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The Nature of Microvariability in Blazar

The Nature of Microvariability in Blazar. Gopal Bhatta Department of Physics Florida International University. Collaborators. Dr James Webb Professor, Department of physics Florida International University Dr Hal Hollingsworth Department of physics

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The Nature of Microvariability in Blazar

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  1. The Nature of Microvariability in Blazar Gopal Bhatta Department of Physics Florida International University

  2. Collaborators • Dr James Webb Professor, Department of physics Florida International University • Dr Hal Hollingsworth Department of physics Florida International University • Dr Joe Pollock Department of Physics and Astronomy Appalachian State University • Students: Gregory Azarnia, Chris Ceron Diana Alvarez

  3. Introduction Characteristics of Blazar • A distant galaxy presumably with a giant black hole at it’s heart • Highly variable • Highly polarized light • High red shift – up to 6.4 (Sloan DSS Quasar ) • Radiation from radio to gamma ray • Non thermal radiation – synchrotron

  4. Blazar Structure

  5. A standard model of a Blazar A present model of Blazar: • 1) Accretion disk • 2) Supermassive black hole at the center • 3) Relativistic Jets Radiation is mainly due to synchrotron and energy flows in the form of high speed jets by shock wave propagation

  6. Variability • Long term ~ years • Short term ~ days or months • Microvariability – intra-day (<0.1 mag)

  7. Microvariability From our collaborator, Dr. Joe Pollock

  8. Micro flux Julian date Previous Work • Emily Howard:The astronomical Journal 127:17-23, 2004 January) • RK421, MRK 501, 3C 345 and BL Lacerate • Correlation with long term light curve • Result • Microvariability more common when flux is changing

  9. Observation SARA consortium that uses 0.9m reflector telescope at Kitt peak National Observatory, Arizona • Monitor a list of Blazars – see the flux state • Color Observation – VRI • Micro-variation – continuously monitor an object for 2- 8 hours

  10. List of the Blazars

  11. Duty Cycle

  12. Correlation betweenMicrovariability and Brightness

  13. BL Lac45 Observation22 Microvariability Observations ( 13 yes 9 N0)

  14. AO 0235+16426 Observations9Microvariability Observations (4 Yes, 5 No)

  15. OJ 28717 Observation14 Microvariability Observations (10 yes 4 No)

  16. 0716+7122 Observations17 Microvariability observations (15 yes, 2 No)

  17. 0716+71 01-22-06

  18. 0716+71 03-10-04

  19. Cause of Microvariability Relativistic Jets • Microvariability is associated to the jet • Highly collimated • Extend up to parsecs • radio blob structure can be resolved • Unresolved in optical and emanating from the core

  20. Jet model explanation Micro-variations could be due to • Shock wave propagation in the jet • Collision between plasma ejections • Jet precession

  21. Future work • Continue the micro-variability monitoring to increase the statistics for duty cycle calculations • Improve the signal to noise ratio by observing the object when they are faint • Extend the micro-variability studies to southern hemisphere Blazars to improve the sample size

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