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GTN The GLAST Telescope Network

GTN The GLAST Telescope Network. Involvement for students and teachers in the science of the GLAST mission Gordon G. Spear Sonoma State University March 2003. GTN. What is it? (some motivation) Gamma-rays, AGNs, Blazars How does it work?

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GTN The GLAST Telescope Network

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  1. GTNThe GLAST Telescope Network Involvement for students and teachers in the science of the GLAST mission Gordon G. Spear Sonoma State University March 2003

  2. GTN • What is it? (some motivation) • Gamma-rays, AGNs, Blazars • How does it work? • Observe using telescopes w/CCDs, analyze and submit data, help others • Join us! • Involvement with exciting science, support the GLAST mission

  3. What is the GTN? • Collaboration among small observatories and observers • Surveillance, lead-up, and follow-up observations of blazars and related objects to be observed by GLAST • Archive magnitude measurements and CCD images • Students, teachers, amateur astronomers, professional astronomers

  4. Science Objectives • Establish base-line optical activity levels for bright, Gamma-loud AGNs • Provide optical lead-up and follow-up observations for GLAST targets • Provide optical triggers for observations by GLAST

  5. What are Gamma-rays? • Just photons, but with very high energies • Photons with energies billions of times greater than visible light photons • Natural sources of Gamma-rays • Man made sources of Gamma-rays • Gamma-rays from space

  6. How are Gamma-rays characterized? • Gamma-rays are characterized by the energy of individual photons. • Energies generally measured in MeV and GeV (millions and billions of eV). • Infrared photons have energies on the order of eV. • One erg is about 600 billion eV (600 GeV). • The erg and the mosquito?

  7. The Objects in the Gamma-Ray Sky • Milky Way glow from cosmic ray interactions with dust • Point sources in the Milky Way are Gamma-ray pulsars (SNRs) • Point sources outside the Milky Way are AGNs (these are the blazars) • Some point sources remain unidentified

  8. AGNs • Active Galactic Nuclei • Extragalactic objects that are more luminous than normal galaxies • The nucleus can be 10 to 100 times brighter than an entire normal galaxy • The underlying galaxy can appear relatively normal (when it can be seen) • Many different types or sub-classes (including Seyfert galaxies, radio galaxies, quasars, and blazars)

  9. A Typical QuasarPKS 1117-248

  10. General Characteristics of AGNs • Extragalactic • More luminous than normal galaxies • Generally point sources (stellar appearance) • Some exhibit jets • Bright in X-rays and Gamma-rays • All exhibit variability at some level!

  11. AGN Unification • All AGN are manifestations of the same physical phenomenon • This phenomenon is the accretion disk and jets associated with a supermassive black hole • The different appearances are simply due to the orientation of the jets and disk to our line of sight

  12. Artistic Impression of an AGN

  13. Voyage into an AGNA Simulation • Starts 100s of Mpc away from AGN • Underlying galaxy is a spiral (20000 stars) • The AGN engine has been switched off • Size scale changes by 10 orders of magnitude

  14. The Blazars • The blazars appear to be AGN for which the jets are pointing directly at us. • We are looking directly down the throat of the dragon! • Spectra (SEDs) have bright compton peak in addition to the typical AGN synchrotron peak. • These are the only prominent point sources in the Gamma-ray sky. (Gamma loud) • Beams of particles moving at relativistic speeds produce intense beams of Gamma-rays. • These are the most variable of the AGNs.

  15. The Synchrotron ProcessProbably produces the synchrotron peak

  16. Inverse Compton ScatteringProbably produces the compton peak

  17. AGN Variability? • All AGNs appear to be variable at some level • The emission lines vary in strength • The continuum levels vary in brightness • Variability has been documented over decades, years, months, weeks, days, and even hours

  18. Characteristics of AGN Variability • Periodicity has NOT been convincingly demonstrated! • Slow, longterm irregular changes • Outbursts (flares) and declines • General increase in variability for shorter wavelengths (higher energy photons) • General increase in variability for longer time scales • Apparent increase in variability with luminosity • Apparent increase in variability with redshift

  19. Available observations Longterm (few per year) Intraday (few per week) Microvariability (many per hour) Lightcurve classification Outbursts Declines Outbursts and declines The blazars Most variable of the AGNs Amplitudes to 4 magnitudes or more Can exhibit detectable variations from night-to-night and within a night AGN Variability Data

  20. A Blazar with a Long History of Observation

  21. B2 1308+326 outbursts B2 1215+303 declines

  22. B2 1215+303 outbursts and declines PG 0804+762 non-blazar AGN

  23. Intraday Variability

  24. BL Lac 0.4 mag in 30 minutes Mrk 501 0.1 mag miniflare

  25. The GTN What is it? The Optical Eyes of GLAST

  26. How does it work? • Small telescopes with CCDs • Schools, students,amateurs, professionals • AAVSO partnership • Robotic telescope systems are ideal • Target objects • One or more objects observable any time of year • Observing techniques • Reduction techniques

  27. Some Examples of GTN Data 3C66A V-filter, stack of 4 2-minute exposures

  28. 3C66A - SSUO & AAVSO

  29. Sonoma State University Observatory

  30. The SSU Robotic Telescope System • Paramount-ME w/Celestron-14 and Apogee AP-47 • 0.4 meter telescope, point to better than 10 arcseconds, track to better than 2 arcsec, CCD with better than 90% QE • Capable of reliable photometry to 18th magnitude • Currently being tested at SSUO • Will be installed at dark site and begin science observations in 2003 • Observe GTN blazar fields every clear night beginning 2003 and continuing through the GLAST mission

  31. Testing the SSU Robotic Telescope Likely dark site installation

  32. How can you participate and contribute? • Obtain CCD observations of GTN blazars • Provide telescope time or telescope access for GTN participants • Reduce and analyze CCD data obtained by other GTN participants • Participate in intense microvariability campaigns • Mentor GTN participants in observing procedures, data reduction, basic astronomy

  33. What is in it for you? • Participation in a significant research program supporting a major space observatory • Opportunities for collaboration with other GTN participants and GLAST scientists • Access to the data in the GTN archive • Announcements of outbursts and other activity reported for blazars and other AGNs • GTN Newsletter (including news about GLAST) • Tutorials and curriculum materials

  34. The GTN Join with us! • Exciting science. • Student projects. • Contribute to the GLAST mission. • Involvement with a major space observatory.

  35. http://glast.sonoma.edu/gtn The Optical Eyes of GLAST

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