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0.1.4 bandpass

Requires:

Synopsis
Calculates a bandpass calibration solution

Description

Determines the amplitude and phase as a function of frequency for each spectral window containing more than one channel. Strong sources (or many observations of moderately strong sources) are needed to obtain accurate bandpass functions. The two solution choices are: Individual antenna/based channel solutions ’B’; and a polynomial fit over the channels ’BPOLY’. The ’B’ solutions can determined at any specified time interval, and is recommended in most applications.

Arguments





Inputs

vis

Name of input visibility file

allowed:

string

Default:

caltable

Name of output gain calibration table

allowed:

string

Default:

field

Select field using field id(s) or field name(s)

allowed:

string

Default:

spw

Select spectral window/channels

allowed:

string

Default:

intent

Select observing intent

allowed:

string

Default:

selectdata

Other data selection parameters

allowed:

bool

Default:

True

timerange

Select data based on time range

allowed:

string

Default:

uvrange

Select data within uvrange (default units meters)

allowed:

any

Default:

variant

antenna

Select data based on antenna/baseline

allowed:

string

Default:

scan

Scan number range

allowed:

string

Default:

observation

Select by observation ID(s)

allowed:

any

Default:

variant

msselect

Optional complex data selection (ignore for now)

allowed:

string

Default:

solint

Solution interval in time[,freq]

allowed:

any

Default:

variant inf

combine

Data axes which to combine for solve (obs, scan, spw, and/or field)

allowed:

string

Default:

scan

refant

Reference antenna name(s)

allowed:

string

Default:

minblperant

Minimum baselines _per antenna_ required for solve

allowed:

int

Default:

4

minsnr

Reject solutions below this SNR (only applies for bandtype = B)

allowed:

double

Default:

3.0

solnorm

Normalize average solution amplitudes to 1.0

allowed:

bool

Default:

False

bandtype

Type of bandpass solution (B or BPOLY)

allowed:

string

Default:

B

smodel

Point source Stokes parameters for source model.

allowed:

doubleArray

Default:

append

Append solutions to the (existing) table

allowed:

bool

Default:

False

fillgaps

Fill flagged solution channels by interpolation

allowed:

int

Default:

0

degamp

Polynomial degree for BPOLY amplitude solution

allowed:

int

Default:

3

degphase

Polynomial degree for BPOLY phase solution

allowed:

int

Default:

3

visnorm

Normalize data prior to BPOLY solution

allowed:

bool

Default:

False

maskcenter

Number of channels to avoid in center of each band

allowed:

int

Default:

0

maskedge

Fraction of channels to avoid at each band edge (in %)

allowed:

int

Default:

5

docallib

Use callib or traditional cal apply parameters

allowed:

bool

Default:

False

callib

Cal Library filename

allowed:

string

Default:

gaintable

Gain calibration table(s) to apply on the fly

allowed:

stringArray

Default:

gainfield

Select a subset of calibrators from gaintable(s)

allowed:

stringArray

Default:

interp

Interpolation mode (in time) to use for each gaintable

allowed:

stringArray

Default:

spwmap

Spectral windows combinations to form for gaintables(s)

allowed:

intArray

Default:

parang

Apply parallactic angle correction

allowed:

bool

Default:

False

Example

 
 
       Determines the amplitude and phase as a function of frequency for  
       each spectral window containing more than one channel.  Strong sources  
       (or many observations of moderately strong sources) are needed to obtain  
       accurate bandpass functions.  The two solution choices are: Individual  
       antenna/based channel solutions ’B’; and a polynomial fit over the channels  
       ’BPOLY’.  The ’B’ solutions can determined at any specified time interval, and  
       is recommended if each channel has good signal-to-noise.  Other, ’BPOLY’ is  
       recommended.  
 
      Keyword arguments:  
      vis -- Name of input visibility file  
              default: none; example: vis=’ngc5921.ms’  
      caltable -- Name of output bandpass calibration table  
              default: none; example: caltable=’ngc5921.bcal’  
 
      --- Data Selection (see help par.selectdata for more detailed information)  
 
      field -- Select field using field id(s) or field name(s).  
                 [run listobs to obtain the list id’s or names]  
              default: ’’=all fields  
              If field string is a non-negative integer, it is assumed a field index  
                otherwise, it is assumed a field name  
              field=’0~2’; field ids 0,1,2  
              field=’0,4,5~7’; field ids 0,4,5,6,7  
              field=’3C286,3C295’; field named 3C286 adn 3C295  
              field = ’3,4C*’; field id 3, all names starting with 4C  
      spw -- Select spectral window/channels  
              default: ’’=all spectral windows and channels  
              spw=’0~2,4’; spectral windows 0,1,2,4 (all channels)  
              spw=’<2’;  spectral windows less than 2 (i.e. 0,1)  
              spw=’0:5~61’; spw 0, channels 5 to 61  
              spw=’0,10,3:3~45’; spw 0,10 all channels, spw 3, channels 3 to 45.  
              spw=’0~2:2:6’; spw 0,1,2 with channels 2 through 6 in each.  
              spw=’0:0~10;15~60’; spectral window 0 with channels 0-10,15-60  
                        NOTE: ’;’ to separate channel selections  
              spw=’0:0~10,1:20~30,2:1;2;3’; spw 0, channels 0-10,  
                       spw 1, channels 20-30, and spw 2, channels, 1,2 and 3  
      intent -- Select observing intent  
                default: ’’  (no selection by intent)  
                intent=’*BANDPASS*’  (selects data labelled with  
                                      BANDPASS intent)  
      selectdata -- Other data selection parameters  
              default: True  
      timerange  -- Select data based on time range:  
              default = ’’ (all); examples,  
              timerange = ’YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss’  
              Note: if YYYY/MM/DD is missing dat defaults to first day in data set  
              timerange=’09:14:0~09:54:0’ picks 40 min on first day  
              timerange= ’25:00:00~27:30:00’ picks 1 hr to 3 hr 30min on next day  
              timerange=’09:44:00’ data within one integration of time  
              timerange=’>10:24:00’ data after this time  
      uvrange -- Select data within uvrange (default meters)  
              default: ’’ (all); example:  
              uvrange=’0~1000klambda’; uvrange from 0-1000 kilo-lambda  
              uvrange=’>4klambda’;uvranges greater than 4 kilo-lambda  
      antenna -- Select data based on antenna/baseline  
              default: ’’ (all)  
              If antenna string is a non-negative integer, it is assumed an antenna index  
                otherwise, it is assumed as an antenna name  
              antenna=’5&6’; baseline between antenna index 5 and index 6.  
              antenna=’VA05&VA06’; baseline between VLA antenna 5 and 6.  
              antenna=’5&6;7&8’; baseline 5-6 and 7-8  
              antenna=’5’; all baselines with antenna 5  
              antenna=’5,6,10’; all baselines with antennas 5, 6 and 10  
       scan -- Select data based on scan number - New, under developement  
               default: ’’ (all); example: scan=’>3’  
       observation -- Observation ID(s).  
                      default: ’’ = all  
                      example: ’0~2,4’  
       msselect -- Optional complex data selection (ignore for now)  
 
       --- Solution parameters  
       solint --  Solution interval in time (units optional), and (optionally)  
                   in frequency.  Frequency pre-averaging can be  
                   specified after a comma in units of channels or Hz.  
                   If nothing is specified for frequency, no freq pre-averaging  
                   will be done.  
       default: ’inf’ (~infinite, up to boundaries controlled by combine,  
                       with no pre-averaging in frequency)  
              Options for time: ’inf’ (~infinite), ’int’ (per integration), any float  
                       or integer value with or without units  
              Options for freq: an integer with ’ch’ suffix will enforce  
                                pre-averaging by the specified number  
                                of channels.  
                                a numeric value suffixed with frequency  
                                units (e.g., ’Hz’,’kHz’,’MHz’) will enforce  
                                pre-averaging by an integral number of  
                                channels amounting to no more than the  
                                specified bandwidth  
              examples: solint=’1min’; solint=’60s’, solint=60 --> 1 minute  
                        solint=’0s’; solint=0; solint=’int’ --> per integration  
                        solint=’-1s’; solint=’inf’ --> ~infinite, up to boundaries  
                        enforced by combine  
                        solint=’inf,8Mhz’ --> ~infinite in time, with  
                                                  8MHz pre-average in freq  
                        solint=’int,32ch’ --> per-integration in time,  
                                                  with 32-channel pre-average  
                                                  in freq  
       combine -- Data axes to combine for solving  
              default: ’scan’ --> solutions will break at obs, field, and spw  
                      boundaries but may extend over multiple scans  
                      (per obs, field and spw) up to solint.  
              Options: ’’,’obs’,’scan’,’spw’,field’, or any comma-separated  
                       combination in a single string  
              example: combine=’scan,spw’  --> extend solutions over scan boundaries  
                       (up to the solint), and combine spws for solving  
       refant -- Reference antenna name(s); a prioritized list may be specified  
               default: ’’ (no reference antenna)  
                example: refant=’13’ (antenna with index 13)  
                         refant=’VA04’ (VLA antenna #4)  
                         refant=’EA02,EA23,EA13’ (EVLA antenna EA02, use  
                                EA23 and EA13 as alternates if/when EA02  
                                drops out)  
               Use ’go listobs’ for antenna listing  
       minblperant -- Minimum number of baselines required per antenna for each solve  
                    Antennas with fewer baaselines are excluded from solutions. Amplitude  
                    solutions with fewer than 4 baselines, and phase solutions with fewer  
                    than 3 baselines are only trivially constrained, and are no better  
                    than baseline-based solutions.  
                    default: 4  
                    example: minblperant=10  => Antennas participating on 10 or more  
                             baselines are included in the solve  
       minsnr -- Reject solutions below this SNR (only applies for bandtype = B)  
               default: 3.0  
       solnorm -- Normalize bandpass amplitudes and phase for each  
               spw, pol, ant, and timestamp  
               default: False (no normalization)  
       bandtype -- Type of bandpass solution (B or BPOLY)  
               default: ’B’; example: bandtype=’BPOLY’  
               ’B’ does a channel by channel solution for each  
                   specified spw.  
               ’BPOLY’ is somewhat experimental. It will fit an  
                   nth order polynomial for the amplitude and phase  
                   as a function of frequency. Only one fit is made  
                   for all specified spw, and edge channels should be  
                   omitted.  
                Use taskname=plotcal in order to compare the results from  
                   B and BPOLY.  
       fillgaps -- Fill flagged solution channels by interpolation  
               default: 0 (don’t interpolate)  
               example: fillgaps=3 (interpolate gaps 3 channels wide and narrower)  
       degamp -- Polynomial degree for BPOLY amplitude solution  
               default: 3; example: degamp=2  
       degphase -- Polynomial degree for BPOLY phase solution  
               default: 3; example: degphase=2  
       visnorm -- Normalize data prior to BPOLY solution  
               default: False; example: visnorm=True  
       maskcenter -- Number of channels to avoid in center of each band  
               default: 0; example: maskcenter=5 (BPOLY only)  
       maskedge -- Fraction of channels to avoid at each band edge (in %)  
               default: 5; example: maskedge=3 (BPOLY only)  
       append -- Append solutions to the (existing) table.  Appended solutions  
                  must be derived from the same MS as the existing  
                  caltable, and solution spws must have the same  
                  meta-info (according to spw selection and solint)  
                  or be non-overlapping.  
               default: False; overwrite existing table or make new table  
 
      --- Other calibrations to apply on the fly before determining bandpass solution  
 
      docallib -- Control means of specifying the caltables:  
               default: False ==> Use gaintable,gainfield,interp,spwmap,calwt  
                        If True, specify a file containing cal library in callib  
      callib -- If docallib=True, specify a file containing cal  
                  library directives  
 
      gaintable -- Gain calibration table(s) to apply  
               default: ’’ (none);  
               examples: gaintable=’ngc5921.gcal’  
                         gaintable=[’ngc5921.ampcal’,’ngc5921.phcal’]  
      gainfield -- Select a subset of calibrators from gaintable(s)  
               default:’’ ==> all sources in table;  
               ’nearest’ ==> nearest (on sky) available field in table  
               otherwise, same syntax as field  
               example: gainfield=’0~3’  
                        gainfield=[’0~3’,’4~6’]  
      interp -- Interpolation type (in time[,freq]) to use for each gaintable.  
                When frequency interpolation is relevant (B, Df, Xf),  
                separate time-dependent and freq-dependent interp  
                types with a comma (freq _after_ the comma).  
                Specifications for frequency are ignored when the  
                calibration table has no channel-dependence.  
                Time-dependent interp options ending in ’PD’ enable a  
                "phase delay" correction per spw for non-channel-dependent  
                calibration types.  
                For multi-obsId datasets, ’perobs’ can be appended to  
                the time-dependent interpolation specification to  
                enforce obsId boundaries when interpolating in time.  
                default: ’’ --> ’linear,linear’ for all gaintable(s)  
                example: interp=’nearest’   (in time, freq-dep will be  
                                             linear, if relevant)  
                         interp=’linear,cubic’  (linear in time, cubic  
                                                 in freq)  
                         interp=’linearperobs,spline’ (linear in time  
                                                       per obsId,  
                                                       spline in freq)  
                         interp=’,spline’  (spline in freq; linear in  
                                            time by default)  
                         interp=[’nearest,spline’,’linear’]  (for multiple gaintables)  
                Options: Time: ’nearest’, ’linear’  
                         Freq: ’nearest’, ’linear’, ’cubic’, ’spline’  
      spwmap -- Spectral windows combinations to form for gaintable(s)  
                default: [] (apply solutions from each spw to that spw only)  
                Example:  spwmap=[0,0,1,1] means apply the caltable solutions  
                          from spw = 0 to the spw 0,1 and spw 1 to spw 2,3.  
                          spwmap=[[0,0,1,1],[0,1,0,1]]  
      parang -- If True, apply the parallactic angle correction (required  
               for polarization calibration)  
               default: False  
 


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