Speaker: Vardan Baghmanyan

Title: “Evidence of Cosmic-Ray excess from local Giant Molecular Clouds”

Abstract:
The study of cosmic-ray (CR) properties in the Galaxy is particularly efficient through the gamma-ray observations of giant molecular clouds (GMCs), which coincide with clear peaks in the gas distribution along the line of sight from a given direction in the Galaxy. Among them of particular interest have the MCs in the star formation region of the Gould Belt, which because of their convenient position in the sky, are ideal candidates for the gamma-ray studies with Fermi-LAT.
In this work, we present the investigation of the nearby (<1 Mpc) giant MCs of the Gould Belt among with Aquila Rift MC using the Fermi-LAT data above 3 GeV. We show that, against expectations, the gamma-ray spectra of Aquila Rift, Rho Oph, and Cepheus have sufficient enhancement over the model expected from the AMS-02 CR measurements, which suggests additional particle acceleration or different propagation effects in the cloud. Assuming that the additional gamma-rays in these clouds are due to pion-decay interactions, we restore the corresponding excess CR spectrum for each cloud and discuss the origin of the detected excess emission.