RBX: The new X-band SAR system from INTA

Revista oficial de la Asociación Española de Teledetección[EN] This paper describes the characteristics and the first results of the RBX system, the new airborne Synthetic Aperture Radar developed at Spanish National Institute of Aerospace Technology. The new system supports submetric resolution with interferometric and polarimetric capabilities. The system architecture has been designed taking into account an easy upgrade ability and the quality of the acquired data, including multiple internal calibration loops.[ES] Este artículo describe las características y los primeros resultados del sistema RBX, nuevo radar de apertura sintética aerotransportado que ha sido desarrollado en el Instituto Nacional de Técnica Aeroespacial. El nuevo sistema soporta resoluciones submétricas con capacidades interferométricas y polarimétricas. La arquitectura del sistema se ha diseñado teniendo en cuenta la facilidad de incorporar mejoras y la calidad de los datos adquiridos, incluyendo múltiples lazos de calibración interna.Larrañaga, J. R., De Porras Bernácer, R., Del Castillo, J., Gimeno, N., Aguilar, P., Baquero, A. M., . . . Sánchez, S. (2014). RBX: The new X-band SAR system from INTA. [RBX: El nuevo radar SAR en banda X del INTA] Revista De Teledeteccion, (41), 89-96. doi:10.4995/raet.2014.2285SWORD899641G. Bonin, P. Dreuillet. 2008. The new ONERA airborne SAR system SETHI. EUSAR, Dresden, Germany.Rodriguez, M. G. (2008). Design of a Coherent Generation and Acquisition System at 1,2GHz. 2008 4th Southern Conference on Programmable Logic. doi:10.1109/spl.2008.4547745Gonzalez Bonilla, M. J., Gomez Miguel, B., Cuerda Muñoz, J. M., Larrañaga Sudupe, J. R., Garcia Rodriguez, M., 2009. INTASAR program. Proceedings IGARSSHORN, RALF; NOTTENSTEINER, ANTON; SCHEIBER, ROLF. 2008. F-SAR – DLR's advanced airborne SAR system onboard DO228. Proceedings EUSARMoreira, A., & Yonghong Huang. (1994). Airborne SAR processing of highly squinted data using a chirp scaling approach with integrated motion compensation. IEEE Transactions on Geoscience and Remote Sensing, 32(5), 1029-1040. doi:10.1109/36.31289

Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at $\lg(E/{\rm eV})=18.5-19.0$ differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass $A > 4$. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

Astrophysical Interpretation Of Pierre Auger Observatory Measurements Of The Uhecr Energy Spectrum And Mass Composition

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The Pierre Auger Observatory Status And Latest Results

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Evidence For A Mixed Mass Composition At The ‘ankle’ In The Cosmic-ray Spectrum

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The energy spectrum of cosmic rays beyond the turn-down around 10^17 eV as measured with the surface detector of the Pierre Auger Observatory

We present a measurement of the cosmic-ray spectrum above 100 PeV using the part of the surface detector of the Pierre Auger Observatory that has a spacing of 750 m. An inflection of the spectrum is observed, confirming the presence of the so-called second-knee feature. The spectrum is then combined with that of the 1500 m array to produce a single measurement of the flux, linking this spectral feature with the three additional breaks at the highest energies. The combined spectrum, with an energy scale set calorimetrically via fluorescence telescopes and using a single detector type, results in the most statistically and systematically precise measurement of spectral breaks yet obtained. These measurements are critical for furthering our understanding of the highest energy cosmic rays