We present a study of the morphology, kinematics and star formation of a sample of 27 isolated spiral galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G), on the basis of Hα Fabry-Perot (FP) data from the GHαFaS instrument at the William Herschel Telescope (WHT) in La Palma, complemented with images at 3.6 micron from the Spitzer

Observations show a clear vertical metallicity gradient in the Galactic bulge, which is often taken as a signature of dissipative processes in the formation of a classical bulge. Various evidence shows, however, that the Milky Way is a barred galaxy with a boxy bulge representing the inner three-dimensional part of the bar. Here we show with a

Optical spectroscopy of the blue star KIC 10449976 shows that it is an extremely helium-rich subdwarf with effective temperature Teff = 40 000 ± 300 K and surface gravity log g = 5.3 ± 0.1. Radial-velocity measurements over a 5 d time-scale show an upper variability limit of ≈50 ± 20 km s-1. Kepler photometry of KIC 10449976 in both long and short

The spectral line polarization of the radiation emerging from a magnetized astrophysical plasma depends on the state of the atoms within the medium, whose determination requires considering the interactions between the atoms and the magnetic field, between the atoms and photons (radiative transitions), and between the atoms and other material

The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and

We have observed Arp 270 using the GHαFaS Fabry-Perot spectrometer on the 4.2m William Herschel Telescope (La Palma). In the edge-on companion we detect a radial gas inflow of ˜ 0.36 M &sun;/yr to the centre and also an axially confined outflow of ˜ 0.24 M &sun;/yr from the nucleus in two opposing directions. We find two different behaviors between