We exploit a sample of 80 000 Sloan Digital Sky Survey central galaxies to investigate the effect of active galactic nucleus (AGN) feedback on their evolution. We trace the demographics of optically selected AGN (Seyferts) as a function of their internal properties and environment. We find that the preeminence of AGN as the dominant ionizing

We present a deep search for and analysis of X-ray sources in a sample of dwarf galaxies (M r < -15.5 mag) located within twelve galaxy clusters from the Kapteyn IAC WHT Enhanced Area Velocity Explores Isaac Newton Telescope Cluster Survey of photometric observations in the r and g using the Wide Field Camera at the 2.5-m Isaac Newton telescope. We

We present the first systematic follow-up of Planck Sunyaev-Zeldovich effect (SZE) selected candidates down to signal-to-noise (S/N) of 3 over the 5000 deg 2 covered by the Dark Energy Survey. Using the MCMF cluster confirmation algorithm, we identify optical counterparts, determine photometric redshifts, and richnesses and assign a parameter, f

Although ultra diffuse galaxies (UDGs) are found in large numbers in clusters of galaxies, the role of the cluster environment in shaping their low surface brightness and large sizes is still uncertain. Here, we examine a sample of UDGs in the Hydra I cluster (D = 51 Mpc) with new radial velocities obtained as part of the LEWIS (Looking into the

The different structures we observe in the Universe result from cosmic evolution starting from primordial seeds. These are believed to have originated from quantum fluctuations. During the inflationary epoch, they were stretched and frozen just after the Big Bang, giving rise to an almost homogeneous, closely Gaussian-distributed Universe. However

Galaxies in the Universe are distributed in a web-like structure characterized by different large-scale environments: dense clusters, elongated filaments, sheetlike walls and under-dense regions, called voids 1-5. The low density in voids is expected to affect the properties of their galaxies. Indeed, previous studies 6-14 have shown that galaxies