Matlab and Octave
  • Extended components by Frank Breitling
    • SolarAzEl.m to add the Sun
    • RADec2AzEl.m to add other astronomical objects

(also published as Matlab package at http://www.mathworks.com/matlabcentral/fileexchange/25617-right-ascensiondeclination-to-azimuthelevation)

    • make-movies.sh

Solar Data Analysis F. Breitling

single station imaging potsdam commissioning
Single station imagingPotsdam commissioning

Solar Data Analysis F. Breitling

single station imaging results from effelsberg
Single station imagingResults from Effelsberg

Solar Data Analysis F. Breitling

single station data combining with gurt
Single station datacombining with GURT

Solar Data Analysis F. Breitling

standard imaging basics
Standard imagingBasics
  • Basic data analysis software
    • CASA (Common Astronomy Software Applications)

http://casa.nrao.edu/

  • Data format
    • Measurements Sets (MS) from CASA
  • Data processing: Standard Imaging Pipeline
    • The LOFAR wiki

http://www.lofar.org/wiki/doku.php?id=software:standard_imaging_pipeline

    • The LOFAR Imaging Cookbook

http://www.mpa-garching.mpg.de/~fdg/LOFAR_cookbook/LOFAR_Cookbook_v2.3.pdf

Solar Data Analysis F. Breitling

standard imaging pipeline
Standard imagingPipeline

Components

  • OLAP: Online Application Processing (Blue Gene/P correlator)
  • DP3/DPPP: Default Pre-Processing Pipeline (for flagging and averaging)
  • BBS: BlackBoard Selfcal (calibration)
  • CImager: Imager

Control

  • via parset files

Solar Data Analysis F. Breitling

standard imaging first solar observations
Standard imagingFirst solar observations

Date: 2010-06-09 10:17:00, 11:41:00, 13:40:00, 15:40:00

Duration: 4 x 10 Min

LOFAR stations: 20 CS +3 RS, i.e.

RS106HBA, RS306HBA, RS503HBA

[CS00{1-7}, CS0{21,30}, CS103] HBA{0,1}

Measured param.: complex visibilities, 2 polarizations

Frequency range: ~150-220 MHz

Subbands /station: 7

Solar Data Analysis F. Breitling

standard imaging data inspection with casaplotms
Standard imagingData Inspection with casaplotms
  • a lot of RFI
  • flagging with flagdata
  • creation of NDPPP.parset
  • reprocessing with NDPPP

Solar Data Analysis F. Breitling

standard imaging sky model
Standard imagingSky model

Calibration using BlackBoard Selfcal requires skymodel

File contents of 078xx.skymodel:

# (Name, Type, Ra, Dec, I, Q, U, V, ReferenceFrequency=\'60e6\',

SpectralIndexDegree=\'0\', SpectralIndex:0=\'0.0\', MajorAxis, MinorAxis, Orientation) = format

# The above line defines the field order and is required.

TauA.neb, GAUSSIAN, 05:34:32.00, +22.00.52.00, 1888.55, 0.0, 0.0, 0.0,81.5e6, 0, -0.299, 420.0, 290.0, 0.0

3C123, POINT, 04:37:04.72, +29.40.15.6, 454.97

3C133, POINT, 05:02:58.58, +25.16.22.7, 44.67

3C131, POINT, 04:53:23.26, +31.29.26.4, 37.54

3C139.2, POINT, 05:24:26.92, +28.12.54.2, 35.88

3C141, POINT, 05:26:43.55, +32.50.02.0, 31.76

3C132, POINT, 04:56:43.00, +22.49.23.7, 24.39

4C29.17, POINT, 05:10:40.10, +29.09.00.5, 19.48

4C29.16, POINT, 05:09:29.50, +29.57.56.3, 17.43

3C138, POINT, 05:21:10.46, +16.38.26.0, 14.63

PKS0531, POINT, 05:34:44.65, +19.27.21.9, 14.52

Taken from “The VLA Low-Frequency Sky Survey” catalog (http://www.cv.nrao.edu/4mass/VLSSlist.shtml)

Solar Data Analysis F. Breitling

standard imaging bbs calibration
Standard imagingBBS calibration

After running the BBS calibration

amplitudes and phases are stable

Solar Data Analysis F. Breitling

standard imaging mwimager
Standard imagingmwimager

after calibration the master worker imager creates:

  • PSF
  • dirty image
  • clean image

Solar Data Analysis F. Breitling

standard imaging dirty image
Standard imagingDirty image

Dirty image

not yet sucessful

Solar Data Analysis F. Breitling

standard imaging next steps
Standard imagingNext steps
  • investigation of 2s clock offset of CS002-CS007

(found by Olaf Wucknitz)

  • BBS calibration without short baselines

(suggested by James Anderson)

  • automatic flagging of RFI
  • travel to ASTRON on July 12-16 and discuss with the experts Ger van Diepen and Ger de Bruyn
  • take more observations, e.g. new data on July 03

Solar Data Analysis F. Breitling

progress documentation
Progress documentation

Solar Data Analysis F. Breitling

solar science data center yearly data volume
Solar Science Data CenterYearly data volume

for solar observations with LOFAR

(assuming a maximum observation time of 8h/d)

Solar Data Analysis F. Breitling

summary
Summary
  • The SKSP is engaged in 3 types of data analysis
  • Dynamic spectra can already be taken, next the new format has to be completed
  • Single station imaging is important for commissioning, single station operations and for our colleagues from GURT
  • Standard imaging is the newest data for the SKSP and will need a lot of attention in the future
  • Ultimately we plan for a Solar Science Data Center and work is ongoing

Solar Data Analysis F. Breitling

references
References
  • User Software Group: http://usg.lofar.org/
  • LOFAR User Forum: http://usg.lofar.org/forum/index.php
  • LOFAR Interface ControlDocuments (ICDs) http://usg.lofar.org/wiki/doku.php?id=documents:lofar_data_products
  • Documentation for the Standard Imaging Pipeline

http://www.lofar.org/wiki/doku.php?id=software:standard_imaging_pipeline

  • The LOFAR Imaging Cookbook

http://www.mpa-garching.mpg.de/~fdg/LOFAR_cookbook/LOFAR_Cookbook_v2.3.pdf

  • Frank Breitling <fbreitling at aip.de> http://www.aip.de/People/fbreitling/

Solar Data Analysis F. Breitling

yearly observation time
Yearly observation time

(Maximum possible)

  • at Exloo (core stations)
  • altitude >10° above horizon

=> tobs=~8 h/d =10x106 s/y

Solar Data Analysis F. Breitling

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