In this paper we present the current status of a XMM-Newton program to observe an optically-defined, complete and unbiased sample of Compton-thick Seyfert 2 galaxies. The main goal of this project is the measurement of the occurrence rate of transition between transmission- (i.e. Compton-thin), and reflection-dominated spectral states. These

The surface-brightness profiles of galaxy disks fall into three main classes, based on whether they are simple exponentials (Type I), bend down at large radii (Type II, `truncations') or bend up at large radii (Type III, `antitruncations'). Here, we discuss how the frequency of these different profiles depends on Hubble type, environment, and the

We report the detection of a transiting Jupiter-sized planet orbiting a relatively bright (V=11.79) K0 V star. We detected the transit light-curve signature in the course of the TrES multisite transiting planet survey and confirmed the planetary nature of the companion via multicolor photometry and precise radial velocity measurements. We designate

We report the discovery of TrES-4, a hot Jupiter that transits the star GSC 02620-00648 every 3.55 days. From high-resolution spectroscopy of the star, we estimate a stellar effective temperature of Teff=6100+/-150 K, and from high-precision z and B photometry of the transit we constrain the ratio of the semimajor axis a and the stellar radius R*

The three helioseismology instruments aboard SOHO observe solar p modes in velocity (GOLF and MDI) and in intensity (VIRGO and MDI). Time series of two months duration are compared and confirm that the instruments indeed observe the same Sun to a high degree of precision. Power spectra of 108 days are compared showing systematic differences between

We report the discovery of two previously unseen X-ray sources detected in a 5ks Chandra/ACIS observation starting on 2008-10-13.15 UT as part of our ongoing Chandra/HST M31 transient program. Due to the low number of counts, no detailed spectral analysis was possible. The spectra were modelled with an absorbed power law of nH = 6.67e20 atoms/ cm2