All-sky search for time-integrated neutrino emission from astrophysical sources with 7 years of IceCube data

Since the recent detection of an astrophysical flux of high energy neutrinos, the question of its origin has not yet fully been answered. Much of what is known about this flux comes from a small event sample of high neutrino purity, good energy resolution, but large angular uncertainties. In searches for point-like sources, on the other hand, the best performance is given by using large statistics and good angular reconstructions. Track-like muon events produced in neutrino interactions satisfy these requirements. We present here the results of searches for point-like sources with neutrinos using data acquired by the IceCube detector over seven years from 2008--2015. The discovery potential of the analysis in the northern sky is now significantly below $E_\nu^2d\phi/dE_\nu=10^{-12}\:\mathrm{TeV\,cm^{-2}\,s^{-1}}$, on average $38\%$ lower than the sensitivity of the previously published analysis of four years exposure. No significant clustering of neutrinos above background expectation was observed, and implications for prominent neutrino source candidates are discussed.Comment: 19 pages, 17 figures, 3 tables; ; submitted to The Astrophysical Journa

The contribution of Fermi-2LAC blazars to the diffuse TeV-PeV neutrino flux

The recent discovery of a diffuse cosmic neutrino flux extending up to PeV energies raises the question of which astrophysical sources generate this signal. One class of extragalactic sources which may produce such high-energy neutrinos are blazars. We present a likelihood analysis searching for cumulative neutrino emission from blazars in the 2nd Fermi-LAT AGN catalogue (2LAC) using an IceCube neutrino dataset 2009-12 which was optimised for the detection of individual sources. In contrast to previous searches with IceCube, the populations investigated contain up to hundreds of sources, the largest one being the entire blazar sample in the 2LAC catalogue. No significant excess is observed and upper limits for the cumulative flux from these populations are obtained. These constrain the maximum contribution of the 2LAC blazars to the observed astrophysical neutrino flux to be $27 \%$ or less between around 10 TeV and 2 PeV, assuming equipartition of flavours at Earth and a single power-law spectrum with a spectral index of $-2.5$. We can still exclude that the 2LAC blazars (and sub-populations) emit more than $50 \%$ of the observed neutrinos up to a spectral index as hard as $-2.2$ in the same energy range. Our result takes into account that the neutrino source count distribution is unknown, and it does not assume strict proportionality of the neutrino flux to the measured 2LAC $\gamma$-ray signal for each source. Additionally, we constrain recent models for neutrino emission by blazars.Comment: 18 pages, 22 figure

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info:eu-repo/semantics/publishe

Understanding and addressing shortfalls in European wild bee data

Understanding and reversing biodiversity decline in the Anthropocene requires robust data on species taxonomic identity, distribution, ecology, and population trends. Data deficits hinder biodiversity assessments and conservation, and despite major advances over the past few decades, our understanding of bee diversity, decline and distribution in Europe is still hampered by such data shortfalls. Using a unique digital dataset of wild bee occurrence and ecology, we identify seven critical shortfalls which are an absence of knowledge on geographic distributions, (functional) trait variation, population dynamics, evolutionary relationships, biotic interactions, species identity, and tolerance to abiotic conditions. We describe “BeeFall,” an interactive online Shiny app tool, which visualizes these shortfalls and highlights missing data. We also define a new impediment, the Keartonian Impediment, which addresses an absence of high-quality in situ photos and illustrations with diagnostic characteristics and directly affects the outlined shortfalls. Shortfalls are highly correlated at both the provincial and national scales, identifying key areas in Europe where knowledge gaps can be filled. This work provides an important first step towards the long-term goal to mobilize and aggregate European wild bee data into a multi-scale, easy access, shareable, and updatable database which can inform research, practice, and policy actions for the conservation of wild bees.SCOPUS: ar.jinfo:eu-repo/semantics/publishe