The Fermi bubble study with future gamma ray experiments
The Fermi bubbles (FBs) are two giant gamma-ray lobes above and below the Galactic center. Their origin is not clear yet and both hadronic and leptonic models are currently allowed. In the hadronic model, the acceleration of protons and/or nuclei and their subsequent interactions with gas in the bubble volume can produce the observed gamma rays and high-energy neutrinos as counterparts. The detection of neutrinos can discriminate between a hadronic and a leptonic origin of the FB. Recently HAWC reported no gamma ray excess from the northern bubble at high latitude, which agrees with Fermi measurements. However, due to the limitation of the searching region and energy at HAWC, the hadronic model is not constrained for the central region of the FB. Here we present a sensitivity study of Cherenkov Telescope Array (CTA) to our FB hadronic model with the morphological analysis and classical on/off analysis based on the realistic CTA deep central and extended survey. As a complement, and for comparison, we study the detectability of the FBs with the future ground-based Cherenkov detector LHAASO as well.