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arXiv · 1903.12097

A new measurement of the Hubble constant and matter content of the Universe using extragalactic background light $\gamma$-ray attenuation

Alberto Domínguez·Radoslaw Wojtak·Justin Finke·Marco Ajello·Kari Helgason·Francisco Prada·Abhishek Desai·Vaidehi Paliya·Lea Marcotulli·Dieter Hartmann
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Abstract

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 $\Omega_{m}=0.29\pm 0.02$.

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Alberto Domínguez, Radoslaw Wojtak, Justin Finke, Marco Ajello, Kari Helgason, Francisco Prada, Abhishek Desai, Vaidehi Paliya, Lea Marcotulli, Dieter Hartmann. 2019-03-28. A new measurement of the Hubble constant and matter content of the Universe using extragalactic background light $\gamma$-ray attenuation. https://doi.org/10.3847/1538-4357%2Fab4a0e

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