Resumen:

In this talk I will present the results of my Diploma Thesis and the first steps of my PhD work. Our goal was to detect, in the Southern Photometric Local Universe Survey (S-PLUS) images, galaxies previously reported in the literature as spectroscopically confirmed or probable members of the Fornax Cluster that do not appear or appear excessively deblended in the S-PLUS DR3 and iDR4 catalogs. This happens because the SExtractor input parameters used to obtain the published catalogs are intended to provide useful data for both galactic and extragalactic purposes. As a main result we obtained catalogs with homogeneous photometry in the direction of the Fornax Cluster. For this purpose we found two sets of parameters suitable to automatically detect and measure different types of astronomical objects: on one hand, faint and/or compact objects close to bright galaxies and, on the other hand, bright and very extended objects. We were able to develop a pipeline that allows us to automate the entire process, works well in other surveys and is ready to be distributed publicly. These catalogs are being used to select targets to observe in the Fornax Cluster region in the framework of the CHANCES project of the 4MOST collaboration. In the first steps of my PhD work we found that the SExtractor parameters found also work for other directions and distances, for example in the Hydra and Antlia Clusters. Two new sets of parameters were also identified: one capable of avoiding excessive splitting in star-forming galaxies and another that allows us to recover photometry of globular clusters and star-forming knots. We have also applied regression techniques with Machine Learning to solve the problem of missing data (lack of information in some filter) in the catalogs, and from this, perform template-fitting for each of the sources using LEPHARE.

Resumen:

4MOST is ESO’s flagship spectroscopic survey facility that will be installed on the 4m VISTA telescope at Cerro Paranal next year. It is a fibre-fed spectrograph able to simultaneously obtain high-resolution spectra for 2400 objects over a field of view of 4.2 square degrees. It will carry out 18 public spectroscopic surveys that are expected to deliver spectra for 25 million objects across the entire Southern hemisphere over the first 5 years of operations from October 2024. We present the CHileAN Cluster galaxy Evolution Survey (CHANCES), one of the public surveys to be carried out with 4MOST. CHANCES will target 300,000 galaxies in and around 150 of the most massive galaxy clusters in the local Universe and out to z=0.45. We will target galaxies out to 5r200 from each cluster, enabling us to map the surrounding filamentary large-scale structures and identify the infalling X-ray groups that mark the key sites for pre-processing of galaxies prior to their arrival into the clusters. A second science focus will be the evolution of the cluster dwarf population in nearby clusters where we will push to stellar masses of 10$^9$ M$_{\odot}$ and below. Such low-mass galaxies outside of clusters are naturally gas-rich and will form the bulk of detections in ongoing and upcoming HI surveys from MeerKAT, ASKAP and SKA. The impact of cluster and group environments on the HI gas contents of low-mass galaxies is a key science objective of these HI surveys and should provide natural synergies with CHANCES.

Resumen:

The Next Generation Fornax Survey (NGFS) targets all baryonic structures down to GC masses within the virial sphere of the Fornax galaxy cluster, utilizing the optical bands $u', g'$, and $i'$ in conjunction with the near-infrared (NIR) $J$ and $K_s$ filters. The NGFS uses an intricate observing technique to reach deep surface brightness limits that allows us to detect ultra-low surface brightness dwarf galaxies. Using the observing efficiency of DECam on the Blanco telescope at CTIO, complemented by NIR observations from VIRCAM on the VISTA telescope at ESO, we have secured large enough samples of galaxies to conduct volume-limited studies of their scaling relations. In this talk, I will present exciting new results based on the H-alpha extension of NGFS, showing intriguing recent star-formation activity in galaxies. Furthermore, I will showcase our most recent findings related to the dynamical properties of satellite galaxies within the Fornax galaxy cluster. Our analysis has identified a distinct transition radius, demarcating two zones where satellites exhibit varying properties of tidal stress. Intriguingly, this substructure mirrors patterns observed in cosmological galaxy simulations. Furthermore, when examining diverse cosmic environments, we discern a comparable transition radius in the Virgo galaxy cluster, as well as among the satellite galaxies of both the Milky Way and Andromeda. Finally, I will also discuss NGFS in the context with our other ongoing projects such as the Neighborhood Watch survey, which targets lower-density environments in the local universe.

Resumen:

Galaxy morphology summarises the internal and external physical processes that lead to the present shapes of galaxies. A reliable morphological classification is therefore essential for analysing and interpreting the physical properties of galaxies. In this presentation, I will discuss the recent Visual Morphology Catalogue (a SDSS-VAC) for the whole MaNGA galaxies. This catalogue introduces an innovative method for morphologically classifying galaxies across the complete Hubble sequence with high accuracy. It enables us to identify not only bars, but also faint tidal streams surrounding galaxies. We also estimated the structural parameters, concentration, asymmetry and clumpiness. This classification, identification and estimation is based on deep images from the DESI Legacy Surveys, coupled with meticulous image processing techniques. We have correlated these findings with galaxy properties such as stellar mass, colours and stellar populations age. This has revealed distinct correlations between bars, tidal streams, and both morphology and stellar mass. Through the galaxy stellar mass function, we have investigated the contribution of each individual morphological type within specific stellar mass ranges. This exploration has unveiled the contribution by each type across different mass thresholds. For instance, Elliptical galaxies exclusively dominate the high mass end, with a non- influence extending to stellar masses below $logM_{\ast}$=10. Conversely, very late galaxies govern the low mass domain. Finally we present results that establish comprehensive connections between all reliably morphological types and the group environmental context (galaxies are divided into central or satellites).

Resumen:

Emission lines in galaxies are a valuable source of information, allowing the study of star formation activity, the identification of active galactic nuclei, among others. The filter configuration of S-PLUS (Southern Photometric Local Universe Survey) is ideal to detect emission by its combination of 7 narrow and 5 broad optical passband filters. An interesting topic to investigate is the characteristics of the emitters in high density environments. Do they present a specific location within the cluster? How is the relation between the emission morphology and the galaxy morphology? The answer to such questions can give us clues about the formation of a given cluster. In this context, the Fornax cluster is a great target to be analyzed, as the Halpha+[NII] emission lines are located within the J0660 band of S-PLUS, and its proximity provides large enough galaxies to study their emission spatial distribution. In this talk we will present our code (P.E.L.E., Pixel-to-pixel Emission Line Estimate) to create Halpha+[NII] maps based on the three filter method applied to S-PLUS images, and our main results derived for 213 Fornax galaxy members, including the spatial distribution and the phase-space diagram of Halpha emitters, the relation between Halpha emission and the galaxy Sersic index, and the comparison between P.E.L.E. maps and the results from Fornax 3D project.

Resumen:

The automated identification of extragalactic objects in large photometric surveys provides reliable and reproducible samples of galaxies in less time than procedures involving human interaction. This problem, however, is more challenging in regions near the Galactic disc where the extinction by dust is greater. We present the methodology for the automatic classification of galaxies and non-galaxies at low Galactic latitude regions using both images and, photometric and morphological near-IR data from the VVVX survey. Using the VVV NIRGC, we analyse by classical and unsupervised statistical methods the most relevant features for galaxy identification. This catalogue was also used to generate datasets of extragalatic candidates from a pipeline and train a Convolutional Neural Network with image data and an Extreme Gradient Boosting architecture with photometric and morphological data. This allows us to derive probability catalogues used to analyse the completeness and purity as a function of the configuration parameters and to explore the best combinations of the models. The resulting classifier reaches an F1-score of 0.67, a purity of 65 per cent and a completeness of 69 per cent. As a test case, we apply this methodology to the VVVX survey in part of the Northern disc region, generating a dataset of 172,396 extragalatic candidates with probabilities of being galaxies. In addition, we present the VVV NIR Galaxy Catalogue.