| VS07s Results
Submitted checklist.txt and checklist.tex is also available |
[Summary | AIPS | Difmap ] |
| Observation code | : | VS07s | AIPS Version | : | 31DEC00 | |
| Date of Observation | : | 2001/194 | Difmap Version | : | 2.3c | |
| Source Name | : | J0137-24 | vsop_difmap used | : | Yes | |
| Calibration Source(s) | : | J0106-40,J0204+15 | ||||
| Ground telescopes | : | Cd, Hh, Mp, Ho, Se | Model Fitted to data | : | No | |
| Tracking Station(s) | : | UZ | Image made | : | No | |
| Correlator | : | Penticton |
| Abstract
PLS radplot of source (J0137-24) showed very little structure, with longer spacing flux approx constant at 1 Jy. No AT light curves. Uncorrected (using only ANTAB values) amplitudes had a flux at 100Mlambda of about 350mJy (Se-Aus baseline), and a flux of about 200mJy at 130Mlambda (Hh-Aus baseline). Both of these flux values are well below the expected value of 1Jy (assuming no variability). However, flux for the calibrators was also very low (between about 50% to 60% of the expected value...based upon the PLS, and assuming no variability). No fringes were found to Ho, Cd (IF2) or Halca. Although the flux on the shortest Halca baselines (about 160Mlambdas) appears like it would only be marginally fringable to Halca (200mJy), based upon the calibrator data this flux in reality was probably much higher. Also, unless the source structure changed a lot, the long spacing flux should have been approx constant (probably closer to the350mJy or higher level). Finally, this experiment was one of three observed around the same time (VS06h, VS07s, VS08c), with only one tracking station (Uz), and all with failed space fringes. I suspect whatever caused the lack of space fringes was not source intrinsic but instead was due to a tracking station problem (???). I suggest re-scheduling this experiment with moderate priority. Priority would have been higher, except it is possible flux on long baselines was low enough that no fringes would have been detected anyways. Antenna gain corection factors were accomplished using scalant in DIFMAP, not CLCOR in AIPS. Hence, the FITS file does not have these corrections applied. |
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| FITLD | DIGICOR=DELCOR=-1 |
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Output file name = VS07S.FITLD |
| MSORT |
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Input file name = VS07S.FITLD, Output file name = VS07S.UVSRT | |
| FIXWT |
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Not done. | |
| INDXR | CPARM(1)=3 CPARM(2)=60 CPARM(3)=0.25 |
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Created NX(1) |
| ANTAB |
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Used a nominal DPFU for Ho, Mp, and Halca. For Halca used a Tsys of 88K, 92K. For Mp used a nominal Tsys of 34K. For Se used a nominal Tsys of 88.8K. For all other GRTs (Cd, Hh, Ho) had non-nominal Tsys values. | |
| APCAL |
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Input: Ty(1) + GC(1) | |
| CLCAL | OPCODE = CALP INTERPOL = 'AMBG' REFANT 5 (Se) |
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| TBOUT | INEXT = 'AN' |
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| TBIN |
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Changed MNTSTA entries in the AN table. Changed Halca from 3 to 2, and changed Hh and Ho to 0. | |
| TBIN |
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Read in DQA1 delay and rate solutions. Couldn't get TAFLG to work properly, so set the delays/rates to zero for Ho, VSOP, and Ced (IF2 only). These antennas did not have good solutions in the DQA1 report, despite often having pfring > 0.95. Simply SNEDTing the bad solutions does not work, since then CLCAL throws out the data. | |
| CLCAL | OPCODE = CALP INTERPOL = 'AMBG' REFANT 5 (Se) |
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| UVFLG | OPCODE = REAS REASON 'NO PRC/LOW DVAL' |
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Needed to unflag the NO PRC/LOW DVAL data... as per the piletter most of this data was ok. |
| FRING | DOCALIB 1 GAINUSE 3 TIMER 0 SEARCH 4,2,1 ANTENNAS -3 SOLINT 10 REFANT 5 (Se) APARM(1)=2 APARM(7)=3 (SNR=3) DPARM(1)=3 (include baseline stacking) DPARM(2)=2000 (2000 ns delay window) DPARM(3)=100 (100mHz rate window) DPARM(4)=0.5 DPARM(5)=0 DPARM(6)=1 |
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Look for Halca solutions with a large window and long solint. Exclude Ho for now (no Ho fringes in the DQA1 report). Lousy solutions. |
| FRING | DOCALIB 1 GAINUSE 3 TIMER 0 SEARCH 4,2,1 ANTENNAS -3 SOLINT 2 REFANT 5 (Se) APARM(1)=2 APARM(7)=3 (SNR=3) DPARM(1)=3 (include baseline stacking) DPARM(2)=2000 (2000 ns delay window) DPARM(3)=100 (100mHz rate window) DPARM(4)=0.5 DPARM(5)=0 DPARM(6)=1 |
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Try again with small solint. Still no good solutions. |
| FRING | DOCALIB 1 GAINUSE 3 TIMER 0 ANTENNAS 5,6 SOLINT 2 REFANT 5 APARM(1)=2 APARM(7)=3 (SNR=3) DPARM(1)=3 (include baseline stacking) DPARM(2)=2000 (2000 ns delay window) DPARM(3)=100 (100mHz rate window) DPARM(4)=0.5 DPARM(5)=1 (Don't do LS solution) DPARM(6)=1 |
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Just try for Halca solutions with the refant and no LS solutions....no luck. Give up. Suspect something was wrong with Halca for all three experiments, VS06h, VS07s, and VS08c. Will just use DQA1 file to generate a ground only image. |
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| CLCOR | OPCODE 'GAIN' ANTENNAS 0 CLCORPRM 1.22,0 |
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Based upon calibrator J0106-40 (which had approximately constant flux from AT light curves), flux was low by about 1.5. Multiply all antennas by root of this factor. Couldn't get any good crossing points with fringes to determine relative gain corrections. |
| UVFLG | OPCODE 'FLAG' REASON 'NO FRINGES' ANTENNAS 3,6 |
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| SPLIT | SOURCES 'J0137-24' DOCALIB 1, GAINUSE 4 |
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Input file: VS07S.UVSRT, Output file: J0137-24.FITS |
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Input file: J0137-24.FITS, Output file: J0137-24.FITS, amplitude |
AIPS Input Files
| ANTAB.TXT INDXR.TXT |
Comments - None - |
AIPS Output Files
| Phase selfcal applied? | No |
| Global amplitude selfcal (gscal) applied? | No |
| Amplitude selfcal on non-global timescales used? | No |
| Modelfit made and saved? | No |
| Image Made and saved? | No |
| Comments on Difmap processing
Didn't make an image. Don't have any Halca data, and low spacing data (Cd-Mp) looked very weird. Something is seriously wrong with this data. |