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Nomenclatura Unesco > (21) Astronomía y Astrofísica

Mostrando recursos 21 - 40 de 592

21. Testing the initial-final mass relationship of white dwarfs - Catalán Ruiz, Sílvia
White dwarfs are the final remnants of low- and intermediate-mass stars. About 95% of main- sequence stars will end their evolutionary pathways as white dwarfs and, hence, the study of the white dwarf population provides details about the late stages of the life of the vast majority of stars.Since white dwarfs are long-lived objects, they also constitute useful objects to study the structure and evolution of our Galaxy. For instance, the initial-final mass relationship, which connects the final mass of a white dwarf with the initial mass of its main-sequence progenitor, is of paramount importance for different aspects in modern...

22. Payload data handling, telemetry and data compression systems for Gaia. - Portell i de Mora, Jordi
Gaia, la nova missió astromètrica de la ESA amb un llançament previst pel 2011, observarà més de mil milions d'estels i altres objectes amb una exactitud sense precedents. Els seus ambiciosos objectius desbanquen completament les missions rivals d'altres agències. Al final de la seva vida útil es generarà el major i més complert mapa tridimensional de la nostra Galàxia.Una missió com aquesta suposa grans esforços tecnològics i de disseny ja que caldrà detectar, seleccionar i mesurar centenars d'estels cada segon, per enviar-ne posteriorment les dades cap a la Terra -a més d'un milió i mig de quilòmetres. Hem centrat el...

23. Modelling And Analysis Of Crack Turning On Aeronautical Structures - Llopart Prieto, Llorenç
La motivació de la tesis deriva en el interès de la indústria aeronàutica a explotar, per mitjà d'un disseny adaptat, la utilització del gir d'esquerda per protegir els reforços situats davant una esquerda que s'està propagant en la xapa d'una estructura integral. L'objectiu principal és l'avaluació i predicció del gir d'esquerda en situacions de càrrega pròximes a Mode I, proporcionant una eina de modelització i un criteri confident. L'entorn industrial sota el qual s'ha realitzat aquest treball requereix una predicció ràpida del comportament estructural proporcionant informació útil als constructors. Per aquest motiu la predicció del gir d'esquerda s'ha investigat utilitzant...

24. Contributions to the Optimisation of aircraft noise abatement procedures - Prats Menéndez, Xavier
Tot i que en les últimes dècades la reducció del soroll emès pels avions ha estat substancial, el seu impacte a la població ubicada a prop dels aeroports és un problema que encara persisteix. Contenir el soroll generat per les operacions d'aeronaus, tot assumint al mateix temps la creixent demanda de vols, és un dels principals desafiaments a que s'enfronten les autoritats aeroportuàries, els proveïdors de serveis per a la navegació aèria i els operadors de les aeronaus. A part de millorar l'aerodinàmica o les emissions sonores de les aeronaus, l'impacte acústic de les seves operacions es pot reduir també...

25. Algorithms and Methods for Robust Geodetic kinematic Positioning - Talaya López, Julià
El sistema NAVSTAR/GPS ha desenvolupat un paper molt important en les tècniques de posicionament cinemàtic geodèsiques, especialment en la determinació de la trajectòries per a la orientació de sensors aerotransportats d'observació de la terra. Amb l'excepció dels sensors fotogramètrics tradicionals la orientació dels sensors moderns aerotransportats depenen completament del posicionament GPS o bé de la integració GPS/INS. Per tant el posicionament GPS ha de ser precís i sobre tot fiable. Aquesta tesis es basa en l'estudi de nous algorismes i configuracions de missions que permetin augmentar el nivells de robustesa i fiabilitat en la determinació de trajectòries cinemàtiques aèries. Des...

26. Searches for point-like and extended neutrino sources close to the galactic center using the antares neutrino telescope - Adrian Martinez, Silvia; Albert, Andreas; André, Michel
A search for cosmic neutrino sources using six years of data collected by the ANTARES neutrino telescope has been performed. Clusters of muon neutrinos over the expected atmospheric background have been looked for. No clear signal has been found. The most signal-like accumulation of events is located at equatorial coordinates R.A. =-46.°8 and decl. =-64.°9 and corresponds to a 2.2s background fluctuation. In addition, upper limits on the flux normalization of an E -2 muon neutrino energy spectrum have been set for 50 pre-selected astrophysical objects. Finally, motivated by an accumulation of seven events relatively close to the Galactic Center...

27. Searches for point-like and extended neutrino sources close to the galactic center using the antares neutrino telescope - Adrian Martinez, Silvia; Albert, Andreas; André, Michel
A search for cosmic neutrino sources using six years of data collected by the ANTARES neutrino telescope has been performed. Clusters of muon neutrinos over the expected atmospheric background have been looked for. No clear signal has been found. The most signal-like accumulation of events is located at equatorial coordinates R.A. =-46.°8 and decl. =-64.°9 and corresponds to a 2.2s background fluctuation. In addition, upper limits on the flux normalization of an E -2 muon neutrino energy spectrum have been set for 50 pre-selected astrophysical objects. Finally, motivated by an accumulation of seven events relatively close to the Galactic Center...

28. Searches for point-like and extended neutrino sources close to the galactic center using the antares neutrino telescope - Adrian Martinez, Silvia; Albert, Andreas; André, Michel
A search for cosmic neutrino sources using six years of data collected by the ANTARES neutrino telescope has been performed. Clusters of muon neutrinos over the expected atmospheric background have been looked for. No clear signal has been found. The most signal-like accumulation of events is located at equatorial coordinates R.A. =-46.°8 and decl. =-64.°9 and corresponds to a 2.2s background fluctuation. In addition, upper limits on the flux normalization of an E -2 muon neutrino energy spectrum have been set for 50 pre-selected astrophysical objects. Finally, motivated by an accumulation of seven events relatively close to the Galactic Center...

29. Dark energy and thermonuclear supernovae - Domínguez, I; Bravo Guil, Eduardo; Piersanti, L; Tornambé, A; Straniero, O; Höfflich, P
Nowadays it is widely accepted that the current Universe is dominated by dark energy and exotic matter, the so called StandardModel of Cosmoloy or _CDM model. All the available data (Thermonuclear Supernovae, Cosmic Microwave Background, Baryon Acoustic Oscillations, Large Scale Structure, etc.) are compatible with a flat Universe made by _70% of dark energy. Up to now observations agree that dark energy may be the vacuum energy (or cosmological constant) although improvements are needed to constrain further its equation of state. In this context, the còsmic destiny of the Universe is no longer linked to its geometry but to the...

30. Dark energy and thermonuclear supernovae - Domínguez, I; Bravo Guil, Eduardo; Piersanti, L; Tornambé, A; Straniero, O; Höfflich, P
Nowadays it is widely accepted that the current Universe is dominated by dark energy and exotic matter, the so called StandardModel of Cosmoloy or _CDM model. All the available data (Thermonuclear Supernovae, Cosmic Microwave Background, Baryon Acoustic Oscillations, Large Scale Structure, etc.) are compatible with a flat Universe made by _70% of dark energy. Up to now observations agree that dark energy may be the vacuum energy (or cosmological constant) although improvements are needed to constrain further its equation of state. In this context, the còsmic destiny of the Universe is no longer linked to its geometry but to the...

31. Simulations of radiative shocks and jet formation in laboratory plasmas - Velarde, Pedro; González, Matthias; Oliva, Eduardo; Kasperczuk, Andrzej; Pisarczyk, Tadeusz; Ullschmied, Jiri; Stehlé, Chantal; Rus, Bedrich; García Senz, Domingo; Bravo Guil, Eduardo; Relaño, Antonio
We present the simulations of two relevant hydrodynamical problems related to astrophysical phenomena performed by three different codes. The numerical results from these codes will be compared in order to test both the numerical method implemented inside them and the influence of the physical phenomena simulated by the codes. Under some conditions laser produced plasmas could be scaled to the typical conditions prevailing in astrophysical plasmas. Therefore, such similarity allows to use existing laser facilities and numerical codes suitable to a laser plasma regime, for studying astrophysical proccesses. The codes are the radiation fluid dynamic 2D ARWEN code and the...

32. Diseño, construcción y uso de una cámara CCD para observaciones astronómicas - Roca Molina, Felipe
En este proyecto se presenta la construcción de una cámara CCD (dispositivo de cargaacoplada) para su uso posterior en aplicaciones astronómicas siguiendo y adaptando lasindicaciones del texto The CCD Camera Cookbook (Berry et al., 1994). Se explica elfuncionamiento de una cámara CCD a nivel sencillo particularizada para el chip TC211de la casa Texas Instuments.Se ha diseñado y construido las placas necesarias y se ha realizado un amplio estudiodel funcionamiento de la circuitería (preamplificador, convertidor A/D) y la lógica delchip TC211. Se ha hecho una breve explicación de la célula peltier (no desarrollada enel presente proyecto pero objeto de futuras ampliaciones)...

33. Simulations of radiative shocks and jet formation in laboratory plasmas - Velarde, Pedro; González, Matthias; Oliva, Eduardo; Kasperczuk, Andrzej; Pisarczyk, Tadeusz; Ullschmied, Jiri; Stehlé, Chantal; Rus, Bedrich; García Senz, Domingo; Bravo Guil, Eduardo; Relaño, Antonio
We present the simulations of two relevant hydrodynamical problems related to astrophysical phenomena performed by three different codes. The numerical results from these codes will be compared in order to test both the numerical method implemented inside them and the influence of the physical phenomena simulated by the codes. Under some conditions laser produced plasmas could be scaled to the typical conditions prevailing in astrophysical plasmas. Therefore, such similarity allows to use existing laser facilities and numerical codes suitable to a laser plasma regime, for studying astrophysical proccesses. The codes are the radiation fluid dynamic 2D ARWEN code and the...

34. Supernovae and dark energy - Domínguez, Inmaculada; Bravo Guil, Eduardo; Piersanti, Luciano; Straniero, Oscar; Tornambé, Amedeo
A decade ago the observations of thermonuclear supernovae at high-redhifts showed that the expansion rate of the Universe is accelerating and since then, the evidence for cosmic acceleration has gotten stronger. This acceleration requires that the Universe is dominated by dark energy, an exotic component characterized by its negative pressure.Nowadays all the available astronomical data (i.e. thermonuclear supernovae, cosmic microwave background, barionic acoustic oscillations, large scale structure, etc.) agree that our Universe is made of about 70% of dark energy, 25% of cold dark matter and only 5% of known, familiar matter. This Universe is geometrically flat, older than previously...

35. Supernovae and dark energy - Domínguez, Inmaculada; Bravo Guil, Eduardo; Piersanti, Luciano; Straniero, Oscar; Tornambé, Amedeo
A decade ago the observations of thermonuclear supernovae at high-redhifts showed that the expansion rate of the Universe is accelerating and since then, the evidence for cosmic acceleration has gotten stronger. This acceleration requires that the Universe is dominated by dark energy, an exotic component characterized by its negative pressure. Nowadays all the available astronomical data (i.e. thermonuclear supernovae, cosmic microwave background, barionic acoustic oscillations, large scale structure, etc.) agree that our Universe is made of about 70% of dark energy, 25% of cold dark matter and only 5% of known, familiar matter. This Universe is geometrically flat, older than previously...

36. A population synthesis study of the luminosity function of hot white dwarfs - Torres Gil, Santiago; García-Berro Montilla, Enrique; Krzesinski, Jurek; Kleinman, Scot J.
Context. We present a coherent and detailed Monte Carlo simulation of the population of hot white dwarfs. We assess the statistical significance of the hot end of the white dwarf luminosity function and the role played by the bolometric corrections of hydrogen-rich white dwarfs at high effective temperatures. Aims. We use the most up-to-date stellar evolutionary models and implement a full description of the observational selection biases to obtain realistic simulations of the observed white dwarf population. Methods. Our theoretical results are compared with the luminosity function of hot white dwarfs obtained from the Sloan Digital Sky Survey (SDSS), for...

37. Supernovae and dark energy - Domínguez, Inmaculada; Bravo Guil, Eduardo; Piersanti, Luciano; Straniero, Oscar; Tornambé, Amedeo
A decade ago the observations of thermonuclear supernovae at high-redhifts showed that the expansion rate of the Universe is accelerating and since then, the evidence for cosmic acceleration has gotten stronger. This acceleration requires that the Universe is dominated by dark energy, an exotic component characterized by its negative pressure.Nowadays all the available astronomical data (i.e. thermonuclear supernovae, cosmic microwave background, barionic acoustic oscillations, large scale structure, etc.) agree that our Universe is made of about 70% of dark energy, 25% of cold dark matter and only 5% of known, familiar matter. This Universe is geometrically flat, older than previously...

38. A population synthesis study of the luminosity function of hot white dwarfs - Torres Gil, Santiago; García-Berro Montilla, Enrique; Krzesinski, Jurek; Kleinman, Scot J.
Context. We present a coherent and detailed Monte Carlo simulation of the population of hot white dwarfs. We assess the statistical significance of the hot end of the white dwarf luminosity function and the role played by the bolometric corrections of hydrogen-rich white dwarfs at high effective temperatures. Aims. We use the most up-to-date stellar evolutionary models and implement a full description of the observational selection biases to obtain realistic simulations of the observed white dwarf population. Methods. Our theoretical results are compared with the luminosity function of hot white dwarfs obtained from the Sloan Digital Sky Survey (SDSS), for...

39. Observation of SN2011fe with INTEGRAL - I : pre-maximum phase - Isern Vilaboy, Jordi; Jean, Pierre; Bravo Guil, Eduardo; Diehl, Roland; Knödlseder, Jurgen; Domingo, A.; Hirschmann, Alina; Hoeflich, Peter; Lebrun, F.; Renaud, M; Soldi, Simona; Elias-Rosa, Nancy; Hernanz Carbó, Margarita; Kulebi, Baybar; Zhang, X.; Badenes, C.; Domínguez Aguilera, Inmaculada; García Senz, Domingo; Jordi, Carme; Lichti, G.; Vedrenne, G.; von Ballmoos, Peter
Context. SN2011fe was detected by the Palomar Transient Factory in M101 on August 24, 2011, a few hours after the explosion. From the early optical spectra it was immediately realized that it was a Type Ia supernova, thus making this event the brightest one discovered in the past twenty years.Aims. The distance of the event offered the rare opportunity of performing a detailed observation with the instruments onboard INTEGRAL to detect the ¿-ray emission expected from the decay chains of 56Ni. The observations were performed in two runs, one before and around the optical maximum, aimed to detect the early...

40. A Super-solar metallicity for the progenitor of Kepler's supernova - Park, Sangwook; Badenes Montoliu, Carles; Mori, Koji; Kaida, Ryohei; Bravo Guil, Eduardo; Schenck, Andrew; Eriksen, Kristoffer A.; Hughes, John P.; Slane, Patrick O.; Burrows, David N.; Lee, Jae-Joon
We have performed deep X-ray observations of the remnant of Kepler's supernova (SN 1604) as a Key Project of the Suzaku Observatory. Our main goal is to detect secondary Fe-peak elements in the supernova (SN) ejecta to gain insights into the Type Ia SN explosion mechanism and the nature of the progenitor. Here, we report our initial results. We made a conclusive detection of X-ray emission lines from highly ionized Mn, Cr, and Ni as well as Fe. The observed Mn-to-Cr line flux ratio is ~0.60, ~30% larger than that measured in Tycho's remnant. We estimate an Mn-to-Cr mass ratio...

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