VS02u Results
Submitted checklist.txt and checklist.tex is also available		   [Summary | AIPS | Difmap ]
Analyst: William Scott
Date Prepared: 27-03-2000
 

Summary
 
Observation code : VS02u    AIPS Version : 15Apr99   
Date of Observation : 1999/95    Difmap Version : 2.3c 
Source Name : J1617-77    vsop_difmap used : Yes 
Calibration Source(s) :          
Ground telescopes : AT, Mp, Ho  Model Fitted to data : Yes 
Tracking Station(s) : GZ, TZ    Image made : Yes 
Correlator : Penticton         

 
Abstract
Data extraction from experiment W030k.
Model
Flux (Jy)
Radius (mas)
Theta (deg)
Major (mas)
Axial ratio
Phi (deg)
TB (10^12 K)
2.46485 0.299638 -79.0817 1.07218 0.445500 -68.8596 0.2349
0.311653 0.190362 101.289 0 0 0 0.0000
(*) Quoted Brightness temperatures assume Gaussian components and are in the local (z=0) frame.


AIPS Data Reduction Notes
 
Task
Adverbs
CL
in
SN
in
CL
out
SN
out
Comments
FITLD DIGICOR=DELCOR=-1
 
 
 
 
 Output file name = VS02U.FITLD 
MSORT
 
 
 
 
 Input file name = VS02U.FITLD, Output file name = VS02U.UVSRT 
INDXR
 
 
 
 
 Created NX(1) 
ANTAB
 
 
 
 
 Used Tsys values of 92,96K for Halca. For the AT, used nominal values (as far as I could tell, all 6 telescopes observed). For Ho, assumed that the "tsys"'s in the tsys file were actually SEFDs. For Mp, used a Tsys value of 46K, extrapolated from the Tsys at 095:20. Output sent to TY(1) and GC(1). 
APCAL
 
1 
 
 
 Input: Ty(1) + GC(1) 
CLCAL OPCODE = CALP
INTERPOL = 'AMBG'
REFANT 1 (AT)
1 
1 
2 
 
  
TBOUT INEXT = 'AN'
 
 
 
 
  
TBIN
 
 
 
 
 Changed MNTSTA entries in the AN table. Changed Halca from 3 to 2, changed Hobart from 2 to 0, and change Hart from 1 to 0 (although the latter change is irrelevant, since there was no Hart data). 
TBIN
 
 
 
2 
 Read in DQA1 delay and rate solutions. 
SNEDT
 
2 
 
3 
 Edited out a bad rate solution for MP. 
CLCAL OPCODE = CALP
INTERPOL = 'AMBG'
REFANT 1 (AT)
2 
3 
3 
 
  
FRING DOCALIB 1
GAINUSE 3
REFANT 1 (AT)
SEARCH 4,5
SOLINT 5
APARM(1)=2
APARM(7)=2 (SNR=2)
APARM(9)=1
DPARM(1)=3 (include baseline
   stacking)
DPARM(2)=100 (100ns delay
   window!)
DPARM(3)=50 (50mHz rate
   window)
DPARM(4)=0.5 (0.5 sec integration
   time)
DPARM(6)=1 (don't average
   in frequency)
BCHAN 0, ECHAN 0
TIMER 0 5 0 0 0 6 0 0, then
TIMER 0 13 0 0 to o 13 30 0
3 
 
 
4 
 Got good solutions for all antennas. Can reduce the delay and rate windows considerably. 
FRING as above, except:
DPARM(2)=30 (30ns delay
   window!)
DPARM(3)=10 (10mHz rate
   window)
TIMER 0
3 
 
 
5 
 Solutions looked great. 
SNEDT
 
5 
 
6 
  
CLCAL OPCODE='CALP'
INTERPOL = 'AMBG'
SMOTYPE = ''
REFANT 1
3 
6 
4 
 
  
TACOP
4 
 
5 
 
  
CLCOR OPCODE = 'GAIN'
ANTENNAS = 1 (AT)
CLCORPRM = 1.23
5 
 
5 
 
 AT-Ho and Mp-Ho baselines have virtually identical UV tracks. However AT baselines have a lower amplitude. Multiply AT baseline by (1.6/1.3)=1.23 to bring them up. Note... AT-Halca baselines also seemed lowish. Also, of the three baselines Mo-Ho, AT-Ho, and AT-Mo, both AT baselines had a similar amplitude (lower), so I am assuming it is the AT that needs the correction. 
CLCOR OPCODE = 'GAIN'
ANTENNAS = 0
CLCORPRM = 1.32
5 
 
5 
 
 From AT light curves, J1617-77 has a fairly constant, slowly decreasing flux. Extrapolated total flux to obs. date was approximately 2.8Jy. Need to multiply antennas by (2.8/1.6)**0.5=1.32 to bring up the zero spacing flux to the proper level. Since all three Aus GRT will need this correction, assume whatever is causing this discrepancy is affecting Halca as well. 
SPLIT SOURCES 'J1617-77'
BCHAN 0, ECHAN 0
DOCALIB 1
GAINUSE 4
APARM(1)=2 (average each
   IF separately)
APARM(2)=0.5
APARM(4)=1
5 
 
 
 
 Input file: VS02U.UVSRT, Output files: J1617-77.FITS 
FITTP
 
 
 
 
 Input files: J1617-77.FITS Output files: J1617-77.FITS amplitude 

AIPS Input Files
ANTAB.TXT
INDXR.TXT		 Comments
- None -

AIPS Output Files
DTSUM_0.LIS
DTSUM_1.LIS
LISTR.LIS
PRTAN.LIS
POSSM01_AP_1.PS
POSSM02_AP_1.PS
POSSM03_AP_1.PS
SN_APCAL_AMP_1.PS
SN_APCAL_AMP_2.PS
SN_CALIB_DEL_1.PS		 SN_CALIB_DEL_2.PS
SN_CALIB_PHA_1.PS
SN_CALIB_PHA_2.PS
SN_CALIB_RAT_1.PS
UVPLT_UV.PS
SN_CALIB_RAT_2.PS
SN_CALIB_SNR_1.PS
SN_CALIB_SNR_2.PS
SN_FRING01_DEL_1.PS
SN_FRING01_DEL_2.PS		 SN_FRING01_RAT_1.PS
SN_FRING01_RAT_2.PS
SN_FRING01_SNR_1.PS
SN_FRING01_SNR_2.PS
UVPLT_UVD.PS
UVPLT_UVPA.PS
VPLOT_AP_1.PS
VPLOT_AP_2.PS
WEIGHTS.PS


Difmap Data Reduction Notes
Phase selfcal applied? Yes
Global amplitude selfcal (gscal) applied? No
Amplitude selfcal on non-global timescales used? No
Modelfit made and saved? Yes
Image Made and saved? Yes
Comments on Difmap processing
Because of the sparce UV coverage, it was very difficult to build a believable model with clean components. Instead, I model fit the data (with a point source + elliptical Gaussian), then used this as "my clean components", then ran a phase self-cal with a 10 minute solution interval. Predictably, the phase-self cal didn't do to much. A model fit to the "post-self-cal" data was made, and this new model was very similar to the initial model (again predictably). As a test I ran gscale, and all the amplitudes gain corrections were less than 5 percent (although I never used these corrections).

Image
Ampl, Phase vs (u,v) Distance
PS (54 kb)
GIF (7 kb)
 Ampl, Phase vs Time
PS (161 kb)
GIF 1, 2		 (u,v) Coverage
PS (28 kb)
GIF (4 kb)
Closure Phase vs Time
PS (120 kb)
GIF 1		 Clean Image
PS (38 kb)
GIF (53 kb)
Modelfit
Ampl, Phase vs (u,v) Distance
PS (54 kb)
GIF (7 kb)
 Ampl, Phase vs Time
PS (161 kb)
GIF 1, 2		 (u,v) Coverage
PS (28 kb)
GIF (4 kb)
Closure Phase vs Time
PS (120 kb)
GIF 1		 Image with model components
PS (39 kb)
GIF (7 kb)

More details on the Images and Modelfits are found in this page.

Model
Flux (Jy)
Radius (mas)
Theta (deg)
Major (mas)
Axial ratio
Phi (deg)
TB (10^12 K)
2.46485 0.299638 -79.0817 1.07218 0.445500 -68.8596 0.2349
0.311653 0.190362 101.289 0 0 0 0.0000
(*) Quoted Brightness temperatures assume Gaussian components and are in the local (z=0) frame.


Last updated on Sun Aug 20 00:44:41 GMT 2000
by db_results.pl version 0.2.0.