VS05q Results
Submitted checklist.txt and checklist.tex is also available		   [Summary | AIPS | Difmap ]
Analyst: Jim Lovell
Date Prepared: 27-04-1999
 

Summary
 
Observation code : VS05q    AIPS Version : 15OCT98   
Date of Observation : 1998/20    Difmap Version : 2.3c 
Source Name : J1316-33    vsop_difmap used : Yes 
Calibration Source(s) : 1334-127         
Ground telescopes : Hart, Shanghai, Mopra, Kashima, Usuda  Model Fitted to data : Yes 
Tracking Station(s) : NZ, TZ    Image made : Yes 
Correlator : Penticton         

 
Abstract
Fringes to HALCA were found during only part of the NZ pass (about one hour in total). No fringes in IF-2 at Shanghai and very low amplitudes at Kashima, suggesting a serious problem. Kashima data were eventually flagged. Analysis of the calibrator source showed Shanghai gain to be underestimated. Multiplying Shanghai gains by a factor of ~1.7 resolved this problem. Usuda gains were also found to be low by a factor of ~1.6. An image and modelfit of the survey source was made.

EBF: 07-OCT-2005: Some editing of data

core is 0.3 +/- 0.1
Model
Flux (Jy)
Radius (mas)
Theta (deg)
Major (mas)
Axial ratio
Phi (deg)
TB (10^12 K)
0.538832 0.0325624 10.6460 0.300271 0.500000 82.9470 0.5833
0.826401 0.619350 -106.708 1.42788 0.496003 71.0171 0.0399
(*) 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 douvcomp = 1
 
 
 
 
 Loaded previously calibrated data for re-analysis 
EXTDEST
 
 
 
 
 Removed previous CL, SN, TY, GC, NX tables to return data to an uncalibrated state 
MSORT
 
 
 
 
 Not really necessary, but did it anyway. 
INDXR cparm(3) 0.25
 
 
1 
 
  
UVFLG antennas = 2,0
bif 2; eif 2
opcode 'flag'
reason 'Shanghai IF 2 bad'
 
 
 
 
 Flagged shaghai IF 2 as it is known to contain invalid data. 
POSSM docalib -1
 
 
 
 
 These plots and DQA show Mopra to be best reference antenna 
ANTAB
 
 
 
 
 Gain curve information from VSOP calibration web page. Nominal Tsys used for Kashima, the rest from log files. Limited data available from Mopra and Usuda. 
APCAL
 
 
 
1 
  
CLCAL refant 4
1 
1 
2 
 
 Amplitude calibration solutions applied 
TACOP inext 'cl'
2 
 
3 
 
 copy CL2 to CL3 to protect CL2 in case of a mistake in CLCOR 
CLCOR opcode 'gain'
clcorprm=0.906,0
gainver 3
3 
 
3 
 
 Penticton gain correction 
CLCOR opcode 'sbdl'
antennas = 1,0
clcorprm -480,-480
antennas = 2,0
clcorprm 1480,1480
antennas = 3,0
clcorprm 1845,1845
antennas = 5,0
clcorprm -1700,-1700
antennas = 6,0
clcorprm -1888,-1888
3 
 
3 
 
 Known delay offsets from DQA report applied before fringe-fitting. 
KRING docalib = 1
gainuse = 3
dofit = 0
refant = 0
soltyp 'nols'
search = 6, 4, 1
solmode = 'SBD'
bparm(5) = 0.5
cparm = 0, 0, 2, 1000, 100,
   -1, -1, -1, 0, 0
antwt = 0
solint = 6
prtlev 1
3 
 
 
2 
 fringes found at most times on all baselines except to HALCA on the second tracking pass, despite the projected baselines crossing some ground baselines. 
KRING docalib = 1
gainuse = 3
dofit = 0
refant = 0
soltyp 'nols'
search = 6, 4, 1
solmode = 'SBD'
bparm(5) = 0.5
cparm = 0, 0, 2, 2500, 1000,
   -1, -1, -1, 0, 0
antwt = 0
solint = 12
prtlev 1
timerang 0,23,30,00,1,1,30,00
3 
 
 
3, 4 
 concentrating on second tracking pass. Increased solint to 12min but still no convincing fringes. Return to FRING and 6 min solint with smaller windows for final fringe-fit. 
FRING docalib = 1
gainuse = 3
refant = 4
search = 6, 1
dparm = 3, 200, 100, 0.5
solint = 6
aparm = 0, 0, 0, 0, 0, 1,
   0.1, 0, 1, 0
3 
 
 
5 
 Final fringe-fit. 
TBOUT outfile 'survey:sn5.txt'
docrt = 1000
 
5 
 
 
 Wrote fringe fit SN table out for editing in snedit.pl 
snedit.pl output file SN6.TXT
 
 
 
 
 Used to flag bad solutions. Much easier than SNSMO 
TBIN infile 'survey:sn6.txt'
 
 
 
6 
 Edited SN table read in 
CLCAL refant 4
3 
6 
4 
 
 Amplitude calibration solutions applied 
POSSM
 
 
 
 
 Plot 10min at two times: 0/21:00 to 21:10 and 1/00:20 to 1/00:30. Shows big phase variation near edge of bandpass for Shanghai and smaller variations for Usuda. Chans 30 to 220 OK 
SPLIT aparm = 2, 0.5, 0
chansel 30, 220, 1
flagver 1
docalib 1
4 
 
 
 
  
FITTP
 
 
 
 
 Data written out for analysis in Difmap 
CLCOR opcode 'gain'
antennas 2,0
clcorprm 1.8,0
4 
 
4 
 
 Gain correction for Shanghai after Difmap examination. 
SPLIT aparm = 2, 0.5, 0
chansel 30, 220, 1
flagver 1
docalib 1
4 
 
 
 
  
FITTP
 
 
 
 
 Data written out for analysis in Difmap again 
CLCOR opcode 'gain'
antennas 6,0
clcorprm 1.7,0
4 
 
4 
 
 Gain correction for Usuda after second Difmap examination. 
SPLIT aparm = 2, 0.5, 0
chansel 30, 220, 1
flagver 1
docalib 1
4 
 
 
 
  
FITTP
 
 
 
 
 Data written out for analysis in Difmap again! 
CLCOR opcode 'gain'
antennas 5,0
clcorprm 32.5,0
4 
 
4 
 
 Gain correction for Kashima after third Difmap examination. 
SPLIT aparm = 2, 0.5, 0
chansel 30, 220, 1
flagver 1
docalib 1
4 
 
 
 
  
FITTP
 
 
 
 
 Data written out for analysis in Difmap again! 
CLCOR opcode 'gain'
antennas 2,6,0
clcorprm 0.92,0
4 
 
4 
 
 Gain correction for Usuda and Shanghai after fourth Difmap examination. 
SPLIT aparm = 2, 0.5, 0
chansel 30, 220, 1
flagver 1
docalib 1
4 
 
 
 
  
FITTP
 
 
 
 
 Data written out for analysis in Difmap again! 

AIPS Input Files
ANTAB.TXT
TABIN.TXT		 Comments
No INDXR.TXT needed as there were no gain jumps during this experiment.

Additional Files
NameDescription
POSSM01_AP.PSPost-calibration spectra (IF 1 and 2) at 0/21:00
POSSM02_AP.PSPost-calibration spectra (IF 1 and 2) at 1/00:20

AIPS Output Files
DTSUM_0.LIS
DTSUM_1.LIS
LISTR.LIS
PRTAN.LIS
POSSM01_AP.PS
POSSM02_AP.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
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
UVPLT_UV.PS		 SN_FRING01_SNR_2.PS
SN_FRING02_DEL_1.PS
SN_FRING02_DEL_2.PS
SN_FRING02_RAT_1.PS
SN_FRING02_RAT_2.PS
SN_FRING02_SNR_1.PS
SN_FRING02_SNR_2.PS
UVPLT_UVD.PS
UVPLT_UVPA.PS
IMAGE.FITS


Difmap Data Reduction Notes
Phase selfcal applied? Yes
Global amplitude selfcal (gscal) applied? Yes
Amplitude selfcal on non-global timescales used? No
Modelfit made and saved? Yes
Image Made and saved? Yes
Comments on Difmap processing
After initial AIPS extraction, 1334-127 data loaded and examined. Only Hart, Mopra and Shanghai observed this source. By comparison with VLBA data (and accounting for variability), Shanghai gain may be down by a factor of about 1.8. First look at J1316-33 supports this and indicates Usuda may be low too. CLCOR in AIPS used to apply 1.8 Gain correction.

Corrected 1334-127 data looks OK now. A simple single circular Gaussian was modelfitted and saved with vs_final_mod. The corrected J1316 data looks a little odd. Ududa gain may be out by about a factor of 1.7. CLCOR used to apply this and data exported again.

J1316 data now looks OK. Flux on short Usuda-Shang baseline ~1.5 Jy maybe a bit high (expect about 1.2 Jy) but will see how it goes. Also, Kashima data has very low amplitudes! Assuming Mopra and Usuda gains are now OK, the Mop-Kashima (0/22:30) and Mop-Usuda (0/21:00) baselines are almost the same, so can guess Kashima correction = 1.3 Jy / 0.04 Jy = 32.5. Corrected in AIPS, but resulting Kashima data is very noisy - bad pointing perhaps. Decided to flag Kashima. After best possible image made with just cleam/selfcal, gscal was run. The result of this flagged all of IF2 (because no amplitude closure) and in IF1, Shanghai and Usuda were re-scaled by 0.91 and 0.93 respectively while VSOP and Mopra were increased by 1.04 and 1.07 respectively (no solution for Hart as no closure). This is most likely an over-compensation of Usuda and Shanghai gains, so applying just those corrections (0.92 each) in AIPS with CLCOR.

Looked at 1334-127 data again, fitted simple circular gaussian to data and saved using vs_final_mod.

J1316 imaged again for last time. Used selfflag to stop flagging of unusable data after phase-selfcal because Mopra-Hart baseline provides constraints that would otherwise be lost with no significant loss of image quality as a result. Saved with vs_final_img.

Model fitting: Started with two circular Gaussians. vs_wplot suggests a VSOP weight increase of about 100. This is set using selfant vsop,false,100. Modelfit converged after about 70 iterations with uvstat(rms) = 0.173 Jy. Changed secondary to elliptical Gaussian and re-converged to get uvstat(rms) = 0.171 Jy, so no significant improvement and circulars Gaussians will do. saved with vs_final_mod.

EBF: 08-OCT-2005: Some editing. See uv data in J1616_FOMALONT_AIPS.FITS

Core 0.3 +/- 0.1

Image
Ampl, Phase vs (u,v) Distance
PS (39 kb)
JPEG (42 kb)
 Ampl, Phase vs Time
PS (250 kb)
JPEG 1, 2, 3		 (u,v) Coverage
PS (21 kb)
JPEG (26 kb)
Closure Phase vs Time
PS (227 kb)
JPEG 1, 2		 Clean Image
PS (32 kb)
JPEG (46 kb)
Modelfit
Ampl, Phase vs (u,v) Distance
PS (39 kb)
JPEG (42 kb)
 Ampl, Phase vs Time
PS (250 kb)
JPEG 1, 2, 3		 (u,v) Coverage
PS (21 kb)
JPEG (26 kb)
Closure Phase vs Time
PS (227 kb)
JPEG 1, 2		 Image with model components
PS (35 kb)
JPEG (39 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)
0.538832 0.0325624 10.6460 0.300271 0.500000 82.9470 0.5833
0.826401 0.619350 -106.708 1.42788 0.496003 71.0171 0.0399
(*) Quoted Brightness temperatures assume Gaussian components and are in the local (z=0) frame.


Last updated on Tue Oct 11 04:38:47 UTC 2005
by db_results.pl version 0.3.