Interpreting the GeV-TeV Gamma-Ray Spectra of Local Giant Molecular Clouds using GEANT4 Simulation

Abstract

Recently, the Fermi-LAT gamma-ray satellite has detected six Giant Molecular Clouds (GMCs) located in the Gould Belt and the Aquila Rift regions. In half of these objects (Taurus, Orion A, Orion B), the observed gamma-ray spectrum can be explained using the Galactic diffused Cosmic Ray (CR) interactions with the gas environments. In the remaining three GMCs (Rho Oph, Aquila Rift, Cepheus), the origin of the gamma-ray spectrum is still not well established. We use the GEometry ANd Tracking (GEANT4) simulation framework in order to simulate gamma-ray emission due to CR/GMC interaction in these three objects, taking into account the gas density distribution inside the GMCs. We find that propagation of diffused Galactic CRs inside these GMCs can explain the Fermi-LAT detected gamma-ray spectra. Further, our estimated TeV-PeV fluxes are consistent with the HAWC upper limits, available for the Aquila Rift GMC. As last step, we compute the total neutrino flux estimated for these GMCs and compare it with the IceCube detection sensitivity.

17 pages, 10 figures

References in corpus (20)

• Time-integrated Neutrino Source Searches with 10 years of IceCube Data
• Parametrization of gamma-ray production cross-sections for pp interactions in a broad proton energy range from the kinematic threshold to PeV energies
• Measurement of the cosmic-ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite
• Heliospheric modulation of cosmic rays during the neutron monitor era: Calibration using PAMELA data for 2006--2010
• Gamma rays from molecular clouds
• The Hunt for Pevatrons: The Case of Supernova Remnants
• The ASTRI Mini-Array of Cherenkov Telescopes at the Observatorio del Teide
• ASTRI Mini-Array Core Science at the Observatorio del Teide
• Nuclear enhancement of the photon yield in cosmic ray interactions
• Sensitivity of the Cherenkov Telescope Array to spectral signatures of hadronic PeVatrons with application to Galactic Supernova Remnants
• Evidence of Cosmic-Ray Excess from Local Giant Molecular Clouds
• Star Forming Regions in Cepheus
• Simulation of Cosmic Rays in the Earth's Atmosphere and Interpretation of Observed Counts in an X-ray Detector at Balloon Altitude Near Tropical Region
• Probing the Sea of Cosmic Rays by Measuring Gamma-Ray Emission from Passive Giant Molecular Clouds with HAWC
• Possible contribution of X-ray binary jets to the Galactic cosmic ray and neutrino flux
• Probing LHAASO Galactic PeVatrons through gamma-ray and neutrino correspondence
• GeV Gamma-ray Emission and Molecular Clouds towards Supernova Remnant G35.6$-$0.4 and the TeV Source HESS J1858+020
• What sources are the dominant Galactic cosmic-ray accelerators?
• An interacting molecular cloud scenario for production of gamma-rays and neutrinos from MAGIC J1835-069, and MAGIC J1837-073
• Background model of Phoswich X-ray detector on board small balloon