Cristian Antonio Vega-Martínez

• PhD in Astronomy
• Professor at University of La Serena

Galaxy groups and clusters are the most massive collapsed structures in the Universe. They assemble hierarchically through the successive mergers of smaller systems. These dense environments play a crucial role in driving the evolution and morphological transformation of their galaxies. The dynamical state of groups and clusters can affect the prop...

Galaxy groups and clusters are the most massive collapsed structures in the Universe. Those structures are formed by collapsing with other smaller structures. Groups and cluster mergers provide an appropriate environment for the evolution and transformation of their galaxies. The merging process of groups and clusters can affect the properties of t...

Context. Nebular emission lines are powerful diagnostics for the physical processes at play in galaxy formation and evolution. Moreover, emission-line galaxies (ELGs) are one of the main targets of current and forthcoming spectroscopic cosmological surveys. Aims. We investigate the contributions to the line luminosity functions (LFs) of different g...

We study the properties of associations of dwarf galaxies and their dependence on the environment. Associations of dwarf galaxies are extended systems composed exclusively of dwarf galaxies, considering as dwarf galaxies those galaxies less massive than $M_{\star , \rm max} = 10^{9.0}$${\rm M}_{\odot }\, h^{-1}$. We identify these particular system...

We study the population of backsplash galaxies at z = 0 in the outskirts of massive, isolated clusters of galaxies taken from the mdpl2-sag semi-analytic catalogue. We consider four types of backsplash galaxies according to whether they are forming stars or passive at three stages in their lifetimes: before entering the cluster, during their first...

Merging of galaxy clusters are some of the most energetic events in the Universe, and they provide a unique environment to study galaxy evolution. We use a sample of 84 merging and relaxed SPT galaxy clusters candidates, observed with the Dark Energy Camera in the 0.11 < z < 0.88 redshift range, to build colour-magnitude diagrams to characterize th...

We study the properties of associations of dwarf galaxies and their dependence on the environment. Associations of dwarf galaxies are extended systems composed exclusively of dwarf galaxies, considering as dwarf galaxies those galaxies less massive than $M_{\star, \rm max} = 10^{9.0}$ ${\rm M}_{\odot}\,h^{-1}$. We identify these particular systems...

We study the population of backsplash galaxies at $z=0$ in the outskirts of massive, isolated clusters of galaxies taken from the MDPL2-SAG semi-analytic catalogue. We consider four types of backsplash galaxies according to whether they are forming stars or passive at three stagesin their lifetimes: before entering the cluster, during their first i...

Merging of galaxy clusters are some of the most energetic events in the Universe, and they provide a unique environment to study galaxy evolution. We use a sample of 84 merging and relaxed SPT galaxy clusters candidates, observed with the Dark Energy Camera in the $0.11<z<0.88$ redshift range, to build colour-magnitude diagrams to characterize the...

Nebular emission lines are powerful diagnostics for the physical processes at play in galaxy formation and evolution. Moreover, emission-line galaxies (ELGs) are one of the main targets of current and forthcoming spectroscopic cosmological surveys. We investigate the contributions to the line luminosity functions (LFs) of different galaxy populatio...

In this work, we combine the semi-analytic model of galaxy formation and evolution sag with the 102 relaxed simulated galaxy clusters from The Three Hundred project, and we study the link between the quenching of star formation (SF) and the physical processes that galaxies experience through their dynamical history in and around clusters. We classi...

In this work, we combine the semi-analytic model of galaxy formation and evolution SAG with the $102$ relaxed simulated galaxy clusters from The Three Hundred project, and we study the link between the quenching of star formation (SF) and the physical processes that galaxies experience through their dynamical history in and around clusters. We clas...

We analyse the connection between the star formation quenching of galaxies and their location in the outskirts of clusters in the redshift range z = [0, 2] by estimating the fraction of red galaxies. More specifically, we focus on galaxies that infall isotropically from those that are infalling alongside filaments. We use a sample of galaxies obtai...

We analyse the connection between the star formation quenching of galaxies and their location in theoutskirts of clusters in the redshift range $z=[0,2]$ by estimating the fraction of red galaxies. More specifically, we focus on galaxies that infall isotropically from those that are infalling alongside filaments. We use a sample of galaxies obtaine...

The environment within dark matter haloes can quench the star formation of galaxies. However, environmental effects beyond the virial radius of haloes (≳ 1 Mpc) are less evident. An example is the debated correlation between colour or star formation in central galaxies and neighbour galaxies in adjacent haloes at large separations of several Mpc, r...

We connect galaxy properties with their orbital classification by analysing a sample of galaxies with stellar mass M⋆ ≥ 108.5h−1M⊙ residing in and around massive and isolated galaxy clusters with mass M200 > 1015h−1M⊙ at redshift z = 0. The galaxy population is generated by applying the semi-analytic model of galaxy formation sag on the cosmologica...

We present a model to track the orbital evolution of “unresolved subhaloes” (USHs) in cosmological simulations. USHs are subhaloes that are no longer distinguished by halo finders as self-bound overdensities within their larger host system due to limited mass resolution. These subhaloes would host “orphan galaxies” in semi-analytic models of galaxy...

We connect galaxy properties with their orbital classification by analysing a sample of galaxies with stellar mass $M_{\star} \geq 10^{8.5}h^{-1}M_\odot$ residing in and around massive and isolated galaxy clusters with mass $M_{200} > 10^{15}h^{-1}M_\odot$ at redshift $z=0$. The galaxy population is generated by applying the semi-analytic model of...

We study the evolution of satellite galaxies in clusters of the c-eagle simulations, a suite of 30 high-resolution cosmological hydrodynamical zoom-in simulations based on the eagle code. We find that the majority of galaxies that are quenched at z = 0 (≳80${{\ \rm per\ cent}}$) reached this state in a dense environment (log10M200[M⊙] ≥13.5). At lo...

We present a new analytic fitting profile to model the ram pressure exerted over satellite galaxies on different environments and epochs. The profile is built using the information of the gas particle distribution in hydrodynamical simulations of groups and clusters of galaxies to measure the ram pressure directly. We show that predictions obtained...

The environment within dark matter haloes can quench the star formation of galaxies. However, environmental effects beyond the virial radius of haloes ($\gtrsim$ 1 Mpc) are less evident. An example is the debated correlation between colour or star formation in central galaxies and neighbour galaxies in adjacent haloes at large separations of severa...

We introduce the Uchuu suite of large high-resolution cosmological N-body simulations. The largest simulation, named Uchuu, consists of 2.1 trillion (128003) dark matter particles in a box of side-length 2.0$\, h^{-1} \rm Gpc$, with particle mass 3.27 × 108$\, h^{-1} \rm M_{\odot }$. The highest resolution simulation, Shin-Uchuu, consists of 262 bi...

We studied a region of 1.636 square degrees corresponding to the VVV tile $b204$. Using SExtractor, we analysed photometric data generating a catalogue of extended sources in this area. In order to confirm these sources as galaxy candidates we visually inspected RGB images looking for typical galaxy features. Using 2MASX and GCMW catalogued sources...

We present an updated model for the evolution of the orbits of "orphan galaxies" to be used in the SAG semi-analytical model of galaxy formation and evolution. In cosmological simulations, orphan galaxies are those satellite galaxies for which, due to limited mass resolution, halo finders lose track of their dark matter subhalos and can no longer b...

We analyse two analytic fitting profiles to model the ram pressure exerted over satellites galaxies for different environments and epochs, using hydrodynamical resimulations of groups and clusters of galaxies to measure the ram pressure from the gas particle distribution. First, we compare the predictions given by a known $\beta$-profile model with...

Context. The extragalactic vision we have through the Milky Way is very unclear. There is significant extinction of the optical emission from objects located in the region called the zone of avoidance (ZOA). NIR wavelengths are less affected by extinction, and therefore the infrared surveys in this zone are a potential source of astronomical discov...

We study the evolution of satellite galaxies in clusters of the C-EAGLE simulations, a suite of 30 high-resolution cosmological hydrodynamical zoom-in simulations based on the EAGLE code. We find that the majority of galaxies that are quenched at $z=0$ ($\gtrsim$ 80$\%$) reached this state in a dense environment (log$_{10}$M$_{200}$[M$_{\odot}$]$\g...

Associations of dwarf galaxies are loose systems composed exclusively of dwarf galaxies. These systems were identified in the Local Volume for the first time more than 30 yr ago. We study these systems in the cosmological framework of the Λ cold dark matter (ΛCDM) model. We consider the Small MultiDark Planck simulation and populate its dark matter...

We explore the build-up of quiescent galaxies using a sample of 28 469 massive (M⋆ ≥ 1011 M⊙) galaxies at redshifts 1.5 < $z$ < 3.0, drawn from a 17.5 deg2 area (0.33 Gpc3 comoving volume at these redshifts). This allows for a robust study of the quiescent fraction as a function of mass at 1.5 < $z$ < 3.0 with a sample ∼40 times larger at log(M⋆/$\...

We present the ROGER (Reconstructing Orbits of Galaxies in Extreme Regions) code, which uses three different machine learning techniques to classify galaxies in, and around, clusters, according to their projected phase-space position. We use a sample of 34 massive, M200 > 1015h−1M⊙, galaxy clusters in the MultiDark Planck 2 (MDLP2) simulation at re...

We present the ROGER (Reconstructing Orbits of Galaxies in Extreme Regions) code, which uses three different machine learning techniques to classify galaxies in, and around, clusters, according to their projected phase-space position. We use a sample of 34 massive, $M_{200}>10^{15} h^{-1} M_{\odot}$, galaxy clusters in the MultiDark Planck 2 (MDLP2...

ROGER presentation in the 62 AAA meeting

Associations of dwarf galaxies are loose systems composed exclusively of dwarf galaxies. These systems were identified in the Local Volume for the first time more than thirty years ago. We study these systems in the cosmological framework of the $\Lambda$ Cold Dark Matter ($\Lambda$CDM) model. We consider the Small MultiDark Planck simulation and p...

We explore the buildup of quiescent galaxies using a sample of 28,469 massive ($M_\star \ge 10^{11}$M$_\odot$) galaxies at redshifts $1.5<z<3.0$, drawn from a 17.5 deg$^2$ area (0.33 Gpc$^3$ comoving volume at these redshifts). This allows for a robust study of the quiescent fraction as a function of mass at $1.5<z<3.0$ with a sample $\sim$40 times...

We use three semi-analytical models (SAMs) of galaxy formation and evolution run on the same 1 h−1 Gpc MultiDark Planck2 cosmological simulation to investigate the properties of [O ii] emission line galaxies at redshift z ∼ 1. We compare model predictions with different observational data sets, including DEEP2–firefly galaxies with absolute magnitu...

We introduce the Uchuu suite of large high-resolution cosmological $N$-body simulations. The largest simulation, named Uchuu, consists of 2.1 trillion ($12800^3$) dark matter particles in a box of 2.0 Gpc/h, and the mass of each particle is $3.27 \times 10^{8}$ Msun/h. The highest resolution simulation, called Shin-Uchuu, consists of 262 billion ($...

In order to constrain the limitations of association methods applied to galaxy surveys, we analysed the catalogue of haloes at z = 0 of a cosmological simulation, trying to reproduce the limitations dealt with by an observational survey. We focused on the percolation method, usually called the friends of friends method, commonly used in the literat...

In order to constraint the limitations of association methods applied to galaxy surveys, we analysed the catalogue of halos at $z=0$ of a cosmological simulation, trying to reproduce the limitations that an observational survey deal with. We focused in the percolation method, usually called Friends of Friends method, commonly used in literature. Th...

We use three semi-analytic models (SAMs) of galaxy formation and evolution run on the same $1 h^{-1}$Gpc MultiDark Planck 2 cosmological simulation to investigate the properties of [OII] emission line galaxies over the redshift range $0.6<z<1.2$. We compare model predictions with different observational data sets, including DEEP2-Firefly galaxies w...

We use the semi-analytic model (SAM) of galaxy formation and evolution SAG coupled with the MULTIDARK simulation MDPL2 to study the evolution of the stellar - gas metallicity relation of galaxies (MZR). We test several implementations of the dependence of the mass loading due to supernovae (SNe).We find that no evolution in the normalization of the...

We introduce the The Three Hundred project, an endeavour to model 324 large galaxy clusters with full-physics hydrodynamical re-simulations. Here we present the dataset and study the differences to observations for fundamental galaxy cluster properties and scaling relations. We find that the modelled galaxy clusters are generally in reasonable agre...

We introduce the THE THREE HUNDRED project, an endeavour to model 324 large galaxy clusters with full-physics hydrodynamical re-simulations. Here we present the data set and study the differences to observations for fundamental galaxy cluster properties and scaling relations. We find that the modelled galaxy clusters are generally in reasonable agr...

We use the semi-analytic model (SAM) of galaxy formation and evolution SAG coupled with the MULTIDARK simulation MDPL2 to study the evolution of the stellar mass-gas metallicity relation of galaxies (MZR). We test several implementations of the dependence of the mass loading due to supernovae (SNe). We find that no evolution in the normalization of...

We present a comparison of the observed evolving galaxy stellar mass functions with the predictions of eight semi-analytic models and one halo occupation distribution model. While most models are able to fit the data at low redshift, some of them struggle to simultaneously fit observations at high redshift. We separate the galaxies into ‘passive’ a...

We present a comparison of the observed evolving galaxy stellar mass functions with the predictions of eight semi-analytic models and one halo occupation distribution model. While most models are able to fit the data at low redshift, some of them struggle to simultaneously fit observations at high redshift. We separate the galaxies into 'passive' a...

We use the semi-analytic model of galaxy formation SAG on the MultiDark simulation MDPL2 to study the relevance of mass quenching and environmental quenching on passive satellite galaxies. We find that environmental processes dominate the star formation (SF) quenching of low mass satellites ($M_{\star} \lesssim 1.3 \times 10^{10}\, {\rm M}_{\odot}$...

We present results from the semi-analytic model of galaxy formation SAG applied on the MultiDark simulation MDPL2. SAG features an updated supernova (SN) feedback scheme and a robust modelling of the environmental effects on satellite galaxies. This incorporates a gradual starvation of the hot gas halo driven by the action of ram pressure stripping...

We present a comparison of nine galaxy formation models, eight semi-analytical and one halo occupation distribution model, run on the same underlying cold dark matter simulation (cosmological box of co-moving width 125$h^{-1}$ Mpc, with a dark-matter particle mass of $1.24\times 10^9 h^{-1}$ Msun) and the same merger trees. While their free paramet...

We present the public release of the MultiDark-Galaxies: three distinct galaxy catalogues derived from one of the Planck cosmology MultiDark simulations (i.e. MDPL2, with a volume of (1 Gpc/$h$)$^{3}$ and mass resolution of $1.5 \times 10^{9} M_{\odot}/h$) by applying the semi-analytic models GALACTICUS, SAG, and SAGE to it. We compare the three mo...

The use of high-quality simulated sky catalogs is essential for the success of cosmological surveys. The catalogs have diverse applications, such as investigating signatures of fundamental physics in cosmological observables, understanding the effect of systematic uncertainties on measured signals and testing mitigation strategies for reducing thes...

We study the stellar populations of bulges of Milky Way-like (MW-like) galaxies with the aim of identifying the physical processes involved in the formation of the bulge of our Galaxy. We use the semi-analytic model of galaxy formation and evolution SAG adapted to this aim; this kind of models can trace the properties of galaxies and their componen...

We study the stellar populations of bulges of Milky Way-like (MW-like) galaxies with the aim of identifying the physical processes involved in the formation of the bulge of our Galaxy. We use the semi-analytic model of galaxy formation and evolution SAG adapted to this aim; this kind of models can trace the properties of galaxies and their componen...

We present a clustering comparison of 12 galaxy formation models (including Semi-Analytic Models (SAMs) and Halo Occupation Distribution (HOD) models) all run on halo catalogues and merger trees extracted from a single {\Lambda}CDM N-body simulation. We compare the results of the measurements of the mean halo occupation numbers, the radial distribu...

We present a comparison of 14 galaxy formation models: 12 different semi-analytical models and 2 halo occupation distribution models for galaxy formation based upon the same cosmological simulation and merger tree information derived from it. The participating codes have proven to be very successful in their own right but they have all been calibra...

We present a fast and accurate method to select an optimal set of parameters in semi-analytic models of galaxy formation and evolution (SAMs). Our approach compares the results of a model against a set of observables applying a stochastic technique called Particle Swarm Optimization (PSO), a self-learning algorithm for localizing regions of maximum...

Finding life in the Universe entirely different to the one evolved on Earth is probable. This is a significant constraint for life-detecting instruments that were sent and may be sent elsewhere in the solar system, as how could we detect life as ‘we don't know it’? How could we detect something when we have no prior knowledge of its composition or...