Results are presented of 2D radiative transfer calculations performed for geometric configurations that simulate partly evacuated small-scale magnetic flux sheets embedded in the ambient solar atmosphere. Temperature distributions in (gray) radiative equilibrium at low optical depths where radiation transfer dominates the energy budget are obtained

We present new deep and accurate space (Advanced Camera for Surveys-Wide Field Planetary Camera 2 on board the Hubble Space Telescope) and ground-based (Suprime-Cam at Subaru Telescope, Mega-Cam at Canada-France-Hawaii Telescope) photometric and astrometric data for the Local Group dwarf irregular IC10. We confirm the significant decrease of the

Using optical-optical and optical-NIR colors, we analyze the radial dependence of age and metallicity inside massive (M sstarf >~ 1010.5 M sun), low-redshift (z 0.1), early-type galaxies (ETGs), residing in both high-density group regions and the field. On average, internal color gradients of ETGs are mainly driven by metallicity, consistent with

A sample of the brightest known Seyfert galaxies from the CfA sample is analyzed on the basis of ISO photometric and spectroscopic data. Regardless of the Seyfert type, the mid-IR continuum emission from these galaxies is found to be correlated with the coronal line emission arising in the nuclear active region. Conversely, the correlation degrades

We present precise optical and near-infrared ground-based photometry of two globular clusters (GCs): ω Cen and 47 Tuc. These photometric catalogs are unbiased in the red giant branch (RGB) region close to the tip. We provide new estimates of the RGB tip (TRGB) magnitudes-mI(TRGB)=9.84+/-0.05, ω Cen; mI(TRGB)=9.46+/-0.06, 47 Tuc-and use these to

In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and we study the dynamo’s mode of operation during both the linear and non-linear saturation regimes. It turns out that in addition to a high growth rate in the linear regime, the dynamo saturates at a level