We obtained GALEX FUV, NUV, and Spitzer/IRAC 3.6 µm photometry for >2000 galaxies, available for 90% of the S4G sample. We find a very tight "GALEX Blue Sequence (GBS)" in the (FUV − NUV) versus (NUV − [3.6]) color-color diagram which is populated by irregular and spiral galaxies, and is mainly driven by changes in the formation timescale (τ ) and a degeneracy between τ and dust reddening. The tightness of the GBS provides an unprecedented way of identifying starforming galaxies and objects that are just evolving to (or from) what we call the "GALEX Green Valley (GGV)". At the red end of the

The planetary nebula (PN) stage is the ultimate fate of stars with mass 1 to 8 solar masses (M⊙). The origin of their complex morphologies is poorly understood, although several mechanisms involving binary interaction have been proposed. In close binary systems, the orbital separation is short enough for the primary star to overfill its Roche lobe as it expands during the Asymptotic Giant Branch (AGB) phase. The excess material ends up forming a common-envelope (CE) surrounding both stars. Drag forces would then result in the envelope being ejected into a bipolar PN whose equator is

In a search for common proper motion companions using the VISTA Hemisphere Survey (VHS) and the 2MASS catalogs we have identi fied a very red (J-Ks = 2.47 mag) late-L dwarf companion of a previously unrecognized M dwarf VHSJ125601.92-125723.9 (hereafter VHS1256-1257), located at a projected angular separation of 8.06"+/-0.03". In this work we present a suite of astrometric, photometric, and spectroscopic observations of this new pair in an effort to confirm the companionship and characterize the components. From low-resolution (R_130-600) optical and near-infrared spectroscopy we classi fied

Our arguments deal with the early evolution of Galactic globular clusters and show why only a few of the supernovae products were retained within globular clusters and only in the most massive cases (M>106 solar masses) while less massive clusters were not contaminated at all by supernovae. Here we show that supernova blast waves evolving in a steep density gradient undergo blowout and end up discharging their energy and metals into the medium surrounding the clusters. This inhibits the dispersal and the contamination of the gas left over from a first stellar generation. Only the ejecta from

Identification of the carriers of the diffuse interstellar bands (DIBs) has been very elusive since the beginning of the last century. Differentcomplex carbon-based molecules - e.g., carbon chains, polycyclicaromatic hydrocarbons (PAHs), and fullerenes - have been proposed asDIB's carriers. If the DIBs arise from large gas phase molecules, such as PAHs and fullerenes, then they are also expected to be present in other carbon-rich space environments like circumstellar shells around evolved stars. Diffuse circumstellar bands (DCBs) in absorption have been unsuccessfully studied for more than

We explore the stellar initial mass function (IMF) of a sample of 49massive quiescent galaxies (MQGs) at 0.9