Using quasar and gamma-ray burst measurements to constrain cosmological dark energy models

Understand

Observational evidence for the accelerated expansion of the universe requires dark energy for its explanation if general relativity is an accurate model of gravity.

• However, dark energy is a mysterious quantity and we do not know much about its nature so understanding dark energy is an exciting scientific challenge.
• Cosmological dark energy models are fairly well tested in the low and high redshift parts of the universe.
• The highest of the low redshift, $z\sim2.3$, region is probed by baryon acoustic oscillation (BAO) measurements and the only high redshift probe is the cosmic microwave background anisotropy which probes the $z\sim1100$ part of redshift space.