Multiple measurements of quasars acting as standard probes: model independent calibration and exploring the Dark Energy Equation of States

Understand

Recently, two classes of quasar samples were identified, which are promising as new cosmological probes extending to higher redshifts.

• The first sample uses the nonlinear relation between the ultraviolet and X-ray luminosities of quasars to derive luminosity distances, whereas the linear sizes of compact radio quasars in the second sample can serve as standardized rulers, providing angular-diameter distances.
• In this study, under the assumption of a flat universe, we refreshed the calibration of multiple measurements of high-redshift quasars (in the framework of a cosmological-model-independent method with the newest Hubble parameters data).
• Furthermore, we placed constraints on four models that characterize the cosmic equation of state ($w$).