arXiv subjects

Valentina P. Miranda

Publications and source records attributed to Valentina P. Miranda.

3 recordsLinked to original sources

arXiv2026

[CII] as a global cold gas tracer in novel hydrodynamical simulations

[CII] emission is a powerful tool for studying the gas content in galaxies, especially at early stages of evolution. Given its low excitation potential, the [CII] 158 μm line is the main coolant of neutral gas in photodissociation regions and giant molecular clouds, hence a tracer of all phases of the interstellar medium. However, there is no consensus on what is the nature of the gas traced by this emission. We aim to provide insights into the physics of the [CII] emission and predictions for future observations. We used four pre-prepared simulations performed with a version of p-gadget-3, which includes the krome chemistry package. We implemented a postprocessing semi-analytical model to simulate the [CII] emission. We analysed an isolated Milky Way-mass-size galaxy, and three merger configurations: a co-rotating, counter-rotating, and perpendicular major mergers of two Milky Way-mass-size galaxies. We reproduce fundamental relations such as the [CII] luminosity and the star formation rate, L[CII]-SFR relation, in which mergers show an extra component for the [CII] emission not traced by the star formation alone. During quiescent or starburst stages, galaxies deviate from the L[CII]-SFR relation. We find that [CII] is a robust tracer of molecular gas, as well as atomic gas in both cold and warm phases on a global scale. Our results indicate that around 50 per cent of the total [CII] emission is traced by molecular gas, while 30 to 40 per cent is traced by atomic and ionised hydrogen regardless of the configuration. Our findings suggest that the nature of the [CII] emission depends strongly on the evolutionary history of galaxies, in which mergers and starbursts act as more efficient drivers of [CII] emission through collision with molecular hydrogen.

astro-ph.GA↗

arXiv2026

Metal-loaded outflows in sub-Milky Way galaxies in the CIELO simulations

Supernova (SN) feedback-driven galactic outflows are a key physical process that contributes to the baryon cycle by regulating the star formation activity, reducing the amount of metals in low-mass galaxies and enriching the circumgalactic (CGM) and intergalactic media (IGM). We aim to understand the chemical loop of sub-Milky Way (MW) galaxies and their nearby regions. We studied 15 simulated central sub-MW galaxies (M* <= 10^10 Msun) and intermediate-mass galaxies (M* \sim 10^10 Msun) from the CIELO-P7 high-resolution simulations. We followed the evolution of the progenitor galaxies, their properties and the characteristics of the outflows within the redshift range z = [0, 7]. We used two dynamically-motivated outflow definitions, unbound outflows and expelled mass rates, to quantify the impact of SN feedback. At z \sim 0, sub-MW galaxies have a larger fraction of their current oxygen mass in the gas phase but have expelled a greater portion beyond the virial radius, compared to their higher-mass counterparts. Galaxies with M* <\sim 10^9 Msun have 10-40 per cent of their total oxygen mass within R200 in the CGM, and an equivalent to 10-60 per cent expelled into the IGM. In contrast, more massive galaxies have most of the oxygen mass locked by the stellar populations. The CGM of low-mass galaxies predominantly contains oxygen low-temperature gas, acting as a metal reservoir. We find that the outflows are more oxygen-rich for sub-MW galaxies, Zout/ZISM \sim 1.5, than for higher-mass galaxies, Zout/ZISM <= 0.5, particularly for z < 2. Mass-loading factors of eta_out \sim 0 - 6 are detected in agreement with observations (abridged).

astro-ph.GA↗

arXiv2025

The mass-metallicity relation of bulges

Context. Bulges, located at the central regions of galaxies, are complex structures, expected to be shaped by the physical processes involved in the assembly history of their host galaxy, such as gravitational collapse, mergers, interactions, and bars. As a consequence a variety of bulges with distinct morphology and chemistry could be produced. Aim. We aim at exploring the existence of a stellar mass-metallicity relation of bulges, MZ*R, and analyze the possible imprint of characteristics features by accretion and migration of stars, which could store information on their assembly histories. Methods. We use 44 central galaxies from the CIELO cosmological simulations. Their stellar masses are within the range of [10^7.6, 10^10.6] Msun. We decomposed the galaxy into bulge and disk using the circularity and binding energies. We track the stellar populations in bulges back in time to their birth location, classifying them as bulge-born in-situ, and disk-born stars and accreted. Results. We find that most of the stars in our bulges are formed in-situ, but 33% of our bulges show a non-negligible contribution of stellar accretion from satellites, which could add to about 35% of the population. The accreted material is generally contribute by two or three satellites at most. In some bulges, we also find up to a 32% of stars that migrated from the disk due to secular evolution, with a median of 10%. Regardless of the formation histories, we found a clear MZ*R for bulges, which is more enriched by about 0.4 dex than the corresponding relation of the disk components, and about 0.15 dex more enriched than the galaxy MZ*R. We find evidence that the dispersion in the bulge MZ*R is influenced by both stellar accretion from satellites and migration from the disk, such that, at a fixed bulge mass, bulges with higher fraction of accreted and migrated stars tend to be less metal-rich (abridged).

astro-ph.GA↗