Exploració per tema "Galàxies"
Ara es mostren els items 1-20 de 30
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A white dwarf catalogue from Gaia-DR2 and the Virtual Observatory
(Oxford University Press, 2018-01-01)
Article
Accés obertWe present a catalogue of 73¿221 white dwarf candidates extracted from the astrometric and photometric data of the recently published Gaia-DR2 catalogue. White dwarfs were selected from the Gaia Hertzsprung–Russell diagram ... -
Breaking the habit: the peculiar 2016 eruption of the unique recurrent nova M31N 2008-12a
(2018-04-10)
Article
Accés obert -
Com les Varietats Invariants formen Espirals i Anells en Galàxies barrades
(2014)
Article
Accés obertL'espectacularitat de les galàxies barrades consisteix no solament en la presència de la barra, allargada en el centre de la galàxia, sinó també en els braços espirals o anells que es desenvolupen en les parts exteriors. ... -
Deep optical images of malin 1 reveal new features
(2015-12-20)
Article
Accés obertWe present Megacam deep optical images (g and r) of Malin 1 obtained with the 6.5m Magellan/Clay telescope, detecting structures down to ~ 28 B mag arcsec-2. In order to enhance galaxy features buried in the noise, we use ... -
Discovery of soft and hard X-ray time lags in low-mass AGNs
(Oxford University Press, 2021-03-05)
Article
Accés obertThe scaling relations between the black hole (BH) mass and soft lag properties for both active galactic nuclei (AGNs) and BH X-ray binaries (BHXRBs) suggest the same underlying physical mechanism at work in accreting BH ... -
Equivalence of Boltzmann and moment equations
(2010-10-28)
Article
Accés obertThe closure problem for the stellar hydrodynamic equations is studied by describing the family of phase space density functions, for which the collisionless Boltzmann equation is strictly equivalent to a finite subset of ... -
Formation of asymmetric arms in barred galaxies
(Oxford University Press, 2023-04-01)
Article
Accés obertWe establish a dynamical mechanism to explain the origin of the asymmetry between the arms observed in some barred disc galaxies, where one of the two arms emanating from the bar ends is very well defined, while the second ... -
From manifolds to Lagrangian coherent structures in galactic bar models
(EDP Sciences, 2018-10-16)
Article
Accés obertWe study the dynamics near the unstable Lagrangian points in galactic bar models using dynamical system tools in order to determine the global morphology of a barred galaxy. We aim at the case of non-autonomous models, in ... -
High-proper-motion white dwarfs and halo dark matter
(Blackwell, 2002-11)
Article
Accés obertThe interpretation of the old, cool white dwarfs recently found by Oppenheimer et al. is still controversial. Whereas these authors claim that they have finally found the elusive ancienthalo white dwarf population that ... -
Hu 1-2: A metal-poor bipolar planetary nebula with fast collimated outflows
(2015-10-27)
Article
Accés obert© 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. We present narrow-band optical and near-IR imaging and optical long-slit spectroscopic observations of Hu 1-2, a Galactic ... -
Hunting for open clusters in Gaia EDR3: 628 new open clusters found with OCfinder
(EDP Sciences, 2022-05)
Article
Accés obertContext. The improvements in the precision of the published data in Gaia EDR3 with respect to Gaia DR2, particularly for parallaxes and proper motions, offer the opportunity to increase the number of known open clusters ... -
Is the metallicity of their host galaxies a good measure of the metallicity of Type Ia supernovae?
(2011-06)
Article
Accés obertThe efficient use of Type Ia supernovae (SNIa) for cosmological studies requires knowledge of any parameter that can affect their luminosity in either systematic or statistical ways. Observational samples of SNIa commonly ... -
Mass-loss and composition of wind ejecta in type I X-ray bursts
(EDP Sciences, 2023-10-17)
Article
Accés obertContext. X-Ray bursts (XRBs) are powerful thermonuclear events on the surface of accreting neutron stars (NSs) where nucleosynthesis of intermediate-mass elements occurs. The high surface gravity of an NS prevents the ... -
New constraints on all flavor Galactic diffuse neutrino emission with the ANTARES telescope
(2017-09-11)
Article
Accés obertThe flux of very high-energy neutrinos produced in our Galaxy by the interaction of accelerated cosmic rays with the interstellar medium is not yet determined. The characterization of this flux will shed light on Galactic ... -
Precessing models and eventual links with galaxy warps
(Universitat Politècnica de Catalunya, 2010-11)
Projecte Final de Màster Oficial
Accés obertThe Restricted Three Body problem is a basic model in celestial mechanics and it has been extensively used in the design of some spatial missions. Sometimes, the designers of these missions consider other similar models ... -
Revisiting the luminosity function of single halo white dwarfs
(EDP Sciences, 2015-09-01)
Article
Accés obertContext. White dwarfs are the fossils left by the evolution of low- and intermediate-mass stars, and have very long evolutionary timescales. This allows us to use them to explore the properties of old populations, like the ... -
Rings and spirals in barred galaxies III. Further comparisons and links to observations
(2010)
Article
Accés restringit per política de l'editorialIn a series of papers, we propose a theory to explain the formation and properties of rings and spirals in barred galaxies. The building blocks of these structures are orbits guided by the manifolds emanating from the ... -
Short-timescale X-ray spectral variability in the Seyfert 1 galaxy NGC 3783
(EDP Sciences, 2022-03-01)
Article
Accés obertAims. We report on the X-ray time-resolved spectral analysis of XMM-Newton observations of NGC 3783. Our main goal is to detect transient features in the Fe K line complex in order to study the dynamics of the innermost ... -
Supermassive black hole winds in X-rays: SUBWAYS: I. Ultra-fast outflows in quasars beyond the local Universe
(EDP Sciences, 2023-02-01)
Article
Accés obertWe present a new X-ray spectroscopic study of 22 luminous (2 × 1045 ¿ Lbol/erg s-1 ¿ 2 × 1046) active galactic nuclei (AGNs) at intermediate redshifts (0.1 ¿ z ¿ 0.4), as part of the SUpermassive Black hole Winds in the ... -
Supermassive black hole winds in X-rays: SUBWAYS: II. HST UV spectroscopy of winds at intermediate redshifts
(EDP Sciences, 2023-02-01)
Article
Accés obertWe present a UV spectroscopic study of ionized outflows in 21 active galactic nuclei (AGN), observed with the Hubble Space Telescope (HST). The targets of the Supermassive Black Hole Winds in X-rays (SUBWAYS) sample were ...