SIMBAD references

2020A&A...642A.150L - Astronomy and Astrophysics, volume 642A, 150-150 (2020/10-1)

Quasars as standard candles. III. Validation of a new sample for cosmological studies.

LUSSO E., RISALITI G., NARDINI E., BARGIACCHI G., BENETTI M., BISOGNI S., CAPOZZIELLO S., CIVANO F., EGGLESTON L., ELVIS M., FABBIANO G., GILLI R., MARCONI A., PAOLILLO M., PIEDIPALUMBO E., SALVESTRINI F., SIGNORINI M. and VIGNALI C.

Abstract (from CDS):

We present a new catalogue of ∼2400 optically selected quasars with spectroscopic redshifts and X-ray observations from either Chandra or XMM-Newton. The sample can be used to investigate the non-linear relation between the ultraviolet (UV) and X-ray luminosity of quasars as well as to build a Hubble diagram up to a redshift of z∼7.5. We selected sources that are neither reddened by dust in the optical and UV nor obscured by gas in the X-rays, and whose X-ray fluxes are free from flux-limit-related biases. After checking for any possible systematics, we confirm, in agreement with our previous works, that the X-ray to UV relation provides distance estimates matching those from supernovae up to z∼1.5, and its slope shows no redshift evolution up to z∼5. We provide a full description of the methodology for testing cosmological models, further supporting a trend whereby the Hubble diagram of quasars is well reproduced by the standard flat cold dark matter model up to z∼1.5-2, but strong deviations emerge at higher redshifts. Since we have minimised all non-negligible systematic effects and proven the stability of the LX-LUV relation at high redshifts, we conclude that an evolution of the expansion rate of the Universe should be considered as a possible explanation for the observed deviation, rather than some systematic (redshift-dependent) effect associated with high-redshift quasars.

Abstract Copyright: © ESO 2020

Journal keyword(s): galaxies: active - quasars: general - quasars: supermassive black holes - methods: statistical

VizieR on-line data: <Available at CDS (J/A+A/642/A150): table3.dat>

Simbad objects: 2429

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2023.01.31-02:17:39

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