Simeon S Stoyanov

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IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 10(18)  eV. Two separate analyses using the half-complete IceCube detector, one a dedicated search for neutrinos from pγ interactions in the prompt phase of(More)
The magnetic properties of ferromagnetic-antiferromagnetic Co-CoO core-shell nanoparticles are investigated as a function of the in-plane coverage density from 3.5% to 15%. The superparamagnetic blocking temperature, the coercivity, and the bias field radically increase with increasing coverage. This behavior cannot be attributed to the overall interactions(More)
Specialized scale factors and scaling equations have been determined for both cyano stretching vibrational frequencies and IR intensities of nitrile molecules, anions and radicals (269 data points in all). Various double and triple-zeta basis sets, viz. 3-21G, 6-31G, 6-311G, 6-31G*, 6-311G*, 6-31+G, 6-311+G, 6-31G**, 6-31+G*, 6-311+G*, 6-31++G**,(More)
A series of sixteen polyhydroxylated trans-restricted 2-arylcinnamic acid analogues 3a-p were synthesized through a one-pot reaction between homophthalic anhydrides and various aromatic aldehydes, followed by treatment with BBr3. The structure of the newly synthesized compounds was confirmed by spectroscopic methods and the configuration around the double(More)
Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This improves the sensitivity(More)
We describe an experimental set up that measures material optical anisotropy and its eventual evolution in real time. The setup is based on a new photopolarimeter that measures the four Stokes parameters of quasi-monochromatic light quickly and simultaneously. The photoinduced anisotropy in the material optical constants is determined from the measured(More)
On 27 December 2004, a giant gamma flare from the Soft Gamma-Ray Repeater 1806-20 saturated many satellite gamma-ray detectors, being the brightest transient event ever observed in the Galaxy. AMANDA-II was used to search for down-going muons indicative of high-energy gammas and/or neutrinos from this object. The data revealed no significant signal, so(More)
Acknowledgments We acknowledge the support of the following agencies: Multiwavelength comparison of selected neutrino point source candidates 7. A. Groß and T. Messarius for the IceCube Collaboration, A source stacking analysis of AGN as neutrino point source candidates with AMANDA The detection of extraterrestrial neutrinos would confirm predictions that(More)
The detection of acoustic signals from ultra-high energy neutrino interactions is a promising method to measure the flux of cosmogenic neutrinos expected on Earth. The energy threshold for this process depends strongly on the absolute noise level in the target material. The South Pole Acoustic Test Setup (SPATS), deployed in the upper part of four boreholes(More)
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