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)