Stokes profiles emerging from the magnetized quiet photosphere and observed by the Solar Optical Telescope (SOT) spectropolarimeter (SP) aboard the Hinode satellite present a large variety of complex shapes. These are indicative of unresolved magnetic structures and/or gradients along the line of sight that have been overlooked in the inversion

We present the basic concept of a new astronomical instrument: SPARC4 - Simultaneous Polarimeter and Rapid Camera in 4 bands. SPARC4 combines in one instrument: (i) photometric and polarimetric modes; (ii) sub-second time-resolution in photometric mode and excellent timeresolution in polarimetric mode; (iii) simultaneous imaging in four broad-bands

Recent advances in the observation and numerical modeling of magnetic flux emergence on small-scales are reviewed. The high-resolution limit of solar photospheric observations has reached scales of order 0".2, or 100-200 km, in recent years. Observations with that resolution show individual flux tubes emerging within single granules in the quiet

Hydrogen emission lines in Mira variable stars are a well-known phenomenon whose origin has been established as related to the propagation of radiative hypersonic shock waves throughout the stellar atmosphere. A polarimetric observation by McLean and Coyne [1] made on omicron Ceti (the prototype of Mira variable stars) has revealed the existence of

Magnetic field topology, thermal structure, and plasma motions are the three main factors affecting the polarization signals used to understand our star. In this theoretical investigation, we focus on the effect that gradients in the macroscopic vertical velocity field have on the non-magnetic scattering polarization signals, establishing the basis

The accretion of minor satellites has been postulated as the most likely mechanism to explain the significant size evolution of massive galaxies over cosmic time. Using a sample of 629 massive (Mstar˜ 1011 M&sun;) galaxies from the near-infrared Palomar/DEEP-2 survey, we explore what fraction of these objects have satellites with 0.01 Msat