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Imaging of Quasars and Active Galactic Nuclei. Fine-Scale Structure Evolution

Imaging of Quasars and Active Galactic Nuclei. Fine-Scale Structure Evolution. Andrey Chuprikov Igor Guirin Astro Space Center Moscow Russia. Observations. We present some results of 4 VLBA experiments ( RDV14, RDV15, RDV16, and RDV17 ) RDV14 15/4/1999 RDV15 10/5/1999 RDV16 21/6/1999

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Imaging of Quasars and Active Galactic Nuclei. Fine-Scale Structure Evolution

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

  2. Observations We present some results of 4 VLBA experiments (RDV14, RDV15, RDV16, and RDV17) • RDV14 15/4/1999 • RDV15 10/5/1999 • RDV16 21/6/1999 • RDV17 02/8/1999 The 8th European VLBI Network Symposium, Torun, Poland

  3. Frequency structure of initial data F0 (MHz) BW (MHz) nCh IF1 2221.22 8 16 IF2 2241.22 8 16 IF3 2331.22 8 16 IF4 2361.22 8 16 IF5 8406.22 8 16 IF6 8476.22 8 16 IF7 8791.22 8 16 IF8 8896.22 8 16 The 8th European VLBI Network Symposium, Torun, Poland

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

  7. Result of Data Processing. Dirty Map of J0017+8135 Before and After application of the Procedure The 8th European VLBI Network Symposium, Torun, Poland

  8. Results of Data Processing. CLEAN MAP of J0017+8135. Observational Session RDV14. 15/4/1999 Observational Session RDV15. 10/5/1999 The 8th European VLBI Network Symposium, Torun, Poland

  9. Results of Data Processing. CLEAN MAP of J0017+8135. Observational Session RDV16. 21/6/1999 Observational Session RDV17. 2/8/1999 The 8th European VLBI Network Symposium, Torun, Poland

  10. Results of Data Processing. Observational Session RDV14. 15/4/1999. CLEAN MAP for J0646+4451 Observational Session RDV15. 15/4/1999. CLEAN MAP for J0808+4950 The 8th European VLBI Network Symposium, Torun, Poland

  11. Results of Data Processing. Observational Session RDV16. 15/4/1999. CLEAN MAP for J1800+7828 Observational Session RDV17. 15/4/1999. CLEAN MAP for J1743-0350 The 8th European VLBI Network Symposium, Torun, Poland

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

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