For the accepted proposals, users are requested to prepare the observing schedule file, at least one week before the observation. The observer who is not familiar with KaVA system is recommended to consult with KaVA user support team (email@example.com) to prepare schedules. KaVA operation & support members take full responsibility for observation and correlation process.
The users are asked to submit a VEX file two weeks before the observation to firstname.lastname@example.org. Observations will be performed by KaVA operators so that users will not be asked to take part in observations.
The correlation process will be carried out by Daejeon correlator at KJCC (Korea-Japan Correlation Center). The correlated data can be downloadable via FTP and its address will be given to the PI via email. Then, users are asked to examine the correlated data and if there is some problem, you can request re-correlation within a month after the correlation. In this case, you should provide the details of your problem clearly. In principle, the raw data used for observations will be recycled one month after the correlation.
Data Rights and Archiving
The PIs will have exclusive access to the data obtained for 18 months after the correlation. This policy is applied to each observation, even if the proposal comprises multi epoch observations. After this exclusive period, the data will be publicly accessible.
1. VEX Preparation
You can download the KaVA VEX example file from here and modify them for your observation. More sample vex files for a specific observation case are also available in the following table. The schedule submission should be done by a standalone vex file including calibration procedures (e.g. sky dipping, hot/cold calibration, focusing, pointing etc.). The correlation parameters must be clearly specified as an example VEX file.
|KaVA C2 mode observation (continuum)
|KaVA K-band astrometric observation
|KaVA+TM 22GHz C4 mode observation (continuum)
|KaVA+TM 43GHz C4 mode observation (continuum)
|KaVA+TM 22GHz C5 mode observation (continuum)
|KaVA+TM 43GHz C5 mode observation (continuum)
2. Frequency Setup (DAS setup)
At present, following observing modes are available. Please refer to the KaVA status report for more details.
3. Check List of Scheduling
Following items are the check list for the success of VLBI observation.
Source-Elevation plot of several fringe finders
Fringe Finder Sources
For a phase referencing observation or calibration purposes, a phase calibrator close to your target source is necessary. List of VLBI calibrators are available as follows.
Tsys measurements and Pointing correction
1. Documentations of KaVA data analysis
Note that the AIPS Cookbook is a useful general guide for calibration and imaging of VLBI data.
http://www.aips.nrao.edu/cook.html : AIPS Cookbook
Hands-on analysis documentation of VLBI data is available in the following URL.
Several documentations related the KaVA data analysis would be helpful.
2. Tips for KaVA data analysis
For some parts of data analysis, KaVA would require special treatment as below :
2.1 Amplitude calibration
For amplitude calibration of KaVA data, KaVA provides the ANTAB files to PIs. The ANTAB file contains the gain curves for each antenna, and system temperature taken during the observation. You will obtain the TY and GC tables, loading the ANTAB file by running the AIPS task "ANTAB".
2.2 Parallactic angle correctionTime variation of a parallactic angle of a source occurs for the receiving system mounted in an azimuth-elevation mounted telescope and generates a phase rotation. This phase rotation can be corrected with the AIPS task "CLCOR" with the adverb of OPCODE='PANG'. In the case of VERA antenna, the field rotator in the receiving room fixes the parallactic angle, and therefore it is not necessary to run "CLCOR" for VERA antennas. But, you have to do this correction for the KVN antennas.
2.3 Editing the AN tableThe doppler velocity shifts due to the earth's rotation and its motion within the solar system and towards the local standard of rest can be corrected using the AIPS task "CVEL". When the ARRNAM keyword in the AN table is "VLBA", then "CVEL" assumes that all data have been fringe-rotated to the centre of the Earth and determine the velocity correction accordingly. KaVA follows the VLBA and fringe rotates to the Earth center. Thus, the ARRNAM keyword in the AN table has to be "VLBA". Please run the task "TABED" and give "VLBA" to the ARRNAME keyword in the AN table.
2.4 Gibbs ringing effects around a bright and narrow spectral line
KaVA contains comparatively-short baselines (~300 km) as a VLBI array, and various Gibbs ringing effects could sometimes be seen in the case of the bright narrow spectral features. It is strongly recommended to smooth such spectral features when you correct the velocity shifts, by running the AIPS task "CVEL" with the adverb of APARM(9)>1.
Figures : Water maser lines in Orion KL in the Tamna-Ulsan baseline
The users can contact any staff member of the KaVA by E-mail
|User Support Team (UST)
|User Support Team (UST)
|Project Director, Total systems
|K. M. Shibata
|Operation, Schedule management, Antenna site in general
|Performance for each antenna
|Phase calibration, Data analysis
|D. Y. Byun
|Array Operation and System Specification
|S. S. Lee
|Observation Preparation and Data Analysis
|D. G. Roh