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Natasha Woods Mentors: Marco Ajello & Masaaki Hayashida

Probing the Geometry and Physics of the Emission Region of Active Galactic Nuclei Using Hard X-Ray Observations. Natasha Woods Mentors: Marco Ajello & Masaaki Hayashida. Outline. AGN & Unified Model Testing the Unified Model Results Conclusions. Introduction. AGN

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Natasha Woods Mentors: Marco Ajello & Masaaki Hayashida

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  1. Probing the Geometry and Physics of the Emission Region of Active Galactic Nuclei Using Hard X-Ray Observations Natasha Woods Mentors: Marco Ajello & Masaaki Hayashida

  2. Outline • AGN & Unified Model • Testing the Unified Model • Results • Conclusions

  3. Introduction • AGN • Majority of energy output unrelated to stellar processes • Compact regions, galaxy center, exceedingly luminous • Classification • Radio luminosity • Spectral properties

  4. Unified Model for AGN • All AGN are intrinsically the same • Perceived differences due to viewing orientation • SMBH, accretion disk, molecular torus, corona

  5. Seyfert Galaxies

  6. Evidence For & Against the Unified Model • Polarized broad emission lines in Sy2 • Sy1 <---> Sy2 • Electron temperature • Fraction of absorbed sources

  7. X-ray Spectra • X-Rays • IC Radiation • Direct, Transmitted, Reflected

  8. Reflection Component • IC reflection peak ~30keV, softening spectra (whiteboard) • Sy1 should have a larger reflection component and photon index than Sy2

  9. High Energy Cut-off • Corona's electrons expected to be thermal • Cut-offs for Sy1 and Sy2 should be compatible, corona's properties are independent of orientation

  10. Relevance • ~100% CXB • Constrain cosmological models and black hole physics

  11. Sample Population • ~200 sources • Swift-BAT hard X-ray Survey • 5 sigma significance level • 3 years exposure • Unbiased, blind search

  12. Models for Spectra • Simple power law model (SPL) fit to individual spectra in Xspec11

  13. Photon Index Histograms

  14. Gaussian and Weighted Averages • Gaussian poorly fit some data • Weighted Averages • based on errors • no model

  15. Stacked Spectra • S/N, mean properties • SPL and PEXRAV fit to spectra

  16. Results: SPL Histograms • (KS p-values)

  17. Results: SPL & PEXRAV Stacked Spectra • PEXRAV>SPL • Photon Indices • Reflection • Energy Cut-off

  18. Conclusion • Photon Index Sy1 > Sy2 • PEXRAV > SPL • Reflection compatible, large errors • Energy Cut-offs different • Future

  19. Acknowledgements

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