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Variability Study of Fermi Blazars

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. Standard model for AGNs. An extragalactic object

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Variability Study of Fermi Blazars

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  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, 108-109 solar masses. • Active Galactic Nucleus • The point source can be 10-100 times the brightness of the underlying galaxy • ~ 10 • Some exhibit jets

  3. 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 3C 279‏ • TeV Blazar PKS 2155-304 ‏

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

  8. Results:

  9. AO 0235+164

  10. B2 1520+31

  11. PKS 2155-304

  12. 3C 279

  13. 3C 66A

  14. Summary

  15. Blazar FSRQs BL Lacs 281 FSRQs 291 BL Lacs

  16. The source We Studied FSRQ BL Lac

  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:

  19. Borrowed from Benoit Lott presentation 3c279 Mrk 421

  20. Variation of Spectral Index with Flux

  21. 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.

  22. Thanks

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