A Hubble Diagram for Quasars

Bisogni, Susanna; Risaliti, Guido; Lusso, Elisabeta

doi:10.3389/fspas.2017.00068

A Hubble Diagram for Quasars

Bisogni, Susanna; Risaliti, Guido; Lusso, Elisabeta

Authors

Susanna Bisogni

Guido Risaliti

Dr Elisabeta Lusso elisabeta.lusso@durham.ac.uk
Academic Visitor

Abstract

The cosmological model is at present not tested between the redshift of the farthest observed supernovae (z ~ 1.4) and that of the Cosmic Microwave Background (z ~ 1,100). Here we introduce a new method to measure the cosmological parameters: we show that quasars can be used as “standard candles” by employing the non-linear relation between their intrinsic UV and X-ray emission as an absolute distance indicator. We built a sample of ~1,900 quasars with available UV and X-ray observations, and produced a Hubble Diagram up to z ~ 5. The analysis of the quasar Hubble Diagram, when used in combination with supernovae, provides robust constraints on the matter and energy content in the cosmos. The application of this method to forthcoming, larger quasar samples, will also provide tight constraints on the dark energy equation of state and its possible evolution with time.

Citation

Bisogni, S., Risaliti, G., & Lusso, E. (2018). A Hubble Diagram for Quasars. Frontiers in Astronomy and Space Sciences, 4, Article 68. https://doi.org/10.3389/fspas.2017.00068

Journal Article Type	Article
Acceptance Date	Dec 19, 2017
Online Publication Date	Jan 8, 2018
Publication Date	Jan 8, 2018
Deposit Date	Apr 13, 2018
Publicly Available Date	Apr 13, 2018
Journal	Frontiers in Astronomy and Space Sciences
Publisher	Frontiers Media
Peer Reviewed	Peer Reviewed
Volume	4
Article Number	68
DOI	https://doi.org/10.3389/fspas.2017.00068

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Copyright Statement
© 2018 Bisogni, Risaliti and Lusso. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.