The way in which the evaluation of any moment of the mass distribution, as given by the Zeldovich (1970) approximation, may be reduced to the computation of an integral is shown. A method for obtaining a two-point correlation function from the product of the density fluctuation and the Lagrangian coordinate is presented. Local approximations that

A study has been undertaken of the physical conditions of the ionized gas within the starburst region of the galaxy NGC 253, using long slit spectroscopy at high spatial and spectral resolution. The aim was to identify the appropriate parameters describing the dynamics of the gas and the excitation conditions, in relation with the starburst process

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We present a long-term programme for timing the eclipses of white dwarfs in close binaries to measure apparent and/or real variations in their orbital periods. Our programme includes 67 close binaries, both detached and semi-detached and with M-dwarfs, K-dwarfs, brown dwarfs or white dwarfs secondaries. In total, we have observed more than 650

We present a study of the long-term evolution of the cloud of aerosols produced in the atmosphere of Jupiter by the impact of an object on 19 July 2009 (Sánchez-Lavega, A. et al. [2010]. Astrophys. J. 715, L155-L159). The work is based on images obtained during 5 months from the impact to 31 December 2009 taken in visible continuum wavelengths and

We present the results of optical and infrared photometry of the quiescent X-ray transient V404 Cyg during the period 1992-2003. The ellipsoidal modulations extracted from the most complete data bases (years 1992, 1998 and 2001) show unequal maxima and minima with relative strength varying from year to year although their peak-to-peak amplitudes