The Stereoscopic Analog Trigger of the MAGIC Telescopes

The current generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs) operate in the very-high-energy (VHE) domain from similar to 100 GeV to similar to 100 TeV. They use electronic digital trigger systems to discern the Cherenkov light flashes emitted by extensive air showers (EASs), from the overwhelming light of the night sky (LoNS) background. Near the telescope energy threshold, the number of emitted Cherenkov photons by gamma-ray-induced EASs is comparable to the fluctuations of the LoNS and the photon distribution at the Cherenkov-imaging camera plane becomes patchy. This results in a severe loss of effectiveness of the digital triggers based on combinatorial logic of thresholded signals. A stereoscopic analog trigger system has been developed for improving the detection capabilities of the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes at the lowest energies. It is based on the analog sum of the photosensor electrical signals. In this article, the architectural design, technical performances, and configuration of this stereoscopic analog trigger, dubbed "Sum-Trigger-II," are described

MAGIC gamma-ray telescopes hunting for neutrinos and their sources

The discovery of an astrophysical flux of high-energy neutrinos by the IceCube Collaboration marks a major breakthrough in the ongoing search for the origin of cosmic rays. Presumably, the neutrinos, together with gamma rays, result from pion decay, following hadronic interactions of protons accelerated in astrophysical objects to ultra-relativistic energies. So far, the neutrino sky map shows no significant indication of astrophysical sources. Here, we report first results from follow-up observations, of sky regions where IceCube has detected muon tracks from energetic neutrinos, using the MAGIC telescopes which are sensitive to gamma rays at TeV energies. Furthermore, we show that MAGIC has the potential to distinguish air showers induced by tau neutrinos from the background of hadronic showers in the PeV-EeV energy range, employing a novel analysis method to the data obtained with high-zenith angle observations.Peer Reviewe

Mejoras en el proceso enseñanza-aprendizaje de Estructuras Metálicas y de Hormigón Armado en Ingeniería Civil

Con la puesta en marcha del Espacio Europeo de Educación Superior se han producido importantes cambios en las asignaturas que se impartían en las titulaciones anteriores. Con el fin de adaptar a este nuevo contexto las metodologías y contenidos de las asignaturas “Estructuras Metálicas” y “Estructuras de Hormigón Armado y Pretensado” del Grado en Ingeniería Civil, durante el curso 2012-13 se constituyó la red “Tecnología de Estructuras en el EEES: Estructuras Metálicas y de Hormigón Armado en Ingeniería Civil”. Mediante la nueva red creada en este curso 2013-14 se pretende continuar el proceso de mejora iniciado el curso anterior, y que incluye una evaluación de los resultados obtenidos con la metodología de enseñanza empleada hasta el momento y planteamiento de propuestas de mejora. En general, las metodologías empleadas continúan siendo adecuadas, aunque pueden y deben ser mejoradas. El principal problema encontrado en este curso ha sido ha sido el considerable incremento en el número de alumnos en ambas asignaturas en el curso 2013-14, manteniendo el número de grupos de teoría, tutorías grupales y prácticas de ordenador que en el curso anterior. No obstante, este hecho ha supuesto un reto en busca de mejoras para futuros cursos

Diseño de un robot para envolver pastillas de jabón

[Resumen] Este trabajo consiste en el diseño y realización de un robot capaz de envolver pastillas de jabón, imitando los movimientos que se hacen de forma manual. Los jabones en cuestión son artesanales, por lo que el dispositivo ha afrontado el reto de adaptarse a las pequeñas variaciones de tamaño de la pastilla. Se ha realizado el diseño mecánico mediante la herramienta Fusion 360, para posteriormente imprimir las piezas en 3D. Por otro lado, la parte correspondiente a la programación del software y la implementación del hardware, se ha realizado en el entorno Arduino. Se ha tratado de conseguir una interfaz de usuario sencilla de utilizar, permitiendo la selección entre un modo manual y uno automático.[Abstract] This work is about the design and fabrication of a robot capable of wrapping bars of soap, imitating manually movements. These soaps are handmade, so the device has faced the challenge of accommodating small size variations. The mechanical design has been carried out using Fusion 360, and later the parts were 3D printed.On the other hand, the software programming part and hardware corresponding implementation has been done using Arduino. The user interface is easy to use, allowing selection between a manual and an automatic mode

Detection of very high energy radiation from the BL lacertae object PG 1553+113 with the MAGIC telescope

In 2005 and 2006, the MAGIC telescope observed very high energy gamma-ray emission from the distant BL Lac object PG 1553 + 113. The overall significance of the signal was 8.8 sigma for 18.8 hr of observation time. The light curve shows no significant flux variations on a daily timescale; the flux level during 2005 was, however, significantly higher compared to 2006. The differential energy spectrum between similar to 90 and 500 GeV is well described by a power law with photon index. Gamma = 4.2 +/- 0.3. The combined 2005 and 2006 energy spectrum provides an upper limit of z = 0.74 on the redshift of the object

Systematic Physical Characterization of the γ-Ray Spectra of 2FHL Blazars

We test different physically motivated models for the spectral shape of the gamma-ray emission in a sample of 128 blazars with known redshifts detected by the Fermi Large Area Telescope (LAT) at energies above 50. GeV. The first nine years of LAT data in the energy range from 300. MeV to 2. TeV are analyzed in order to extend the spectral energy coverage of the 2FHL blazars in our sample. We compare these spectral data to four leptonic models for the production of gamma-rays through Compton scattering by a population of electrons with different spectral shapes. In the first three models we consider Compton scattering in the Thomson regime with different acceleration mechanisms for the electrons. In the fourth model we consider Compton scattering by a pure power-law distribution of electrons with spectral curvature due to scattering in the Klein-Nishina regime. The majority of blazar gamma-ray spectra are preferentially fit with either a power law with exponential cutoff in the Thomson regime or a power-law electron distribution with Compton scattering in the Klein-Nishina regime, while a log-parabola with a low-energy power-law and broken power-law spectral shape in the Thomson regime appears systematically disfavored, which is likely a consequence of the restriction to pure Thomson scattering that we imposed on those models. This finding may be an indication that the gamma-ray emission from flat-spectrum radio quasars (FSRQs) in the 2FHL catalog is dominated by Compton scattering of radiation from the dusty torus, while in the case of BL Lac objects, it is dominated by synchrotron self-Compton radiation

Statistics of VHE γ-rays in temporal association with radio giant pulses from the Crab pulsar

Aims. The aim of this study is to search for evidence of a common emission engine between radio giant pulses (GPs) and very-high-energy (VHE, E& x2004;> & x2004;100 GeV) gamma-rays from the Crab pulsar. Methods. We performed 16 h of simultaneous observations of the Crab pulsar at 1.4 GHz with the Effelsberg radio telescope and the Westerbork Synthesis Radio Telescope (WSRT), and at energies above 60 GeV we used the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes. We searched for a statistical correlation between the radio and VHE gamma-ray emission with search windows of different lengths and different time lags to the arrival times of a radio GP. A dedicated search for an enhancement in the number of VHE gamma-rays correlated with the occurrence of radio GPs was carried out separately for the P1 and P2 phase ranges, respectively. Results. In the radio data sample, 99444 radio GPs were detected. We find no significant correlation between the GPs and VHE photons in any of the search windows. Depending on phase cuts and the chosen search windows, we find upper limits at a 95% confidence level on an increase in VHE gamma-ray events correlated with radio GPs between 7% and 61% of the average Crab pulsar VHE flux for the P1 and P2 phase ranges, respectively. This puts upper limits on the flux increase during a radio GP between 12% and 2900% of the pulsed VHE flux, depending on the search window duration and phase cuts. This is the most stringent upper limit on a correlation between gamma-ray emission and radio GPs reported so far

MAGIC observations of PG 1553+113 during a multiwavelength campaign in July 2006

The active galactic nucleus PG1553+113 was observed by the MAGIC telescope in July 2006 during a multiwavelength campaign, in which telescopes in the optical, X-ray, and very high energies participated. Although the MAGIC data were affected by strong atmospheric absorption (calima), they were analyzed after applying a correction. In 8.5 h, a signal was detected with a significance of 5.0 sigma. The integral flux above 150 GeV was (2.6 +/- 0.9) x 10(-7) ph s(-1) m(-2). By fitting the differential energy spectrum with a power law, a spectral index of -4.1 +/- 0.3 was obtained