ORCID Profile
0000-0002-5425-0641
Current Organisation
Swinburne University of Technology
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Publications
Pericentric passage-driven star formation in satellite galaxies and their hosts: CLUES from local group simulations
Publisher: Oxford University Press (OUP)
Date: 12-06-2021
Abstract: Local Group satellite galaxies show a wide ersity of star formation histories (SFHs) whose origin is yet to be fully understood. Using hydrodynamical simulations from the Constrained Local UniversE project, we study the SFHs of satellites of Milky Way-like galaxies in a cosmological context: while in the majority of the cases the accretion on to their host galaxy causes the satellites to lose their gas, with a subsequent suppression in SF, in about 25 per cent of our s le we observe a clear enhancement of SF after infall. Peaks in SF clearly correlate with the satellite pericentric passage around its host and, in one case, with a satellite–satellite interaction. We identify two key ingredients that result in enhanced SF after infall: galaxies must enter the host’s virial radius with a reservoir of cold gas Mgas, inf/Mvir, inf ≳ 10−2 and with a minimum pericentric distance ≳10 kpc (mean distance ∼50 kpc for the full s le), in order to form new stars due to compression of cold gas at pericentric passage. On the other hand, satellites that infall with little gas or whose pericentric distance is too small, have their gas ram-pressure stripped and subsequent SF quenched. The pericentric passage of satellites likewise correlates with SF peaks in their hosts, suggesting that this mechanism induces bursts of SF in satellites and central galaxies alike, in agreement with recent studies of our Galaxy’s SFH. Our findings can explain the recently reported multiple stellar populations observed in dwarf galaxies such as Carina and Fornax, and should be taken into account in semi-analytic models of galaxy formation and satellite quenching.
CLUES about M33: the reversed radial stellar age gradient in the outskirts of Triangulum galaxy
Publisher: Oxford University Press (OUP)
Date: 08-08-2018
OUP accepted manuscript
Publisher: Oxford University Press (OUP)
Date: 2019
DOI: 10.1093/MNRAS/STZ565
The Three Hundred Project: The evolution of galaxy cluster density profiles
Publisher: Oxford University Press (OUP)
Date: 06-12-2018
The Three Hundred project: shapes and radial alignment of satellite, infalling, and backsplash galaxies
Publisher: Oxford University Press (OUP)
Date: 21-05-2020
Abstract: Using 324 numerically modelled galaxy clusters, we investigate the radial and galaxy–halo alignment of dark matter subhaloes and satellite galaxies orbiting within and around them. We find that radial alignment depends on distance to the centre of the galaxy cluster but appears independent of the dynamical state of the central host cluster. Furthermore, we cannot find a relation between radial alignment of the halo or galaxy shape with its own mass. We report that backsplash galaxies, i.e. objects that have already passed through the cluster radius but are now located in the outskirts, show a stronger radial alignment than infalling objects. We further find that there exists a population of well radially aligned objects passing very close to the central cluster’s centre that were found to be on highly radial orbit.
The three hundred project: galaxy cluster mergers and their impact on the stellar component of brightest cluster galaxies
Publisher: Oxford University Press (OUP)
Date: 31-01-2022
Abstract: Using the data set of the three hundred project, i.e. a suite of 324 hydrodynamical resimulations of cluster-sized haloes, we study galaxy cluster mergers and their effect on colour and luminosity changes of their brightest cluster galaxies (BCG). We track the main progenitor of each halo at z = 0 and search for merger situations based on its mass accretion history, defining mergers as very rapid increases in the halo mass. Based upon the evolution of the dynamical state of the cluster we define a pre- and post-merger phase. We create a list of all these events and statistically study their mass ratio and time-scales, with the former verifying that all instances are in fact major mergers. By comparing to a control s le of clusters without mergers, we study the effect mergers have on the stellar component of the BCG. Analysing the mass, age, and metallicity of the BCG stellar particles, we find that the stellar content of BCGs grows significantly during mergers and, even though the main growth mechanism is the accretion of older stars, there is even a burst in star formation induced by the merger. In our simulations, BCGs in mergers form in median around 70 per cent more stars than those normally growing, although this depends on the radius considered for defining the BCG. Regarding observable properties, we see an increase in SDSS-u luminosity of 20 per cent during mergers, accompanied by a slightly slower increase of the galaxy g − r colour as compared to the control s le.
TheThreeHundred project: backsplash galaxies in simulations of clusters
Publisher: Oxford University Press (OUP)
Date: 03-02-2020
Abstract: In the outer regions of a galaxy cluster, galaxies either may be falling into the cluster for the first time or have already passed through the cluster centre at some point in their past. To investigate these two distinct populations, we utilize TheThreeHundred project, a suite of 324 hydrodynamical resimulations of galaxy clusters. In particular, we study the ‘backsplash population’ of galaxies: those that have passed within R200 of the cluster centre at some time in their history, but are now outside of this radius. We find that, on average, over half of all galaxies between R200 and 2R200 from their host at $z$ = 0 are backsplash galaxies, but that this fraction is dependent on the dynamical state of a cluster, as dynamically relaxed clusters have a greater backsplash fraction. We also find that this population is mostly developed at recent times ($z$ ≲ 0.4), and is dependent on the recent history of a cluster. Finally, we show that the dynamical state of a given cluster, and thus the fraction of backsplash galaxies in its outskirts, can be predicted based on observational properties of the cluster.
The Three Hundred Project: The stellar angular momentum evolution of cluster galaxies
Publisher: EDP Sciences
Date: 08-2021
DOI: 10.1051/0004-6361/202038425
Abstract: Using 324 numerically modelled galaxy clusters as provided by T HE T HREE H UNDRED project, we study the evolution of the kinematic properties of the stellar component of haloes on first infall. We selected objects with M star 5 × 10 10 h −1 M ⊙ within 3 R 200 of the main cluster halo at z = 0 and followed their progenitors. We find that although haloes are stripped of their dark matter and gas after entering the main cluster halo, there is practically no change in their stellar kinematics. For the vast majority of our ‘galaxies’ – defined as the central stellar component found within the haloes that form our s le – their kinematic properties, as described by the fraction of ordered rotation, and their position in the specific stellar angular momentum−stellar mass plane j star − M star are mostly unchanged by the influence of the central host cluster. However, for a small number of infalling galaxies, stellar mergers and encounters with remnant stellar cores close to the centre of the main cluster, particularly during pericentre passage, are able to spin up their stellar component by z = 0.
The Three Hundred project: the gas disruption of infalling objects in cluster environments
Publisher: Oxford University Press (OUP)
Date: 07-01-2021
Abstract: We analyse the gas content evolution of infalling haloes in cluster environments from The Three Hundred project, a collection of 324 numerically modelled galaxy clusters. The haloes in our s le were selected within 5R200 of the main cluster halo at $z$ = 0 and have total halo mass M200 ≥ 1011h−1M⊙. We track their main progenitors and study their gas evolution since their crossing into the infall region, which we define as 1–4R200. Studying the radial trends of our populations using both the full phase-space information and a line-of-sight projection, we confirm the Arthur et al. (2019) result and identify a characteristic radius around 1.7R200 in 3D and at R200 in projection at which infalling haloes lose nearly all of the gas prior their infall. Splitting the trends by subhalo status,we show that subhaloes residing in group-mass and low-mass host haloes in the infall region follow similar radial gas-loss trends as their hosts, whereas subhaloes of cluster-mass host haloes are stripped of their gas much further out. Our results show that infalling objects suffer significant gaseous disruption that correlates with time-since-infall, cluster-centric distance, and host mass, and that the gaseous disruption they experience is a combination of subhalo pre-processing and object gas depletion at a radius that behaves like an accretion shock.
Related Organisations
Related Funding Activities
Simulando El Universo: Desde Las Estructuras A Grandes Escalas Hasta Nuestro Entorno Local
Start Date: 2017
End Date: 2021
Funder: Ministerio de Economía y Competitividad
View Funded Activity