A complementary view of the Galactic plane in TeV gamma rays by HAWC and H.E.S.S

The H.E.S.S. collaboration recently published its Galactic Plane Survey, which is a deep survey of half of the Milky Way in TeV gamma-rays, using almost 10 years of observations. It contains 78 sources, including 16 new sources. On the other hand, the HAWC collaboration also published its 2HWC catalogue based on 507 days of data. It is the result of the first source search performed with the complete HAWC detector, covering two thirds of the sky. In this search, 39 sources have been reported, amongst them 16 detected for the first time at TeV energies. The HAWC data set doubled since then, revealing 10 more sources. Both instruments are very different in terms of conception, observation and regarding event analysis and reconstruction, but they operate at a similar energy range. In a sense, they are very complementary. I will present a comparison of the Galactic plane seen by both instruments in the overlapping region, highlight the similarities and differences which arise from intrinsic properties of the instruments and from their dedicated data analysis, and show that background estimation is a major ingredient.