XZ: X-ray spectroscopic redshifts of obscured AGN

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• Charlotte Simmonds
• Monday 14 August 2017, 11:30-12:30
• Ryle Large Meeting Room, Kavli Building.

If you have a question about this talk, please contact Simon Hodgkin.

Redshifts are fundamental for our understanding of extragalactic X-ray sources. Ambiguous counterpart associations, expensive optical spectroscopy and/or multi-mission multiwavelength coverage to resolve degeneracies make estimation often difficult in practice. Here we present a new method to constrain redshifts from the full X-ray spectrum directly, by Bayesian model fitting of low-resolution spectra. We demonstrate our approach on real Chandra Deep Field South data, determining 29 redshifts which have optical spectroscopic redshifts. Our accuracy is up to ∆z=0.5, with only three outliers which can be explained by incorrect optical associations. Through extensive simulations we verify the method. To work optimally, AGN need be obscured and have at least ∼200 (XMM-Newton) or ∼150 (Chandra/ACIS) counts. Not meeting these conditions does not lead to wrong redshifts, only large uncertainties. We conclude with predictions for the upcoming eROSITA and ATHENA missions.

This talk is part of the Institute of Astronomy Extra Talks series.

This talk is included in these lists:

• Cambridge Astronomy Talks
• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Institute of Astronomy Extra Talks
• Institute of Astronomy Talk Lists
• Ryle Large Meeting Room, Kavli Building

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