Looking for the Signals of the Missing Baryons in the Extragalactic Background Light

TL;DR

This paper proposes that high-energy electron/positron rays could illuminate the warm-hot intergalactic medium (WHIM), causing excess extragalactic background light (EBL), offering a new method to detect missing baryons in the universe.

Contribution

It introduces a novel approach using anomalous bremsstrahlung from high-energy particles to detect the WHIM through EBL measurements, addressing the missing baryon problem.

Findings

High-energy electrons/positrons can light up the WHIM via anomalous bremsstrahlung.

Excess EBL may explain discrepancies between direct and indirect measurements.

Proposes a new observational window to study the universe's missing baryons.

Abstract

The missing baryons in the universe are assumed to be hidden in the whole space as a warm-hot intergalactic medium (WHIM). Finding them is one of the important subjects in modern cosmology. In this paper, we point out that the very high energy electron/positron rays may light up the WHIM due to the anomalous bremsstrahlung according to an improved Bethe-Heitler formula. The resulting excess of the extragalactic background light (EBL) can be observed by the direct measurement method. A possible explanation on the difference between the direct and indirect measurements of EBL is also proposed. Thus, we find a new window to probe the WHIM properties via the EBL.