arXiv subjects

Richards P. Albuquerque

Publications and source records attributed to Richards P. Albuquerque.

5 recordsLinked to original sources

arXiv2026

SAMI and TNG-Cluster: tracing galaxy spin and environmental transformation across cluster phase-space and cosmic time

The dense environment of galaxy clusters suppresses star formation and alters the kinematic properties of infalling satellites through gas stripping, tidal interactions, gravitational harassment and starvation. Projected phase-space diagrams connect the present-day distribution of cluster galaxies to their accretion histories. We combine SAMI Galaxy Survey integral field spectroscopy with the TNG-Cluster simulation to investigate how the stellar spin parameter ($λ_R$), $(g-i)$ colour, and sSFR vary across projected phase-space infall regions. At $z = 0$, TNG-Cluster reproduces the direction and broad strength of the phase-space trends observed in SAMI, including the weak yet significant $λ_R$-clustercentric distance correlation. Leveraging this agreement, we extend the analysis across the last 8 Gyr, tracing the statistical evolution of galaxy properties within each infall region, and complement this with individual orbital histories of representative satellites. While colour and sSFR show clear monotonic gradients with both phase-space position and cosmic time, $λ_R$ behaves differently: it remains largely uniform across the outer infall regions, with only the virialised core exhibiting systematically lower values, and displays a slow monotonic decline toward the present day across all regions. We find that angular momentum suppression driven by the cluster environment is a slow, cumulative process requiring several Gyr of exposure to the cluster core, modulated by orbital history and stellar mass. This gradual nature explains why the $λ_R$-environment correlation appears weak across phase-space regions in statistical samples; the effect emerges when individual satellite histories are tracked, revealing a sustained dynamical response to prolonged cluster residence.

astro-ph.GA↗

arXiv2026

When galaxies cross cold fronts: wind tunnel simulations of ram pressure stripping

Cluster collisions and mergers are among the most energetic phenomena in the low redshift Universe. These interactions disturb the intracluster medium creating regions with density and temperature discontinuities, such as sloshing spirals. There is evidence that such environments can influence galaxy evolution. This study aims to understand how a galaxy that crosses an environment with discontinuities in density and temperature can be affected. To this end, a set of simulations was conducted using a wind tunnel setup into which a {MW-like mass} galaxy was inserted. A total of eight models were created, namely two control runs and six with distinct density and temperature transitions along the tunnel, comprising simulations with low density and high density environments. Results show that galaxies lose {considerably} more gas due to the higher density encountered when crossing denser and discontinuous regions in comparison to a constant density environment. The star formation rate exhibits a brief enhancement when the galaxy enters the denser section of the tunnel and {(u-i)} color index also undergoes slight changes, initially becoming bluer. However, even in the simulations with the most intense transitions, changes {in star formation rate and color index} are not substantial, reaching at most 5\% difference in relation to the control models. By the end of the simulation runs, star formation rate and color index are similar to the control runs. These results suggest that crossing intracluster medium discontinuities can induce measurable effects in a galaxy, but these are subtle and short-lived.

astro-ph.GA↗

arXiv2026

Simulations of collision and sloshing in the galaxy group NGC 5098/5096

The study of galaxy groups is essential to understanding the evolutionary history of large-scale structures in the Universe. These dense environments have a significant impact on galaxy evolution, influencing their gas content, morphology, and star formation activity. In this work we analyse in detail the system NGC~5098$/$5096 composed of two galaxy groups. We performed hydrodynamical $N$-body simulations of a galaxy group collision aimed at reproducing the gas sloshing and surface brightness distribution observed in X-ray data. We conducted a detailed X-ray analysis and generated mock image \textit{Chandra} observations from our simulations. The resulting corrected mock image surface brightness profiles show good agreement with the observed data. The relative line-of-sight velocity between NGC~5098 and NGC~5096 is $v_{\mathrm{los}} = 700$ km s$^{-1}$, with a projected separation of $d_{\mathrm{proj}} = 155$ kpc, suggesting that the collision occurs nearly in the line-of-sight. Our simulations were performed with an inclination angle of $80^\circ$ in order to reproduce the dynamical constraints. We also find a correlation between the dark matter and intragroup light distributions when comparing the residual dark matter map with the intragroup light morphology. Our best-fitting model is consistent with these observational constraints and provides a plausible dynamical scenario for the current state of the NGC~5098 group interaction with NGC 5096.

astro-ph.GA↗

arXiv2024

Simulating the arrival of the southern substructure in the galaxy cluster Abell 1758

Abell 1758 (z~0.278) is a galaxy cluster composed of two structures: A1758N and A1758S, separated by ~2.2 Mpc. The northern cluster is itself a dissociative merging cluster that has already been modelled by dedicated simulations. Recent radio observations revealed the existence of a previously undetected bridge connecting A1758N and A1758S. New simulations are now needed to take into account the presence of A1758S. We wish to evaluate which orbital configuration would be compatible with a bridge between the clusters. Using N-body hydrodynamical simulations that build upon the previous model, we explore different scenarios that could have led to the current observed configuration. Five types of orbital approaches were tested: radial, tangential, vertical, post-apocentric, and outgoing. We found that the incoming simulated scenarios are generally consistent with mild enhancements of gas density between the approaching clusters. The mock X-ray images exhibit a detectable bridge in all cases. Compared to measurements of Chandra data, the amplitude of the X-ray excess is overestimated by a factor of ~2--3 in the best simulations. The scenario of tangential approach proved to be the one that best matches the properties of the profiles of X-ray surface brightness. The scenarios of radial approach of vertical approach are also marginally compatible.

astro-ph.CO↗

arXiv2024

Unraveling the collision scenario of the dissociative galaxy cluster Abell 56 through hydrodynamic simulations

In galaxy cluster collisions, the gas can be separated from dark matter halos. Abell~56 displays signatures of a dissociative bullet-like merger with a possible high inclination angle between the plane of orbit and the sky. Our objective is to provide a comprehensive description of the features observed in the collision scenario of Abell~56. Additionally, we aim to apply a potential weak lensing mass bias correction attributed to the merger to evaluate its impact on our findings. To investigate this, we perform tailored hydrodynamical $N$-body simulations, varying the impact parameter. We initially identified an early scenario at $0.12$\,Gyr after the central passage that reproduces some observational features. However, the mean temperature of $9.7$\,keV exceeded the observed value. Our best model corresponds to the late scenario at $0.52$\,Gyr after the pericenter, reproducing observed features of Abell~56, with an inclination of $58^\circ$. These features include the offset of $103$\,kpc between the main gas density peak and the south dark matter density peak, gas morphology, a line of sight relative velocity of $184$\,km\,s$^{-1}$, and a mean temperature of $6.7$\,keV. This late model provides a plausible scenario to describe the dynamics of Abell~56. The weak lensing mass bias did not significantly impact the overall dynamics of this cluster merger.

astro-ph.GA↗