Molecular environment, reverberation, and radiation from the pulsar wind nebula in CTA 1

We estimate the molecular mass around CTA 1 using data from Planck and the Harvard CO survey. We observe that the molecular mass in the vicinity of the complex is not enough to explain the TeV emission observed by VERITAS, even under favorable assumptions for the cosmic-ray acceleration properties of the supernova remnant. This supports the idea that the TeV emission comes from the PWN. Here, we model the spectrum of the PWN at possible different stages of its evolution, including both the dynamics of the PWN and the SNR and their interaction via the reverse shock. We have included in the model the energy lost via radiation by particles and the particles escape when computing the pressure produced by the gas. This leads to an evolving energy partition, since for the same instantaneous sharing of the injection of energy provided by the rotational power, the field and the particles are affected differently by radiation and losses. We present the model, and study in detail how the spectrum of a canonical isolated PWN is affected during compression and re-expansion and how this may impact on the CTA 1 case. By exploring the phase-space of parameters that lead to radii in agreement with those observed, we then analyze different situations that might represent the current stage of the CTA 1 PWN, and discuss caveats and requirements of each one.Comment: 13 pages, 8 figures, accepted for publication in MNRA

Compact formulae, dynamics and radiation of charged particles under synchro-curvature losses

We consider the fundamental problem of charged particles moving along and around a curved magnetic field line, revising the synchro-curvature radiation formulae introduced by Cheng and Zhang (1996). We provide more compact expressions to evaluate the spectrum emitted by a single particle, identifying the key parameter that controls the transition between the curvature-dominated and the synchrotron-dominated regime. This parameter depends on the local radius of curvature of the magnetic field line, the gyration radius, and the pitch angle. We numerically solve the equations of motion for the emitting particle by considering self-consistently the radiative losses, and provide the radiated spectrum produced by a particle when an electric acceleration is balanced by its radiative losses, as it is assumed to happen in the outer gaps of pulsar's magnetospheres. We compute the average spectrum radiated throughout the particle trajectory finding that the slope of the spectrum before the peak depends on the location and size of the emission region. We show how this effect could then lead to a variety of synchro-curvature spectra. Our results reinforce the idea that the purely synchrotron or curvature losses are, in general, inadequate to describe the radiative reaction on the particle motion, and the spectrum of emitted photons. Finally, we discuss the applicability of these calculations to different astrophysical scenarios.Comment: 9 pages, 5 figures, 2 tables. Accepted for publication in MNRAS main journal. References update

Time-dependent modeling of TeV-detected, young pulsar wind nebulae

The increasing sensitivity of instruments at X-ray and TeV energies have revealed a large number of nebulae associated with bright pulsars. Despite this large data set, the observed pulsar wind nebulae (PWNe) do not show a uniform behavior and the main parameters driving features like luminosity, magnetization, and others are still not fully understood. To evaluate the possible existence of common evolutive trends and to link the characteristics of the nebula emission with those of the powering pulsar, we selected a sub-set of 10 TeV detections which are likely ascribed to young PWNe and model the spectral energy distribution with a time-dependent description of the nebulae's electron population. In 9 of these cases, a detailed PWNe model, using up-to-date multiwavelength information, is presented. The best-fit parameters of these nebula are discussed, together with the pulsar characteristics. We conclude that TeV PWNe are particle-dominated objects with large multiplicities, in general far from magnetic equipartition, and that relatively large photon field enhancements are required to explain the high level of Comptonized photons observed. We do not find significant correlations between the efficiencies of emission at different frequencies and the magnetization. The injection parameters do not appear to be particularly correlated with the pulsar properties either. We find that a normalized comparison of the SEDs (e.g., with the corresponding spin-down flux) at the same age significantly reduces the spectral distributions dispersion.Comment: 38 pages, 20 figures, 8 tables. Accepted for publication in the Journal of High Energy Astrophysics (JHEAp

Historical drying of wetlands in the middle Guadalquivir (Spain). Eco-cultural, economic and health relations

Análisis de los procesos de desecación histórica que han sufrido algunos humedales de la zona que, en la Depresión del Guadalquivir, comprende el tramo medio de dicho río, con estudio detallado de algunos casos significativos. Contrasta esta actitud desecadora con la posterior valoración y protección de un conjunto de lagunas que ofrecen un contrapunto de gran valor ecológico en un paisaje de actividad agraria dominante. Las singularidades paisajísticas y la biodiversidad que albergan estos humedales han sido la base para la transformación de aquel paisaje agrario en un conjunto destacado y singular por su patrimonio natural. Desvelar las circunstancias y avatares acaecidos en este proceso será el objetivo de nuestro estudio. Para ello se acuñan dos términos originales de esta investigación: «lamafobia» o «elosfobia», que tratarán de concretar esta obsesión desecadora presente en estos lugares a lo largo de siglos.An analysis of the historical drying up process that suffered some wetlands in the depression in middle stretch of the Guadalquivir River (Spain), with detailed study of some significant cases. This attitude contrast with the current valuation and protection of a set of ponds which offer a counterpoint of great ecological value in a landscape of dominant agricultural activity. Landscape features and biodiversity that exist in these wetlands have been the reason for the transformation of the agrarian landscape in a in a prominent and singular set for its natural heritage. One of the objectives of our study is to reveal the circumstances and vicissitudes that occurred in this process. To do this we discovered two original terms of this research: «lamafobia» o «elosfobia», that realized the obsession with the drying up of this places for centuries

An assessment of the pulsar outer gap model. II: Implications for the predicted γ\gamma-ray spectra

One of the most important predictions of any gap model for pulsar magnetospheres is the predicted $\gamma$-ray spectra. In the outer gap model, the properties of the synchro-curvature radiation are sensitive to many parameters, whose realistic ranges have been studied in detail in an accompanying paper. There we demonstrated that the uncertainty in the radius of curvature, the magnetic field geometry, and the X-ray surface flux may affect by orders of magnitude the predicted flux and spectral peak in the $\gamma$-ray regime. Here, we present a systematic, numerical study of the impact of the different parameters on the particle dynamics along the gap and calculate the emitted synchro-curvature radiation along the trajectory. By integrating the emitted radiation along the gap and convolving it with a parametrized particle distribution, we discuss how the comparison with the wealth of {\em Fermi}-LAT data can be used to constrain the applicability of the model. The resulting spectra show very different energy peaks, fluxes and shapes, qualitatively matching the great variety of the observed {\em Fermi}-LAT pulsars. In particular, if we see a large fraction of photons emitted from the initial part of the trajectory, we show that the spectra will be flatter at the low-energy {\it Fermi}-LAT regime (100 MeV -- 1 GeV). This provides a solution for such observed flat spectra, while still maintain synchro-curvature radiation as the origin of these photons.Comment: 9 pages, 6 figures, 1 table. Accepted for pubblication in MNRAS main journal. References update

An assessment of the pulsar outer gap model. I: Assumptions, uncertainties, and implications for the gap size and the accelerating field

The popular outer gap model of magnetospheric emission from pulsars has been widely applied to explain the properties observed in $\gamma$-rays. However, its quantitative predictions rely on a number of approximations and assumptions that are usually overlooked. Here we examine them, reviewing the main ingredients entering in the model, evaluating their range of uncertainties. Usually, in the quantitative applications of the model, key parameters like the radius of curvature and the energies of the interacting photons are taken to be a fixed, single value. Instead, here we explore their realistic ranges, and the impact of these on the consistency of the model itself. We conclude that the popular evaluation of the trans-field size of the gap as a function of period and period derivative, is unreliable and affected by a huge dispersion. Last, the exploration of the possible values for the radius of curvature, the local magnetic field and other quantities deserve more attention for quantitative applications of the outer gap model, like the calculation of $\gamma$-ray spectra, which is the subject of an accompanying paper.Comment: 19 pages, 5 figures, 3 tables. Accepted for pubblication in MNRAS main journal. References update

Representaciones sociales del empleo y desempleo de población del País Vasco

Con la base teórico metodológica de las representaciones sociales (RS) se analizan los conceptos de empleo y desempleo en dos grupos poblacionales del País Vasco: jóvenes de 20 y menos años y adultos mayores de 21 años y más. Se utiliza la técnica asociativa de listados libres para conocer el contenido y estructura de las RS, así como la identificación del núcleo central y los elementos periféricos. Para los participantes el empleo es una ocupación que implica acceso al dinero, favorece la satisfacción de necesidades, genera felicidad. Para los mayores de 21 años es un medio para obtener dignidad, realización y futuro. El desempleo implica la falta de dinero, crisis y pobreza, genera desesperanza, depresión y agobio. Para los mayores de 21 años genera problemas, deudas, depresión y angustia, favorece la marginación y culpan a los políticos y al gobierno de su existencia. Se concluye con propuestas de afrontamiento ante el desempleo por parte de participantes.With the theoretical methodological basis of social representations (SR), concepts of employment and unemployment were analyzed in two population groups from the Basque Country: people 20 years old and under and adults over 21 years old. The associative technique of free listings was used in order to know the content and structure of SR, as well as the identification of the central nucleus and the peripheral elements. For the participants employment is an occupation that implies earning money, allows the needs’ satisfaction, and generates happiness. For the group that was 21 years old or older it means, obtaining dignity, to be satisfied and a sure future. Unemployment leads to a lack of money, crisis and poverty, causes hopelessness, depression and overwhelms the person. For the participants over 21 it generates problems, debts, depression, anguish, marginalization and the politicians and the government are blamed for its existence. We conclude with proposals from participants for coping with unemployment

Discovery of recurring slope lineae candidates in Mawrth Vallis, Mars

We thank NASA, JPL, University of Arizona, Malin Space Science Systems, Arizona State University, and The Johns Hopkins University Applied Physics Laboratory for providing HiRISE, CTX, CRISM images and related products free of charge. A.B. acknowledges the Swedish Research Council for supporting his research in cold arid environments. L.S. acknowledges the German Academic Exchange Service (DAAD) for her PhD scholarship. We acknowledge the Wallenberg Foundation and the Kempe Foundation for supporting the research activities. Data Availability All of the remote sensing data used in this study are freely available from the Planetary Data System (http://pds.nasa.gov) and from sensor-specific websites such as http://hirise.lpl.arizona.edu/ and http://crism-map.jhuapl.edu/. All the data products analysed for this study are included as web references in the figure captions and text of this article.Peer reviewedPublisher PD

Inverse sampling and triangular sequential designs to compare a small proportion with a reference value

Inverse sampling and formal sequential designs may prove useful in reducing the sample size in studies where a small population proportion p is compared with a hypothesized reference proportion p0. These methods are applied to the design of a cytogenetic study about chromosomal abnormalities in men with a daughter affected by Turner's syndrome. First it is shown how the calculated sample size for a classical design depends on the parameterization used. Later this sample size is compared with the required sample size in an inverse sampling design and a triangular sequential design using four different parameterizations (absolute differences, log-odds ratio, angular transform and Sprott's transform). The expected savings in sample size, when the alternative hypothesis is true, are 20% of the fixed sample size for the inverse sampling design and 40% for the triangular sequential design

Statistical mechanics and the description of the early universe : (II). Principle of detailed balance and primordial ⁴He formation

If the universe is slightly non-extensive, and the distribution functions are not exactly given by those of Boltzmann-Gibbs, the primordial production of light elements will be non-trivially modified. In particular, the principle of detailed balance (PDB), of fundamental importance in the standard analytical analysis, is no longer valid, and a non-extensive correction appears. This correction is computed and its influence is studied and compared with previous works, where, even when the universe was considered as an slightly non-extensive system, the PDB was assumed valid. We analytically track the formation of Helium and Deuterium, and study the kind of deviation one could expect from the standard regime. The correction to the capture time, the moment in which Deuterium can no longer be substantially photo-disintegrated, is also presented. This allows us to take into account the process of the free decay of neutrons, which was absent in all previous treatments of the topic. We show that even when considering a first (linear) order correction in the quantum distribution functions, the final output on the primordial nucleosynthesis yields cannot be reduced to a linear correction in the abundances. We finally obtain new bounds upon the non-extensive parameter, both comparing the range of physical viability of the theory, and using the latest observational data.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí