arXiv subjects

Santi Roca-Fàbrega

Publications and source records attributed to Santi Roca-Fàbrega.

At least 19 recordsLinked to original sources

arXiv2026

The AGORA High-resolution Galaxy Simulations Comparison Project. IX - Part 1: Effects of a Major Galaxy Merger on Star Formation of a Milky Way-mass Galaxy Progenitor

Given their highly nonlinear dynamics and sensitivity to initial conditions, galaxy mergers are a compelling area to conduct a simulation code comparison. We perform a comparative study of a major galaxy merger at $z \approx 4.5$ in cosmological zoom-in hydrodynamic simulations of a Milky Way-mass galaxy progenitor. The comparison employs the AGORA CosmoRun suite of nine well-calibrated, state-of-the-art numerical codes, each adopting a different stellar feedback scheme. We find that the evolution of the star formation rate (SFR) during the interaction is strongly shaped by the stellar feedback type. Using kinetic feedback in the feedback model drives a pronounced merger-induced starburst that starts to subside before coalescence; using thermal feedback without kinetic feedback yields prolonged SFR growth even after coalescence; and using delayed cooling or radiation pressure results in highly fluctuating SFR. Tracking gas particles in particle-based codes reveals that kinetic feedback facilitates gas inflow from the secondary galaxy onto the primary galaxy between the first periapsis and apoapsis, thus producing an earlier and more prominent starburst. In contrast, thermal feedback, augmented by superbubble or delayed-cooling feedback, suppresses gas cooling, creates a more extended gas distribution, and hinders strong starbursts during the merger. We also observe an inverse correlation between burst fraction and pre-merger gas fraction that is independent of feedback models. Overall, these results highlight the sensitivity of simulated galaxy mergers' star formation response to stellar feedback prescriptions. This study indicates that galaxy mergers may serve as a good testbed for stellar feedback processes in cosmological simulations.

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arXiv2026

The AGORA High-resolution Galaxy Simulations Comparison Project. IX - Part 2: Effects of a Major Galaxy Merger on the Stellar Morphology of a Milky Way-mass Galaxy Progenitor

Galaxy mergers, with their high sensitivity to initial conditions, provide a valuable setting for comparative studies of galaxy simulation codes. Following our first paper focusing on merger-driven star formation, we present a code comparison examining the morphological transformation impact of a major galaxy merger at $z \approx 4.5$ on a Milky Way-mass galaxy progenitor. Our analysis employs nine state-of-the-art codes from the AGORA CosmoRun cosmological zoom-in simulation suite. For this merger, we show that the adopted stellar feedback type influences the galaxy's compaction and stellar disc formation. Codes with purely thermal feedback produce a merger remnant that forms a disc and becomes compact primarily during and after coalescence; codes that include kinetic feedback begin disc formation and compaction around the first periapsis; and codes with strong delayed cooling or superbubble feedback suppress disc formation and produce a more extended remnant. In contrast, the orientation of the remnant disc is code-independent. In all codes, the rotational angular momentum of the remnant disc aligns with the interaction's orbital angular momentum rather than the pre-merger rotational axis, implying that the infalling gas preserves its orbital angular momentum to form a new disc. Comparisons with the Santa Cruz semi-analytic model show reasonable agreement in stellar mass and half-mass radius, yet the model underpredicts (overpredicts) the dark matter fraction and velocity dispersion for codes exhibiting strong compaction (expansion). The systematic dependence of our remnants' morphology on feedback schemes demonstrates that merger remnant morphology may serve as a powerful probe of stellar feedback processes.

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arXiv2026

Invariant manifolds in barred galaxy simulations. II. Quantitative evidence of manifold-trapping in spiral arm formation

The main goal of this work is to quantify, through a robust methodology, the contribution of invariant manifolds to the formation of spiral arms in a pure N-body simulation, setting up a machinery to perform similar tests in other and more complex simulations. We computed the invariant manifolds associated with the hyperbolic equilibrium points of the effective potential and quantified the fraction of particles whose motion is governed by these phase-space structures. We then compared the temporal evolution of this trapped fraction with the strength of the spiral arms, traced by the A2 Fourier amplitude. We find a correlation between the fraction of trapped particles in the unstable exterior branches of the invariant manifolds and the strength of spiral arms. In particular, we determine that up to 50% of all the particles located on the spiral arms region (and up to 90% from the manifold-compatible population) are trapped by the manifolds, with oscillations of period of the order of 100 Myr. Invariant manifolds provide a dynamically relevant framework for understanding the formation of spiral structure in pure N-body simulations of barred galaxies. We present the first quantitative evidence, based on a fully self-consistent N-body model, that a significant fraction of spiral-arm particles is governed by manifold-driven dynamics. These particles act as seeds of overdensities that subsequently evolve into fully developed spiral arms through the delayed gravitational response of the disc to the self-gravity of the manifold-trapped material. The influence of the invariant manifolds remains non-negligible at all times, and phases of stronger spiral structure are associated with higher trapped fractions.

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arXiv2026

The AGORA High-resolution Galaxy Simulations Comparison Project. XI: Solving the Non-Spherical Morphology and Evolution of Dark Matter Halos with Haskap Pie

We introduce a halo solving and tracking procedure that intrinsically treats dark matter halos as non-spherical objects by leveraging the bound particle searching techniques used in Haskap Pie. The AGORA Collaboration's hydrodynamic simulation CosmoRun}project provides a useful laboratory to explore trends in dark matter halo morphology that are revealed by our new procedure in the context of any dispersions or similarities between the codes. We find that several morphological and shape measures were very responsive to high mass ratio mergers. The greatest difference in these measures between the simulation codes were related to timing discrepancies and the dynamical state of the halos prior to the mergers. Most other quantities were similar across codes, including several secular and redshift-dependent trends in various dynamical quantities that showed a departure from Virial Theorem (e.g., overdensity and halo mass). We find that halo spin and the ratio between the semi-major and the semi-minor axis peaked at 4>z>2 before declining at low redshift. Also, halo overdensity is both mass-dependent and redshift-dependent, diverging for low mass halos at low redshift. Our method contributes a new perspective on these trends that have not been fully replicated in other works due to our emphasis on fundamentally non-spherical halos and measures of morphology that correspondingly do not assume spherical symmetry.

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arXiv2026

Invariant manifolds in barred galaxy simulations. I. Material density waves

We investigate the dynamical origin and kinematic signatures of spiral structure in an N-body simulation of an isolated barred galaxy, assessing whether invariant manifold theory provides a consistent dynamical framework to disentangle the disc particle populations and to identify those that genuinely build, trace, and sustain the spiral arms. We compute the Jacobi energy of disc particles and classify them relative to the energies of the equilibrium points, thereby isolating manifold-compatible orbits. We analyse their spatial distribution and velocity structure to characterise spiral-related streaming motions. The Jacobi constant provides a physically motivated dynamical separator that reveals three distinct kinematic populations: (i) low-energy particles on nearly circular orbits populating most of the disc, (ii) high-energy particles associated with banana orbits, and (iii) manifold-compatible particles originating near the bar and following transit orbits along the spiral arms. Only the manifold-compatible population generates the prominent outward-migrating ridge observed in the R - v_phi plane and reproduces the characteristic spiral streaming pattern. In contrast, the low-energy population exhibits a global quasi-circular motion with small perturbations induced by the self-gravity of the spiral structure. Our results demonstrate that the spiral arms are dynamically traced by the manifold-compatible population, which forms the backbone of the structure and drives effective radial transport. The bulk of low-energy disc particles responds to the spiral perturbation similarly to the traditional density wave picture, enhancing the density contrast caused by the invariant-manifold compatible particles. In this framework, barred spiral arms emerge as material structures sustained by manifold-guided transport, with the surrounding disc behaving as a system of material density waves.

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arXiv2026

The AGORA High-resolution Galaxy Simulations Comparison Project. X: Formation and Evolution of Galaxies at the High-redshift Frontier

Recent observations from JWST have revealed unexpectedly luminous galaxies, exhibiting stellar masses and luminosities significantly higher than predicted by theoretical models at Cosmic Dawn. In this study, we present a suite of cosmological zoom-in simulations targeting high-redshift ($z \geq 10$) galaxies with dark matter halo masses in the range $10^{10} - 10^{11}\ {\rm M}_{\odot}$ at $z=10$, using state-of-the-art galaxy formation simulation codes (Enzo, Ramses, Changa, Gadget-3, Gadget-4, and Gizmo). This study aims to evaluate the convergence of the participating codes and their reproducibility of high-redshift galaxies with the galaxy formation model calibrated at relatively low redshift, without additional physics for high-redshift environments. The subgrid physics follows the AGORA CosmoRun framework, with adjustments to resolution and initial conditions to emulate similar physical environments in the early universe. The participating codes show consistent results for key galaxy properties (e.g., stellar mass), but also reveal notable differences (e.g., metallicity), indicating that galaxy properties at high redshifts are highly sensitive to the feedback implementation of the simulation. Massive halos (${\rm M}_{\rm halo}\geq5\times10^{10}\,{\rm M}_{\odot}$ at $z=10$) succeed in reproducing observed stellar masses, metallicities, and UV luminosities at $10\leq z\leq12$ without requiring additional subgrid physics, but tend to underpredict those properties at higher redshift. We also find that varying the dust-to-metal ratio modestly affects UV luminosity of simulated galaxies, whereas the absence of dust significantly enhances it. In future work, higher-resolution simulations will be conducted to better understand the formation and evolution of galaxies at Cosmic Dawn.

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arXiv2026

Survival or Destruction: Effects of Spheroidal Satellite Collisions on Bars in Milky Way-Like Galaxies

Although stellar bars are prevalent in local galaxies, unbarred galaxies constitute a significant fraction, particularly at high redshifts. While some galaxies are unbarred by nature due to stability against the bar instability, several mechanisms capable of transforming barred galaxies into unbarred systems have also been proposed, such as central mass concentration, specific dark matter halo morphologies and tidal interactions. Regarding galactic interactions, mergers can undoubtedly disrupt bars while potentially destroying the entire disk. However, the effects of pure collisions (non-merging scenarios) on bars remain unclear, with limited existing studies yielding contradictory conclusions. Here we aim to systematically investigate the disruptive effects of collisions on bars hosted by Milky Way-like galaxies using N-body/SPH simulations. We model collisions between the barred galaxy and a spherical intruder, conducting multiple simulations by varying interaction parameters, with mass ratios set at 1:3, 1:5, and 1:15. We find that bars are remarkably robust, with most interactions failing to significantly reduce their strength or pattern speed. Only off-center high-inclination retrograde collisions can effectively destroy bars, while central high-inclination collisions can substantially decrease the pattern speed. Such destruction and deceleration primarily arise from gravitational forces rather than gas-related processes. Notably, compared to collisions occurring along the bar's major axis, those along the minor axis cause greater weakening but can slow the bar's natural deceleration. Furthermore, changes in mass resolution do not significantly affect the results when the resolution is better than ~10^5 Solar mass.

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arXiv2025

Tidally-induced radial migration waves in LMC-like galaxies

Stellar radial migration has predominantly been examined in isolated disc galaxies where non-axisymmetric structures drive the process. By contrast, while tidal interactions are known for having an influence, their contribution remains comparatively under explored. The LMC, the nearest disc galaxy to the Milky Way (MW) and currently interacting with the SMC, provides a unique laboratory to investigate this interplay. We aim to quantify the impact of tidal interactions on radial migration and metallicity distribution in high-resolution simulations of LMC-like disc galaxies. We leverage a subsample of KRATOS, a suite of 28 pure $N$-body simulations of the LMC-SMC-MW system. Specifically, we use 6 simulations of both isolated and interacting LMC-like galaxies, exploring different values of the Toomre stellar parameter $Q$. These simulations allow to map the evolution of the stars' guiding radii $R_g(t)$ and compute radial migration fluxes in interacting systems and compare with their isolated counterparts, allowing to quantify the link between tidal interactions, radial migration, non-axisymmetric patterns, disc internal stability, and radial metallicity distribution. We present tidally-triggered wave-like radial migration fluxes reaching up to $\sim40\%$ of disc stellar mass per Gyr. This wave-like migration appears during the satellite's pericentre passages, almost independently of $Q$ and induces a metallicity drop of $\sim$3-5\% of the isolated galaxy's maximum metallicity in the inner disc. Additionally, in the isolated simulations, the extent of variation in the bar's resonance region coincides with the mixing zones in the metallicity distribution. We propose a novel description of a wave-like radial migration flux as a dynamical response of a galaxy undergoing tidal interactions and sketch its impact on the galaxy's metallicity distribution.

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arXiv2025

The AGORA High-resolution Galaxy Simulations Comparison Project. VIII: Disk Formation and Evolution of Simulated Milky Way Mass Galaxy Progenitors at $1<z<5$

We investigate how differences in the stellar feedback produce disks with different morphologies in Milky Way-like progenitors over 1 $\leq z \leq 5$, using eight state-of-the-art cosmological hydrodynamics simulation codes in the \textit{AGORA} project. In three of the participating codes, a distinct, rotation-dominated inner core emerges with a formation timescale of $\lesssim 300$ Myr, largely driven by a major merger event, while two other codes exhibit similar signs of wet compaction -- gaseous shrinkage into a compact starburst phase -- at earlier epochs. The remaining three codes show only weak evidence of wet compaction. Consequently, we divide the simulated galaxies into two groups: those with strong compaction signatures and those with weaker ones. Galaxies in these two groups differ in size, stellar age gradients, and disk-to-total mass ratios. Specifically, codes with strong wet compaction build their outer disks in an inside-out fashion, leading to negative age gradients, whereas codes with weaker compaction feature flat or positive age gradients caused primarily by outward stellar migration. Although the stellar half-mass radii of these two groups diverge at $z \sim 3$, the inclusion of dust extinction brings their sizes and shapes in mock observations closer to each other and to observed galaxies. We attribute the observed morphological differences primarily to variations in the stellar feedback implementations -- such as delayed cooling timescales, and feedback strengths -- that regulate both the onset and duration of compaction. Overall, our results suggest that disk assembly at high redshifts is highly sensitive to the details of the stellar feedback prescriptions in simulations.

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arXiv2025

Dark matter spiral arms in Milky Way-like halos

The coupling between the dark matter (DM) halo and the stellar disc is a key factor in galactic evolution. While the interaction between structures like the Galactic bar and DM halos has been explored (e.g. slowing down of the bar due to dynamical friction), the effect of spiral arms on the DM halo distribution has received limited attention. We analyze a suite of simulations featuring strong stellar spiral arms, ranging in complexity from test-particle models to fully cosmological hydrodynamical simulations. Using Fourier transforms, we characterize the phase and amplitude of the stellar spirals at different times and radii. We then apply the same methodology to DM particles near the stellar disc and compare trends in Fourier coefficients and phases between the two components. We detect a clear spiral arm signal in the DM distribution, correlated with the stellar spirals, confirming the reaction of the halo. The strength of the DM spirals consistently measures around 10\% of that of the stellar spiral arms. In the $N$-body simulation, the DM spiral persistently trails the stellar spiral arm by approximately $10^\circ$. A strong spiral signal of a few km\,s$^{-1}$ appears in the radial, azimuthal, and vertical velocities of halo particles, distinct from the stellar kinematic signature. In a test-particle simulation with an analytical spiral potential (omitting self-gravity), we reproduce a similar density and kinematic response, showing that the test-particle halo responds in the same way as the $N$-body halo. Finally, we also find the rest of the simulations, indicating that the dynamical signatures of the forced response in the DM halo are independent of the dynamical origin of the stellar spiral arms. We reveal the ubiquitous presence of DM spiral arms in Milky Way-like galaxies, driven by a forced response to the stellar spiral potential. (ABR)

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arXiv2025

Tidal interaction can stop galactic bars: on the LMC non-rotating bar

Context: Using Gaia DR3 data, Jiménez-Arranz et al. (2024a) computed the LMC bar pattern speed using three different methods. One of them suggested that the LMC might be hosting a bar that barely rotates, and is slightly counter-rotating with respect to the LMC disc, with a pattern speed of $Ω_p = -1.0 \pm 0.5$ km/s/kpc. Aims: To confirm that tidal interactions can trigger the LMC hosting a non-rotating bar due to its interaction with the SMC, which could cause the LMC bar to slow down significantly until it (momentarily) stops. Methods: We analyse a subset of models (K9 and K21) from the KRATOS suite (Jiménez-Arranz et al. 2024b) where we detected non-rotating bars. We make use of two different methods to track the evolution of the bar pattern speed: the program patternSpeed.py (Dehnen et al. 2023), and temporal finite-differences of the change rate the bar major axis' phase angle. Results: In the second LMC-SMC-like pericenter passage of K9, the bar of the LMC-like galaxy weakens to almost disappear and regenerates with a pattern speed that suffers a slowdown from $Ω_p \sim 20$ km/s/kpc to $Ω_p \sim 0$ km/s/kpc in less than 75 Myr. Then, the bar rotates at less than $Ω_p \sim 3-5$ km/s/kpc for around 100 Myr, until it recovers the initial (before interaction) pattern speed of $Ω_p \sim 10$ km/s/kpc. The results for the K21 simulation are comparable. Conclusions: This work is the first direct evidence that galactic bars can be slowed down or even stopped by tidal interaction, which strengthens the possibility of the LMC hosting a non-rotating bar, and can add an alternative formation scenario for observed slow-rotating bars.

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arXiv2024

The AGORA high-resolution galaxy simulations comparison project: CosmoRun data release

The AGORA Cosmorun (arXiv:2106.09738) is a set of hydrodynamical cosmological zoom-in simulations carried out within the AGORA High-resolution Galaxy Simulations Comparison Project (arXiv:1308.2669,arXiv:1610.03066). These simulations show the formation and evolution of a Milky Way-sized galaxy using eight of the most widely used numerical codes in the community (Art-I, Enzo, Ramses, Changa, Gadget-3, Gear, Gizmo, and Arepo). In this short report, we describe the public release of the raw output data from all of these simulations at z = 8, 7, 6, 5, 4, 3, 2 (plus at z=1, 0 when available), and several metadata files containing the halo centers, virial quantities, and merger trees. The data from even thinner timesteps will be released as soon as the upcoming collaboration papers (VII-IX) are submitted and accepted.

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arXiv2024

The AGORA High-resolution Galaxy Simulations Comparison Project IV: Halo and Galaxy Mass Assembly in a Cosmological Zoom-in Simulation at $z\le2$

In this fourth paper from the AGORA Collaboration, we study the evolution down to redshift $z=2$ and below of a set of cosmological zoom-in simulations of a Milky Way mass galaxy by eight of the leading hydrodynamic simulation codes. We also compare this CosmoRun suite of simulations with dark matter-only simulations by the same eight codes. We analyze general properties of the halo and galaxy at $z=4$ and 3, and before the last major merger, focusing on the formation of well-defined rotationally-supported disks, the mass-metallicity relation, the specific star formation rate, the gas metallicity gradients, and the non-axisymmetric structures in the stellar disks. Codes generally converge well to the stellar-to-halo mass ratios predicted by semi-analytic models at $z\sim$2. We see that almost all the hydro codes develop rotationally-supported structures at low redshifts. Most agree within 0.5 dex with the observed MZR at high and intermediate redshifts, and reproduce the gas metallicity gradients obtained from analytical models and low-redshift observations. We confirm that the inter-code differences in the halo assembly history reported in the first paper of the collaboration also exist in CosmoRun, making the code-to-code comparison more difficult. We show that such differences are mainly due to variations in code-dependent parameters that control the time-stepping strategy of the gravity solver. We find that variations in the early stellar feedback can also result in differences in the timing of the low-redshift mergers. All the simulation data down to $z=2$ and the auxiliary data will be made publicly available.

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arXiv2024

The AGORA High-resolution Galaxy Simulations Comparison Project. V: Satellite Galaxy Populations In A Cosmological Zoom-in Simulation of A Milky Way-mass Halo

We analyze and compare the satellite halo populations at $z\sim2$ in the high-resolution cosmological zoom-in simulations of a $10^{12}\,{\rm M}_{\odot}$ target halo ($z=0$ mass) carried out on eight widely-used astrophysical simulation codes ({\sc Art-I}, {\sc Enzo}, {\sc Ramses}, {\sc Changa}, {\sc Gadget-3}, {\sc Gear}, {\sc Arepo-t}, and {\sc Gizmo}) for the {\it AGORA} High-resolution Galaxy Simulations Comparison Project. We use slightly different redshift epochs near $z=2$ for each code (hereafter ``$z\sim2$') at which the eight simulations are in the same stage in the target halo's merger history. After identifying the matched pairs of halos between the {\it CosmoRun} simulations and the DMO simulations, we discover that each {\it CosmoRun} halo tends to be less massive than its DMO counterpart. When we consider only the halos containing stellar particles at $z\sim2$, the number of satellite {\it galaxies} is significantly fewer than that of dark matter halos in all participating {\it AGORA} simulations, and is comparable to the number of present-day satellites near the Milky Way or M31. The so-called ``missing satellite problem' is fully resolved across all participating codes simply by implementing the common baryonic physics adopted in {\it AGORA} and the stellar feedback prescription commonly used in each code, with sufficient numerical resolution ($\lesssim100$ proper pc at $z=2$). We also compare other properties such as the stellar mass$-$halo mass relation and the mass$-$metallicity relation. Our work highlights the value of comparison studies such as {\it AGORA}, where outstanding problems in galaxy formation theory are studied simultaneously on multiple numerical platforms.

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arXiv2024

The AGORA High-resolution Galaxy Simulations Comparison Project. VI. Similarities and Differences in the Circumgalactic Medium

We analyze the circumgalactic medium (CGM) for eight commonly-used cosmological codes in the AGORA collaboration. The codes are calibrated to use identical initial conditions, cosmology, heating and cooling, and star formation thresholds, but each evolves with its own unique code architecture and stellar feedback implementation. Here, we analyze the results of these simulations in terms of the structure, composition, and phase dynamics of the CGM. We show properties such as metal distribution, ionization levels, and kinematics are effective tracers of the effects of the different code feedback and implementation methods, and as such they can be highly divergent between simulations. This is merely a fiducial set of models, against which we will in the future compare multiple feedback recipes for each code. Nevertheless, we find that the large parameter space these simulations establish can help disentangle the different variables that affect observable quantities in the CGM, e.g., showing that abundances for ions with higher ionization energy are more strongly determined by the simulation's metallicity, while abundances for ions with lower ionization energy are more strongly determined by the gas density and temperature.

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arXiv2022

Distinguishing Between Photoionized and Collisionally Ionized Gas in the Circumgalactic Medium

Most studies of highly ionized plasmas have historically assumed ions are either in photoionization equilibrium, PIE, or collisional ionization equilibrium, CIE, sometimes including multiple phases with different relevant mechanisms. Simulation analysis packages, on the other hand, tend to use precomputed ion fraction tables which include both mechanisms, among others. Focusing on the low-density, high temperature phase space likely to be most relevant in the circumgalactic medium, in this work we show that most ions can be classified as 'PI' or 'CI' on an ion-by-ion basis. This means that for a cloud at a particular point in phase space, some ions will be created primarily by PI and others by CI, with other mechanisms playing only very minor roles. Specifically, we show that ions are generally CI if the thermal energy per particle is greater than $\sim6$\% of their ionization energy, and PI otherwise. We analyse the accuracy of this ansatz compared to usual PIE/CIE calculations, and show the surprisingly minor dependence of this conclusion on redshift and ionizing background.

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arXiv2022

Phase spirals in cosmological simulations of Milky Way-size galaxies

We study the vertical perturbations in the galactic disc of the Milky Way-size high-resolution hydrodynamical cosmological simulation named GARROTXA. We detect phase spirals in the vertical projection $Z- V_{Z}$ of disc's stellar particles for the first time in this type of simulations. Qualitatively similar structures were detected in the recent Gaia data, and their origin is still under study. In our model the spiral-like structures in the phase space are present in a wide range of times and locations across the disc. By accounting for an evolving mix of stellar populations, we observe that, as seen in the data, the phase spirals are better observed in the range of younger-intermediate star particles. We measure the intensity of the spiral with a Fourier decomposition and find that these structures appear stronger near satellite pericenters. Current dynamical models of the phase spiral considering a single perturber required a mass at least of the order of 10$^{10}$ M$_\odot$, but all three of our satellites have masses of the order of $\sim$10$^8$ M$_\odot$. We suggest that there are other mechanisms at play which appear naturally in our model such as the physics of gas, collective effect of multiple perturbers, and a dynamically cold population that is continuously renovated by the star formation Complementing collisionless isolated N-body models with the use of fully-cosmological simulations with enough resolution can provide new insights into the nature/origin of the phase spiral.

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arXiv2021

The bi-modal $^7$Li distribution of the Milky Way's thin-disk dwarf stars: The role of Galactic-scale events and stellar evolution

The lithium abundance, A(Li), in stellar atmospheres suffers from various enhancement and depletion processes during the star's lifetime. While several studies have demonstrated that these processes are linked to the physics of stellar formation and evolution, the role that Galactic-scale events play in the galactic A(Li) evolution is not yet well understood. We aim to demonstrate that the observed A(Li) bi-modal distribution, in particular in the FGK-dwarf population, is not a statistical artefact and that the two populations connect through a region with a low number of stars. We also want to investigate the role that Galactic-scale events play in shaping the A(Li) distribution of stars in the thin disk. We use statistical techniques along with a Galactic chemical evolution model for A(Li) that includes most of the well-known $^7$Li production and depletion channels. We confirm that the FGK main-sequence stars belonging to the Milky Way's thin disk present a bi-modal A(Li) distribution. We demonstrate that this bi-modality can be generated by a particular Milky Way star formation history profile combined with the stellar evolution's $^7$Li depletion mechanisms. We show that A(Li) evolution can be used as an additional proxy for the star formation history of our Galaxy.

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