We would like to inform you about the KVN operation and user support as follows.
- Following email accounts are available for proposal submission, observation, correlation and user support.
- kvnprop@kasi.re.kr: proposal submission and informing its result
- kvnobs@kasi.re.kr : observing schedule submission, observation related requests and questions for the accepted proposal only.
- kjcc@kasi.re.kr : correlated data distribution and correlation related requests.
- kvnhelp@kasi.re.kr: general questions from the users including scheduling, observations, systems, and so on (regardless of the proposal acceptance).
※ We strongly recommend to use official email above rather than the personal email for the KVN
- Schedule Preparation
- You will be notified when your observation is scheduled by the KVN scheduling officer. Then, your schedule file must be submitted to kvnobs@kasi.re.kr one week before your observing date.
※ If your schedule submission is delayed, your observation may not be assigned.
- For the KVN schedule submission, PI should submit both a stand-alone vex file and a SCHED key file. In the vex file, please specify calibration procedures for hot/cold calibration, sky dipping, pointing, etc. Calibration procedures of KVN can be found here.
- We also request PIs to specify your correlation parameters at the beginning of the vex file (in case of KaVA observation) or in the key file (in case of KVN observation) for proper correlation processing.
※ In particular, PIs who request for sub-array or dual-beam observations for KaVA should provide a frequency matching table for the correct correlation.
- Please include at least two fringe finder scans, each lasting five or more minutes at the first and latter part of observation in order to search the delay and rate offsets for the correlation. We strongly recommend placing those scans at least every two hours.
- Observation
- Your observations are fully covered by KVN operation team.
- After the observation, the result will be reported to PI in two weeks by kvnobs@kasi.re.kr
- Target of opportunity (ToO) observations will not be able to be schedule on the desirable date if observations with other network (e.g. KVN+VERA, KVN+EVN etc) has already been scheduled.
- Correlation and Data Validation/Distribution
- Daejeon correlator or DiFX software correlator output is a standard FITS file. The first correlated data inspection is done by DQA (data quality analyzer) and if there is no problem this will be provided to the PIs via FTP including auxiliary files such as ANTAB, Tsys plots etc.
- FTP address for downloading the data will be informed to the PI’s email that you submit the schedule to kvnobs@kais.re.kr.
- After one month (in case of KaVA) and two weeks (in case of KVN) later of a correlated data distribution to PIs, disk modules which contains raw observing data can be recycled without notice. Therefore, PIs should investigate the correlated output carefully and if there is issue to discuss, please email us (kjcc@kais.re.kr) about that.
※ In order to request re-correlation or raw data keeping, PI should provide adequate evidence.
Work Flow of KVN AOC
- Operation :
schedule Announce (KVN Scheduler) → assign support scientist (UST) → schedule Preparation (PI) → schedule Submission (PI to kvnobs@kasi.re.kr) → schedule check (AOC) → submit schedule (AOC) → observation (AOC) → observation feedback (AOC) → weekly AOC meeting → observation report (AOC to PI)
※ PI should discuss with an assigned support scientist first if there are questions and requests.
- Correlation :
data arrival → correlation queue → check observation status & correlation parameters → run correlation → correlated data inspection (DQA) → data distribution (DQA to PI)
※ Correlation feedback is also reported during the weekly AOC meeting
※ If there is an issue related to correlated data, PI should consult a support scientist first or an email (kjcc@kasi.re.kr), not to ask KJCC members directly.
Data reduction
Notice on Paper Preparation
- We strongly recommend for all the papers using KVN, regardless of single dish or VLBI, to acknowledge KREONET who supports the high-speed connection between 3 KVN stations.
- An Example of Acknowledgement for papers using KVN (DiFX):
We are grateful to the staff of the KVN who helped to operate the array and to correlate the data. The KVN and a high-performance computing cluster are facilities operated by the KASI (Korea Astronomy and Space Science Institute). The KVN observations and correlations are supported through the high-speed network connections among the KVN sites provided by the KREONET (Korea Research Environment Open NETwork), which is managed and operated by the KISTI (Korea Institute of Science and Technology Information).
- An Example of Acknowledgement for papers using KVN (no DiFX) or KVN single dish antennas:
We are grateful to the staff of the KVN who helped to operate the array and to correlate the data. The KVN is a facility operated by the KASI (Korea Astronomy and Space Science Institute). The KVN observations and correlations are supported through the high-speed network connections among the KVN sites provided by the KREONET (Korea Research Environment Open NETwork), which is managed and operated by the KISTI (Korea Institute of Science and Technology Information).
KVN VLBI Observations
VLBI observations with KVN are remotely conducted at the KVN Array Operation Center in KASI, Daejeon.
The obsevations are based on a schedule file in
VEX (VLBI EXperiment) format. A VEX file contains various information relevant to individual observation
such as sources, system setup, observing time, calibration mode, etc. The VEX file can be prepared
either by using a VLBI scheduling software Sched
or by modifying template VEX files. PIs are kindly asked to prepare and submit the VEX files to KVN AOC
(kvnobs@kasi.re.kr) so that the AOC conducts the observations after double-checking the VEX files.
PIs will be informed via email after the observations and correlations.
For preparation of KVN VLBI observations, users can find some helpful information at the following links:
KVN Single Dish Observations
Single dish observations with KVN radio telescopes can be conducted either at individual KVN radio observatory or at the KVN Array Operation Center in KASI, Daejeon. Graphical user interface is available for the observations. Observational data are stored in CLASS (Continuum and Line Analysis Single-dish Software) format. The CLASS is one of Gildas packages developed at IRAM observatory. KVN field systems understand Python languages so that Python scripts may be used for the observations. In principle, PIs are supposed to conduct their own observations. The following observational modes are available for various purposes:
Cal and SkyDip for calibrating the data, Position Switching, Frequency Switching, Grid Mapping, Five Pointing, and Focus for spectroscopic observations, Cross Scan and OTF for continuum observations.
Continuum polarization observations and spectroscopic observations can be automatically conducted using Python scripts. Simultaneus multifrequency observations are available either at four frequency bands (22, 43, 86, 129GHz) in single polarization (LCP or RCP) or at two frequency bands in dual polarizations. Source catalogs are in a format readable by ASTRO software, one of Gildas packages.
One may find some useful information for the observations at the following links: