Difference between revisions of "EVLA 6cmWideband Tutorial SN2010FZ"

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== Overview ==
+
#REDIRECT [[EVLA 6cmWideband Tutorial SN2010FZ-CASA4.4]]
This article describes the calibration and imaging of a single-pointing 6cm EVLA wideband continuum dataset on the galaxy NGC2967 (UGC5180) which was the location of the supernova candidate SN2010FZ.  No supernova was detected in this observation, but the galactic continuum emission from this face-on spiral is adequately imaged. The data were taken in RSRO mode, with 1024 MHz of bandwidth in each of two widely spaced basebands (comprised each of 8 128 MHz spectral windows), spanning 4.5 to 7.5 GHz.  We will use wideband imaging techniques in this tutorial.
 
 
 
This is a more advanced tutorial, and if you are a relative novice (and <em>particularly</em> for EVLA continuum calibration and imaging), it is <em>strongly</em> recommended that you start with the [[EVLA Continuum Tutorial 3C391]] before tackling this dataset.  We will not include basic information on CASA processing in this tutorial.
 
 
 
== CASA Versions ==
 
 
 
This tutorial was written for the CASA Version 3.2.1 (release r15198 26 May 2011).
 
 
 
== Obtaining the Data ==
 
 
 
The scheduling block (SB) processed appears in the EVLA archive under program AS1015 as
 
<tt>AS1015_sb1658169_1.55388.89474846065</tt>
 
and was run on 2010-07-11 from 21:28 to 22:28 UT (size 37.74GB).
 
 
 
For the purposes of this tutorial, we have provided the raw SDM data (as would be extracted from the archive) as well as measurement sets created by filling the data (with the {{importevla}} task) and upon time-averaging to 10s (after application of the online flags). 
 
 
 
To start your tutorial, depending on which dataset you start with, proceed to:
 
* <em>To start with the raw SDM data:</em> Start with the section below titled "Importing your EVLA data from SDM". This is where you would start if you were reducing data from the archive.
 
* <em>To start with the raw filled MS:</em> Start with the section below titled "Application of Online Flags and Averaging your MS".
 
* <em>To start with the flagged and averaged MS:</em> Start with the section below titled "Examining and Flagging your Averaged MS".
 
 
 
== Importing your EVLA data from SDM ==
 
 
 
For the purposes of this tutorial, we assume that the SDM is resident on disk, in this case at the location:
 
<pre>/lustre/smyers/AS1015/AS1015_sb1658169_1.55388.89474846065</pre> 
 
Use the actual location of your data when you carry out the commands.
 
 
 
The {{listsdm}} task will print out a summary of the scans, fields, spectral windows, and antennas present in your SDM.
 
 
 
<source lang="python">
 
# In CASA
 
listsdm('/lustre/smyers/AS1015/AS1015_sb1658169_1.55388.89474846065')
 
</source>
 
 
 
In the logger you should see:
 
<pre>
 
================================================================================
 
  SDM File: /lustre/smyers/AS1015/AS1015_sb1658169_1.55388.89474846065
 
================================================================================
 
  Observer: Dr. Alicia M. Soderberg
 
  Facility: EVLA, D-configuration
 
      Observed from 2010/07/11/21:28:28.41 to 2010/07/11/22:28:17.73 (UTC)
 
      Total integration time = 3589.32 seconds (1.00 hours)
 
 
Scan listing:
 
  Timerange (UTC)          Scan FldID  FieldName      SpwIDs        Intent(s)
 
  21:28:28.41 - 21:29:27.40    1    0  J0925+0019      [0, 1]  CALIBRATE_PHASE
 
  21:29:27.40 - 21:30:57.16    2    0  J0925+0019      [0, 1]  CALIBRATE_PHASE
 
  21:30:57.16 - 21:32:26.91    3    0  J0925+0019      [0, 1]  CALIBRATE_PHASE
 
  21:32:26.91 - 21:33:56.67    4    0  J0925+0019      [0, 1]  CALIBRATE_PHASE
 
  21:33:56.67 - 21:34:56.50    5    0  J0925+0019      [0, 1]  CALIBRATE_PHASE
 
  21:34:56.50 - 21:35:56.34    6    0  J0925+0019      [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_PHASE
 
  21:35:56.34 - 21:37:26.09    7    0  J0925+0019      [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_PHASE
 
  21:37:26.09 - 21:38:25.93    8    0  J0925+0019      [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_PHASE
 
  21:38:25.93 - 21:39:55.68    9    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:39:55.68 - 21:41:25.44  10    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:41:25.44 - 21:42:55.19  11    1  SN2010FZ       [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:42:55.19 - 21:44:24.94  12    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17] OBSERVE_TARGET
 
  21:44:24.94 - 21:45:54.70  13    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17] OBSERVE_TARGET
 
  21:45:54.70 - 21:47:24.45  14    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:47:24.45 - 21:47:54.37  15    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:47:54.37 - 21:49:24.12  16    0  J0925+0019      [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_PHASE
 
  21:49:24.12 - 21:50:53.88  17    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:50:53.88 - 21:52:23.63  18    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:52:23.63 - 21:53:53.39  19    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:53:53.39 - 21:55:23.14  20    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:55:23.14 - 21:56:52.89  21    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:56:52.89 - 21:58:22.65  22    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:58:22.65 - 21:58:52.57  23    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  21:58:52.57 - 22:00:22.32  24    0  J0925+0019      [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_PHASE
 
  22:00:22.32 - 22:01:52.07  25    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:01:52.07 - 22:03:21.83  26    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:03:21.83 - 22:04:51.58  27    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:04:51.58 - 22:06:21.34  28    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:06:21.34 - 22:07:51.09  29    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:07:51.09 - 22:09:20.85  30    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:09:20.85 - 22:09:50.76  31    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:09:50.76 - 22:11:20.52  32    0  J0925+0019      [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_PHASE
 
  22:11:20.52 - 22:12:50.27  33    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:12:50.27 - 22:14:20.02  34    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:14:20.02 - 22:15:49.78  35    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:15:49.78 - 22:17:19.53  36    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:17:19.53 - 22:18:49.29  37    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:18:49.29 - 22:20:19.04  38    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:20:19.04 - 22:20:48.96  39    1  SN2010FZ        [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  OBSERVE_TARGET
 
  22:20:48.96 - 22:22:18.71  40    0  J0925+0019      [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_PHASE
 
  22:22:18.71 - 22:23:48.47  41    2  3C286          [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_BANDPASS CALIBRATE_AMPLI
 
  22:23:48.47 - 22:25:18.22  42    2  3C286          [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_BANDPASS CALIBRATE_AMPLI
 
  22:25:18.22 - 22:26:47.98  43    2  3C286          [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_BANDPASS CALIBRATE_AMPLI
 
  22:26:47.98 - 22:28:17.73  44    2  3C286          [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  CALIBRATE_BANDPASS CALIBRATE_AMPLI
 
 
Spectral window information:
 
  SpwID  #Chans  Ch0(MHz)  ChWidth(kHz) TotBW(MHz)  Baseband
 
  0      64      7686.0    2000.0      128.0      BB_4   
 
  1      64      7836.0    2000.0      128.0      BB_8   
 
  2      64      4488.0    2000.0      128.0      BB_4   
 
  3      64      4616.0    2000.0      128.0      BB_4   
 
  4      64      4744.0    2000.0      128.0      BB_4   
 
  5      64      4872.0    2000.0      128.0      BB_4   
 
  6      64      5000.0    2000.0      128.0      BB_4   
 
  7      64      5128.0    2000.0      128.0      BB_4   
 
  8      64      5256.0    2000.0      128.0      BB_4   
 
  9      64      5384.0    2000.0      128.0      BB_4   
 
  10    64      6488.0    2000.0      128.0      BB_8   
 
  11    64      6616.0    2000.0      128.0      BB_8   
 
  12    64      6744.0    2000.0      128.0      BB_8   
 
  13    64      6872.0    2000.0      128.0      BB_8   
 
  14    64      7000.0    2000.0      128.0      BB_8   
 
  15    64      7128.0    2000.0      128.0      BB_8   
 
  16    64      7256.0    2000.0      128.0      BB_8   
 
  17    64      7384.0    2000.0      128.0      BB_8   
 
 
Field information:
 
  FldID  Code  Name            RA            Dec            SrcID
 
  0      D      J0925+0019      09:25:07.82  +000.19.13.933  0   
 
  1      NONE  SN2010FZ        09:42:04.77  +000.19.51.000  1   
 
  2      K      3C286            13:31:08.29  +030.30.32.959  2   
 
 
Antennas (27):
 
  ID    Name  Station  Diam.(m)  Lat.          Long.
 
  0    ea01  W09      25.0      +000.00.00.0  +000.00.00.0
 
  1    ea02  E02      25.0      +033.53.51.0  -107.37.25.2
 
  2    ea03  E09      25.0      +033.54.01.1  -107.37.04.4
 
  3    ea04  W01      25.0      +033.53.53.6  -107.36.45.1
 
  4    ea05  W08      25.0      +033.54.00.5  -107.37.05.9
 
  5    ea06  N06      25.0      +033.53.53.0  -107.37.21.6
 
  6    ea08  N01      25.0      +033.54.10.3  -107.37.06.9
 
  7    ea09  E06      25.0      +033.54.01.8  -107.37.06.0
 
  8    ea10  N03      25.0      +033.53.57.7  -107.36.55.6
 
  9    ea11  E04      25.0      +033.54.04.8  -107.37.06.3
 
  10    ea12  E08      25.0      +033.53.59.7  -107.37.00.8
 
  11    ea13  N07      25.0      +033.53.55.1  -107.36.48.9
 
  12    ea14  E05      25.0      +033.54.12.9  -107.37.07.2
 
  13    ea15  W06      25.0      +033.53.58.8  -107.36.58.4
 
  14    ea16  W02      25.0      +033.53.56.4  -107.37.15.6
 
  15    ea17  W07      25.0      +033.54.00.9  -107.37.07.5
 
  16    ea18  N09      25.0      +033.53.54.8  -107.37.18.4
 
  17    ea19  W04      25.0      +033.54.19.0  -107.37.07.8
 
  18    ea20  N05      25.0      +033.53.59.1  -107.37.10.8
 
  19    ea21  E01      25.0      +033.54.08.0  -107.37.06.7
 
  20    ea22  N04      25.0      +033.53.59.2  -107.37.05.7
 
  21    ea23  E07      25.0      +033.54.06.1  -107.37.06.5
 
  22    ea24  W05      25.0      +033.53.56.5  -107.36.52.4
 
  23    ea25  N02      25.0      +033.53.57.8  -107.37.13.0
 
  24    ea26  W03      25.0      +033.54.03.5  -107.37.06.2
 
  25    ea27  E03      25.0      +033.54.00.1  -107.37.08.9
 
  26    ea28  N08      25.0      +033.54.00.5  -107.37.02.8
 
</pre>
 
The C-band data of interest is contained in scans 6-44 and spans spectral windows 2 to 17.
 
 
 
We use the {{importevla}} task to convert the SDM dataset from the archive to a CASA Measurement Set (MS).
 
 
 
<source lang="python">
 
# In CASA
 
importevla(asdm='/lustre/smyers/AS1015/AS1015_sb1658169_1.55388.89474846065', \
 
          vis='SN2010FZ_filled.ms',online=True,flagzero=True, \
 
          shadow=True,applyflags=False,tbuff=1.5,flagbackup=False)
 
</source>
 
 
 
Here we had the task create (but not apply) the online flagging commands, plus flags for zero-clipping and shadowing.  The timeranges for the online flags were extended by 1.5sec (the integration time was 1sec) to account for some timing mismatches present in the EVLA data at this time.  These online flags indicated times where the antennas were not on source (e.g. slewing) or had other detectable faults. The created flagging commands will be stored in the <tt>FLAG_CMD</tt> MS table and can be applied later.  Note that if you set <tt>applyflags=True</tt> here then after filling the task will go ahead and apply the flags for you.
 
 
 
For the purposes of this exercise, in order to save time and disk space, we have turned off the automatic creation of flag column backups by setting <tt>flagbackup=False</tt>.  If we make a mistake and need to recover flags then we will have to rerun all previous commands.  We recommend that for real data processing that you leave the default value <tt>flagbackup=True</tt> in this and subsequent tasks.
 
 
 
You now have a MS called <tt>SN2010FZ_filled.ms</tt> in your working area.  This should be 37GB like the SDM.
 
 
 
== Application of Online Flags and Averaging your MS ==
 
 
 
If you are starting from the filled MS, you can find this at the AOC at:
 
<pre>/lustre/smyers/AS1015/SN2010FZ_filled.ms</pre>
 
Again, use the actual location of this file for your system.
 
 
 
NOTE: the following step will not work in Version 3.2.1 (you will get a blank plot) but should in later versions).
 
You can examine the commands stored in the <tt>FLAG_CMD</tt> table using {{flagcmd}}.
 
<source lang="python">
 
# In CASA
 
flagcmd(vis='SN2010FZ_filled.ms',flagmode='table',optype='plot')
 
</source>
 
This will bring up a <tt>matplotlib</tt> plotter.  You can have it plot to a PNG file instead:
 
<source lang="python">
 
# In CASA
 
flagcmd(vis='SN2010FZ_filled.ms',flagmode='table',optype='plot',outfile='plotSN2010FZ_flagcmd.png')
 
</source>
 
 
 
To apply the flags also use {{flagcmd}}:
 
<source lang="python">
 
# In CASA
 
flagcmd(vis='SN2010FZ_filled.ms',flagmode='table',optype='apply',flagbackup=False)
 
</source>
 
This can take a while for our 37GB dataset.  It took 20min on my workstation.
 
 
 
With the known bad data flagged, we can now split out the data we want and also average down in time to make a smaller MS.
 
For D-configuration (max baselines 1km) we can safely average to 3s or even 10s to reduce dataset size:
 
<source lang="python">
 
# In CASA
 
split(vis='SN2010FZ_filled.ms',outputvis='SN2010FZ_filled10s.ms',datacolumn='data',timebin='10s')
 
</source>
 
This can also take a while for our 37GB dataset.  It took 20min on my workstation.
 
 
 
You now have a MS called <tt>SN2010FZ_filled10s.ms</tt> in your working area.
 
 
 
== Examining and Flagging your Averaged MS ==
 
 
 
If you are starting from the pre-flagged averaged split MS, you can find this at the AOC at:
 
<pre>/lustre/smyers/AS1015/SN2010FZ_filled10s.ms</pre>
 
 
 
We use {{listobs}} to summarize our new MS:
 
<source lang="python">
 
# In CASA
 
listobs('SN2010FZ_filled10s.ms')
 
</source>
 
Scan 6 is a dummy scan so we will use scans 7 to 44 when we process our data.
 
 
 
To plot up the antenna positions in the array:
 
<source lang="python">
 
# In CASA
 
plotants('SN2010FZ_filled10s.ms')
 
</source>
 
 
 
NOTE: if after this point or any other you get table locks, use {{clearstat}} to clear them:
 
<source lang="python">
 
# In CASA
 
clearstat
 
</source>
 
 
 
Now we examine the MS looking for bad data to flag. The useful spw are 2~17. To get an idea of the data layout, plot a single baseline/channel versus time. We will use {{plotms}} - this will bring up an interactive GUI that will display 2-D Y vs.X style line plots:
 
<source lang="python">
 
# In CASA
 
plotms(vis='SN2010FZ_filled10s.ms',field='',spw='2~17:31~31',antenna='ea01&ea02',correlation='RR,LL',xaxis='time',yaxis='amp')
 
</source>
 

Latest revision as of 13:55, 12 November 2015