Dottorato - PhD thesis
Area Tematica: RSN 1: Galassie e Cosmologia - RSN 2: Stelle, popolazioni stellari e mezzo interstellare
Referente: Daniela Carollo (
Titolo: Optical-to-radio galaxy evolution studies in high-redshift cluster environments with ELT and SKA precursors
Decorrenza: 15.10.2025
Dwarf galaxies are the most abundant type of galaxies and in the hierarchical model of structureformation are thought to be the building blocks of the Universe because they are the first systemsthat collapse, form stars, pollute the surrounding intergalactic medium, and later merge to formlarger galaxies. These systems are characterized by their small size and low luminosity with smallstellar masses. Dwarf galaxies are typically classified based on their morphology: i) late-type dwarfs,which include dwarf irregulars (dIs) and blue compact dwarfs (BCDs), ii) early-type dwarfs comprisingdwarf spheroidals (dSphs), dwarf ellipticals (dEs), and ultra-faint dwarfs (UFDs). They can also becategorized by the presence or absence of a central nucleus (nucleated or non-nucleated) and bytheir star formation (SF) activity (star-forming or quenched).An interesting class of dwarf galaxies is represented by those objects with an elliptical shape and witha bright core component in the central region. Although these dwarfs are considered dEs due to theirsimilarity in surface brightness, it is yet unknown whether these systems are transitional dwarfgalaxies, an intermediate product of the transformation from gas-rich late-type dwarfs into gas-poorearly-type dwarfs, or they represent an independent class of early-type dwarfs. It is also not clear whatroles play, in their evolution, internal processes, such as stellar feedback, and environmental effects.These questions can be addressed by detecting and studying samples of dwarfs spanning a variety ofmasses in different environments, from galaxy clusters to groups, and in isolation. The unprecedenteddepth, spatial resolution, and field of view of the Euclid space telescope will contribute to addressingthese open questions.
In this project PhD students will work with photometric data from the Euclid space telescope to detectand characterize early type dwarf galaxies with large bright cores (ETdG-blcs). Students will learn towork with Euclid high resolution images, in VIS (visible) and NISP (near infrared) combined with theEuclid catalog from the official pipeline. The initial work will be carried out with Euclid quick releasedata (Q1) followed by Euclid Data Release 1 when publicly available. There will be also opportunitiesto work with medium resolution spectroscopic data to analyse the stellar populations of the ETdG-blcs, and to determine: 1) accurate redshifts, 2) star formation rate (SFR), 3) star formation history(SFH), 3) stellar population properties (metallicity, age), and 4) dynamical mass. Similar analysis willbe performed on classical dEs, and dwarf irregular galaxies (dIs) with the aim to understand thetransitional nature of ETdG-blcs, or if they have a different origin. Students will also learn to work withstellar populations synthesis models in combination with photoionization codes for interpretation andanalysis of different spectral classes. She/He will have the possibility to work at international facilitiesthrough an extended network of collaborators.
