arXiv subjects

Laura Sánchez-Menguiano

Publications and source records attributed to Laura Sánchez-Menguiano.

14 recordsLinked to original sources

arXiv2026

The Gas-Phase Mass-Metallicity Relation of Dwarf Galaxies Across Large-Scale Environments Using the CAVITY Parent Sample

The gas-phase mass-metallicity relation (MZR) of galaxies shows a noticeable break in slope and increased scatter at low stellar masses, suggesting that the physical processes governing chemical enrichment differ between dwarf and high-mass systems. Dwarf galaxies are highly susceptible to internal and environmental mechanisms due to shallow potential wells. We assess whether a single MZR describes dwarf galaxies across diverse large-scale environments using the CAVITY parent sample. We examine the MZR and star formation rate (SFR) of dwarfs with stellar masses 8.9 < log(M_star/M_sun) < 9.5. Using SDSS optical spectra, we measured emission line fluxes via the pyPipe3D pipeline to derive the MZR and SFR for 353, 311, and 22 dwarf galaxies in voids, filaments, and clusters, respectively. We find a systematic variation in the MZR slope, which is steeper in voids (0.28 +/- 0.03) and progressively flatter in clusters (0.17 +/- 0.08), indicating an environmental dependence in this mass regime. When separated by local environment, isolated and non-isolated dwarfs in voids show no significant differences. Isolated dwarfs in filaments exhibit properties similar to void counterparts. However, non-isolated filament galaxies display flatter MZR slopes, comparable to cluster dwarfs. We report both large- and local-scale environmental dependencies in the gas-phase metallicity and MZR slope. Consistent with the pre-processing framework, our results indicate that the local environment becomes significant within cosmic web filaments, affecting the chemical enrichment and star formation of low-mass systems. This suggests that part of the MZR scatter in dwarf galaxies arises from environmental effects.

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arXiv2026

The CAVITY project. The spatially resolved SFR of galaxies in voids

The mass in the Universe is distributed non-uniformly, originating the Large Scale Structure (LSS), characterised by clusters, filaments, walls and voids. Galaxies in voids are bluer, later type, less massive, and have slower evolution than galaxies in denser environments. The effect of the void environment on properties such as star formation rate (SFR) is still under discussion. We tackle this by estimating spatially-resolved SFR from extinction-corrected Halpha luminosities of 220 void galaxies from the CAVITY survey. These observations consist of optical integral field unit data cubes from the PMAS/PPaK spectrograph at Calar Alto Observatory. We measure the continuum-subtracted emission lines to obtain maps of SFR, specific star formation rate (sSFR) and extinction. We assess global properties and radial profiles up to 2 half-light radii. We compare with galaxies in filaments and walls from the CALIFA survey using the same methodology, building a control sample matched in morphology and stellar mass. We find no significant differences in SFR and sSFR, although void galaxies tend to have larger SFR, especially for early spirals. This effect is present for Sa galaxies at all galactocentric distances, and in the outer parts of late-type spirals, evidencing slower transition to quiescence and less evolved discs. Void late-type galaxies have lower extinction. Using extinction normalised by stellar mass surface density as a proxy for gas mass fraction, we find it larger for void early spirals, especially in outer regions. This indicates the effect of the void environment on the transition from star forming to passive.

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arXiv2025

The impact of bars on the properties of HII regions in the TIMER survey

In this study we perform a comparative analysis of the properties of the HII regions located in different areas of barred galaxies, with the aim of investigating the impact of bars on the physical properties of the ionised gas. Based on integral field spectroscopy data for 17 barred galaxies covering approximately the central 6x6 kpc, we detect a total of 2200 HII regions, of which 331 are located within the nuclear disc (also known as circumnuclear regions), 661 in the bar region, and 1208 in the disc. Among the physical properties of the HII regions, we explore the O/H and N/O abundances, H$α$ luminosity, dust extinction, electron density, and H$α$ equivalent width. We find clear differences in the properties of the HII regions between the nuclear disc, the bar and the disc, that could be explained by an enhancement in the molecular gas concentration in the central parts driven by bar-induced gas flows. As this gas is channelled towards the galaxy centre, the most extreme values in the analysed properties are found for the circumnuclear HII regions. Unlike the bar strength, galaxy mass does seem to affect the properties of the HII regions, with massive galaxies presenting higher values in most of the properties, possibly due to the increased amount of gas in these systems. This study provides evidence that the bar-driven redistribution of material within the galaxy inner parts causes significant differences in the HII region properties depending on their location within the galaxies.

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arXiv2025

Rendezvous in CAVITY: Kinematics and gas properties of an isolated dwarf-dwarf merging pair in a cosmic void region

Galaxy mergers are pivotal events in the evolutionary history of galaxies, with their impact believed to be particularly significant in dwarf galaxies. We report the serendipitous identification of an isolated merging dwarf system with a total stellar mass of M$_{\rm \star}$$\sim$10$^{9.7}$M$_{\rm \odot}$, located in the centre of a cosmic void. This system is one of the rare examples, and possibly the first, of merging dwarf galaxy pairs studied within the central region of a cosmic void. Using CAVITY PPAK-IFU data combined with deep optical broadband imaging from the Isaac Newton Telescope, we analysed the kinematics and ionized gas properties of each dwarf galaxy in the system by employing a full spectral fitting technique. The orientation of this merging pair relative to the line of sight allowed us to determine the dynamical mass of each component, showing that both had similar dynamical masses within galactocentric distances of up to 2.9 kpc. While the gas-phase metallicity of both components is consistent with that of star-forming dwarf galaxies, the star formation rates observed in both components exceed those typically reported for equally massive star-forming dwarf galaxies. This indicates that the merger has presumably contributed to enhancing star formation. Furthermore, we found no significant difference in the optical g-r colour of this merging pair compared to other merging dwarf pairs across different environments. While most merging events occur in group-like environments with high galaxy density and the tidal influence of a host halo, and isolated mergers typically involve galaxies with significant mass differences, the identified merging pair does not follow these patterns. We speculate that the global dynamics of the void or past three-body encounters involving components of this pair and a nearby dwarf galaxy might have triggered this merging event.

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arXiv2025

The puzzle of isolated and quenched dwarf galaxies in cosmic voids

We report, for the first time, the detection of a sample of quenched and isolated dwarf galaxies (with 8.9 $<$ log(M$_{\rm \star}$/M$_{\rm \odot}$) $<$ 9.5) in the least dense regions of the cosmic web, including voids, filaments, and walls. These dwarfs have no neighbouring galaxy within 1.0~Mpc in projected distance. Based on the full spectral fitting of their central spectra using Sloan Digital Sky Survey data, these galaxies are gas-deprived, exhibit stellar mass assembly very similar to dwarfs in the central regions of galaxy clusters, and have experienced no significant star formation in the past 2 Gyr. Additionally, analysis of r-band images from the Dark Energy Camera Legacy Survey showed that these dwarf galaxies host a central Nuclear Star Cluster (NSC). Detecting quenched, isolated dwarf galaxies in cosmic voids indicates that environmental factors are not the sole drivers of their quenching. Internal mechanisms, such as feedback from in-situ star formation, also contributing to the NSC formation, black holes, or variations in conditions during their formation, offer potential explanations for star formation suppression in these galaxies. These findings highlight the need for a significant revision in our understanding of baryonic physics, particularly concerning the formation and evolution of low-mass galaxies.

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arXiv2024

CAVITY: Calar Alto Void Integral-field Treasury surveY. I. First public data release

The Calar Alto Void Integral-field Treasury surveY (CAVITY) is a legacy project aimed at characterising the population of galaxies inhabiting voids, which are the most under-dense regions of the cosmic web, located in the Local Universe. This paper describes the first public data release (DR1) of CAVITY, comprising science-grade optical data cubes for the initial 100 out of a total of $\sim$300 galaxies in the Local Universe ($0.005 < z < 0.050$). These data were acquired using the integral-field spectrograph PMAS/PPak mounted on the 3.5m telescope at the Calar Alto observatory. The DR1 galaxy sample encompasses diverse characteristics in the color-magnitude space, morphological type, stellar mass, and gas ionisation conditions, providing a rich resource for addressing key questions in galaxy evolution through spatially resolved spectroscopy. The galaxies in this study were observed with the low-resolution V500 set-up, spanning the wavelength range 3745-7500 Å, with a spectral resolution of 6.0 Å (FWHM). Here, we describe the data reduction and characteristics and data structure of the CAVITY datasets essential for their scientific utilisation, highlighting such concerns as vignetting effects, as well as the identification of bad pixels and management of spatially correlated noise. We also provide instructions for accessing the CAVITY datasets and associated ancillary data through the project's dedicated database.

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arXiv2024

The CAVITY project. The spatially resolved stellar population properties of galaxies in voids

The Universe is shaped as a web-like structure, formed by clusters, filaments, and walls that leave large volumes in between named voids. Galaxies in voids have been found to be of a later type, bluer, less massive, and to have a slower evolution than galaxies in denser environments (filaments and walls). However, the effect of the void environment on their stellar population properties is still unclear. We aim to address this question using 118 optical integral field unit datacubes from the Calar Alto Void Integral-field Treasury surveY (CAVITY), observed with the PMAS/PPaK spectrograph at the 3.5m telescope at the Calar Alto Observatory (Almería, Spain). We used the non-parametric full spectral fitting code STARLIGHT to estimate their stellar population properties: stellar mass, stellar mass surface density, age, star formation rate (SFR), and specific star formation rate (sSFR). We analysed the results through the global and spatially resolved properties. Then, we compared them with a control sample of galaxies in filaments and walls from the CALIFA survey, matched in stellar mass and morphological type. Key findings include void galaxies having a slightly higher half-light radius (HLR), lower stellar mass surface density, and younger ages across all morphological types, and slightly elevated SFR and sSFR (only significant enough for Sas). Many of these differences appear in the outer parts of spiral galaxies in voids (HLR > 1), which are younger and exhibit a higher sSFR, indicative of less evolved discs. This trend is also found for early-type spirals, suggesting a slower transition from star-forming to quiescent states in voids. Our analysis indicates that void galaxies, influenced by their surroundings, undergo a more gradual evolution, especially in their outer regions, with a more pronounced effect for low-mass galaxies.

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arXiv2024

More fundamental than the fundamental metallicity relation: The effect of the stellar metallicity on the gas-phase mass-metallicity and gravitational potential-metallicity relations

Context. One of the most fundamental scaling relations in galaxies is observed between metallicity and stellar mass -- the mass-metallicity relation (MZR) -- although recently a stronger dependence of the gas-phase metallicity with the galactic gravitational potential ($Φ\rm ZR$) has been reported. Further dependences of metallicity on other galaxy properties have been revealed, with the star formation rate (SFR) being one of the most studied and debated secondary parameters in the relation (the so-called fundamental metallicity relation). Aims. In this work we explore the dependence of the gas-phase metallicity residuals from the MZR and $Φ\rm ZR$ on different galaxy properties in the search for the most fundamental scaling relation in galaxies. Methods. We applied a random forest regressor algorithm on a sample of 3430 nearby star-forming galaxies from the SDSS-IV MaNGA survey. Using this technique, we explored the effect of 147 additional parameters on the global oxygen abundance residuals obtained after subtracting the MZR. Alternatively, we followed a similar approach with the metallicity residuals from the $Φ\rm ZR$. Results. The stellar metallicity of the galaxy is revealed as the secondary parameter in both the MZR and the $Φ\rm ZR$, ahead of the SFR. This parameter reduces the scatter in the relations $\sim 10-15\%$. We find the 3D relation between gravitational potential, gas metallicity, and stellar metallicity to be the most fundamental metallicity relation observed in galaxies.

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arXiv2023

Stellar mass is not the best predictor of galaxy metallicity. The gravitational potential-metallicity relation $Φ\rm ZR$

Interpreting the scaling relations followed by galaxies is a fundamental tool for assessing how well we understand galaxy formation and evolution. Several scaling relations involving the galaxy metallicity have been discovered through the years, the foremost of which is the scaling with stellar mass. This so-called mass-metallicity relation is thought to be fundamental and has been subject to many studies in the literature. We study the dependence of the gas-phase metallicity on many different galaxy properties to assess which of them determines the metallicity of a galaxy. We applied a random forest regressor algorithm on a sample of more than 3000 nearby galaxies from the SDSS-IV MaNGA survey. Using this machine-learning technique, we explored the effect of 148 parameters on the global oxygen abundance as an indicator of the gas metallicity. $M_{\rm \star}$/$R_e$, as a proxy for the baryonic gravitational potential of the galaxy, is found to be the primary factor determining the average gas-phase metallicity of the galaxy ($Z_g$). It outweighs stellar mass. A subsequent analysis provides the strongest dependence of $Z_g$ on $M_\star / R_e^{\,0.6}$. We argue that this parameter traces the total gravitational potential, and the exponent $α\simeq 0.6$ accounts for the inclusion of the dark matter component. Our results reveal the importance of the relation between the total gravitational potential of the galaxy and the gas metallicity. This relation is tighter and likely more primordial than the widely known mass-metallicity relation.

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arXiv2023

Stellar mass-metallicity relation throughout the large-scale structure of the Universe: CAVITY mother sample

Void galaxies are essential for understanding the physical processes that drive galaxy evolution because they are less affected by external factors than galaxies in denser environments, that is, in filaments, walls, and clusters. The stellar metallicity of a galaxy traces the accumulated fossil record of the star formation through the entire life of the galaxy. A comparison of the stellar metallicity of galaxies in various environments, including voids, filaments, walls, and clusters can provide valuable insights into how the large-scale environment affects the chemical evolution of the galaxy. We present the first comparison of the relation of the total stellar mass versus central stellar metallicity between galaxies in voids, filaments, walls, and clusters with different star formation history (SFH) types, morphologies, and colours for stellar masses between $10^{8.0}$ to $10^{11.5}$ solar masses and redshift $0.01<z<0.05$. We applied non-parametric full spectral fitting techniques (pPXF and STECKMAP) to 10807 spectra from the SDSS-DR7 (987 in voids, 6463 in filaments and walls, and 3357 in clusters) and derived their central mass-weighted average stellar metallicity ($\rm [M/H]_M$). We find that galaxies in voids have slightly lower stellar metallicities on average than galaxies in filaments and walls (by~$\sim~0.1$~dex), and they are much lower than those of galaxies in clusters (by~$\sim~0.4$~dex). These differences are more significant for low-mass ($ \sim~10^{9.25}~{\rm M_\odot}$) than for high-mass galaxies, for long-timescale SFH (extended along time) galaxies than for short-timescale SFHs (concentrated at early times) galaxies, for spiral than for elliptical galaxies, and for blue than for red galaxies.

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arXiv2020

Local and global gas metallicity versus stellar age relation in MaNGA galaxies

The search for new global scaling relations linking physical properties of galaxies has a fundamental interest. Furthermore, their recovery from spatially resolved relations has been one of the spotlights of integral field spectroscopy (IFS). In this study we investigate the existence of global and local relations between stellar age ($Age_\star$) and gas-phase metallicity ($Z_g$). To this aim, we analyze IFS data for a sample of 736 star-forming disk galaxies from the MaNGA survey. We report a positive correlation between the global $Z_g$ and $D(4000)$ (an indicator of stellar age), with a slope that decreases with increasing galaxy mass. Locally, a similar trend is found when analyzing the $Z_g$ and $D(4000)$ of the star-forming regions, as well as the residuals resulting from removing the radial gradients of both parameters. The local laws have systematically smaller slopes than the global one. We ascribe this difference to random errors, that make the true slope of the $Age_\star-Z_g$ relation to be systematically underestimated when performing a least square fitting. The explored relation is intimately linked with the already known relation between gas metallicity and star formation rate at fixed mass, both presenting a common physical origin.

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arXiv2020

Arm-interarm gas abundance variations explored with MUSE: the role of spiral structure in the chemical enrichment of galaxies

Spiral arms are the most characteristic features of disc galaxies, easily distinguishable due to their association with ongoing star formation. However, the role of spiral structure in the chemical evolution of galaxies is unclear. Here we explore gas-phase abundance variations between arm and interarm regions for a sample of 45 spiral galaxies using high spatial resolution VLT/MUSE Integral Field Spectroscopy data. We report the presence of more metal-rich HII regions in the spiral arms with respect to the corresponding interarm regions for a large subsample of galaxies ($45-65\%$ depending on the adopted calibrator for the abundance derivation). A small percentage of the sample is observed to display the opposite trend, that is, more metal-poor HII regions in the spiral arms compared to that of the interarms ($5-20\%$ depending on the calibrator). We investigate the dependence of the variations with three galaxy properties: the stellar mass, the presence of bars, and the flocculent/grand design appearance of spiral arms. In all cases, we observe that the arm-interarm abundance differences are larger (positive) in more massive and grand-design galaxies. This is confirmed by an analogous spaxel-wise analysis, which also shows a noticeable effect of the presence of galactic bars, with barred systems presenting larger (positive) arm-interarm abundance variations than unbarred systems. The comparison of our results with new predictions from theoretical models exploring the nature of the spirals would highly impact on our knowledge on how these structures form and affect their host galaxies.

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arXiv2019

Characterizing the local relation between star formation rate and gas-phase metallicity in MaNGA spiral galaxies

The role of gas accretion in galaxy evolution is still a matter of debate. The presence of inflows of metal-poor gas that trigger star formation bursts of low metallicity has been proposed as an explanation for the local anti-correlation between star formation rate (SFR) and gas-phase metallicity ($\rm Z_g$) found in the literature. In the present study, we show how the anti-correlation is also present as part of a diversified range of behaviours for a sample of more than 700 nearby spiral galaxies from the SDSS IV MaNGA survey. We have characterized the local relation between SFR and $\rm Z_g$ after subtracting the azimuthally averaged radial profiles of both quantities. $60\%$ of the analyzed galaxies display a $\rm SFR-Z_g$ anti-correlation, with the remaining $40\%$ showing no correlation ($19\%$) or positive correlation ($21\%$). Applying a Random Forest machine-learning algorithm, we obtain that the slope of the correlation is mainly determined by the average gas-phase metallicity of the galaxy. Galaxy mass, $g-r$ colors, stellar age, and mass density seem to play a less significant role. This result is supported by the performed 2nd-order polynomial regression analysis. Thus, the local $\rm SFR-Z_g$ slope varies with the average metallicity, with the more metal-poor galaxies presenting the lowest slopes (i.e., the strongest $\rm SFR-Z_g$ anti-correlations), and reversing the relation for more metal-rich systems. Our results suggest that external gas accretion fuels star-formation in metal-poor galaxies, whereas in metal-rich systems the gas comes from previous star formation episodes.

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arXiv2017

Towards a new classification of galaxies: principal component analysis of CALIFA circular velocity curves

We present a galaxy classification system for 238 (E1-Sdm) CALIFA (Calar Alto Legacy Integral Field Area) galaxies based on the shapes and amplitudes of their circular velocity curves (CVCs). We infer the CVCs from the de-projected surface brightness of the galaxies, after scaling by a constant mass-to-light ratio based on stellar dynamics - solving axisymmetric Jeans equations via fitting the second velocity moment $V_{\mathrm{rms}}=\sqrt{V^2+σ^2}$ of the stellar kinematics. We use principal component analysis (PCA) applied to the CVC shapes to find characteristic features and use a $k$-means classifier to separate circular curves into classes. This objective classification method identifies four different classes, which we name slow-rising (SR), flat (FL), round-peaked (RP) and sharp-peaked (SP) circular curves. SR are typical for low-mass, late-type (Sb-Sdm), young, faint, metal-poor and disc-dominated galaxies. SP are typical for high-mass, early-type (E1-E7), old, bright, metal-rich and bulge-dominated galaxies. FL and RP appear presented by galaxies with intermediate mass, age, luminosity, metallicity, bulge-to-disk ratio and morphologies (E4-S0a, Sa-Sbc). The discrepancy mass factor, $f_d=1-M_{*}/M_{dyn}$, have the largest value for SR and SP classes ($\sim$ 74 per cent and $\sim$ 71 per cent, respectively) in contrast to the FL and RP classes (with $\sim$ 59 per cent and $\sim$ 61 per cent, respectively). Circular curve classification presents an alternative to typical morphological classification and appears more tightly linked to galaxy evolution.

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