The Hubble constant H _ { 0 } and matter density \Omega _ { m } of the Universe are measured using the latest \gamma -ray attenuation results from Fermi -LAT and Cherenkov telescopes .
This methodology is based upon the fact that the extragalactic background light supplies opacity for very high energy photons via photon-photon interaction .
The amount of \gamma -ray attenuation along the line of sight depends on the expansion rate and matter content of the Universe .
This novel strategy results in a value of H _ { 0 } = 67.4 _ { -6.2 } ^ { +6.0 } km s ^ { -1 } Mpc ^ { -1 } and \Omega _ { m } = 0.14 _ { -0.07 } ^ { +0.06 } .
These estimates are independent and complementary to those based on the distance ladder , cosmic microwave background ( CMB ) , clustering with weak lensing , and strong lensing data .
We also produce a joint likelihood analysis of our results from \gamma rays and these from more mature methodologies , excluding the CMB , yielding a combined value of H _ { 0 } = 66.6 \pm 1.6 km s ^ { -1 } Mpc ^ { -1 } and \Omega _ { m } = 0.29 \pm 0.02 .