1. X-ray Redshifts for Obscured Active Galactic Nuclei with AXIS Deep and Intermediate Surveys.
- Author
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Peca, Alessandro, Cappelluti, Nico, Marchesi, Stefano, Hodges-Kluck, Edmund, and Foord, Adi
- Subjects
ACTIVE galactic nuclei ,REDSHIFT ,X-ray spectra ,X-rays - Abstract
This study presents the capabilities of the AXIS telescope in estimating redshifts from X-ray spectra alone (X-ray redshifts, XZs). Through extensive simulations, we establish that AXIS observations enable reliable XZ estimates for more than 5500 obscured active galactic nuclei (AGNs) up to redshift z ∼ 6 in the proposed deep (7 Ms) and intermediate (375 ks) surveys. Notably, at least 1600 of them are expected to be in the Compton-thick regime ( log N H / cm − 2 ≥ 24 ), underscoring the pivotal role of AXIS in sampling these elusive objects that continue to be poorly understood. XZs provide an efficient alternative for optical/infrared faint sources, overcoming the need for time-consuming spectroscopy, the potential limitations of photometric redshifts, and potential issues related to multi-band counterpart association. This approach will significantly enhance the accuracy of constraints on the X-ray luminosity function and obscured AGN fractions up to high redshifts. This white paper is part of a series commissioned for the AXIS Probe Concept Mission; additional AXIS white papers can be found at the AXIS website. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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