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In this paper we report the results of a $gamma$-ray study of IceCubes extraterrestrial neutrino candidates detected as track-like events. Using 70 months of Fermi-LAT observations, a likelihood analysis of all $1-300$ GeV photons within 5 degrees of the track-like neutrino candidates origin was undertaken, to search for spatially coincident $gamma$-ray emission. One of IceCubes HESE track events was found to be spatially coincident with a $gamma$-ray bright active galactic nucleus (AGN), PKS 0723-008. We find however, that the chance probability for Fermi-LAT detected AGN to be spatially coincident with a single HESE track-like event is high ($sim37$%). We therefore find no evidence of $gamma$-ray emission associated with the detection of IceCubes HESE track-like neutrino candidates. Upper limits were calculated in the energy range of $1-300$ GeV, assuming a point source origin for the neutrino events considered. The implications for the non-detection of $gamma$-ray emission from the source of the HESE track-like events are briefly discussed. The large time period analysed in our study did however, reveal two new $gamma$-ray point sources. With a flux of ($1.28 pm 0.08$) $times 10^{-9}$ photons cm$^{-2}$ s$^{-1}$, in the $1-300$ GeV energy range, and an associated TS value of 220.6, one of these new point sources is positionally coincident with the AGN PKS 1346-112. The other point source has a $1-300$ GeV flux of ($7.95 pm 1.23$) $times 10^{-10}$ photons cm$^{-2}$ s$^{-1}$ and an associated TS value of 92.4. This new point source is spatially coincident with the radio source NVSS J072534+021645 suggesting that it too is an AGN.
The Baikal Gigaton Volume Detector (Baikal-GVD) is a km$^3$-scale neutrino detector currently under construction in Lake Baikal, Russia. The detector currently consists of 2304 optical modules arranged on 64 vertical strings. Further extension of the
We report on the first search for extra-terrestrial neutrino-induced cascades in IceCube. The analyzed data were collected in the year 2007 when 22 detector strings were installed and operated. We will discuss the analysis methods used to reconstruct
Very recently, diffuse gamma rays with $0.1,{rm PeV}<E_gamma <1,rm PeV$ have been discovered from the Galactic disk by the Tibet air shower array and muon detector array (Tibet AS+MD array). While the measured sub-PeV flux may be compatible with the
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The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope observatory is a pair conversion telescope sensitive to gamma-rays over more than four energy decades, between 20 MeV and more than 300 GeV. Acting in synergy with the Gamma-ray Bu