Exploring the association of Fermi sources with Young Stellar Objects

Massive protostars have associated bipolar outflows which can produce strong shocks when interact with the surrounding medium. Some theoretical models predict that particle acceleration at relativistic velocities can occur leading to gamma ray emission. In order to identify young stellar objects (YSO) that might emit gamma rays, we have crossed the Fermi First Year Catalog with catalogs of known YSOs, obtaining a set of candidates by spatial correlation. We have conducted Montecarlo simulations to find the probability of chance coincidence. Our results indicate that ∼70% of the candidates should be gamma-ray sources with a confidence of ∼5ρ. σ International Astronomical Union 2011.Instituto Argentino de Radioastronomí

Exploring the association of Fermi sources with Young Stellar Objects

Massive protostars have associated bipolar outflows which can produce strong shocks when interact with the surrounding medium. Some theoretical models predict that particle acceleration at relativistic velocities can occur leading to gamma ray emission. In order to identify young stellar objects (YSO) that might emit gamma rays, we have crossed the Fermi First Year Catalog with catalogs of known YSOs, obtaining a set of candidates by spatial correlation. We have conducted Montecarlo simulations to find the probability of chance coincidence. Our results indicate that ∼70% of the candidates should be gamma-ray sources with a confidence of ∼5ρ. σ International Astronomical Union 2011.Instituto Argentino de Radioastronomí

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

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

INTEGRAL serendipitous detection of the gamma-ray microquasar LS 5039

LS 5039 is the only X-ray binary persistently detected at TeV energies by the Cherenkov HESS telescope. It is moreover a gamma-ray emitter in the GeV and possibly MeV energy ranges. To understand important aspects of jet physics, like the magnetic field content or particle acceleration, and emission processes, such as synchrotron and inverse Compton (IC), a complete modeling of the multiwavelength data is necessary. LS 5039 has been detected along almost all the electromagnetic spectrum thanks to several radio, infrared, optical and soft X-ray detections. However, hard X-ray detections above 20 keV have been so far elusive and/or doubtful, partly due to source confusion for the poor spatial resolution of hard X-ray instruments. We report here on deep (300 ksec) serendipitous INTEGRAL hard X-ray observations of LS 5039, coupled with simultaneous VLA radio observations. We obtain a 20-40 keV flux of 1.1 +/- 0.3 mCrab (5.9 (+/-1.6) X 10^{-12} erg cm^{-2} s^{-1}), a 40-100 keV upper limit of 1.5 mCrab (9.5 x 10^{-12} erg cm^{-2}s^{-1}), and typical radio flux densities of about 25 mJy at 5GHz. These hard X-ray fluxes are significantly lower than previous estimates obtained with BATSE in the same energy range but, in the lower interval, agree with extrapolation of previous RXTE measurements. The INTEGRAL observations also hint to a break in the spectral behavior at hard X-rays. A more sensitive characterization of the hard X-ray spectrum of LS 5039 from 20 to 100 keV could therefore constrain key aspects of the jet physics, like the relativistic particle spectrum and the magnetic field strength. Future multiwavelength observations would allow to establish whether such hard X-ray synchrotron emission is produced by the same population of relativistic electrons as those presumably producing TeV emission through IC.Comment: 4 pages LaTeX, 1 postscript figure, to appear in Proceedings of the conference "The Multi-Messenger Approach to High-Energy Gamma-ray Sources" Barcelona/Spain (2006

Diseño de Metodologías Activas para Másteres

El objetivo de la Universidad de Burgos desde el Máster en Inspección, Restauración, Rehabilitación y Eficiencia Energética de Edificación (MIREE), es la implementación de metodologías docentes activas con el fin de la formación del alumnado, a través de casos concretos y reales que adicionalmente reportarán un beneficio social. Alguno de estos métodos pueden ser el estudio de casos, la resolución de ejercicios y problemas, el aprendizaje basado en problemas y orientado a proyectos, el aprendizaje cooperativo, etc. Lo que pretendemos con las metodologías activas de aprendizaje es, que los alumnos adquieran las competencias propuestas en el programa docente, desarrollando un aprendizaje profundo en cada una de ellas. Para ello debemos evitar que el profesorado monopolice la docencia, y es necesario comunicarles tanto al alumnado como al profesorado, que la docencia es una inversión en beneficio mutuo. La realización de este tipo de proyectos favorece notablemente a los alumnos ya que desarrollan la motivación de aprendizaje o puesta en práctica de las enseñanzas recibidas, pero lo que sin duda es motivador para ellos es el reconocimiento social al trabajo realizado. Esto se ve reflejado en la Estrategia Europea 2020 a nivel universitario que habla de reforzar la cooperación entre la Universidad, Investigación y Empresa

Supersymmetric defects in the Maldacena-Nunez background

We find supersymmmetric configurations of a D5-brane probe in the Maldacena-Nunez background which are extended along one or two of the spatial directions of the gauge theory. These embeddings are worldvolume solitons which behave as codimension two or one defects in the gauge theory and preserve two of the four supersymmetries of the background.Comment: 37 pages, 2 figures, LaTeX; v2: references adde

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

An updated biostratigraphy for the late Aragonian and Vallesian of the Vallès-Penedès Basin (Catalonia)

The Vallès-Penedès Basin (Catalonia, Spain) is a classical area for the study of the Miocene land mammal faunas and includes one of the densest and most continuous records in Eurasia. Furthermore, it is the type area for the Vallesian European land mammal age. After decades of study a huge amount of bio- and magnetostratigraphic data have been collected, allowing an unprecedented dating accuracy. Here we provide an updated local biostratigraphy for the late Aragonian, Vallesian and Turolian of the Vallès-Penedès Basin. This new biostratigraphic scheme is almost exclusively based on fossil rodents, which are the most abundant and one of the best known mammal orders in the area. Our proposal represents a significant refinement compared to previous attempts and provides a formal diagnosis and description of each zone, as well as clear definition of boundaries and a reference locality and section. The chronology of zone boundaries and main bioevents is based on detailed magnetostratigraphic data. The defined biozones allow for the correlation of the sites without associated magnetostratigraphical data. Finally, the correlation of the Vallès-Penedès local zones with other detailed local biostratigraphies, such as those of the Calatayud-Montalbán and Teruel basins (east-central Spain) is discussed. The sequence and chronology of the main bioevents is roughly comparable, although the rodent succession and the structure of the assemblage show important differences between these areas

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