1. Variability Study of Fermi Blazars
Students
Bindu Rani
Debbijoy Bhattacharya
Hüsne Dereli
Reham Mostafa Ayoub
Ravi Joshi
Renyi Ma
Supervisors
Peter Willmore
Benoit Lott
Varsha Chitnis
Gulab Dewanga

2. Standard model for AGNs
An extragalactic object
More luminous than normal galaxies
Generally compact, point sources (stellar appearance) at the center of a galaxy. Supermassive Black hole, solar masses.
Active Galactic Nucleus
The point source can be times the brightness of the underlying galaxy
 ~ 10
Some exhibit jets

3. AGN Classification AGN Type
the angle between the observer and the object
the mass of the object
how much mass the black hole accretes
AGN Classification
According to Emission lines
According to Radio-Optical flux ratio
A) Radio-Loud AGNs (Jets)‏
1.Radio Galaxies
2.Radio-loud Quasars
3.Blazars
a) BL Lac
b) FSRQ (OVV)
B) Radio-Quiet AGNs (No Jets)‏
1. Seyfert galaxies (Type I and Type II)
2. LINERs
3. Radio-quiet quasars/QSOs

4. Blazars AGNs with jets, pointing directly at us.
Radiation from the jet swamps out all other sources
Highly relativistic beams, particles in the jets, the observed gamma rays.
Extreme variability at all frequencies
FSRQs: lower polarization
BL Lac: high polarization,

5. BLLacs
FSRQs

6. List of sources BL Lac : AO 0235+164 ‏ 3C 66A ‏ FSRQ :‏ B2 1520+31
TeV Blazar
PKS ‏

7. Analysis methods : Likelihood Analysis Aperture Photometry
Spectral Analysis in energy bands
Light curves
Aperture Photometry

8. Results:

9. AO

10. B

11. PKS

12. 3C 279

13. 3C 66A

14. Summary

15. Blazar
FSRQs BL Lacs
281 FSRQs
291 BL Lacs

16. The source We Studied 3C 279 3C 66A (ISP) B2 1520+31 AO 0235+164 (LSP)
FSRQ
BL Lac
3C 279
3C 66A (ISP) B
AO (LSP)
PKS (HSP)

17. Our Results 1. BL Lacs have a relatively flat spectra than FSRQs.
2. For some sources the spectra is better fitted with broken power law than simple power law.
3. Do not show significant spectral index variation.

18. Results:

20. Borrowed from Benoit Lott presentation
3c279
Mrk 421

21. Variation of Spectral Index with Flux

22. Future Plan
 More detailed study is needed in order to understand the emission mechanism of different source classes.
 Study the variation of spectral index in greater detail.
 To understand the energetics and dynamics of jet and accretion disk, one need to study the objects over a broad energy band.
 The simultaneous multiwavelength study will help to constrain crucial parameters of jet emissions.
 Study their evolution as a class.

23. Thanks