Investigating the correlations between IceCube high-energy neutrinos and Fermi-LAT <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>-ray observations
Rong-Lan Li, Ben-Yang Zhu, Yun-Feng Liang
Abstract
We use ten years of publicly available IceCube data to investigate the correlations between high-energy neutrinos and various Fermi-LAT gamma-ray samples. This work considers the following gamma-ray samples: the third Fermi-LAT catalog of high-energy sources (3FHL), $>100\text{ }\text{ }\mathrm{GeV}$ Fermi-LAT events, the LAT 12-year source catalog (4FGL), the fourth catalog of active galactic nuclei (4LAC), and subsets of these samples. For each sample, both a single-source analysis and a stacking analysis are performed. We find no indication that the sources in these samples produce significant high-energy neutrinos. From the null search results, we infer that each source population can produce no more than $\ensuremath{\sim}2.5%--36%$ (at the 95% confidence level, for a spectral index of $\ensuremath{-}2.5$) of the IceCube's diffuse neutrino flux. Since we are using a larger (ten-year) dataset of IceCube neutrinos, the constraints are improved by a factor of $\ensuremath{\sim}2$ compared to those based on three years of data.