Spectral and variability properties of LS 5039 from radio to very high-energy gamma-rays

Microquasars are X-ray binaries with relativistic jets. The microquasar LS 5039 turned out to be the first high-energy gamma-ray microquasar candidate due to its likely association with the EGRET source 3EG J1824-1514. Further theoretical studies supported this association, which could be extended to other EGRET sources. Very recently, Aharonian et al. (2005) have communicated the detection of the microquasar LS 5039 at TeV energies. This fact confirms the EGRET source association and leaves no doubt about the gamma-ray emitting nature of this object. The aim of the present work is to show that, applying a cold-matter dominated jet model to LS 5039, we can reproduce many of the spectral and variability features observed in this source. Jet physics is explored, and some physical quantities are estimated as a by-product of the performed modeling. Although at the moment only LS 5039 has been detected on the entire electromagnetic spectrum, it does not seem unlikely that other microquasars will show similar spectral properties. Therefore, an in-depth study of the first gamma-ray microquasar, on theoretical grounds supported by observations, can render a useful knowledge applicable elsewhere.Comment: 3 pages, 3 figures, 1 Table. Proceedings of the conference: Relativistic Astrophysics and Cosmology: Einstein's Legac

Análisis de la accesibilidad urbanística y arquitectónica: SIG de la accesibilidad de Mallorca

La movilidad es un derecho fundamental de todos los ciudadanos de aquí que el análisis de la accesibilidad y evaluación sea una exigencia que han de considerar los planificadores territoriales. Actualmente las tecnologías de la información geográfica constituyen un instrumento que facilitan el reconocimiento de las barreras arquitectónicas y urbanísticas, tanto desde el punto de vista técnico como del ciudadano. Sobre esta base, el presente artículo muestra el desarrollo del Sistema de Información Geográfica de la Accesibilidad de Mallorca (SIGMA) cuyo objetivo principal es el de facilitar información actualizada y precisa al ciudadano y, al mismo tiempo, diseñar una herramienta de análisis, evaluación y soporte a la toma de decisiones para la mejora de la accesibilidad urbana y arquitectónica. El proyecto se ha desarrollado de acuerdo al Decreto 20/2003 del Reglamento de Supresión de Barreras Arquitectónica, Boletín Oficial de las Islas Baleares 18-03-2003). La construcción del SIGMA ha sido realizada por un equipo de investigación de la Universidad de las Islas Baleares y un grupo de trabajo del Área de Accesibilidad del Consell de Mallorca.Mobility is a fundamental right of all citizens that is why the analysis accessibility and its evaluation are demands that have to be considered by the territorial planners. Currently geographical information technologies are instruments that provide the recognition of the architectural barriers and urban, both from the technical and from the citizen’s point of view. On this base, the present article shows the development of the Accessibility's Geographic information System of Majorca (SIGMA) whose main goal is that one of to provide up-to-date information and precise to the citizen and, at the same time, to design a tool of analysis, evaluation and support to the decision making for the improvement of the urban accessibility and architectural. The project has been developed according to the regulations (Decree 20/2003 of the Regulations of Barrier Suppression Architectural, Official Gazette of Balearic Islands 18-03-2003). The construction of the SIGMA has been made by a team of investigation of the University of Balearic Islands and a working group of the Area of Accessibility of the Council of Majorca

Synchrotron emission from secondary leptons in microquasar jets

We present a model to estimate the synchrotron radio emission generated in microquasar (MQ) jets due to secondary pairs created via decay of charged pions produced in proton-proton collisions between stellar wind ions and jet relativistic protons. Signatures of electrons/positrons are obtained from consistent particle energy distributions that take into account energy losses due to synchrotron and inverse Compton (IC) processes, as well as adiabatic expansion. The space parameter for the model is explored and the corresponding spectral energy distributions (SEDs) are presented. We conclude that secondary leptonic emission represents a significant though hardly dominant contribution to the total radio emission in MQs, with observational consequences that can be used to test some still unknown processes occurring in these objects as well as the nature of the matter outflowing in their jets

Theoretical overview on high-energy emission in microquasars

Microquasar (MQ) jets are sites of particle acceleration and synchrotron emission. Such synchrotron radiation has been detected coming from jet regions of different spatial scales, which for the instruments at work nowadays appear as compact radio cores, slightly resolved radio jets, or (very) extended structures. Because of the presence of relativistic particles and dense photon, magnetic and matter fields, these outflows are also the best candidates to generate the very high-energy (VHE) gamma-rays detected coming from two of these objects, LS 5039 and LS I +61 303, and may be contributing significantly to the X-rays emitted from the MQ core. In addition, beside electromagnetic radiation, jets at different scales are producing some amount of leptonic and hadronic cosmic rays (CR), and evidences of neutrino production in these objects may be eventually found. In this work, we review on the different physical processes that may be at work in or related to MQ jets. The jet regions capable to produce significant amounts of emission at different wavelengths have been reduced to the jet base, the jet at scales of the order of the size of the system orbital semi-major axis, the jet middle scales (the resolved radio jets), and the jet termination point. The surroundings of the jet could be sites of multiwavelegnth emission as well, deserving also an insight. We focus on those scenarios, either hadronic or leptonic, in which it seems more plausible to generate both photons from radio to VHE and high-energy neutrinos. We briefly comment as well on the relevance of MQ as possible contributors to the galactic CR in the GeV-PeV range.Comment: Astrophysics & Space Science, in press (invited talk in the conference: The multimessenger approach to the high-energy gamma-ray sources", Barcelona/Catalonia, in July 4-7); 10 pages, 6 figures, 2 tables (one reference corrected

Coastal warming under climate change: Global, faster and heterogeneous

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe assessment of expected changes in coastal sea surface temperature (SST) on a global scale is becoming increasingly important due to the growing pressure on coastal ecosystems caused by climate change. To achieve this objective, 17 Global Climate Models from CMIP6 were used, with data from historical and hist-1950 experiments spanning 1982–2050. This analysis highlights significant warming of coastal areas worldwide, with higher and more variable rates of warming than observed in previous decades. All basins are projected to experience an increase in coastal SST near 1 °C by mid-century, with some regions exhibiting nearshore SST anomalies exceeding 2 °C for the period 2031–2050 relative to 1995–2014. Regarding the Eastern Upwelling Boundary Systems, only the Canary upwelling system and the southern part of the Humboldt upwelling system manage to show lower-than-average SST warming rates, maintaining, to a certain extent, their ability to buffer global warmingXunta de Galicia | Ref. ED431C 2021/44Xunta de Galicia | Ref. ED481B-2021-108Fundação para a Ciência e a Tecnologia | Ref. UIDP/50017/2020Fundação para a Ciência e a Tecnologia | Ref. UIDB/50017/2020Ministerio de Ciencia e Innovación y Xunta de Galicia | Ref. PRTR-C17·I1Ministerio de Ciencia e Investigación | Ref. TED2021-129524B-I0

Towards a population of HMXB/NS microquasars as counterparts of low-latitude unidentified EGRET sources

The discovery of the microquasar LS 5039 well within the 95% conficence contour of the Unidentified EGRET Source (UES) 3EG J1824-1514 was a major step towards the possible association between microquasars (MQs) and UESs. The recent discovery of precessing relativistic radio jets in LS I +61 303, a source associated for long time with 2CG 135+01 and with the UES 3EG J0241+6103, has given further support to this idea. Finally, the very recently proposed association between the microquasar candidate AX J1639.0-4642 and the UES 3EG J1639-4702 points towards a population of High Mass X-ray Binary (HMXB)/Neutron Star (NS) microquasars as counterparts of low-latitude unidentified EGRET sources.Comment: 12 pages, 7 figures. Proceedings of the Conference "The Multiwavelength Approach to Unidentified Gamma-ray Sources", to appear in the journal Astrophysics and Space Scienc

Gamma-ray binaries

Recent observations have shown that some compact stellar binaries radiate the highest energy light in the universe. The challenge has been to determine the nature of the compact object and whether the very high energy gamma-rays are ultimately powered by pulsar winds or relativistic jets. Multiwavelength observations have shown that one of the three gamma-ray binaries known so far, PSR B1259-63, is a neutron star binary and that the very energetic gamma-rays from this source and from another gamma-ray binary, LS I +61 303, may be produced by the interaction of pulsar winds with the wind from the companion star. At this time it is an open question whether the third gamma-ray binary, LS 5039, is also powered by a pulsar wind or a microquasar jet, where relativistic particles in collimated jets would boost the energy of the wind from the stellar companion to TeV energies.Comment: 4 pages, 3 figures. Invited talk to appear in Proceedings of the conference "The Multi-Messenger Approach to High-Energy Gamma-ray Sources", Barcelona, 4-7 July 200

Poor scaling between elastic energy release and eruption intensity at Tungurahua Volcano, Ecuador

An important objective in volcanology is the quantification of eruption intensity through the study of elastic energy propagated into the atmosphere and ground. To better understand the relation between elastic wave radiation and eruptive activity we deployed seismic, acoustic, and video instrumentation at the active Tungurahua Volcano (Ecuador) in Nov.-Dec. of 2004. Our data show that plume expansion scales very poorly with both seismic and acoustic trace energy and only the initial amplitude of the acoustic signal is perhaps correlated with initial plume rise speeds. In general, the eventual size of Tungurahua eruption plumes does not appear to be controlled by elevated material accelerations within the conduit, which are primary influences on elastic energy radiation. This result has vital implications for volcano observatories, which are interested in using seismic and acoustic trace amplitudes as proxies for eruption magnitudes