The Astrophysical Multimessenger Observatory Network (AMON) has been built with the purpose of enabling near real-time coincidence searches using data from leading multimessenger observatories and ...astronomical facilities. Its mission is to evoke discovery of multimessenger astrophysical sources, exploit these sources for purposes of astrophysics and fundamental physics, and explore multimessenger datasets for evidence of multimessenger source population AMON aims to promote the advancement of multimessenger astrophysics by allowing its participants to study the most energetic phenomena in the universe and to help answer some of the outstanding enigmas in astrophysics, fundamental physics, and cosmology. The main strength of AMON is its ability to combine and analyze sub-threshold data from different facilities. Such data cannot generally be used stand-alone to identify astrophysical sources. The analyses algorithms used by AMON can identify statistically significant coincidence candidates of multimessenger events, leading to the distribution of AMON alerts used by partner observatories for real-time follow-up that may identify and, potentially, confirm the reality of the multimessenger association. We present the science motivation, partner observatories, implementation and summary of the current status of the AMON project.
AMON: Transition to real-time operations Cowen, D.F.; Keivani, A.; Tešić, G.
EPJ Web of Conferences,
01/2016, Volume:
116
Journal Article, Conference Proceeding
Peer reviewed
Open access
The Astrophysical Multimessenger Observatory Network (AMON) will link the world's leading high-energy neutrino, cosmic-ray, gamma-ray and gravitational wave observatories by performing real-time ...coincidence searches for multimessenger sources from observatories' subthreshold data streams. The resulting coincidences will be distributed to interested parties in the form of electronic alerts for real-time follow-up observation. We will present the science case, design elements, current and projected partner observatories, status of the AMON project, and an initial AMON-enabled analysis. The prototype of the AMON server has been online since August 2014 and processing archival data. Currently, we are deploying new high-uptime servers and will be ready to start issuing alerts as early as winter 2015/16.
Tau Neutrinos in IceCube Cowen, D F; Collaboration, the IceCube
Journal of physics. Conference series,
03/2007, Volume:
60, Issue:
1
Journal Article
Peer reviewed
Open access
Tau neutrino detection in IceCube would be strong evidence for the presence of cosmologically-produced neutrinos. In addition to the well-known "double bang" signature, we describe here five ...additional channels that we believe will not only extend the energy range over which IceCube can be sensitive to tau neutrinos, but also provide useful control over systematic uncertainties via self-consistency checks amongst all detection channels.
Event reconstruction is a central step in many particle physics experiments, turning detector observables into parameter estimates; for example estimating the energy of an interaction given the ...sensor readout of a detector. A corresponding likelihood function is often intractable, and approximations need to be constructed. Here, in our work, we first show how the full likelihood for a many-sensor detector can be broken apart into smaller terms, and secondly how we can train neural networks to approximate all terms solely based on forward simulation. Our technique results in a fast, flexible, and close-to-optimal surrogate model proportional to the likelihood and can be used in conjunction with standard inference techniques allowing for a consistent treatment of uncertainties. We illustrate our technique for parameter inference in neutrino telescopes based on maximum likelihood and Bayesian posterior sampling. Given its great flexibility, we also showcase our method for geometry optimization enabling to learn optimal detector designs. Lastly, we apply our method to realistic simulation of a ton-scale water-based liquid scintillator detector.
We studied parental provisioning and chick growth rates of Cassin’s aukletPtychoramphus aleuticusat Triangle Island, British Columbia, Canada, from 1996 to 1999. Auklet reproductive performance and ...ocean climate conditions during these years were highly variable, and reflected in the diet composition. Chick growth was maximal when the diet was predominated by copepods, in particularNeocalanus cristatus. Provisioning and growth were high in 1999, intermediate in 1997 and poor in 1998. Exceptional was 1996, when growth was low but provisioning rates were high. Provisioning and growth were depressed late in 1997 and throughout 1998 when larval rockfishSebastesspp. (5200 cal g–1) replacedN. cristatus(6236 cal g–1) in the nestling diet. Zooplankton surveys indicated thatN. cristatuswas substantially more abundant in May 1999 than in May 1998, and during 1999 the auklets foraged in areas with the highest concentrations of copepods. Through impacts on prey availability, variation in ocean climate affects the reproductive performance of Cassin’s auklet. Performance tends to be favorable in years when spring is late and cold, and poor when spring is early and warm. Equations for predicting food delivery rates from 24 h mass changes of chicks were highly year-specific, precluding their application in other years or at other sites where Cassin’s auklets breed. Between-year differences were also found in relationships between adult provisioning and chick growth. These were strongly positively related in 1999, positively related in 1996 and 1997, but unrelated in 1998; differences attributed to the magnitude of temporal variation in the nestling diet. Finally, we detected annual differences in parental response to chick needs. In 1999, parents delivered more food to chicks in poor condition and less to those in better condition, responses not observed in 1998. Different responses between years may have reflected variation in the availability of prey.
Neutrino physics with IceCube Cowen, D F
Journal of physics. Conference series,
05/2008, Volume:
110, Issue:
6
Journal Article
Peer reviewed
Open access
The IceCube Neutrino Observatory is an ice Cherenkov detector under construction at the South Pole, Antarctica. When completed, the physical volume of the detector will be approximately one km3. The ...Observatory will be sensitive to a number of topics in fundamental neutrino physics, such as neutrino oscillations and decay, by virtue of its ability to distinguish neutrino flavours over a wide range of neutrino energies. We present the status of the construction of the Observatory, some recent analysis results, a brief discussion of its sensitivity to fundamental neutrino parameters and planning currently underway for low and high energy extensions to the baseline array.
We present a summary of the flavor composition measurements for the diffuse astrophysical neutrino flux using data from the IceCube Neutrino Observatory at the South Pole. IceCube has identified ...candidate astrophysical tau neutrinos through two different approaches. One approach used a dedicated particle identification algorithm for the classification and reconstruction of the 'Double Cascade' event topology, a signature of tau neutrino charged current interactions. This first approach is applied to the High Energy Starting Events (HESE) sample, an all-sky, all-flavor set of neutrino events with energy above 60~TeV encompassing 12 years of IceCube livetime. We show that the addition of more years of data and updated ice properties on the HESE sample delivers tighter constraints on the flavor composition of the astrophysical neutrino flux than previous IceCube analyses, in particular when it is fit in combination with high statistics samples of through-going tracks and cascades. A second approach uses a sensitive machine-learning-based selection technique that finds seven candidate events in 9.7 years of IceCube data. This approach excludes the zero astrophysical tau neutrino hypothesis at the highest statistical significance to date.
PDF
