The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in ...short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.
The unidentified TeV source in Cygnus is now confirmed by follow-up observations from 2002 with the HEGRA stereoscopic system of Cherenkov Telescopes. Using all data (1999 to 2002) we confirm this ...new source as steady in flux over the four years of data taking, extended with radius 6.2′ (±$1.2^\prime_{\rm stat}$ ± $0.9^\prime_{\rm sys}$) and exhibiting a hard spectrum with photon index -1.9. It is located in the direction of the dense OB stellar association, Cygnus OB2. Its integral flux above energies $E>1$ TeV amounts to ~5% of the Crab assuming a Gaussian profile for the intrinsic source morphology. There is no obvious counterpart at radio, optical nor X-ray energies, leaving TeV J2032+4130 presently unidentified. Observational parameters of this source are updated here and some astrophysical discussion is provided. Also included are upper limits for a number of other interesting sources in the FoV, including the famous microquasar Cygnus X-3.
El trabajo plantea una propuesta para el procesamiento de índices de disponibilidad léxica (ámbito educativo) mediante herramientas estadísticas más eficientes que las usadas en la última década. El ...planteamiento asociado deriva una ruta de ejercicio interdisciplinar entre lingüistas y estadísticos que capitaliza los corpus lingüísticos, tratándolos como estudios correlacionales dentro del marco de la minería de datos. Se muestran resultados iniciales de la fase cuantitativa del estudio La escuela secundaria como reguladora de los factores discursivos correlativos entre disponibilidad léxica y movilidad social, procesados con metodología de lingüística de corpus y software estadístico libre, correlacionando, con alta eficiencia, índices de disponibilidad léxica y perspectiva de movilidad social en alumnos de secundaria en Saltillo, Coahuila, México, y como un corpus viable de ser correlacionado con bases de datos parciales o censuales para la toma de decisiones en el aula y la política pública por la posibilidad de correlación entre bases de datos.
For the first time an excess of photons above an energy threshold of 730 GeV from the giant radio galaxy M 87 has been measured at a significance level above 4 σ. The data have been taken during the ...years 1998 and 1999 with the HEGRA stereoscopic system of 5 imaging atmospheric Cherenkov telescopes. The excess of $107.4\,\pm\,26.8$ events above 730 GeV corresponds to an integral flux of 3.3% of the Crab flux or $N_\gamma(E > 730\,\mbox{GeV}) = (0.96 \pm 0.23) \times 10^{-12}$ phot cm-2 s-1. M 87 is located at the center of the Virgo cluster of galaxies at a relatively small redshift of $z = 0.00436$ and is a promising candidate among the class of giant radio galaxies for the emission of TeV γ-radiation. The detection of TeV γ-rays from M 87 – if confirmed – would establish a new class of extragalactic source in this energy regime since all other AGN detected to date at TeV energies are BL Lac type objects.
Complex permittivity is the physical property that describes the interaction between matter and an electromagnetic field. This property is related to the structural and physico-chemical properties ...such as water and soluble solids content or water activity of the material.
The complex permittivity of different aqueous solutions, fresh and osmotically dehydrated cherry tomatoes was measured and related to the products’ composition. Results showed that fruits osmotically dehydrated with sucrose solutions reached the lowest loss factors but the maximum penetration depth (
D
p). On the other hand, fruits immersed in binary salt solutions showed the inverse tendency. For products impregnated with ternary solutions an intermediate behaviour was observed. Calcium lactate addition had no significant effects on complex permittivity at 2.45
GHz, but its presence increased the effective loss factor at low frequency.
The dielectric properties of fruits and vegetables can be modified by controlling osmotic process variables (time, temperature, pressure and osmotic solution composition) in order to improve their further drying with microwaves.
We present the result of the observation of the ultrafaint dwarf galaxy Willman 1 performed with the 17 m MAGIC telescope during 15.5 hr between March and May 2008. No significant gamma -ray emission ...was found. We derived upper limits of the order of 10-12 ph cm-2 s-1 on the integral flux above 100 GeV, which we compare with predictions from several of the established neutralino benchmark models in the mSUGRA parameter space. The neutralino annihilation spectra are defined after including the recently quantified contribution of internal bremsstrahlung from the virtual sparticles that mediate the annihilation. Flux boost factors of three orders of magnitude are required even in the most optimistic scenario to match our upper limits. However, uncertainties in the dark matter intrinsic and extrinsic properties (e.g., presence of substructures, Sommerfeld effect) may significantly reduce this gap.
We present results of the multiwavelength campaign on the TeV blazar Mkn 501 performed in 2006 July, including MAGIC for the very-high-energy (VHE) Delta *g-ray band and Suzaku for the X-ray band. A ...VHE Delta *g-ray signal was clearly detected with an average flux above 200 GeV of ~20% of the Crab Nebula flux, which indicates a low state of source activity in this energy range. No significant variability has been found during the campaign. The VHE Delta *g-ray spectrum can be described by a simple power law from 80 GeV to 2 TeV with a photon index of 2.8 +/- 0.1, which corresponds to one of the steepest photon indices observed in this energy range so far for this object. The X-ray spectrum covers a wide range from 0.6 to 40 keV, and is well described by a broken power law, with photon indices of 2.257 +/- 0.004 and 2.420 +/- 0.012 below and above the break energy of 3.24+0.13 -0.12 keV. No apparent high-energy cut-off is seen above the break energy. Although an increase of the flux of about 50% is observed in the X-ray band within the observation, the data indicate a consistently low state of activity for this source. Time-resolved spectra show an evidence for spectral hardening with a flux level. A homogeneous one-zone synchrotron self-Compton (SSC) model can adequately describe the spectral energy distribution (SED) from the X-ray to the VHE Delta *g-ray bands with a magnetic field intensity B = 0.313 G and a Doppler beaming factor Delta *d = 20, which are similar to the values in the past multiwavelength campaigns in high states. Based on our SSC parameters derived for the low state, we are able to reproduce the SED of the high state by just changing the Lorentz factor of the electrons corresponding to the break energy in the primary electron spectrum. This suggests that the variation of the injected electron population in the jet is responsible for the observed low-high state variation of the SED.
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