TeV gamma-ray survey of the northern sky using the ARGO-YBJ detector

The Astrophysical Radiation with Ground-based Observatory at Yang Ba Jing (ARGO-YBJ) detector is an extensive air shower array that has been used to monitor the northern gamma-ray sky at energies above 0.3 TeV from 2007 November to 2013 January. In this paper, we present the results of a sky survey in the declination band from -10 degrees to 70 degrees, using data recorded over the past five years. With an integrated sensitivity ranging from 0.24 to similar to 1 Crab units depending on the declination, six sources have been detected with a statistical significance greater than five standard deviations. Several excesses are also reported as potential gamma-ray emitters. The features of each source are presented and discussed. Additionally, 95% confidence level upper limits of the flux from the investigated sky region are shown. Specific upper limits for 663 GeV gamma-ray active galactic nuclei inside the ARGO-YBJ field of view are reported. The effect of the absorption of gamma-rays due to the interaction with extragalactic background light is estimated.