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Multicolor Microvariability Observations of BL Lac Object: 1ES 1959+650

Multicolor Microvariability Observations of BL Lac Object: 1ES 1959+650. Whitney Wills Advisor: Michael Carini Western Kentucky University. Manufacturer: Group 128 Primary Diameter: 0.6m f-ratio: 11 Design: True Cassegrain Started building process in 1975.

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Multicolor Microvariability Observations of BL Lac Object: 1ES 1959+650

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  1. Multicolor Microvariability Observations of BL Lac Object: 1ES 1959+650 Whitney Wills Advisor: Michael Carini Western Kentucky University

  2. Manufacturer: Group 128 Primary Diameter:0.6m f-ratio: 11 Design: True Cassegrain Started building process in 1975 Bell Astrophysical Observatory

  3. Bell Astrophysical Observatory • Refurbishment 1999-2000 • Apogee Ap2p CCD camera • Image scale: 0.59arc/pixel, binned 2x2

  4. Major Projects at Bell • AGN Monitoring – Dr. Michael Carini • Transiting Extra Solar Planets – Dr. Charles McGruder • Monitoring of Wolf-Rayet Stars – Dr. Sergey Marchenko • HOU – Dr. Barnaby • Jupiter and Saturn Week 2002-2003

  5. Observations • Student run sessions from WKU’s campus or onsite • Exposures of 180sec in V and I filters • Continuous monitoring for approximately 8 hrs

  6. What are Active Galactic Nuclei? 1 Normal Galaxy

  7. Normal Galaxies Spiral: M31 Elliptical: M87 Irregular: LMC

  8. What are Active Galactic Nuclei? 1 Normal Galaxy + 1 Super Massive Black Hole at Center

  9. Super Massive Black Hole

  10. What are Active Galactic Nuclei? 1 Normal Galaxy + 1 Super Massive Black Hole at Center + 1 Accretion Disk

  11. Accretion Disk

  12. What are Active Galactic Nuclei? 1 Normal Galaxy + 1 Super Massive Black Hole at Center + 1 Accretion Disk + 2 Relativistic Jets of Material

  13. Relativistic Jets

  14. What are Active Galactic Nuclei? 1 Normal Galaxy + 1 Super Massive Black Hole at Center + 1 Accretion Disk + 2 Relativistic Jets of Material =AGN

  15. Active Galactic Nuclei

  16. What are BL Lacertae Objects? • The most extreme example of an AGN • Highly variable polarization • Featureless optical spectra • Highly variable continuum emission at all wavelengths

  17. LBL vs. HBL Urry, C.M., Advances in Space Research, Vol. 21, Issue 1-2, p. 89, 1998

  18. Why Study Them? • Featureless continuum means continuum radiation is the only diagnostic • Models of AGNs need data • External Compton scattering model • Radio and optical radiation up-scattered to gamma-ray radiation • Predicts wavelength dependent lag • Short timescales--microvariability

  19. Microvariability • Variations with timescales of hours • Provide the tightest constraints on the size of the emission region

  20. Reductions • Image Reduction and Analysis Facility (IRAF) • Removed background and thermal noise from the pictures (Bias and Dark levels) and removed non-linearity (flat field) • Measured the brightness inside a circular aperture centered on the star

  21. Before Reduction

  22. After Reduction

  23. Finding the Aperture • Used an image examiner tool in IRAF • Found the full width, half max of the point spread function of the object and each of the comparison stars • Took the average of the fwhm and used it as the aperture radius in a parameter in IRAF

  24. Calculating Differential Magnitudes & Errors • Using the Phot tool in IRAF, magnitudes were found • Using these magnitudes, the difference between the object and comp stars were found • This new differential magnitude was then plotted against the UT time • The standard deviation between each of the images was used for the error

  25. OJ 287 (LBL)

  26. 1ES 1959+650 (HBL)

  27. Light Curve –1 ES1959+650 I Filter

  28. Light Curve – 1ES 1959+650 V Filter

  29. Light Curves – BL Lac (LBL) Tosti, G. et al., BL Lac Phenomenon, ASP Conference Series volume 159 (1999)

  30. Light Curves – MRK 501 (HBL) Miller , H. R. et al., BL Lac Phenomenon, ASP Conference Series, volume 159, 75 (1999)

  31. Conclusions • Need more data! • Need to increase the exposure time to 240 seconds

  32. Work with 0.6m telescope that included gathering data and troubleshooting Actual experience with software professional astronomers use (IRAF) Experience presenting research at conferences at and away from WKU: Argonne Undergraduate Symposium (2002 & 2003) AAS: 2003 Summer & 2004 Winter Meetings Sigma Xi – Honorable Mention Posters at the Capital (2002 & 2003) WKU Student Colloquia Invited Speaker at NSSTC Opportunities

  33. Telescope Operators: Dr. Michael Carini Dr. David Barnaby Whitney Wills Data Analysts: Dr. Michael Carini Whitney Wills Acknowledgements This project has been supported by NASA, the Kentucky Space Grant Consortium and the Applied Research and Technology Program at WKU

  34. Questions?

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