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26 - 29 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 1 Imaging of Quasars and Active Galactic Nuclei. Fine-Scale Structure Evolution.

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Presentation on theme: "26 - 29 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 1 Imaging of Quasars and Active Galactic Nuclei. Fine-Scale Structure Evolution."— Presentation transcript:

1 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 1 Imaging of Quasars and Active Galactic Nuclei. Fine-Scale Structure Evolution Andrey Chuprikov Igor Guirin Astro Space Center Moscow Russia

2 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 2 Observations We present some results of 4 VLBA experiments (RDV14, RDV15, RDV16, and RDV17) RDV1415/4/1999 RDV1510/5/1999 RDV1621/6/1999 RDV1702/8/1999

3 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 3 Frequency structure of initial data F0 (MHz) BW (MHz) nCh IF IF IF IF IF IF IF IF

4 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 4 Dual-Frequency Calibration of the Ionosphere Delay The trick is to compensate the ionosphere delay before Self-Calibration with multiplication the Visibility by A linear combination of group delays in S (2200 MHz) and X (8400 MHz) band yields straightforwardly the ionosphere delay :

5 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 5 Calibration of the Atmosphere Delay The Multi Band Delay (MBD) fitting is used to determine the Atmosphere/Troposphere model errors

6 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 6 Data processing The main idea is to compensate the ionosphere / atmosphere Delays before Self-Calibration This can be made with Fitting of the Multi Band Dalay In many cases, such procedure can improve the source image essentially Analysis of the obtained image allows to reveal changes in the source structure

7 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 7 Result of Data Processing. Dirty Map of J Before and After application of the Procedure

8 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 8 Results of Data Processing. CLEAN MAP of J Observational Session RDV14. 15/4/1999 Observational Session RDV15. 10/5/1999

9 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 9 Results of Data Processing. CLEAN MAP of J Observational Session RDV16. 21/6/1999 Observational Session RDV17. 2/8/1999

10 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 10 Results of Data Processing. Observational Session RDV14. 15/4/1999. CLEAN MAP for J Observational Session RDV15. 15/4/1999. CLEAN MAP for J

11 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 11 Results of Data Processing. Observational Session RDV16. 15/4/1999. CLEAN MAP for J Observational Session RDV17. 15/4/1999. CLEAN MAP for J

12 September 2006 The 8th European VLBI Network Symposium, Torun, Poland 12 Conclusion 1.Our experience demonstrates that usage of the Procedure of Multi Band Delay Fitting could essentially improve the resulting image of source 2.Particularly, application of this method for Dual Frequency (S/X) VLBA data allows to monitor sources for variability milliarcsecond structural changes


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