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. Correlation between Microvariability and slope ObjectMicroNo Micro MRK 4211.91.2 3C 3452.50.4 BL Lac2.31.4 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 Micro flux Julian date Previous Work

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 Source# of Nights observed # of Microvariability runs RADecZType AO 0235 2692 h 38 min 16 o 37’0.94BL Lac 0420-0121124 h 23 min -01 o 20’0.915OVV 0716+7124207 h 21 min 71 o 20’0.30?BL Lac 0735+171037 h 38 min 17 o 42’0.424?BL Lac 0736+017637 h 36 min 01 o 50’0.191BL Lac OJ 28718148 h 51 min 20 o 06’0.306BL lac 1156+29512311 h 59 min 29 o 14’0.729OVV 3C 2736312 h 29 min 02 o 08’0.1575QSO 3C 27920612 h 56 min -05 o 47’0.5362OVV ON 2314414 h 35 min 16 o 30’0.102OVV 3C 34516916 h 42 min +39 o 48’0.5938OVV 1510-0898415 h 12 min -09 o 58’0.36OVV BL Lac513322 h 02 min 42 o 16’0.069BL Lac 3C 44617622 h 35 min 16 o 30’1.404OVV

11. Duty Cycle Object# Obs. (as of 8/2007) Total timeMicro timeDuty CycleRedshiftType 0235+164 822.55 11.97977.4%0.94BL Lac 0716+71 17123.3 120.7890.3%0.30BL Lac OJ 287 1236.47 28.13277.13%0.306BL Lac 3C 279 814.65 12.8487%00.536 BL Lac 3C 345 413.534 9.07767%0.593 OVV Q 3C 454.3 611.372 7.62663.35%0.859OVV Q 3C 446 410.493 6.648 84.1%1.40OVV Q BL Lac 21 65.45 44.238 67%0.069 BL

12. Correlation between Microvariability and Brightness Name# of ObservationsMicro YesMicro NoCorrelation Coeff. AO 0235+164954-0.04 0420-01954-0.45 S1 0716+7117152-0.26 OJ 28713103-0.15 3C 2798620.04 3C 3455320.56 3C 454.36420.12 BL Lac21147-0.12

13. BL Lac 45 Observation 22 Microvariability Observations ( 13 yes 9 N0)

14. AO 0235+164 26 Observations 9Microvariability Observations (4 Yes, 5 No)

15. OJ 287 17 Observation 14 Microvariability Observations (10 yes 4 No)

16. 0716+71 22 Observations 17 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