VS03l Results
Submitted checklist.txt and checklist.tex is also available		   [Summary | AIPS | Difmap ]
Analyst: Zhi-Qiang Shen
Date Prepared: 21-06-1999
 

Summary
 
Observation code : VS03l    AIPS Version : 15OCT98   
Date of Observation : 1998/53    Difmap Version : 2.3c 
Source Name : J1626-29    vsop_difmap used : Yes 
Calibration Source(s) : 1622-253         
Ground telescopes : HartRAO, Hobart, Seshan25  Model Fitted to data : Yes 
Tracking Station(s) : TZ    Image made : Yes 
Correlator : Penticton         

 
Abstract
Strong fringes were easily detected on ground-ground baselines. For ground-space baselines, good fringes were found up to ~01:00 (UT), then some weak fringes were seen with lower SNR (probably related to the resolution of source structure at longer baselines).

Both imaging and modelfitting went very well.

Calibration source (1622-253) has a correlated flux density of 0.7 Jy on Hobart-Seshan25 baseline, consistent with the result from VS07g.
Model
Flux (Jy)
Radius (mas)
Theta (deg)
Major (mas)
Axial ratio
Phi (deg)
TB (10^12 K)
0.264823 0.0921679 95.5400 0.285594 0.797017 -19.6025 0.1988
0.602193 0.207290 -96.1110 0.695059 0.607871 -60.0671 0.1001
(*) 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
dotable=1
 
 
 
 
 Output = VS03L.FITLD 
MSORT sort='TB'
 
 
 
 
 Input = VS03L.FITLD; Output = VS03L.MSORT 
INDXR cparm(3)=1
 
 
1 
 
 index uv data with 1 min CL entry interval 
TACOP
1 
 
2 
 
 protect CL1 
ANTAB
 
 
 
 
 determine the Tsys and gain curve, 95K for Halca 
APCAL opcode=' '
 
 
 
1 
 generate an amplitude calibration solution table 
CLCAL opcode='CALI'
interpol=' '
refant=0
2 
1 
3 
 
 apply amplitude calibration solution 
FRING docalib=1
flagv=-1
refant=3
solint=4
timer=0, 23, 0, 0, 0, 23,
   2, 0
aparm=2, 0, 0, 0, 0, 1, 5, 0
dparm=1, 0, 0, 0, 0, 0, 0, 1
antwt=1, 1, 1, 30
3 
 
 
12 
 a single short scan run with an option zeroing the rate (dparm(8)=1). FG table was not applied since it flagged out data to Seshan25. 
CLCAL opcode='CALI'
interpol=' '
smotype='VLBI'
refant=3
calsour='J1626-29'
3 
12 
8 
 
 apply single solution to whole dataset 
FRING docalib=1
flagv=-1
refant=3
solint=4
timer=0, 0, 0, 0, 0, 23, 0, 0
aparm=2, 0, 0, 0, 0, 1, 3, 0
dparm=1, 500, 250, 0
antwt=1, 1, 1, 30
8 
 
 
16 
 run FRING before time 0,23,0,0 with SNR cutoff=3 
FRING docalib=1
flagv=-1
refant=3
solint=4
timer=0, 23, 0, 0, 0, 0, 0, 0
aparm=2, 0, 0, 0, 0, 1, 1, 0
dparm=1, 100, 50, 0
antwt=1, 1, 1, 30
8 
 
 
20 
 run FRING after time 0,23,0,0 with SNR cutoff=1 in narrow searching windows 
CLCAL opcode='CALP'
interpol='AMBG'
smotype='VLBI
refant= 3
timer=0,0,0,0 0 23,0,0
cals=sour='1622-253'
(cal=sour='J1626-29')
8 
16 
9 
 
 run 2 times (once for each source) 
CLCAL opcode='CALP'
interpol='AMBG'
smotype='VLBI
refant= 3
timer=0, 23, 0, 0, 0, 0, 0, 0
cals=sour='1622-253'
(cal=sour='J1626-29')
8 
20 
9 
 
 run 2 times (once for each source) 
TACOP
9 
 
10 
 
 protect CL9 
CLCOR antenna=0
clcorprm=0.91,0
10 
 
10 
 
 Penticton gain correction 
TASAV
 
 
 
 
 copy all extension tables to a dummy file 
SPLIT docalib=1
douvcomp=1
aparm= 2, 0, 0, 1, 0
10 
 
 
 
 make calibrated single-source data J1629-29.SPLIT and 1622-253.SPLIT 
FITTP
 
 
 
 
 export each single-source file in FITS format to disk file for further imaging analysis 

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

AIPS Output Files
PRTAN.LIS
LISTR.LIS
DTSUM_0.LIS
DTSUM_1.LIS
UVPLT_UV.PS
UVPLT_UVD.PS
UVPLT_UVPA.PS
SN_APCAL_AMP_2.PS
SN_APCAL_AMP_1.PS
SN_FRING1_DEL_1.PS
SN_FRING1_DEL_2.PS
SN_FRING1_RAT_1.PS
SN_FRING1_RAT_2.PS
SN_FRING1_SNR_1.PS		 SN_FRING1_SNR_2.PS
SN_FRING2_DEL_1.PS
SN_FRING2_DEL_2.PS
SN_FRING2_RAT_1.PS
SN_FRING2_RAT_2.PS
SN_FRING2_SNR_1.PS
SN_FRING2_SNR_2.PS
SN_FRING3_DEL_1.PS
SN_FRING3_DEL_2.PS
SN_FRING3_RAT_1.PS
SN_FRING3_RAT_2.PS
SN_FRING3_SNR_1.PS
SN_FRING3_SNR_2.PS
SN_CALIB_DEL_1.PS		 SN_CALIB_DEL_2.PS
SN_CALIB_RAT_1.PS
SN_CALIB_RAT_2.PS
SN_CALIB_SNR_1.PS
SN_CALIB_SNR_2.PS
SN_CALIB_PHA_1.PS
SN_CALIB_PHA_2.PS
POSSM01_AP_1.PS
POSSM01_AP_2.PS
VPLOT_AP_1.PS
VPLOT_AP_2.PS


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
average data over 30 sec (uvaver 30,true)

raise the weight of HALCA (selfant VSOP_SC,false,30)

clean and phase self-cal with uniform weighting (uvw 2,-1... etc)

switch to natural weighting to clean more flux (uvw 0,-1 ... etc)

try gscale but keep non-closing data (selfflag false,3,4; gscale true) HARTRAO 1.01 HOBART 1.08 SESHAN25 0.97 VSOP_SC 0.94 HARTRAO 1.01 HOBART 1.08 SESHAN25 1.04 VSOP_SC 0.91

no more amp self-cal!

final image obtained with uniform weighting: peak=0.384 Jy/beam, RMS=1.9 mJy/beam; beam=0.916 mas x 0.328 mas @ 11.5 deg

try several models (1-component, 2-component, circular or/and elliptical) to fit the calibrated data

Image
Ampl, Phase vs (u,v) Distance
PS (121 kb)
GIF (9 kb)
 Ampl, Phase vs Time
PS (363 kb)
GIF 1, 2		 (u,v) Coverage
PS (63 kb)
GIF (5 kb)
Closure Phase vs Time
PS (192 kb)
GIF 1		 Clean Image
PS (40 kb)
GIF (60 kb)
Modelfit
Ampl, Phase vs (u,v) Distance
PS (121 kb)
GIF (9 kb)
 Ampl, Phase vs Time
PS (362 kb)
GIF 1, 2		 (u,v) Coverage
PS (63 kb)
GIF (5 kb)
Closure Phase vs Time
PS (192 kb)
GIF 1		 Image with model components
PS (45 kb)
GIF (8 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)
0.264823 0.0921679 95.5400 0.285594 0.797017 -19.6025 0.1988
0.602193 0.207290 -96.1110 0.695059 0.607871 -60.0671 0.1001
(*) Quoted Brightness temperatures assume Gaussian components and are in the local (z=0) frame.


Last updated on Thu Jun 24 23:25:39 GMT 1999
by db_results.pl version 0.2.0.