Written by Seiji Kameno (Kagoshima University, Japan)
Translated and edited by Tomoharu Kurayama
(VERA, National Astronomical Observatory of Japan, Japan)
We are going to analyze the data observing a simple-structure radio source DA193. The observation frequency is 15 GHz. The VLBA stations are used, and the observation time is only about 20 minutes. Although this is very short observation, the map dynamic range exceeds 1000. At first, let’s see the results.
(u, v) plot
|Observation date||2001 August 17|
|VLBI array||VLBA (10 stations)|
|Observed sources||DA193 (Note: Originally the target source of this observation is NGC1052. DA193 is observed for calibration.)|
|Observation frequency||15.4 GHz|
|Bandwidth||16 MHz × 2 IF, 64 frequency channels/IF|
|Data size||97.3 MB|
Procedure of analysis
We are going to analyze the data with AIPS and difmap. We carry out the data calibration mainly with AIPS, and imaging and self-calibration with difmap.
- Processing by AIPS
- Lesson 1.
- Loading data into AIPS
- Lesson 2.
- Confirming the data
- Lesson 3.
- Calibrating amplitudes of visibilities
- Lesson 4.
- Fringe fitting (calibration of delay)
- Lesson 5.
- Bandpass calibration (calibration of frequency characteristics)
- Lesson 6.
- Reducing data size by frequency integration
- Lesson 7.
- Creating FITS file in order to image with difmap
- Processing by difmap
- Lesson 8.
- Loading data into difmap
- Lesson 9.
- Displaying visibilities and time integration
- Lesson 10.
- Fragging bad data (avoiding bad data from analysis)
- Lesson 11.
- Creating a dirty map
- Lesson 12.
- Lesson 13.
- Self-calibration of phase
- Lesson 14.
- Self-calibration of amplitude
- Lesson 15.
- Creating a final image