Measurement of the Extragalactic Background Light with VERITAS

Understand

The extragalactic background light records the history of infrared, optical and ultraviolet light radiation including re-radiation since the epoch of reionization.

• While challenging to measure directly, it can be measured indirectly via its impact on observed spectra of extragalactic gamma-ray emitters.
• VERITAS, a ground-based imaging atmospheric-Cherenkov telescope array sensitive to gamma rays above 100 GeV, has accrued 10 years of observations of hard-spectrum blazars.
• The energy and redshift range covered enables the measurement of the EBL in the range 0.56-56~$\mu$m, accessing the poorly constrained cosmic infrared background region.