Q0906+6930: The Q0906+6930: The Highest Redshift BlazarHighest Redshift Blazar
GLAST for Lunch – 11.18.04GLAST for Lunch – 11.18.04David Sowards-EmmerdDavid Sowards-Emmerd
Quiz from previous talk: What’s wrong with this slide????
How did we find it?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 positionColor + faint + radio as a possible method for selecting hi-z radio bright quasars.
Survey SelectionSurvey 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.
J0906+6930J0906+6930Very 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…
Spectroscopy IssuesSpectroscopy Issues• Wavelength range – dependent on setup• Resolution vs. S/N• Order overlap – worse with HET• Blocking filters• Sky subtraction• Near-IR flux calibration• Fringing
Properties of J0906+6930Properties of J0906+6930
RadioS1.4 = 91 mJyS8.4 = 188 mJyS15 = 115 mJyS43 = 42 mJyα1.4-8.4 = -0.4OpticalI ~ 23X-ray Not detected by RASSγ-rayEGRET – 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
BroadbandBroadband SED SED
Redshifted 3C279 SED for comparison.
Fun with SSC models!
VLBA Follow-upVLBA Follow-up
15 GHz 43 GHz
JET!(multi-epoch obs. would be nice!)
X-ray Follow-upX-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.
Black Hole Mass EstimatesBlack 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.
Related Future Lunch Talk IdeasRelated Future Lunch Talk Ideas• EBL attenuation
• CMB upscatter in jets
• Black hole mass estimates
• AGN classification (unrelated)