Because of the high energies and long distances to the sources, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz invariance violation (LIV). Superluminal LIV enables the decay of photons at high energy. The high altitude water Cherenkov (HAWC) observatory is among the most sensitive gamma-ray instruments currently operating above 10 TeV.
View Article and Find Full Text PDFWe present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date.
View Article and Find Full Text PDFIn this Letter, owing to a production error, the penultimate version of the PDF was published. The HTML version was always correct. The PDF has been corrected online.
View Article and Find Full Text PDFSS 433 is a binary system containing a supergiant star that is overflowing its Roche lobe with matter accreting onto a compact object (either a black hole or neutron star). Two jets of ionized matter with a bulk velocity of approximately 0.26c (where c is the speed of light in vacuum) extend from the binary, perpendicular to the line of sight, and terminate inside W50, a supernova remnant that is being distorted by the jets.
View Article and Find Full Text PDFIn this work, the effect of sodium citrate mixed with tobacco, in the presence and absence of SBA-15 material, was studied by thermogravimetric analysis coupled to Fourier-transform infrared spectrometry under N and air atmospheres. Depending on the atmosphere used, the decomposition of sodium citrate changes considerably at high temperatures, mainly due to the oxidation of the residue. The analysis of the experimental and calculated derivative thermogravimetric data of the sodium citrate/SBA-15 mixtures allows the observation of marked widening of the peaks appearing at lower temperatures, due to the presence of SBA-15, while the expected peak at high temperatures in air completely disappears.
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