Several studies of nearby active galactic nuclei (AGNs) have shown that the soft X-ray emission presents a size and morphology resembling that of the narrow-line region (NLR) traced by [O III]. Since the NLR is mainly constituted by gas photoionized by the AGN, it seems logical to assume that this is also the primary source of the soft X-ray

What is the origin of the different dwarf galaxy types? The classification into dwarf irregular (dIrr), spheroidal (dSph), and transition (dT) types is based on their present-day properties. However, star formation histories (SFHs) reconstructed from deep color-magnitude diagrams (CMDs) provide details on the early evolution of galaxies of all

We investigate the optical and Wide-field Survey Explorer (WISE) colors of “E+A” identified post-starburst galaxies, including a deep analysis of 190 post-starbursts detected in the 2 μm All Sky Survey Extended Source Catalog. The post-starburst galaxies appear in both the optical green valley and the WISE Infrared Transition Zone. Furthermore, we

In this thesis we have studied three independent tools to get information on cosmological parameters: the large scale structure (LSS) of matter in the Universe, galaxy clusters and the cosmic microwave background (CMB). In the study of the LSS we have provided an analytical recipe for computing the conditional mass function (CMF), i.e. the mass

The discovery of γ-ray emission from radio-loud narrow-line Seyfert 1 (NLSy1) galaxies has questioned the need for large black hole masses ( ≳ 108 M⊙) to launch relativistic jets. We present near-infrared data of the γ-ray-emitting NLSy1 FBQS J1644+2619 that were collected using the camera CIRCE (Canarias InfraRed Camera Experiment) at the 10.4-m

We identify six ultra-diffuse galaxies (UDGs) outside clusters in three nearby isolated groups (0.014 z 0.026) using very deep imaging in three different Sloan Digital Sky Survey filters (g, r and I bands) from the IAC Stripe 82 Legacy Project. By comparing with the abundance of UDGs in rich galaxy clusters, we find that the density of UDGs (i.e