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A GUIDE FOR HANDLING SWARM HIGH-ANGULAR RESOLUTION DATA - since 2017
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- Residual delay corrections for broadband continuum -
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Corrections for time-dependent phase due to residual delay errors
Steps -
- 1. Find a nearby compact source as a calibrator
- 2. Constrict a pesudo point-source model at a phase center
- 3. Split the calibrator source into scan-based subsets
- 4. Solve for bandpass from each of the scan-based subsets
- 5. Normalize the bandpass solutions
- 6. Inspect the phase plots of the relevant spectra to determine
the magnitude of phase slope due to residual delay
- 7. Fit the spectral phase to a linear or a polinomial function of time
- 8. Interpolate the phase solutions to the target source in time
Miriad programs -
- 1. uvaver
- 2. smablcal
- 3. smagpplt
- 4. smatbpass
Scripts -
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Correction for elevation-dependent phase due to residual delay errors
Steps -
- 1. Find a few compact sources with a good elevation coverage as calibrators
- 2. Constrict pesudo point-source models at a phase center for each of them
- 3. Split the calibrator sources into scan-based subsets
- 4. Solve for bandpass from each of the scan-based subsets
- 5. Normalize the bandpass solutions
- 6. Inspect the phase plots of the relevant spectra
to determine the magnitude of phase slope due to residual delay
- 7. Fit the spectral phase to a parabolic or a polinomial function of elevation
- 8. Interpolate the phase solutions to the target source in elevation
Miriad programs -
- 1. uvaver
- 2. smablcal
- 3. smagpplt
- 4. smaelbpass
Scripts -
- Correction for residual delay due to atmosphere -
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Geometrical residual delay errors
Steps -
- 1. Find the antenna file used in the observing track
- 2. Find the antenna offsets
- 3. Or use the updated (corrected) antenna files
- 4. Determine delay error corrections for each antenna
- 5. Setup the inputs for uvedit/smauvedit
Miriad programs -
- 1. smauvedit (geometric corrections)
Scripts -
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Atmosphere model
Steps -
- 1. ****
- 2. ****
....
- N. ****
Miriad programs -
- 1. smauvedit (with delay corrections for air mass)
Scripts -
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References -
- 1.
Interferometry and Synthesis in Radio Astronomy, 3rd edition, A. Richard Thompson, James M. Moran, George W. Swenson Jr., Springer (2017)
- 2.The
am
atmospheric model, Scott Paine, SMA Technical Memo 152 (2017)
- 3.Total Power Atmospheric Phase Correction at the SMA, James Battat,
SMA Technical Memo 154 (2004)
- 4. Delay Errors in Single- and Double-Sideband Interferometer Systems
A. R. Thompson, L. R. D'ddario, D. T. Emerson and P. J. Napier, ALMA Memo 561 (2006)
- 5. Radio path length correction using water vapour radiometry,
R. J. Sault, G. J. Carrad, P. J. Hall, J. Crofts, arXiv:astro-ph/0701016 (2006)
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Meeting notes -
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