The Universe is not distributed uniformly. Galaxies are arranged in a gigantic cosmic web made of voids, filaments, and galaxy clusters. These filaments act as enormous “cosmic highways” through which matter and galaxies flow toward the densest regions of the Universe. Understanding how these structures influence galaxy evolution is one of the major goals of modern astrophysics. In this work, we analyzed hundreds of thousands of galaxies from the Sloan Digital Sky Survey (SDSS) to study how galaxy density changes around cosmic filaments in the nearby Universe. Our main goal was to determine

Dormant black holes in X-ray transients can be identified by the presence of broad Hα emission lines from quiescent accretion discs. Unfortunately, short-period cataclysmic variables can also produce broad Hα lines, especially when viewed at high inclinations, and are thus a major source of contamination. Here we compare the full width at half maximum (FWHM) and equivalent width (EW) of the Hα line in a sample of 20 quiescent black hole transients and 354 cataclysmic variables (305 from SDSS I to IV) with secure orbital periods (Porb) and find that: (1) FWHM and EW values decrease with Porb

Nuclear star clusters are dense and compact stellar systems, with sizes of a few parsecs, found at the centers of many galaxies. Their formation is thought to be closely connected to the assembly history of their host galaxies, and astronomers think that these clusters contain important clues about how galaxies formed and evolved over cosmic time. Recent studies suggest that different formation pathways may operate in late- and early-type galaxies, but the dominant mechanisms and their dependence on galaxy morphology remain unclear. While most observational studies have focused on early-type