Search results for "star"
showing 10 items of 4285 documents
La sonrisa del éxito: figuraciones de una subjetividad exigida
2014
El presente artículo analiza cómo se afianza en la escena social la corporalidad del liderazgo. Para ello, aborda imágenes y narrativas que circulan en los entramados simbólicos de la cultura del bienestar, que también se denomina como cultura activa. El cuerpo del liderazgo se ofrece al público mediante estrategias positivas y negativas. Éstas, en la medida que encumbran el estilo de vida activo, demonizan aquellas prácticas que no responden a los valores sanitarios y productivos promulgados por el ethos empresarial emergente. Se concluye que la encarnación de una subjetividad emprendedora se impone paulatinamente como parámetro de integración de un individuo en los diagramas económicos y …
Validación de la Escala de Satisfacción con la Vida y su relación con las dimensiones del Autoconcepto en universitarios peruanos
2018
Life satisfaction has been the object of several studies, mostly assessed with the Satisfaction with Life Scale (SWLS). Recently, interest has been shown in the relationship between life satisfaction and self-concept, because life satisfaction seems to depend on the cultural context. The purpose of this research was to study the properties of the SWLS in a sample of Peruvian students, and to analyze the relationship between life satisfaction and self-concept in the Peruvian context. The study population consisted of 527 university students from Lima, Peru. Firstly, a confirmatory factor analysis was estimated and assessed, and reliability estimates of the scale and its items were calculated…
A quantum dynamics study of the benzopyran ring opening guided by laser pulses
2014
Abstract The ring-opening photoisomerization of benzopyran, which occurs via a photochemical route involving a conical intersection, has been studied with quantum dynamics calculations using the multi-configuration time-dependent Hartree method (MCTDH). We introduce a mechanistic strategy to control the conversion of benzopyran to merocyanine with laser pulses. We use a six-dimensional model developed in a previous work for the potential energy surfaces (PES) based on an extension of the vibronic-coupling Hamiltonian model (diabatization method by ansatz), which depends on the most active degrees of freedom. The main objective of these quantum dynamics simulations is to provide a set of str…
Full-dimensional control of the radiationless decay in pyrazine using the dynamic Stark effect
2014
We present a full quantum-mechanical study of the laser control of the radiationless decay between the B3u(nπ(*)) and B2u(ππ(*)) states of pyrazine using the dynamic Stark effect. In contrast to our previous study [Sala et al., J. Chem. Phys. 140, 194309 (2014)], where a four-dimensional model was used, all the 24 degrees of freedom are now included in order to test the robustness of the strategy of control. Using a vibronic coupling Hamiltonian model in a diabatic representation, the multi-layer version of the multi-configuration time-dependent Hartree method is exploited to propagate the corresponding wave packets. We still observe a trapping of the wavepacket on the B2u(ππ(*)) potential …
Diving below the spin-down limit: Constraints on gravitational waves from the energetic young pulsar PSR J0537-6910
2021
We present a search for continuous gravitational-wave signals from the young, energetic X-ray pulsar PSR J0537-6910 using data from the second and third observing runs of LIGO and Virgo. The search is enabled by a contemporaneous timing ephemeris obtained using NICER data. The NICER ephemeris has also been extended through 2020 October and includes three new glitches. PSR J0537-6910 has the largest spin-down luminosity of any pulsar and is highly active with regards to glitches. Analyses of its long-term and inter-glitch braking indices provided intriguing evidence that its spin-down energy budget may include gravitational-wave emission from a time-varying mass quadrupole moment. Its 62 Hz …
X-ray emission from young brown dwarfs in the Orion Nebula Cluster
2005
We use the sensitive X-ray data from the Chandra Orion Ultradeep Project (COUP) to study the X-ray properties of 34 spectroscopically-identified brown dwarfs with near-infrared spectral types between M6 and M9 in the core of the Orion Nebula Cluster. Nine of the 34 objects are clearly detected as X-ray sources. The apparently low detection rate is in many cases related to the substantial extinction of these brown dwarfs; considering only the BDs with $A_V \leq 5$ mag, nearly half of the objects (7 out of 16) are detected in X-rays. Our 10-day long X-ray lightcurves of these objects exhibit strong variability, including numerous flares. While one of the objects was only detected during a sho…
A coronal explosion on the flare star CN Leonis
2008
We present simultaneous high-temporal and high-spectral resolution observations at optical and soft X-ray wavelengths of the nearby flare star CN Leo. During our observing campaign a major flare occurred, raising the star's instantaneous energy output by almost three orders of magnitude. The flare shows the often observed impulsive behavior, with a rapid rise and slow decay in the optical and a broad soft X-ray maximum about 200 seconds after the optical flare peak. However, in addition to this usually encountered flare phenomenology we find an extremely short (~2 sec) soft X-ray peak, which is very likely of thermal, rather than non-thermal nature and temporally coincides with the optical …
Very Deep inside the SN 1987A Core Ejecta: Molecular Structures Seen in 3D
2017
Most massive stars end their lives in core-collapse supernova explosions and enrich the interstellar medium with explosively nucleosynthesized elements. Following core collapse, the explosion is subject to instabilities as the shock propagates outwards through the progenitor star. Observations of the composition and structure of the innermost regions of a core-collapse supernova provide a direct probe of the instabilities and nucleosynthetic products. SN 1987A in the Large Magellanic Cloud (LMC) is one of very few supernovae for which the inner ejecta can be spatially resolved but are not yet strongly affected by interaction with the surroundings. Our observations of SN 1987A with the Ataca…
High Resolution X-ray Spectroscopy of T Tauri Stars in the Taurus-Auriga Complex
2006
Differences have been reported between the X-ray emission of accreting and non-accreting stars. Some observations have suggested that accretion shocks could be responsible for part of the X-ray emission in Classical T Tauri stars (CTTS). We present high-resolution X-ray spectroscopy of nine pre-main sequence stars in order to test the proposed spectroscopic differences between accreting and non-accreting pre-main sequence stars. We use X-ray spectroscopy from the XMM-Newton Reflection Grating Spectrometers and the EPIC instruments. We interpret the spectra using optically thin thermal models with variable abundances, together with an absorption column density. For BP Tau and AB Aur we deriv…
Subarcsecond Location of IGR J17480-2446 with Rossi XTE
2012
On 2010 October 13, the X-ray astronomical satellite Rossi XTE, during the observation of the newly discovered accretion powered X-ray pulsar IGR J17480--2446, detected a lunar occultation of the source. From knowledge of lunar topography and Earth, Moon, and spacecraft ephemeris at the epoch of the event, we determined the source position with an accuracy of 40 mas (1{\sigma} c.l.), which is interesting, given the very poor imaging capabilities of RXTE (\sim 1\circ). For the first time, using a non-imaging X-ray observatory, the position of an X-ray source with a subarcsecond accuracy is derived, demonstrating the neat capabilities of a technique that can be fruitfully applied to current a…