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Q0906+6930: The Highest Redshift Blazar

Q0906+6930: The Highest Redshift Blazar. GLAST for Lunch – 11.18.04 David Sowards-Emmerd. Quiz from previous talk: What’s wrong with this slide????. How did we find it?. Serendipity! J0906+6930 was part of a radio/X-ray selected survey of EGRET -like blazar candidates.

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Q0906+6930: The Highest Redshift Blazar

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  1. Q0906+6930: The Highest Redshift Blazar GLAST for Lunch – 11.18.04 David Sowards-Emmerd Quiz from previous talk: What’s wrong with this slide????

  2. How did we find it? • Serendipity! J0906+6930 was part of a radio/X-ray selected • survey of EGRET-like blazar candidates. • Very faint optical counterpart at precise radio position • Color + faint + radio as a possible method for selecting hi-z radio bright quasars.

  3. Survey Selection • Motivation: GLAST should detect thousands of blazars, • the current samples contain only ~hundreds of blazars. • Coordinated observing campaigns are much easier if there’s • a source list to work from. • Selected 710 sources (northern hemisphere) using our • Figure of Merit ranking technique. • Significant correlation of these candidate blazar source • positions with residual/background EGRET photons.

  4. J0906+6930 Very significant detection of the Lyman break along with several other lines. Exact redshift is a bit uncertain due to absorption of Lyα To be re-observed with a different setup at HET – instrument issues…

  5. Spectroscopy Issues • Wavelength range – dependent on setup • Resolution vs. S/N • Order overlap – worse with HET • Blocking filters • Sky subtraction • Near-IR flux calibration • Fringing

  6. Properties of J0906+6930 Radio S1.4 = 91 mJy S8.4 = 188 mJy S15 = 115 mJy S43 = 42 mJy α1.4-8.4 = -0.4 Optical I ~ 23 X-ray Not detected by RASS γ-ray EGRET – upper limit only – lies in the overlap between two 3EG sources So… why do we believe it’s a blazar?  Implications for SZ/CMB experiments

  7. Broadband SED Fun with SSC models! Redshifted 3C279 SED for comparison.

  8. VLBA Follow-up  JET! (multi-epoch obs. would be nice!) 15 GHz 43 GHz

  9. X-ray Follow-up CHANDRA Observations to search for CMB photons Compton upscattered by the jet. Similar observations have been performed for other high-z quasars, but few X-ray jets (non-core components) have been seen.

  10. Black Hole Mass Estimates Follow-up optical spectroscopy is needed to place better constraints on the mass of the central black hole The SiIV/OIV line is not ideal for this, but it’s the only line we’ve got at the moment.

  11. Related Future Lunch Talk Ideas • EBL attenuation • CMB upscatter in jets • Black hole mass estimates • AGN classification (unrelated)

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