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| Version 1.9 Build 1488 |
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| Package | alma | |
| Module | alma | |
| Tool | iramcalibrater |
This function performs a flux density scale calibration using the selected calibration sources and spectral windows. Previously bandpassed and phase calibrated data are used to find the flux calibration needed. If fixed is unspecified, the function will execute in interactive mode, and the user will be queried for names and flux densities of known calibrators (at least one of the fields specified in fieldnames must be specified). The flux densities of the remaining fields and the efficiencies of the antennas will be derived and reported. In this mode, the user can iteratively change the flux density(ies) of the fixed-flux density calibrators to achieve the efficiencies expected.
If fixed is specified with any flux densities, this function will run in NON-interactive mode, and the user will have no opportunity to iterate as described above. This mode is useful if flux densities are confidently known a priori. In fixed, specify flux densities as a vector of string quantities (i.e., with units, e.g., '5Jy', or "5Jy 3.4Jy"). The values will be matched one-for-one with the field names in fieldnames. If only a subset of fields have known flux densities which the user desires fixed, list these fields first in fieldnames, or specify '-1Jy' for the flux densities of fields that should be derived. This mode assumes that the user is confident in the specification of known flux densities, and the fixed and derived flux densities/efficiencies will be automatically applied.
Timerange(s) may be specified to limit the range of data used in the calculation by using the timerange parameter. Specify these as pairs of times in a string. The format for the times can be: YYYY/MM/DD/hh:mm:ss, hh:mm:ss, hh:mm, or HH.xxh. In the latter two cases, the date will be assumed from the dataset. Note that the trailing 'h' in the third option specifies units of hours (e.g., 19:30:00 is the same as 19.5h ; in fact any appropriate time quantity (as string) may be specified). The number of time values specified must be even, with each pair representing a different timerange.
Use the numchancont parameter to specify (if necessary) the number of channels in the spectral window(s) that should be used for determining the flux scale.
| fieldnames | Field names of calibrators to be used | ||
| Allowed: | Vector of Strings | ||
| fixed | Fixed flux densities for known calibrators (as string quantities) | ||
| Allowed: | Vector of Strings | ||
| freqgrp | spectral windows to be used in the bandpass calibration | ||
| Allowed: | '3mm-LSB' || '3mm-USB' || '1mm' || '1mm-LSB' || '1mm-USB' | ||
| Default: | '3mm-LSB' | ||
| timerange | Timerange(s) specified in pairs | ||
| Allowed: | String | ||
| Default: | ' ' | ||
| plot | Display flux renormalized amplitudes | ||
| Allowed: | Bool | ||
| Default: | F | ||
| gibb | number of central channels to reject in solution | ||
| Allowed: | Int | ||
| Default: | 2 | ||
| drop | percentage of channels to ignore on edges of band | ||
| Allowed: | Int | ||
| Default: | 5 | ||
| numchancont | Number of channels in continuum spectral window | ||
| Allowed: | Int | ||
| Default: | 64 | ||
myic:=iramcalibrater('10feb97-g067.ms')
myic.phcor(F)
myic.rf(fieldname='0528+134', freqgrp='3mm-LSB')
myic.phase(fieldnames=['0528+134', '0415+379'], freqgrp='3mm-LSB')
myic.flux(fieldnames=['0528+134', '0415+379', 'MWC349'],
fixed=['2.92Jy','6.25Jy'],
freqgrp='3mm-LSB',
timerange='18:30 19:00 21.25h 21.5h',
plot=T)
myic.done()
In the example, data for three fields in the 3mm lower sideband during the time intervals 18:30-19:00 and and 21:15-21:30 are used in the flux density scale calibration, and only the first two fields have fixed flux densities specified (the third will be derived).