SAOLIM, a prototype of a low cost System for Adaptive Optics with Lucky Imaging

A prototype of a low cost Adaptive Optics (AO) system has been developed at the Instituto de Astrofisica de Andalucia (CSIC) and tested at the 2.2m telescope of the Calar Alto observatory. We present here the status of the project, which includes the image stabilization system and compensation of high order wavefront aberrations with a membrane deformable mirror. The image stabilization system consists of magnet driven tip-tilt mirror. The higher order compensation system comprises of a Shack-Hartmann sensor, a membrane deformable mirror with 39 actuators and the control computer that allows operations up to 420Hz in closed loop mode. We have successfully closed the high order AO loop on natural guide stars. An improvement of 4 times in terms of FWHM was achieved. The description and the results obtained on the sky are presented in this paper.Comment: Accepted for publishing in PASP, 11 pages, 14 figures, 6 table

Internal and relative motions of the Taurus and Ophiuchus star-forming regions

We investigate the internal and relative motions of the Taurus and Ophiuchus star-forming regions using a sample of young stars with accurately measured radial velocities and proper motions. We find no evidence for expansion or contraction of the Taurus complex, but a clear indication for a global rotation, resulting in velocity gradients, this suggests a common origin, possibly related to that of Gould's Belt.Comment: 2 figure

Contribución al conocimiento de la deglaciación reciente y morfología asociada del Corral del Veleta (Sierra Nevada)

[Resumen] El Corral del Veleta fue el último reducto glaciar de Sierra Nevada. Desde el Tardiglaciar la deglaciación ha sido progresiva, aunque con fluctuaciones de retroceso-avance. Respecto a la Pequeña Edad del Hielo se detectan diferentes fases con morfologías significativas y en cuanto a los tiempos posteriores la morfogénesis denuncia una merma paulatina del glaciar. En la actualidad el Corral sólo alberga pequeñas placas de hielo adosadas a las paredes. En profundidad parecen existir masas heladas (¿pergelisol?, ¿hielo?) en proceso de fusión.[Abstract] The Corral del Veleta has been the last residual glacier of the Sierra Nevada. Since late glacial times deglaciation has been progressive, interrupted by glacier advance-retrocession fluctuations. The Little Ice Age covers diferent morphological stages. The posterior sequences indicate the gradual reduction of the glacier. At present persist only sorne small ice remnants close to the cirquewall. In the ground of the cirque still exist frozen masses (pergelisol, ice?), affected by melting processe

Efficient solvability of Hamiltonians and limits on the power of some quantum computational models

We consider quantum computational models defined via a Lie-algebraic theory. In these models, specified initial states are acted on by Lie-algebraic quantum gates and the expectation values of Lie algebra elements are measured at the end. We show that these models can be efficiently simulated on a classical computer in time polynomial in the dimension of the algebra, regardless of the dimension of the Hilbert space where the algebra acts. Similar results hold for the computation of the expectation value of operators implemented by a gate-sequence. We introduce a Lie-algebraic notion of generalized mean-field Hamiltonians and show that they are efficiently ("exactly") solvable by means of a Jacobi-like diagonalization method. Our results generalize earlier ones on fermionic linear optics computation and provide insight into the source of the power of the conventional model of quantum computation.Comment: 6 pages; no figure