A class of spatially flat models with a cosmological constant and a primordial broken scale invariant (BSI) spectrum of adiabatic perturbations is confronted with the most up-to-date observational data of CMB and matter power spectrum. The theoretical model includes a parameter n_b for the number of quanta in the non-vacuum initial state, and a

We present the search for symbiotic stars in the Northern Galactic Plane within the IPHAS imaging survey. The criterion used to select this class of objects is a combination of the IPHAS r--Hα vs. r--i color-color diagram with the 2MASS J--H vs. H--K diagram. This allows us to distinguish symbiotic stars from other classes of Hα -emitting evolved

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We combine bright XMM-Newton data with the Chandra Deep Field South observations to explore the behavior of the intrinsic AGN absorption, as a function of redshift and luminosity. Our sample consists of 359 sources selected in the hard 2-8 keV band, spanning the flux range 6 × 10-16-3 × 10-13 erg~cm-2~s-1 with a high rate of spectroscopic or

stronomers have long learned to classify spirals in terms of their morphological features, primarily their bulges, discs, and bars. In addition other properties of discs are used in classification, notably spiral arms, warps and truncations. In this paper we show how with modern techniques parts of the basis of these standard classifications are

We present medium-resolution VLT/FORS2 spectroscopy of six cataclysmic variables (CVs) discovered by the Sloan Digital Sky Survey (SDSS). We determine orbital periods for SDSSJ023322.61+005059.5 (96.08 +/- 0.09min), SDSSJ091127.36+084140.7 (295.74 +/- 0.22min), SDSSJ103533.02+055158.3 (82.10 +/- 0.09min) and SDSSJ121607.03+052013.9 (most likely 98