The realization of multimessenger astrophysics is opening up a new field of exploration of the most energetic phenomena in the universe. Astrophysical messengers associated with each of the four ...fundamental forces reach detectors buried deep underground or underwater, spread across wide swaths of land, and orbiting high above us in space. Recent detection of coincident real-time signals amongst these experiments heralds the birth of high-energy multimessenger astronomy and enables us to begin exploring and understanding their astrophysical sources. The Astrophysical Multimessenger Observatory Network (AMON) is currently linking multiple current and future high-energy neutrino, cosmic ray, gamma ray and gravitational wave observatories into a single virtual system, facilitating real-time coincidence searches for multimessenger astrophysical transients. AMON will generate alerts that will enable rapid follow-up of potential electromagnetic counterparts. We present the science case, design elements, partner observatories, and status of AMON.
We summarize the science opportunity, design elements, current and projected partner observatories, and anticipated science returns of the Astrophysical Multimessenger Observatory Network (AMON). ...AMON will link multiple current and future high-energy, multimessenger, and follow-up observatories together into a single network, enabling near real-time coincidence searches for multimessenger astrophysical transients and their electromagnetic counterparts. Candidate and high-confidence multimessenger transient events will be identified, characterized, and distributed as AMON alerts within the network and to interested external observers, leading to follow-up observations across the electromagnetic spectrum. In this way, AMON aims to evoke the discovery of multimessenger transients from within observatory subthreshold data streams and facilitate the exploitation of these transients for purposes of astronomy and fundamental physics. As a central hub of global multimessenger science, AMON will also enable cross-collaboration analyses of archival datasets in search of rare or exotic astrophysical phenomena.
We report new limits on cosmic neutrino fluxes from the test flight of the Antarctic Impulsive Transient Antenna (ANITA) experiment, which completed an 18.4 day flight of a prototype long-duration ...balloon payload, called ANITA-lite, in early 2004. We search for impulsive events that could be associated with ultrahigh energy neutrino interactions in the ice and derive limits that constrain several models for ultrahigh energy neutrino fluxes and rule out the long-standing -burst model.
Between 2011 March and 2014 August Swift responded to 20 triggers from the IceCube neutrino observatory, observing the IceCube 50 per cent confidence error circle in X-rays, typically within 5 h of ...the trigger. No confirmed counterpart has been detected. We describe the Swift follow-up strategy and data analysis and present the results of the campaign. We discuss the challenges of distinguishing the X-ray counterpart to a neutrino trigger from serendipitous uncatalogued X-ray sources in the error circle, and consider the implications of our results for future strategies for multimessenger astronomy, with particular reference to the follow-up of gravitational wave triggers from the advanced-era detectors.
We present results of an archival coincidence analysis between Fermi Large Area Telescope (LAT) gamma-ray data and public neutrino data from the IceCube neutrino observatory's 40-string (IC 40) and ...59-string (IC 59) observing runs. Our analysis has the potential to detect either a statistical excess of neutrino + gamma-ray ( + γ) emitting transients or, alternatively, individual high gamma-multiplicity events, as might be produced by a neutrino observed by IceCube coinciding with a LAT-detected gamma-ray burst. Dividing the neutrino data into three data sets by hemisphere (IC 40, IC 59-North, and IC 59-South), we construct uncorrelated null distributions by Monte Carlo scrambling of the neutrino data sets. We carry out signal-injection studies against these null distributions, demonstrating sensitivity to individual + γ events of sufficient gamma-ray multiplicity, and to + γ transient populations responsible for >13% (IC 40), >9% (IC 59-North), or >8% (IC 59-South) of the gamma-coincident neutrinos observed in these data sets, respectively. Analyzing the unscrambled neutrino data, we identify no individual high-significance neutrino + high gamma-multiplicity events and no significant deviations from the test statistic null distributions. However, we observe a similar and unexpected pattern in the IC 59-North and IC 59-South residual distributions that we conclude reflects a possible correlation (p = 7.0%) between IC 59 neutrino positions and persistently bright portions of the Fermi gamma-ray sky. This possible correlation should be readily testable using eight years of further data already collected by IceCube. We are currently working with Astrophysical Multimessenger Observatory Network (AMON) partner facilities to generate low-latency + γ alerts from Fermi-LAT gamma-ray and IceCube and ANTARES neutrino data and distribute these in real time to AMON follow-up partners.
We modelled how nestling growth rates of Cassin’s Auklet (Ptychoramphus aleuticus (Pallas, 1811)) varied with timing of peak copepod prey availability at two breeding colonies in British Columbia: on ...Triangle Island, in the California Current Ecosystem, and Frederick Island, in the Gulf of Alaska Ecosystem. We used time series of nestling growth rates and estimated the seasonal timing of peak biomass of the copepod Neocalanus cristatus (Krøyer, 1848) using a temperature-dependent phenology equation. We developed a single model to examine intercolony differences in the effect of the timing of regional peak prey biomass on seabird nestling growth rates. This model indicated nestling growth rates on Triangle Island varied widely and were positively associated with timing of peak zooplankton biomass, such that higher growth rates were observed when the peak biomass occurred later in the breeding season. In contrast, nestling growth rates were consistently high at Frederick Island, where peak copepod biomass always occurred relatively late. If ocean climate warming results in a poleward shift of Neocalanus abundance and induces earlier and more narrow timing of availability, then episodes of poor nestling growth will increase in frequency on Triangle Island and could eventually affect auklets on more northerly colonies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
ABSTRACT We present a targeted search for blazar flux-correlated high-energy ( 1 TeV) neutrinos from six bright northern blazars, using the public database of northern hemisphere neutrinos detected ...during "IC40" 40-string operations of the IceCube neutrino observatory (2008 April to 2009 May). Our six targeted blazars are subjects of long-term monitoring campaigns by the VERITAS TeV γ-ray observatory. We use the publicly available VERITAS light curves to identify periods of excess and flaring emission. These predefined intervals serve as our "active temporal windows" in a search for an excess of neutrinos, relative to Poisson fluctuations of the near-isotropic atmospheric neutrino background, which dominates at these energies. After defining the parameters of an optimized search, we confirm the expected Poisson behavior with Monte Carlo simulations prior to testing for excess neutrinos in the actual data. We make two searches: one for excess neutrinos associated with the bright flares of Mrk 421 that occurred during the IC40 run, and one for excess neutrinos associated with the brightest emission periods of five other blazars (Mrk 501, 1ES 0806+524, 1ES 1218+304, 3C 66A, and W Comae), all significantly fainter than the Mrk 421 flares. We find no significant excess of neutrinos from the preselected blazar directions during the selected temporal windows. We derive 90% confidence upper limits on the number of expected flux-associated neutrinos from each search. These limits are consistent with previous point-source searches and Fermi GeV flux-correlated searches. Our upper limits are sufficiently close to the physically interesting regime that we anticipate that future analyses using already-collected data will either constrain models or yield discovery of the first blazar-associated high-energy neutrinos.
Abstract Water-based liquid scintillators (WbLS) are a new class of detector materials that provide efficient and tunable detection of both Cherenkov and scintillation light. A massive WbLS neutrino ...detector with suitable photosensor coverage for low intensity light detection could therefore reconstruct the momentum of an energetic charged particle and also have enhanced low-energy sensitivity. These materials are also better suited for metal doping broadening the potential scientific utility. We recently constructed and commissioned a 1-ton WbLS detector with good photosensor coverage and a capable data acquisition and calibration system. We intend to use this flexible detector system as a testbed for WbLS R&D. In this paper we give an overview of the 1-ton system and provide some early results.
The design of water supply infrastructure depends on local conditions such as geophysical features, available technology, traditions, culture, and available human and economic resources. The costs ...for designing, building, maintaining, monitoring, and replacing the required infrastructure escalate when any of these factors is inadequate or insufficient. Furthermore, effects of global climate change increase the risk associated to existing infrastructure, calling for more robust, flexible, and adaptable technologies. We present the design and development of the first physical prototype of the Filardo Pump™, a low-cost, robust, sustainable, water-powered pump that addresses these challenges with many advantages over existing technologies: 1) it requires no external energy source, 2) it works immersed in a free-flowing, unaltered body of water, 3) it is operable in shallow water and low flow conditions, 4) it has low cost and low weight relative to work performed, and 5) it can be made small for households or scaled up for industrial applications. We show proof of concept for this novel pump and describe its development through scaling geometrical aspects and testing different materials for its operation. The proposed technology presents an opportunity for low-cost, sustainable, low carbon footprint water supplies for households, agricultural and industrial applications everywhere, not just in the rural developing world.
•Development of a self-sustained water pump with applications to energy harvesting.•Constructed with two plastic sheets, with a permanent but unstable deformation.•Materials/construction ensure a robust, sustainable, economically affordable device.•We show proof of concept and develop its performance by scaling geometrical aspects.
Core-collapse supernovae are among the prime candidate sources of high energy neutrinos. Accordingly, the IceCube collaboration has started a program to search for such a signal. IceCube operates an ...online search for neutrino bursts, forwarding the directions of candidate events to a network of optical telescopes for immediate follow-up observations. If a supernova is identified from the optical observations, in addition to a directional coincidence a temporal
γ
–
ν
coincidence also needs to be established. To achieve this, we present a method for estimating the supernova explosion time from its light curve using a simple model. We test the model with supernova light curve data from SN1987A, SN2006aj and SN2008D and show that the explosion times can be determined with an accuracy of better than a few hours.
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