Related papers: Unsupervised classification reveals new evolutiona…
The galaxy evolution is believed to be conditioned by the environment. Isolated galaxies or galaxies in poor groups are an excellent laboratory to study evolutionary mechanisms where effects of the environment are minimal. We present new…
The environment plays a critical role in galaxy evolution, with galaxy clusters and their infall regions offering diverse conditions that shape galaxies before they enter the dense cluster core, a process known as ``pre-processing''.…
A major problem in extragalactic astronomy is the inability to distinguish in a robust, physical, and model independent way how galaxy populations are related to each other and to their formation histories. A similar, but distinct, and also…
Although the optical colour-magnitude diagram of galaxies allows one to select red sequence objects, neither can it be used for galaxy classification without additional observational data such as spectra or high-resolution images, nor to…
We develop a Principal Component Analysis aimed at classifying a sub-set of 27,350 spectra of galaxies in the range 0.4 < z < 1.0 collected by the VIMOS Public Extragalactic Redshift Survey (VIPERS). We apply an iterative algorithm to…
Explaining the formation and evolution of galaxies is one of the most challenging problems in observational cosmology. Many observations suggest that galaxies we see today could have evolved from the merging of smaller subsystems. Evolution…
During the last ten years, a considerable amount of effort has been made to develop algorithms for automatic classification of variable stars. That has been primarily achieved by applying machine learning methods to photometric datasets…
We explore the evolution of the Colour-Magnitude Relation (CMR) and Luminosity Function (LF) at 0.4<z<1.3 from the VIMOS Public Extragalactic Redshift Survey (VIPERS) using ~45,000 galaxies with precise spectroscopic redshifts down to…
It is an obvious statement that all the galaxies we see today in and around our Local Group have been forming and evolving for a significant fraction of the age of the Universe. It is not a great leap of logic to further state that the…
We present a data-driven fuzzy set framework for classifying galaxies into the red sequence, blue cloud, and green-valley populations using multiple observables from the Sloan Digital Sky Survey (SDSS DR18). Unlike traditional methods based…
[abridged] Building upon a previous study, we define a method to blindly identify galaxies that underwent, and may still be undergoing, a fast downfall of their star-formation activity, that is, a more than 80% drop in star-formation rate…
Several conclusions have been reached over the last few years concerning high-redshift galaxies: (1) The excess of faint blue galaxies is due to dwarf galaxies. (2) Star formation peaks at redshifts z ~1-2. (3) It appears to occur piecemeal…
The redshift distribution of near-IR selected galaxies is often used to attempt to discriminate between the classical view of galaxy formation, in which present-day luminous galaxies were assembled at early times and evolve due to the…
(Abridged) This work explores the existence of high redshift massive galaxies unveiled with Spitzer+IRAC, but missed by conventional selection techniques based on optical and near-infrared observations. To this end, we use the…
Compact stellar systems such as Ultra-compact dwarfs (UCDs) and Globular Clusters (GCs) around galaxies are known to be the tracers of the merger events that have been forming these galaxies. Therefore, identifying such systems allows to…
We study Red Misfits, a population of red, star-forming galaxies in the local Universe. We classify galaxies based on inclination-corrected optical colours and specific star formation rates derived from the Sloan Digital Sky Survey Data…
A common assumption is that galaxies fall in two distinct regions on a plot of specific star-formation rate (SSFR) versus galaxy stellar mass: a star-forming Galaxy Main Sequence (GMS) and a separate region of `passive' or `red and dead…
We have selected a sample of 88 nearby (z<0.1) galaxy clusters from the SDSS-DR4 with redshift information for the cluster members. We have derived global properties for each cluster, such as their mean recessional velocity, velocity…
The discovery of numerous luminous, super-early galaxies at $z>10$ by JWST has revealed a striking diversity in their ultraviolet (UV) properties, ranging from extremely blue, dust-poor systems to a smaller population of significantly…
Structural properties posses valuable information about the formation and evolution of galaxies, and are important for understanding the past, present, and future universe. Here we use unsupervised machine learning methodology to analyze a…