[daip] New Ticket - [!JUM-709073]: HI Imaging with Multiple Spectral Windows in AIPS

Tue May 22 15:18:51 EDT 2012

New Ticket: HI Imaging with Multiple Spectral Windows in AIPS

Hello,

A student of mine is working on EVLA HI imaging of a nearby galaxy group (project 12A-074).  The data contain 16 spectral windows, each 1 MHz wide, all of which overlap by 50% (see frequency table information below).   The raw data set is about 26 GB in size, and each execution of SPFLG is taking multiple hours to load; we thus have used UVCOP to copy out each spectral window for data processing.  My specific questions are as follows.

1.  How can we put these 16 spectral window UV databases back together?  I have tried UVGLU but the number of visibilities in the resulting dataset does not seem to equal the sum of the inputs.  

2.  Assuming that I am left with one calibrated UV database that contains all 16 spectral windows (either by leaving the dataset intact and calibrating all 16 windows simultaneously, or by somehow putting all of the smaller spectral window databases back together again), are there any special IMAGR inputs required to correctly handle the gridding of datapoints from these overlapping spectral windows?   

Thank you,
John

  ID Source           Qual  Calcode RA(2000.0)     Dec(2000.0)  No. vis

   1 J0842+1835      : 0000   D     08:42:05.0942  18:35:40.991  115479

   2 R1/UGC 4685     : 0000         08:57:01.0000  13:11:57.000  593892

   3 1331+305=3C286  : 0000   K     13:31:08.2880  30:30:32.959   34749

  ID Source            Freq(GHz) Velocity(Km/s) Rest freq (GHz)

   1 All Sources          1.3977         0.0000          0.0000

     IF(  2)              1.3987         0.0000          0.0000

     IF(  3)              1.3997         0.0000          0.0000

     IF(  4)              1.4007         0.0000          0.0000

     IF(  5)              1.4017         0.0000          0.0000

     IF(  6)              1.4027         0.0000          0.0000

     IF(  7)              1.4037         0.0000          0.0000

     IF(  8)              1.4047         0.0000          0.0000

     IF(  9)              1.3972         0.0000          0.0000

     IF( 10)              1.3982         0.0000          0.0000

     IF( 11)              1.3992         0.0000          0.0000

     IF( 12)              1.4002         0.0000          0.0000

     IF( 13)              1.4012         0.0000          0.0000

     IF( 14)              1.4022         0.0000          0.0000

     IF( 15)              1.4032         0.0000          0.0000

     IF( 16)              1.4042         0.0000          0.0000

Frequency Table summary

FQID IF#      Freq(GHz)      BW(kHz)   Ch.Sep(kHz)  Sideband

   1   1       1.39769620    1000.0001      7.8125      1

       2       1.39869620    1000.0001      7.8125      1

       3       1.39969620    1000.0001      7.8125      1

       4       1.40069620    1000.0001      7.8125      1

       5       1.40169620    1000.0001      7.8125      1

       6       1.40269620    1000.0001      7.8125      1

       7       1.40369620    1000.0001      7.8125      1

       8       1.40469620    1000.0001      7.8125      1

       9       1.39719620    1000.0001      7.8125      1

      10       1.39819620    1000.0001      7.8125      1

      11       1.39919620    1000.0001      7.8125      1

      12       1.40019620    1000.0001      7.8125      1

      13       1.40119620    1000.0001      7.8125      1

      14       1.40219620    1000.0001      7.8125      1

      15       1.40319620    1000.0001      7.8125      1

      16       1.40419620    1000.0001      7.8125      1

Ticket Details
===================
Ticket ID: JUM-709073
Department: AIPS Data Processing
Priority: Default
Status: Open
Link:  https://help.nrao.edu/staff/index.php?_m=tickets&_a=viewticket&ticketid=1799