# The Realm of the First Quasars in the Universe: the X-ray View

**Authors:** C. Vignali (1), W.N. Brandt (2), O. Shemmer (2), A. Steffen (2), D.P., Schneider (2), S. Kaspi (3,4) (Dipartimento di Astronomia, Universita' di, Bologna, Italy; (2) Department of Astronomy, Astrophysics, Pennsylvania, State University, University Park, USA; (3) Wise Observatory, Tel Aviv, University, Israel; (4) Physics Department, Technion, Haifa, Israel)

arXiv: 0704.1299 · 2007-05-23

## TL;DR

This paper reviews X-ray observations of high-redshift quasars, highlighting their similar properties to local quasars and suggesting that their small-scale X-ray emission regions are unaffected by cosmic evolution.

## Contribution

It provides a comprehensive review of X-ray properties of z>4 quasars, emphasizing the consistency across cosmic time and the implications for AGN emission regions.

## Key findings

- X-ray properties of high-redshift quasars are similar to local ones
- Small-scale X-ray emission regions are insensitive to cosmic evolution
- Supports the universality of AGN X-ray emission mechanisms

## Abstract

We review the X-ray studies of the highest redshift quasars, focusing on the results obtained with Chandra and XMM-Newton. Overall, the X-ray and broad-band properties of z>4 quasars and local quasars are similar, suggesting that the small-scale X-ray emission regions of AGN are insensitive to the significant changes occurring at z=0-6.

## Full text

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## Figures

3 figures with captions in the complete paper: https://tomesphere.com/paper/0704.1299/full.md

## References

14 references — full list in the complete paper: https://tomesphere.com/paper/0704.1299/full.md

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Source: https://tomesphere.com/paper/0704.1299