198 research outputs found

    Spatial data infrastructure (SDI) for inventory rockfalls with fragmentation information

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    The version of record of this article, first published in Natural Hazards is available online at Publisher's webside: https://doi.org/10.1007/s11069-022-05282-2The fragmentation phenomenon has a significant effect on rockfall risk assessment. This information is difficult to obtain, but it is key to improving rockfall modelling. For this reason, the RockModels team has gathered data on the fragmentation of several natural events since 2014 that nowadays wants to share them with professionals, academics and stakeholders. The best way for the dissemination of this information is the use of standard or data specifications in order to be interoperable. A fragmentation rockfall database has been created using all the gathered information, according to the INSPIRE Natural Hazard Area Data Specification currently in force. However, new tables have had to be added, since this specification does not consider fragmentation data. There are currently 6000 records of geometries of source areas, envelopes, deposits and mostly individual blocks. A web mapping application, with an automatic function for coordinate reference system transformation, has been created to facilitate access to the spatial database information. All that was developed on open-source software such as OpenLayers JavaScript library, database (PostGre-PostGIS) and the map generating Web Map Service (GeoServer). As more data are collected, the database can be easily updated and the new information will be published. Moreover, to improve data interpretation, a future task is to incorporate 3D models on the web application. The existence of this public database will facilitate research and advance in knowledge of this kind of natural hazards.Peer ReviewedPostprint (published version

    On the physical meaning of the 2.1 keV absorption feature in 4U 1538-52

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    The improvement of the capabilities of nowadays X-ray observatories, like Chandra or XMM- Newton, offers the possibility to detect both absorption and emission lines and to study the nature of the matter surrounding the neutron star in X-ray binaries and the phenomena that produce these lines. The aim of this work is to discuss the different physical scenarios in order to explain the meaning of the significant absorption feature present in the X-ray spectrum of 4U 1538−52. Using the last available calibrations, we discard the possibility that this feature is due to calibration, gain effects or be produced by the X-ray background or a dust region. Giving the energy resolution of the XMM-Newton telescope we could not establish if the line is formed in the atmosphere of the neutron star or by the dispersion of the stellar wind of the optical counterpart.This work was supported by the MICINN project number AYA2010-15431

    Discussing the physical meaning of the absorption feature at 2.1 keV in 4U 1538–52

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    High resolution X-ray spectroscopy is a powerful tool for studying the nature of the matter surrounding the neutron star in X-ray binaries and its interaction between the stellar wind and the compact object. In particular, absorption features in their spectra could reveal the presence of atmospheres of the neutron star or their magnetic field strength. Here we present an investigation of the absorption feature at 2.1 keV in the X-ray spectrum of the high mass X-ray binary 4U 1538–52 based on our previous analysis of the XMM-Newton data. We study various possible origins and discuss the different physical scenarios in order to explain this feature. A likely interpretation is that the feature is associated with atomic transitions in an O/Ne neutron star atmosphere or of hydrogen and helium like Fe or Si ions formed in the stellar wind of the donor.This work was supported by the Spanish Ministry of Education and Science “De INTEGRAL a IXO: binarias de rayos X y estrellas activas”, project number AYA2010-15431, partially by GV2014/088 and MIF/14G04. JJRR acknowledges the support by the Spanish Ministerio de Educación y Ciencia under grant PR2009-0455 and by the Vicerectorat d’Investigació, Desenvolupament i Innovació de la Universitat d’Alacant under grant GRE12-35

    Metamateriales Quirales Basados en Manivelas de Cinco Segmentos

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    A new structure formed by five segments cranks is here presented. By using numerical simulations, we show that a material composed by a 2D periodical distribution of a unit cell based on such structures is able to produce electromagnetic rotatory dispersion and circular dichroism. The symmetry requirements on the unit cell are analyzed in order to obtain a material with homogeneous and isotropic behavior for normal incidence. The material can exhibit several resonant frequencies, where the rotation angle reaches a peak of ±90Âș and the transmitted wave changes from linear to elliptical polarization.IngenierĂ­a, Industria y ConstrucciĂł

    Effectiveness of a Computerized Home-Based Cognitive Stimulation Program for Treating Cancer-Related Cognitive Impairment

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    Cancer patients assert that after chemotherapy their cognitive abilities have deteriorated. Cognitive stimulation is the clinical treatment of choice for reversing cognitive decline. The current study describes a computerized home-based cognitive stimulation program in patients who survived breast cancer. It aims to assess safety and effectiveness of cognitive stimulation in the oncology population. A series of 45-min training sessions was completed by the participants. A thorough assessment was performed both before and after the intervention. The mini-Mental Adjustment to Cancer Scale, the Cognitive Assessment for Chemo Fog Research, and the Functionality Assessment Instrument in Cancer Treatment–Cognitive Function served as the main assessment tools. The State-Trait Anxiety Inventory, Beck Depression Inventory, Brief Fatigue Inventory, and Measuring Quality of Life–The World Health Organization data were gathered as secondary outcomes. Homebased cognitive stimulation demonstrated beneficial effects in the oncology population, with no side effects being reported. Cognitive, physical, and emotional improvements were observed, along with decreased interference in daily life activities and a better overall quality of life

    Resolving iron emission lines in 4U 1538-52 with XMM-Newton

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    The X-ray Universe 2011, Presentations of the Conference held in Berlin, Germany, 27-30 June 2011. Available online at: http://xmm.esac.esa.int/external/xmm_science/workshops/2011symposium/, article id.275We present the results of a XMM-Newton observation of the high-mass X-ray binary 4U 1538-52 at orbital phases between 0.75-1.00 (in the eclipse-ingress phase). Here we concentrate on the study of discrete features in the energy range from 5.9 keV to 7.8 keV, i.e. on the iron Kα line region, using the EPIC/PN instrument on board XMM-Newton observatory. We clearly see a Kα neutral iron line at around 6.4 keV and were able to distinguish two hot lines from highly photoionized Fe XXV and Fe XXVI. We discuss the implications of the simultaneous presence of iron with both low and high ionization levels.This work was supported by the Spanish Ministry of Education and Science De INTEGRAL a IXO: binarias de rayos X y estrellas activas AYA2010-15431 and partially supported by Primera ciencia con el GTC: La astronomía española en vanguardia de la astronomía europea CSD200670. KLP and JPO acknowledge support from the UK Space Agency. JJRR acknowledges support by the Spanish Ministerio de Educación y Ciencia (MEC) under grant PR2009-0455. This work made use of data obtained through the XMM-Newton Science Archive (XSA), rovided by European Space Agency (ESA)

    An XMM-Newton view of FeKα in high-mass X-ray binaries

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    We present a comprehensive analysis of the whole sample of available XMM-Newton observations of high-mass X-ray binaries (HMXBs) until August 2013, focusing on the FeKα emission line. This line is key to better understanding the physical properties of the material surrounding the X-ray source within a few stellar radii (the circumstellar medium). We collected observations from 46 HMXBs and detected FeKα in 21 of them. We used the standard classification of HMXBs to divide the sample into different groups. We find that (1) different classes of HMXBs display different qualitative behaviours in the FeKα spectral region. This is visible especially in SGXBs (showing ubiquitous Fe fluorescence but not recombination Fe lines) and in Îł Cass analogues (showing both fluorescent and recombination Fe lines). (2) FeKα is centred at a mean value of 6.42 keV. Considering the instrumental and fits uncertainties, this value is compatible with ionization states that are lower than Fe xviii. (3) The flux of the continuum is well correlated with the flux of the line, as expected. Eclipse observations show that the Fe fluorescence emission comes from an extended region surrounding the X-ray source. (4) We observe an inverse correlation between the X-ray luminosity and the equivalent width of FeKα (EW). This phenomenon is known as the X-ray Baldwin effect. (5) FeKα is narrow (σline< 0.15 keV), reflecting that the reprocessing material does not move at high speeds. We attempt to explain the broadness of the line in terms of three possible broadening phenomena: line blending, Compton scattering, and Doppler shifts (with velocities of the reprocessing material V ~ 1000 km s-1). (6) The equivalent hydrogen column (NH) directly correlates to the EW of FeKα, displaying clear similarities to numerical simulations. It highlights the strong link between the absorbing and the fluorescent matter. (7) The observed NH in supergiant X-ray binaries (SGXBs) is in general higher than in supergiant fast X-ray transients (SFXTs). We suggest two possible explanations: different orbital configurations or a different interaction compact object – wind. (8) Finally, we analysed the sources IGR J16320-4751 and 4U 1700-37 in more detail, covering several orbital phases. The observed variation in NH between phases is compatible with the absorption produced by the wind of their optical companions. The results clearly point to a very important contribution of the donor’s wind in the FeKα emission and the absorption when the donor is a supergiant massive star.The work of A.G.G. has been supported by the Spanish MICINN under FPI Fellowship BES-2011-050874 associated to the project AYA2010-15431. This work was supported partially by the Generalitat Valenciana project number GV2014/088 and by the Vicerectorat d’InvestigaciĂł, Desenvolupament i InnovaciĂł de la Universitat d’Alacant under grant GRE12-35. J.J.R.R. acknowledges the support by the Matsumae International Foundation fellowship No14G04

    An XMM-Newton view of FeKα in High Mass X-rays Binaries

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    We present a comprehensive analysis of the whole sample of available XMM-Newton observations of High Mass X-ray Binaries (HMXBs) until August, 2013, focusing on the FeKα emission line. This line is a key tool to better understand the physical properties of the material surrounding the X-ray source within a few stellar radii (the circumstellar medium). We have collected observations from 46 HMXBs, detecting FeKα in 21 of them. We have used the standard classification of HMXBs to divide the sample in different groups. We find that: (1) FeKα is centred at a mean value of 6.42 keV. Considering the instrumental and fits uncertainties, this value is compatible with ionization states lower than Fe XVIII. (2) The flux of the continuum is well correlated with the flux of the line, as expected. Eclipse observations show that the Fe fluorescence emission comes from an extended region surrounding the X-ray source. (3) FeKα is narrow (σ_{line}<0.15 keV), reflecting that the reprocessing material does not move at high speeds. We attempt to explain the broadness of the line in terms of three possible broadening phenomena: line blending, Compton scattering and Doppler shifts (with velocities of the reprocessing material V ∌ 1000 km/s). (4) The equivalent hydrogen column (N_H) directly correlates with the EW of FeKα, displaying clear similarities to numerical simulations. It highlights the strong link between the absorbing and the fluorescent matter. The obtained results clearly point to a very important contribution of the donor's wind in the FeKα emission and the absorption when the donor is a supergiant massive star.Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA). This research has made use of software obtained from NASA’s High Energy Astrophysics Science Archive Research Center (HEASARC). The work of AGG has been supported by the Spanish MICINN under FPI Fellowship BES-2011-050874 associated to the project AYA2010-15431

    Searching for unknown counterparts in X-ray binary systems using Virtual Observatory tools

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    In the framework of an ongoing programme, we have developed strategies to discover and characterize optical/infrared unknown counterparts to X-ray binary systems using the standard tools of the Virtual Observatory. First, we have selected some potential candidates from different X-ray catalogues. Then we have used the Virtual Observatory tools to search for optical and infrared point data sources that were coincident with the position of the X-ray source. In this work we present some examples of our ongoing programme showing the potential of the Virtual Observatory as a discovery tool.Part of this work was supported by the Spanish Ministry of Education and Science project number AYA2010-15431, by the Vicerectorat d'InvestigaciĂł, Desenvolupament i InnovaciĂł de la Universitat d'Alacant project number GRE12-35, and by the Generalitat Valenciana project number GV2014/088. JJRR acknowledges the support by the Matsumae International Foundation Research Fellowship program 2014, No14G04
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