IRAS16293 Band9 - Calibration for CASA 3.3: Difference between revisions

From CASA Guides
Jump to navigationJump to search
No edit summary
No edit summary
Line 309: Line 309:
In Figure 1 you will see the corresponding plot for the first dataset (X39b) showing antenna 0 (DA41).
In Figure 1 you will see the corresponding plot for the first dataset (X39b) showing antenna 0 (DA41).


[[File:uid___A002_X3d55cb_X90c.mstsys.DA41.spw0.png|200px|thumb|right|'''Fig. 1.''' Example for the output of the commands that plots the tsys spws. Find a description in the text.]]
[[File:uid___A002_X3d55cb_X90c.mstsys.DA41.spw0.png|300px|thumb|right|'''Fig. 1.''' Example for the output of the commands that plots the tsys spws. Find a description in the text.]]





Revision as of 17:13, 21 May 2012


  • This portion of the guide covers calibration of the raw visibility data. To skip to the imaging portion of the guide, see: IRAS16293_Band9_-_Imaging.

Overview

This part of the casa guide will guide you through the basic inspection of the data, paying special attention to detect data that needs to be flagged. The guide goes later to the process of full calibration to split the data at the end.

The general procedure in this guide follows the other ALMA CASA guides: NGC3256Band3 and AntennaeBand7.

Unpack the Data

Once you have downloaded the IRAS16293_Band9_UnCalibratedMSandTablesForReduction.tgz, unpack the file in a terminal outside CASA using

tar -xvzf IRAS16293_Band9_UnCalibratedMSandTablesForReduction.tgz

cd IRAS16293_Band9_UnCalibratedMSandTablesForReduction

You have a number of files with extensions ".ms", which are CASA measurement set (MS) files. You will also see files containing system temperature (Tsys), water vapor radiometer (WVR), and antenna position information.

To start CASA type

casapy

Be sure that you are using the right version indicated for this guide.

Initial Inspection

The first step we will do through all the calibration process is to define an array with the uid's that corresponds to the datasets names. This will allow to make the calibration of the four datasets one after another, using an for-loop inside python. We will then calibrate the data individually and concatenate them at the end, before proceeding with the imaging part.

Note that if you exit CASA and want to continue with the calibration using these arrays, you will have to re-issue the command again to make it available for the current CASA execution.

To start, and give an example of this process, we will create txt format files for the output of the listobs task, which will give us useful information about the observations.


# In CASA

rawdata=['uid___A002_X3d4118_X39b.ms','uid___A002_X3d55cb_X575.ms',
         'uid___A002_X3d55cb_Xb50.ms','uid___A002_X3d55cb_X90c.ms']

# We create the text files for listobs for each dataset

for data in rawdata:
  listobs(vis=data,listfile=data+'.listobs')

Note that after cutting and pasting a for-loop you often have to press return several times to make the command executes. The output will be sent to the CASA logger. Next there is an example of a useful part of the output that the first listobs of the previews command produces.

Fields: 11
  ID   Code Name                RA              Decl          Epoch   SrcId nVis   
  0    none 1924-292            19:24:51.05600 -29.14.30.1280 J2000   0     169125 
  1    none nrao530 ph          17:33:02.72400 -13.04.49.4860 J2000   1     289170 
  2    none Juno                16:25:31.63031 -05.49.08.9209 J2000   2     82890  
  3    none 1625-254            16:25:46.98000 -25.27.38.3300 J2000   3     276480 
  4    none IRAS16293-2422-a    16:32:22.99200 -24.28.36.0000 J2000   4     132450 
  5    none IRAS16293-2422-a    16:32:22.47925 -24.28.36.0000 J2000   4     99915  
  6    none IRAS16293-2422-a    16:32:22.73563 -24.28.36.0000 J2000   4     99960  
  7    none IRAS16293-2422-a    16:32:22.73563 -24.28.32.5000 J2000   4     99915  
  8    none IRAS16293-2422-a    16:32:22.47925 -24.28.29.0000 J2000   4     99945  
  9    none IRAS16293-2422-a    16:32:22.73563 -24.28.29.0000 J2000   4     99945  
  10   none IRAS16293-2422-a    16:32:22.99200 -24.28.29.0000 J2000   4     99915  
   (nVis = Total number of time/baseline visibilities per field) 
Spectral Windows:  (25 unique spectral windows and 2 unique polarization setups)
  SpwID  #Chans Frame Ch1(MHz)    ChanWid(kHz)  TotBW(kHz)  Corrs  
  0           4 TOPO  184550      1500000       7500000     I   
  1         128 TOPO  231257.813  15625         2000000     XX  YY  
  2           1 TOPO  232234.375  1796875       1796875     XX  YY  
  3         128 TOPO  229257.813  15625         2000000     XX  YY  
  4           1 TOPO  230234.375  1796875       1796875     XX  YY  
  5         128 TOPO  217242.188  15625         2000000     XX  YY  
  6           1 TOPO  216234.375  1796875       1796875     XX  YY  
  7         128 TOPO  215242.188  15625         2000000     XX  YY  
  8           1 TOPO  214234.375  1796875       1796875     XX  YY  
  9         128 TOPO  703257.813  15625         2000000     XX  YY  
  10          1 TOPO  704234.375  1796875       1796875     XX  YY  
  11        128 TOPO  692492.188  15625         2000000     XX  YY  
  12          1 TOPO  691484.375  1796875       1796875     XX  YY  
  13        128 TOPO  690492.188  15625         2000000     XX  YY  
  14          1 TOPO  689484.375  1796875       1796875     XX  YY  
  15        128 TOPO  688492.188  15625         2000000     XX  YY  
  16          1 TOPO  687484.375  1796875       1796875     XX  YY  
  17       3840 TOPO  703312.744  488.28125     1875000     XX  YY  
  18          1 TOPO  704249.756  1875000       1875000     XX  YY  
  19       3840 TOPO  692237.256  488.28125     1875000     XX  YY  
  20          1 TOPO  691299.756  1875000       1875000     XX  YY  
  21       3840 TOPO  690437.256  488.28125     1875000     XX  YY  
  22          1 TOPO  689499.756  1875000       1875000     XX  YY  
  23       3840 TOPO  688437.256  488.28125     1875000     XX  YY  
  24          1 TOPO  687499.756  1875000       1875000     XX  YY  
Sources: 176
  ID   Name                SpwId RestFreq(MHz)  SysVel(km/s) 
  0    1924-292            0     -              -            
  0    1924-292            25    -              -            
  0    1924-292            26    -              -            
  0    1924-292            27    -              -            
  0    1924-292            28    -              -            
  0    1924-292            29    -              -            
  0    1924-292            30    -              -            
  0    1924-292            31    -              -            
  0    1924-292            32    -              -            
  0    1924-292            33    -              -            
  0    1924-292            34    -              -            
  0    1924-292            35    -              -            
  0    1924-292            36    -              -            
  0    1924-292            37    -              -            
  0    1924-292            38    -              -            
  0    1924-292            39    -              -            
  0    1924-292            1     -              -            
  0    1924-292            2     -              -            
  0    1924-292            3     -              -            
  0    1924-292            4     -              -            
  0    1924-292            5     -              -            
  0    1924-292            6     -              -            
  0    1924-292            7     -              -            
  0    1924-292            8     -              -            
  0    1924-292            9     -              -            
  0    1924-292            10    -              -            
  0    1924-292            11    -              -            
  0    1924-292            12    -              -            
  0    1924-292            13    -              -            
  0    1924-292            14    -              -            
  0    1924-292            15    -              -            
  0    1924-292            16    -              -            
  0    1924-292            17    -              -            
  0    1924-292            18    -              -            
  0    1924-292            19    -              -            
  0    1924-292            20    -              -            
  0    1924-292            21    -              -            
  0    1924-292            22    -              -            
  0    1924-292            23    -              -            
  0    1924-292            24    -              -            
  1    nrao530 ph          0     -              -            
  1    nrao530 ph          25    -              -            
  1    nrao530 ph          26    -              -            
  1    nrao530 ph          27    -              -            
  1    nrao530 ph          28    -              -            
  1    nrao530 ph          29    -              -            
  1    nrao530 ph          30    -              -            
  1    nrao530 ph          31    -              -            
  1    nrao530 ph          32    -              -            
  1    nrao530 ph          33    -              -            
  1    nrao530 ph          34    -              -            
  1    nrao530 ph          35    -              -            
  1    nrao530 ph          36    -              -            
  1    nrao530 ph          37    -              -            
  1    nrao530 ph          38    -              -            
  1    nrao530 ph          39    -              -            
  1    nrao530 ph          1     -              -            
  1    nrao530 ph          2     -              -            
  1    nrao530 ph          3     -              -            
  1    nrao530 ph          4     -              -            
  1    nrao530 ph          5     -              -            
  1    nrao530 ph          6     -              -            
  1    nrao530 ph          7     -              -            
  1    nrao530 ph          8     -              -            
  2    Juno                0     -              -            
  2    Juno                25    -              -            
  2    Juno                26    -              -            
  2    Juno                27    -              -            
  2    Juno                28    -              -            
  2    Juno                29    -              -            
  2    Juno                30    -              -            
  2    Juno                31    -              -            
  2    Juno                32    -              -            
  2    Juno                33    -              -            
  2    Juno                34    -              -            
  2    Juno                35    -              -            
  2    Juno                36    -              -            
  2    Juno                37    -              -            
  2    Juno                38    -              -            
  2    Juno                39    -              -            
  1    Juno                9     -              -            
  1    Juno                10    -              -            
  1    Juno                11    -              -            
  1    Juno                12    -              -            
  1    Juno                13    -              -            
  1    Juno                14    -              -            
  1    Juno                15    -              -            
  1    Juno                16    -              -            
  1    Juno                17    -              -            
  1    Juno                18    -              -            
  1    Juno                19    -              -            
  1    Juno                20    -              -            
  1    Juno                21    -              -            
  1    Juno                22    -              -            
  1    Juno                23    -              -            
  1    Juno                24    -              -            
  3    1625-254            0     -              -            
  3    1625-254            25    -              -            
  3    1625-254            26    -              -            
  3    1625-254            27    -              -            
  3    1625-254            28    -              -            
  3    1625-254            29    -              -            
  3    1625-254            30    -              -            
  3    1625-254            31    -              -            
  3    1625-254            32    -              -            
  3    1625-254            33    -              -            
  3    1625-254            34    -              -            
  3    1625-254            35    -              -            
  3    1625-254            36    -              -            
  3    1625-254            37    -              -            
  3    1625-254            38    -              -            
  3    1625-254            39    -              -            
  2    1625-254            1     -              -            
  2    1625-254            2     -              -            
  2    1625-254            3     -              -            
  2    1625-254            4     -              -            
  2    1625-254            5     -              -            
  2    1625-254            6     -              -            
  2    1625-254            7     -              -            
  2    1625-254            8     -              -            
  2    1625-254            17    -              -            
  2    1625-254            18    -              -            
  2    1625-254            19    -              -            
  2    1625-254            20    -              -            
  2    1625-254            21    -              -            
  2    1625-254            22    -              -            
  2    1625-254            23    -              -            
  2    1625-254            24    -              -            
  2    nrao530 ph          9     -              -            
  2    nrao530 ph          10    -              -            
  2    nrao530 ph          11    -              -            
  2    nrao530 ph          12    -              -            
  2    nrao530 ph          13    -              -            
  2    nrao530 ph          14    -              -            
  2    nrao530 ph          15    -              -            
  2    nrao530 ph          16    -              -            
  3    nrao530 ph          17    -              -            
  3    nrao530 ph          18    -              -            
  3    nrao530 ph          19    -              -            
  3    nrao530 ph          20    -              -            
  3    nrao530 ph          21    -              -            
  3    nrao530 ph          22    -              -            
  3    nrao530 ph          23    -              -            
  3    nrao530 ph          24    -              -            
  4    IRAS16293-2422-a    0     -              -            
  4    IRAS16293-2422-a    25    -              -            
  4    IRAS16293-2422-a    26    -              -            
  4    IRAS16293-2422-a    27    -              -            
  4    IRAS16293-2422-a    28    -              -            
  4    IRAS16293-2422-a    29    -              -            
  4    IRAS16293-2422-a    30    -              -            
  4    IRAS16293-2422-a    31    -              -            
  4    IRAS16293-2422-a    32    -              -            
  4    IRAS16293-2422-a    33    -              -            
  4    IRAS16293-2422-a    34    -              -            
  4    IRAS16293-2422-a    35    -              -            
  4    IRAS16293-2422-a    36    -              -            
  4    IRAS16293-2422-a    37    -              -            
  4    IRAS16293-2422-a    38    -              -            
  4    IRAS16293-2422-a    39    -              -            
  3    IRAS16293-2422-a    9     -              -            
  3    IRAS16293-2422-a    10    -              -            
  3    IRAS16293-2422-a    11    -              -            
  3    IRAS16293-2422-a    12    -              -            
  3    IRAS16293-2422-a    13    -              -            
  3    IRAS16293-2422-a    14    -              -            
  3    IRAS16293-2422-a    15    -              -            
  3    IRAS16293-2422-a    16    -              -            
  4    IRAS16293-2422-a    17    -              -            
  4    IRAS16293-2422-a    18    -              -            
  4    IRAS16293-2422-a    19    -              -            
  4    IRAS16293-2422-a    20    -              -            
  4    IRAS16293-2422-a    21    -              -            
  4    IRAS16293-2422-a    22    -              -            
  4    IRAS16293-2422-a    23    -              -            
  4    IRAS16293-2422-a    24    -              -            
Antennas: 15:
  ID   Name  Station   Diam.    Long.         Lat.         
  0    DA41  A003      12.0 m   -067.45.16.5  -22.53.27.0  
  1    DA43  A075      12.0 m   -067.45.17.9  -22.53.21.4  
  2    DA47  A026      12.0 m   -067.45.18.8  -22.53.28.3  
  3    DV02  A077      12.0 m   -067.45.10.1  -22.53.25.9  
  4    DV03  A137      12.0 m   -067.45.15.2  -22.53.22.7  
  5    DV05  A082      12.0 m   -067.45.08.3  -22.53.29.2  
  6    DV07  A076      12.0 m   -067.45.20.5  -22.53.33.8  
  7    DV09  A046      12.0 m   -067.45.17.0  -22.53.29.3  
  8    DV10  A071      12.0 m   -067.45.19.9  -22.53.23.5  
  9    DV12  A011      12.0 m   -067.45.14.4  -22.53.28.4  
  10   DV13  A072      12.0 m   -067.45.12.6  -22.53.24.0  
  11   DV14  A025      12.0 m   -067.45.18.7  -22.53.27.4  
  12   DV15  A074      12.0 m   -067.45.12.1  -22.53.32.0  
  13   DV17  A138      12.0 m   -067.45.17.1  -22.53.34.4  
  14   DV18  A053      12.0 m   -067.45.17.3  -22.53.31.2  

You can see the ID that is assigned for each source, starting with ID 0. 1924-292 is the calibrator for bandpass, Juno for amplitud (flux), 1625-254 and nrao530 ph are for phase calibration, and the remaining 7 fields of IRAS16293-2422-a are the seven pointings for our mosaic of the target source.

Spectral windows are also marked with numbers from 0 24, with 0 containing WVR information. Spws 17, 19, 21, and 23 contain the sience data (TDM mode). The CO (6-5) line emission is contained in spw 21. Spw 18, 20, 22, and 24 contain channel averages of the data in spectral windows 17, 19, 21, 23, respectively. These spws will not be used for the offline data reduction. All the remaining spw that appear in the section of sources, and that do not appear in the Spectral Windows are related to WVR measurements for each antenna, so you will not need them for the calibration. Spws 9, 11, 13, and 15 are associated with tsys measurements, and we will apply these information to the science spws later.

Visualization and exploration of Tsys and WVR tables

Next we need to check the plotting for tsys and wvr tables to make sure whether they have issues that might affect their application to the data. Whenever we see an odd behavior in the tables we need to flag the corresponding sience data to prevent wrong results in the calibration steps. The next command will plot the tsys in the next way: it will produce many plots, each one of them will show an antenna, with the four spw that tsys covers, for all the targets, and with different colors for different times, so you can trace the behavior for tsys with time, among others. Note that in spw 19 and 21, the overlap with the tsys spw (11 and 13) is not set correctly. This is due to an error in the frequencies for the tsys when the observations were done. You do not have to worry about this, since any issue coming from the error have already been handled. Note, however that the portions of the spectra that do not have tsys information cannot be used. This does not represent a problem, since that part corresponds to the edge of the baseband. Also note that the CO (6-5) line is not affected by this. In Figure 1 you will see the corresponding plot for the first dataset (X39b) showing antenna 0 (DA41).

Fig. 1. Example for the output of the commands that plots the tsys spws. Find a description in the text.


# In CASA
# Plot TDM Tsys tables, and show locations of FDM spws  
os.system('rm -rf Tsysplots')
for vis in rawdata:
  aU.plotbandpass('3.3_apriori_tables/'+vis+'.tsys',ms=vis,
                overlay='time', xaxis='freq', 
                yaxis='amp',subplot=22,interactive=False,
                showatm=True,
                chanrange='5~122',showfdm=True,
                figfile='Tsysplots/'+vis+'tsys.png')