We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy gamma-ray observatory. Previously, the TeV emission has been attributed to the ...pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14sigma) and measure a photon index of 2.20 + or - 0.10 sub(stat) + or - 0.20 sub(sys). The TeV emission is extended, covering the region near PSR J1907+0602 and also extending toward SNR G40.5-0.5. When fitted with a two-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma sub(src) = 0.degrees44 + or - 0.degrees02. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5-0.5, 0.degrees33 away.
We report the discovery of TeV gamma-ray emission from the Type Ia supernova remnant (SNR) G120.1+1.4, known as Tycho's SNR. Observations performed in the period 2008-2010 with the VERITAS ...ground-based gamma-ray observatory reveal weak emission coming from the direction of the remnant, compatible with a point source located at 00h25m27.s0, + 64?10'50'' (J2000). The TeV photon spectrum measured by VERITAS can be described with a power law dN/dE = C(E/3.42 TeV)-- Delta *G with Delta *G = 1.95 ? 0.51stat ? 0.30sys and C = (1.55 ? 0.43stat ? 0.47sys) X 10--14 cm--2 s--1 TeV--1. The integral flux above 1 TeV corresponds to ~0.9% of the steady Crab Nebula emission above the same energy, making it one of the weakest sources yet detected in TeV gamma rays. We present both leptonic and hadronic models that can describe the data. The lowest magnetic field allowed in these models is ~80 Delta *mG, which may be interpreted as evidence for magnetic field amplification.
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► Optimization of heat capacities is proposed for 16 AIIIBV phases. ► The new correlation approach is based on the similarity of thermodynamic properties of isostructural phases. ► ...Heat capacities are calculated for previously poorly studied phases TlN and AlP.
A semi-empirical approach to the critical analysis of thermodynamic data is proposed and applied in this work. As an example, sets of numerous experimental and calculated heat capacity values of 16 isostructural AIIIBV compounds were taken from the literature. A critical analysis of heat capacities of 16 AIIIBV compounds was then made based on the correlative optimization method. As a result, a set of mutually agreed equations CPo=a+b·10-3-c·105·T-2 was proposed to describe the heat capacities of these phases. Two continuums of relations CP(T)vs. logarithm of the sum of atomic numbers of elements A and B were obtained for the AIIIBV phases, of both sphalerite and wurtzite types, in the temperature range from 260 to 1500K. Based on the proposed equations, heat capacity values were predicted for the previously unstudied (or poorly studied) phases TlN and AlP within the temperature ranges from 260 to 1018K from 260 to 1500K, respectively. The proposed correlative method of thermodynamic functions can be applied to other different groups of isostructural organic and inorganic compounds.
The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-π0s produced at forward pseudorapidities (2.6<η<4.0) in p+p, p+Al, and p+Au collisions at a center-of-mass ...energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back π0 pairs in p+Al and p+Au collisions compared to the p+p data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. Furthermore, the larger suppression found in p+Au relative to p+Al collisions exhibits a dependence of the saturation scale $Q^{2}_{s}$ on the mass number A . A linear scaling of the suppression with A1/3 is observed with a slope of -0.09±0.01.
The Schwarzschild-Couder Telescope (SCT) is a telescope concept proposed for the Cherenkov Telescope Array. It employs a dual-mirror optical design to remove comatic aberrations over an 8∘ field of ...view, and a high-density silicon photomultiplier camera (with a pixel resolution of 4 arcmin) to record Cherenkov emission from cosmic ray and gamma-ray initiated particle cascades in the atmosphere. The prototype SCT (pSCT), comprising a 9.7 m diameter primary mirror and a partially instrumented camera with 1536 pixels, has been constructed at the Fred Lawrence Whipple Observatory. The telescope was inaugurated in January 2019, with commissioning continuing throughout 2019. We describe the first campaign of observations with the pSCT, conducted in January and February of 2020, and demonstrate the detection of gamma-ray emission from the Crab Nebula with a statistical significance of 8.6σ.
ABSTRACT Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the universe. The detection of ...significant emission above 100 GeV from a distant quasar would show that some of the radiated gamma-rays escape pair-production interactions with low-energy photons, be it the extragalactic background light (EBL), or the radiation near the supermassive black hole lying at the jet's base. VERITAS detected gamma-ray emission up to ∼200 GeV from PKS 1441+25 (z = 0.939) during 2015 April, a period of high activity across all wavelengths. This observation of PKS 1441+25 suggests that the emission region is located thousands of Schwarzschild radii away from the black hole. The gamma-ray detection also sets a stringent upper limit on the near-ultraviolet to near-infrared EBL intensity, suggesting that galaxy surveys have resolved most, if not all, of the sources of the EBL at these wavelengths.
In this work, we report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at $\sqrt{s_{NN}}$ =3.0 GeV, measured by the STAR experiment in the kinematic ...acceptance of rapidity (y) and transverse momentum (pT) within -0.5 < y < 0 and 0.4 < pT < 2.0 GeV/c. In the most central 0–5% collisions, a proton cumulant ratio is measured to be C4/C2 = –0:85 ± 0:09 (stat:)±0:82 (syst:), which is 2σ below the Poisson baseline with respect to both the statistical and systematic uncertainties. The hadronic transport UrQMD model reproduces our C4/C2 in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in C4/C2 is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3 GeV.
According to the
in silico
consensus activity prediction, a series of 3,6-disubstituted 1,2,4,5-tetrazines were synthesized as promising inhibitors of the Maillard reaction. In addition to the ...studies of antiglycation activity, a comparative
in vitro
evaluation of the effect of the synthesized compounds on the ADP-induced rabbit platelet aggregation model was carried out. Compounds with antiglycation and antiplatelet activities significantly higher than that of the reference drugs, aminoguanidine and acetylsalicylic acid, were revealed.
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