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 $\Omega_{ m}=0.29\pm 0.02$.
Categories: astro-ph.CO