The classification of very high resolution panchromatic images from urban areas is addressed. The spectral information, i.e. the gray level of each pixel, does generally not ensure a reliable classification. In this paper, we investigate the use of an area filter to extract information about the inter-pixel dependency. The classification is then performed using a Support Vector Machines (SVM) c...

We report the first detection of X-ray emission from a brown dwarf in the Pleiades, the M7-type Roque 14, obtained using the EPIC detectors on XMM-Newton. This is the first X-ray detection of a brown dwarf intermediate in age between ≈ 12 and ≈ 320 Myr. The emission appears persistent, although we cannot rule out flare-like behaviour with a decay timescale > 4 ks. The time-averaged X-ray lumino...

Solar analogues approximately 100 Myr old may have dusty debris from collisions within evolving cometary belts, and such remnant discs might also be associated with earlier stellarspin braking. We observed at 1.2 mm wavelength a sample of 17 fast and slow rotators, mostly single K dwarfs, in the 100 Myr Pleiades cluster. No dust was detected for individual stars or the ensemble, so there are no...

Context. Stellar clusters are open windows to understand stellar evolution. Specifically, the change with time and the dependence on mass of different stellar properties. As such, they are our laboratories where different theories can be tested. Aims. We try to understand the origin of the connection between lithium depletion in F, G and K stars, rotation and activity, in particular in the Plei...

We have undertaken a LTE analysis of the high-excitation 7774 Å O I triplet in high-resolution, moderate signal-to-noise spectra of 15 Pleiades (HET/HRS) and 8 M34 (Keck/HIRES) open cluster dwarfs. Effective temperatures range from 5048 6172 K for the Pleiades sample and from 5290 6130 K for the M34 sample. Relative O abundances have been derived using model atmospheres interpolated from four d...