We use fossil record techniques on the CALIFA sample to study how galaxies in the local universe have evolved in terms of their chemical content. We show how the metallicity and the mass-metallicity relation (MZR) evolve through time for the galaxies in our sample and how this evolution varies when we divide them based on their mass, morphology and star-forming status. We also check the impact of measuring the metallicity at the centre or the outskirts. We find the expected results that the most massive galaxies got enriched faster, with the MZR getting steeper at higher redshifts. However, once we separate the galaxies into morphology bins this behaviour is not as clear, which suggests that morphology is a primary factor to determine how fast a galaxy gets enriched, with mass determining the amount of enrichment. We also find that star-forming galaxies appear to be converging in their chemical evolution, that is, the metallicity of star-forming galaxies of different mass is very similar at recent times compared to several Gyr ago.
Variations in the stellar initial mass function (IMF) have been invoked to explain the spectroscopic and dynamical properties of early-type galaxies. However, no observations have yet been able to disentangle the physical driver. We analyse here a sample of 24 early-type galaxies drawn from the CALIFA survey, deriving in a homogeneous way their stellar population and kinematic properties. We find that the local IMF is tightly related to the local metallicity, becoming more bottom-heavy towards metal-rich populations. Our result, combined with the galaxy mass-metallicity relation, naturally exp…
We analyze radial stellar metallicity and kinematic profiles out to 1Re in 244 CALIFA galaxies ranging from morphological type E to Sd, to study the evolutionary mechanisms of stellar population gradients. We find that linear metallicity gradients exhibit a clear correlation with galaxy morphological type - with early type galaxies showing the steepest gradients. We show that the metallicity gradients simply reflect the local mass-metallicity relation within a galaxy. This suggests that the radial stellar population distribution within a galaxys effective radius is primarily a result of the \e…
The metallicity of local galaxies is tightly related not only to stellar mass, i.e. the mass-metallicity relation, but also to the star formation rate (SFR) through the so-called fundamental metallicity relation (FMR); more active galaxies show lower metallicities at fixed mass. Interestingly, high-z galaxies up to z~2.5 follow the same relation defined by SDSS locally. However, different shapes have been proposed for local galaxies, and the existence of a FMR and the role of the SFR has been recently questioned by some authors. In this paper we first discuss the various parametrizations of th…
We explore the effects of environment in the evolution of late-type galaxies by studying the radial profiles of light- and mass-weighted metallicities of galaxies in two discrete environments: field and groups. We use a sample of 167 late-type galaxies, with stellar masses $9\le \log(M_{\star}/M_{\odot}) \le 12$, drawn from the CALIFA survey. We make a study of the metallicity of galaxies in these two environments which includes the comparison of the metallicity as a function of the radius, at a characteristic scale, and as a function of a the stellar mass surface density. We find significant …
Differential enrichment between $α$- and Fe-peak elements is known to be strongly connected with the shape of the star formation history (SFH), the star formation efficiency (SFE), the inflow and outflow of material, and even the shape of the Initial Mass Function (IMF). However, beyond the Local Group detailed explorations are mostly limited to early-type galaxies due to the lack of a good proxy for [$α$/Fe] in late-type ones, limiting our understanding of the chemical enrichment process. We intent to extend the explorations of [$α$/Fe] to late-type galaxies, in order to understand the detail…
We use spatially and temporally resolved maps of stellar population properties of 300 galaxies from the CALIFA integral field survey to investigate how the stellar metallicity (Z*) relates to the total stellar mass (M*) and the local mass surface density ($μ$*) in both spheroidal and disk dominated galaxies. The galaxies are shown to follow a clear stellar mass-metallicity relation (MZR) over the whole 10$^9$ to 10$^{12}$ M$_{\odot}$ range. This relation is steeper than the one derived from nebular abundances, which is similar to the flatter stellar MZR derived when we consider only young star…
We present a novel method to retrieve the chemical structure of galaxies using integral field spectroscopy data through the stellar Metallicity Distribution Function (MDF). This is the probability distribution of observing stellar populations having a metallicity $Z$. We apply this method to a set of $550$ galaxies from the CALIFA survey. We present the behaviour of the MDF as a function of the morphology, the stellar mass and the radial distance. We use the stellar metallicity radial profiles retrieved as the first moment of the MDF, as an internal test for our method. The gradients in these …
We resolve spatially the star formation history of 300 nearby galaxies from the CALIFA integral field survey to investigate: a) the radial structure and gradients of the present stellar populations properties as a function of the Hubble type; and b) the role that plays the galaxy stellar mass and stellar mass surface density in governing the star formation history and metallicity enrichment of spheroids and the disks of galaxies. We apply the fossil record method based on spectral synthesis techniques to recover spatially and temporally resolved maps of stellar population properties of spheroi…
We use optical integral-field spectroscopic (IFS) data from 103 nearby galaxies at different stages of the merging event, from close pairs to merger remnants provided by the CALIFA survey, to study the impact of the interaction in the specific star formation and oxygen abundance on different galactic scales. To disentangle the effect of the interaction and merger from internal processes, we compared our results with a control sample of 80 non-interacting galaxies. We confirm the moderate enhancement (2-3 times) of specific star formation for interacting galaxies in central regions as reported …
We perform spatially resolved stellar population analysis for a sample of 69 early-type galaxies (ETGs) from the CALIFA integral field spectroscopic survey, including 48 ellipticals and 21 S0's. We generate and quantitatively characterize profiles of light-weighted mean stellar age and metallicity within $\lesssim 2R_e$, as a function of radius and stellar-mass surface density $μ_*$. We study in detail the dependence of profiles on galaxies' global properties, including velocity dispersion $σ_e$, stellar mass, morphology. ETGs are universally characterized by strong, negative metallicity gradi…
We present an updated version of the mass--metallicity relation (MZR) using integral field spectroscopy data obtained from 734 galaxies observed by the CALIFA survey. These unparalleled spatially resolved spectroscopic data allow us to determine the metallicity at the same physical scale ($\mathrm{R_{e}}$) for different calibrators. We obtain MZ relations with similar shapes for all calibrators, once the scale factors among them are taken into account. We do not find any significant secondary relation of the MZR with either the star formation rate (SFR) or the specific SFR for any of the calib…
While studies of gas-phase metallicity gradients in disc galaxies are common, very little has been done in the acquisition of stellar abundance gradients in the same regions. We present here a comparative study of the stellar metallicity and age distributions in a sample of 62 nearly face-on, spiral galaxies with and without bars, using data from the CALIFA survey. We measure the slopes of the gradients and study their relation with other properties of the galaxies. We find that the mean stellar age and metallicity gradients in the disc are shallow and negative. Furthermore, when normalized to…
Methods to recover the fossil record of galaxy evolution encoded in their optical spectra have been instrumental in processing the avalanche of data from mega-surveys along the last decade, effectively transforming observed spectra onto a long and rich list of physical properties: from stellar masses and mean ages to full star formation histories. This promoted progress in our understanding of galaxies as a whole. Yet, the lack of spatial resolution introduces undesirable aperture effects, and hampers advances on the internal physics of galaxies. This is now changing with 3D surveys. The mappi…
We analyze the spatially resolved star formation history of 300 nearby galaxies from the CALIFA integral field spectroscopic survey to investigate the radial structure and gradients of the present day stellar populations properties as a function of Hubble type and galaxy stellar mass. A fossil record method based on spectral synthesis techniques is used to recover spatially and temporally resolved maps of stellar population properties of spheroidal and spiral galaxies with masses $10^9$ to $7 \times 10^{11}$ M$_\odot$. The results show that galaxy-wide spatially averaged stellar population pro…
This work investigates the fundamental mechanism(s) that drive galaxy evolution in the Local Universe. By comparing two proxies of star-formation sensitive to different timescales, such as EW(H$α$) and colours like $g-r$, one may distinguish between smooth secular evolution (ageing) and sudden changes (quenching) on the recent star formation history of galaxies. Building upon the results obtained from a former study based on 80.000 SDSS single-fibre measurements, we now focus on spatially-resolved (on kpc scales) galaxies, comparing with a sample of 637 nearby objects observed by the CALIFA su…
Context: According to numerical simulations, stars are not always kept at their birth galactocentric distances but migrate. The importance of this radial migration in shaping galactic light distributions is still unclear. However, if it is indeed important, galaxies with different surface brightness (SB) profiles must display differences in their stellar population properties. Aims: We investigate the role of radial migration on the light distribution and the radial stellar content by comparing the inner colour, age and metallicity gradients for galaxies with different SB profiles. We define t…
We investigate the stellar population properties of passive spiral galaxies in the CALIFA survey. Nine spiral galaxies that have NUV-r > 5 and no/weak nebular emission lines in their spectra are selected as passive spirals. Our passive spirals lie in the redshift range of 0.001 < z < 0.021 and have stellar mass range of 10.2 < log(M_{\star}/M_{\odot}) < 10.8. They clearly lie in the domain of early-type galaxies in the WISE IR color-color diagram. We analyze the stellar populations out to two effective radius, using the best-fitting model to the measured absorption line-strength indices in the…
Helium is the second most common chemical species in the Universe. The study of helium abundance has the potential to unravel the chemical evolution of and within galaxies. In this study, we provide an empirical calibration for the singly ionized helium abundance: $12+\log_{10}({\rm He}^+/{\rm H}^+)$, based on the emission line flux ratio He$_{\lambda5876}$/H$α$ from Galactic and extragalactic HII regions compiled from the literature. Based on this calibrator, we explore for the first time the helium abundance in a large sample of HII regions located in galaxies representative of the nearby Un…
We study, for the first time in a statistically significant and well-defined sample, the relation between the outer-disk ionized-gas metallicity gradients and the presence of breaks in the surface brightness profiles of disk galaxies. SDSS g'- and r'-band surface brightness, (g'- r') color, and ionized-gas oxygen abundance profiles for 324 galaxies within the CALIFA survey are used for this purpose. We perform a detailed light-profile classification finding that 84% of our disks show down- or up-bending profiles (Type II and Type III, respectively) while the remaining 16% are well fitted by on…
We present here a brief summary of the status of the on-going CALIFA survey with an em- phasis on the results that have been recently published. In particular, we make a summary of the most relevant results found regarding the properties of Hii regions discovered using this survey, and the evidence uncovered for an inside-out growth of galaxies. In particular, we present an updated version of our results on the exploration of the Mass-Metallicity relation using spatial resolved information, with almost the double number of objects analysed, and an enlarged number of galaxies in the lower-mass …
We investigate the stellar population properties of bulges and disks separately for 34 S0s using integral field spectroscopy from the Calar Alto Legacy Integral Field Area survey. The spatially resolved stellar age and metallicity of bulge and disk components have been simultaneously estimated using the penalized pixel fitting method with photometrically defined weights for the two components. We find a tight correlation between age and metallicity for bulges, while the relation for disks has a larger scatter than that of bulges. This implies that the star formation histories of the disks are …
The metallicity of a supernova (SN) progenitor, together with its mass, is one of the main parameters that rules their outcome. We present a metallicity study of 115 nearby SN host galaxies (0.005<z<0.03) which hosted 142 SNe using Integral Field Spectroscopy (IFS) from the CALIFA survey. Using O3N2 we found no statistically significant differences between the gas-phase metallicities at the locations of the three main SN types (Ia, Ib/c and II) all having ~8.50$\pm$0.02 dex. The total galaxy metallicities are also very similar and we argue that this is because our sample consists only of SNe d…
Star clusters are known to have smaller intrinsic metallicity spreads than dwarf galaxies due to their shorter star formation timescales. Here we use individual spectroscopic [Fe/H] measurements of stars in 19 Local Group dwarf galaxies, 13 Galactic open clusters, and 49 globular clusters to show that star cluster and dwarf galaxy linear metallicity distributions are binomial in form, with all objects showing strong correlations between their mean linear metallicity $\bar{Z}$ and intrinsic spread in metallicity $σ(Z)^{2}$. A plot of $σ(Z)^{2}$ versus $\bar{Z}$ shows that the correlated relatio…
Chemical abundance variations in the ISM provide important information about the galactic evolution, star-formation and enrichment histories. Recent observations of disk galaxies suggest that if large-scale azimuthal metallicity variations appear in the ISM, they are linked to the spiral arms. In this work, using a set of chemodynamical simulations of the Milky Way-like spiral galaxies, we quantify the impact of gas radial motions~(migration) in the presence of a pre-existing radial metallicity gradient and the local ISM enrichment on both global and local variations of the mean ISM metallicit…
The Calar Alto Legacy Integral Field Area (CALIFA) survey, a pioneer in integral field spectroscopy legacy projects, has fostered many studies exploring the information encoded on the spatially resolved data on gaseous and stellar features in the optical range of galaxies. We describe a value-added catalogue of stellar population properties for CALIFA galaxies analysed with the spectral synthesis code STARLIGHT and processed with the PyCASSO platform. Our public data base (http://pycasso.ufsc.br/, mirror at http://pycasso.iaa.es/) comprises 445 galaxies from the CALIFA Data Release 3 with COMB…
This paper characterizes the radial structure of stellar population properties of galaxies in the nearby universe, based on 300 galaxies from the CALIFA survey. The sample covers a wide range of Hubble types, and galaxy stellar mass. We apply the spectral synthesis techniques to recover the stellar mass surface density, stellar extinction, light and mass-weighted ages, and mass-weighted metallicity, for each spatial resolution element in our target galaxies. To study mean trends with overall galaxy properties, the individual radial profiles are stacked in seven bins of galaxy morphology. We co…
We derive maps of the observed velocity of ionized gas, the oxygen abundance, and the extinction (Balmer decrement) across the area of the four spiral galaxies NGC36, NGC180, NGC6063, and NGC7653 from integral field spectroscopy obtained by the Calar Alto Legacy Integral Field Area (CALIFA) survey. We searched for spiral arms through Fourier analysis of the spatial distribution of three tracers (non-circular motion, enhancement of the oxygen abundance, and of the extinction) in the discs of our target galaxies. The spiral arms (two-armed logarithmic spirals in the deprojected map) are shown in…
Upcoming large-area narrow band photometric surveys, such as J-PAS, will enable us to observe a large number of galaxies simultaneously and efficiently. However, it will be challenging to analyse the spatially-resolved stellar populations of galaxies from such big data to investigate galaxy formation and evolutionary history. We have applied a convolutional neural network (CNN) technique, which is known to be computationally inexpensive once it is trained, to retrieve the metallicity and age from J-PAS-like narrow band images. The CNN was trained using mock J-PAS data created from the CALIFA I…
We characterize in detail the radial structure of the stellar population properties of 300 galaxies in the nearby universe, observed with integral field spectroscopy in the CALIFA survey. The sample covers a wide range of Hubble types, from spheroidal to spiral galaxies, ranging in stellar masses from $M_\star \sim 10^9$ to $7 \times 10^{11}$ $M_\odot$. We derive the stellar mass surface density ($μ_\star$), light-weighted and mass-weighted ages ($\langle {\rm log}\,age\rangle _L$, $\langle {\rm log}\,age\rangle _M$), and mass-weighted metallicity ($\langle {\rm log}\,Z_\star\rangle _M$), appl…
H ii regions in galaxies are the sites of star formation and thus particular places to understand the build-up of stellar mass in the universe. The line ratios of this ionized gas are frequently used to characterize the ionization conditions. We use the Hii regions catalogue from the CALIFA survey (~5000 H ii regions), to explore their distribution across the classical [OIII]/Hbeta vs. [NII]/Halpha diagnostic diagram, and how it depends on the oxygen abundance, ionization parameter, electron density, and dust attenuation. We compared the line ratios with predictions from photoionization models…
We incorporate new scale-intelligent models of metal-enriched star formation (\starss) with surrogate models of primordial stellar feedback (\starnet) into the astrophysics simulation code \enzo to analyze the impact of heterogeneous metal enrichment on the first galaxies. Our study includes the earliest generations of stars and the protogalaxies ($10^6 \lesssim M_v/M_\odot \lesssim 10^8$) containing them. We compare results obtained with the new methods to two common paradigms of metallicity initial conditions in simulations: ignoring the metallicity initial condition and assuming a uniform m…
We develop a model for stochastic pre-enrichment and self-enrichment in globular clusters (GCs) during their formation process. GCs beginning their formation have an initial metallicity determined by the pre-enrichment of their surrounding protocloud, but can also undergo internal self-enrichment during formation. Stochastic variations in metallicity arise because of the finite numbers of supernova. We construct an analytic formulation of the combined effects of pre-enrichment and self-enrichment and use Monte Carlo models to verify that the model accurately encapsulates the mean metallicity a…
We present interferometric CO observations made with the Combined Array for Millimeter-wave Astronomy (CARMA) of galaxies from the Extragalactic Database for Galaxy Evolution survey (EDGE). These galaxies are selected from the Calar Alto Legacy Integral Field Area (CALIFA) sample, mapped with optical integral field spectroscopy. EDGE provides good quality CO data (3$σ$ sensitivity $Σ_{\rm mol}$ $\sim$ 11 M$_\odot$ pc$^{-2}$ before inclination correction, resolution $\sim1.4$ kpc) for 126 galaxies, constituting the largest interferometric CO survey of galaxies in the nearby universe. We describ…
The production and distribution of metals in the diffuse intergalactic medium (IGM) have implications for galaxy formation models and the baryon (re)cycling process. The relative abundance of metals in high versus low-ionization states has also been argued to be sensitive to the Universe's reionization history. However, measurements of the background metallicity of the IGM at z~4 are sparse and in poor agreement with one another, and reduced sensitivity in the near-IR renders detecting individual metal absorbers nearly impossible. We present a new clustering-based technique that enables the de…
Galaxy evolution is generally affected by tidal interactions. Firstly, in this series, we reported several effects which suggest that tidal interactions contribute to regulating star formation (SF). To confirm that so, we now compare stellar mass assembly histories and SF look-back time annular profiles between CALIFA survey tidally and non-tidally perturbed galaxies. We pair their respective star-forming regions at the closest stellar mass surface densities to reduce the influence of stellar mass. The assembly histories and annular profiles show statistically significant differences so that h…
We investigate the colour-magnitude relation of metal-poor globular clusters, the 'blue tilt', in the Hydra and Centaurus galaxy clusters and constrain the primordial conditions for star cluster self-enrichment. We analyse U,I photometry for about 2500 globular clusters in the central regions of Hydra and Centaurus, based on FORS1@VLT data. We convert the measured colour-magnitude relations into mass-metallicity space and obtain a scaling of Z \propto M^{0.27 \pm 0.05} for Centaurus GCs and Z \propto M^{0.40 \pm 0.06} for Hydra GCs, consistent with results in other environments. We find that t…
We present an extended version of the spectral synthesis code STARLIGHT designed to incorporate both $λ$-by-$λ$ spectra and photometric fluxes in the estimation of stellar population properties of galaxies. The code is tested with simulations and data for 260 galaxies culled from the CALIFA survey, spatially matching the 3700--7000 Å optical datacubes to GALEX near and far UV images. The sample spans E--Sd galaxies with masses from $10^9$ to $10^{12} M_\odot$ and stellar populations all the way from star-forming to old, passive systems. Comparing results derived from purely optical fits with t…
The spatial variations of stellar population properties within a galaxy are intimately related to their formation process. Therefore, spatially resolved studies of galaxies are essential to uncover their formation and assembly. The Javalambre Photometric Local Universe Survey (J-PLUS) is a dedicated multi-filter designed to observed ~8500 deg2 using twelve narrow-, intermediate- and broad-band filters in the optical range. In this study, we test the potential of the multi-filter observation carried out with J-PLUS to investigate the properties of spatially-resolved nearby galaxies. We present …
We present different chemical evolution models for the ultrafaint dwarf galaxy Bootes I. We either assume that the galaxy accretes its mass through smooth infall of gas of primordial chemical composition (classical models) or adopt mass accretion histories derived from the combination of merger trees with semi-analytical modelling (cosmologically-motivated models). Furthermore, we consider models with and without taking into account inhomogeneous mixing in the ISM within the galaxy. The theoretical predictions are then compared to each other and to the body of the available data. From this ana…
We analyse the chemical properties of three z~8 galaxies behind the galaxy cluster SMACS J0723.3-7327, observed as part of the Early Release Observations programme of the James Webb Space Telescope (JWST). Exploiting [O III]4363 auroral line detections in NIRSpec spectra, we robustly apply the direct Te method for the very first time at such high redshift, measuring metallicities ranging from extremely metal poor (12+log(O/H)~7) to about one-third solar. We also discuss the excitation properties of these sources, and compare them with local strong-line metallicity calibrations. We find that no…
Nitrogen-Loud Quasars from the Dark Energy Spectroscopic Instrument. II. Broad-Line Region Metallicity and Relative Nitrogen Enrichment
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences（中国科学院空间应用工程与技术中心）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文学院）；Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所粒子天体物理重点实验室）
We explore the effect of AGN activity on the star formation history of galaxies by analysing the stellar population properties of ten pairs of nearby twin galaxies -- selected as being visually similar except for the presence of an AGN. The selection of such twin samples represents a method to study AGN feedback, as recently proposed by del Moral Castro et al. We use integral field unit (IFU) data from CALIFA, stacked within three fixed apertures. AGN galaxies in a twin pair suggest more evolved stellar populations than their non-AGN counterpart 90% of the time, regardless of aperture size. A …
We measure the star formation rate (SFR) per unit gas mass and the star formation efficiency (SFE$_{\rm gas}$ for total gas, SFE$_{\rm mol}$ for the molecular gas) in 81 nearby galaxies selected from the EDGE-CALIFA survey, using $^{12}$CO(J=1-0) and optical IFU data. For this analysis we stack CO spectra coherently by using the velocities of H$α$ detections to detect fainter CO emission out to galactocentric radii $r_{\rm gal} \sim 1.2 r_{25}$ ($\sim 3 R_{\rm e}$), and include the effects of metallicity and high surface densities in the CO-to-H$_2$ conversion. We determine the scale lengths f…
We present a summary of our project that studies galaxies hosting type Ia supernova (SN Ia) at different redshifts. We present Gran Telescopio de Canarias (GTC) optical spectroscopy of six SN Ia host galaxies at redshift $z\sim 0.4-0.5$. They are joined to a set of SN Ia host galaxies at intermediate-high redshift, which include galaxies from surveys SDSS and COSMOS. The final sample, after a selection of galaxy spectra in terms of signal-to-noise and other characteristics, consists of 680 galaxies with redshift in the range $0.04 < z < 1$. We perform an inverse stellar population synthesis wi…
We present the relation between the star formation rate surface density, $Σ_{\rm SFR}$, and the hydrostatic mid-plane pressure, P$_{\rm h}$, for 4260 star-forming regions of kpc size located in 96 galaxies included in the EDGE-CALIFA survey covering a wide range of stellar masses and morphologies. We find that these two parameters are tightly correlated, exhibiting smaller scatter and strong correlation in comparison to other star-forming scaling relations. A power-law, with a slightly sub-linear index, is a good representation of this relation. Locally, the residuals of this correlation show …
Linking the Metallicity Enrichment History to the Star Formation History: An SFH-regulated Chemical Evolution Model and Its Implications for the Gas Cycling Process
The disrupted chemical enrichment history of the Milky Way driven by gas accretion
South-Western Institute for Astronomy Research, Yunnan University（西南天文研究所，云南大学）；Yunnan Key Laboratory of Survey Science, Yunnan University（云南省测绘科学重点实验室，云南大学）；Department of Astronomy, Xiamen University（天文学系，厦门大学）；Institute of Astronomy, University of Cambridge（天文学研究所，剑桥大学）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（天文与空间科学学院，中国科学院大学）；National Astronomical Observatories, Chinese Academy of Sciences（国家天文台，中国科学院）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（天文与天体物理前沿研究院，北京师范大学）；Key Laboratory of Radio Astronomy and Technology, Chinese Academy of Sciences（射电天文与技术重点实验室，中国科学院）
We use Chandra X-ray data to measure the metallicity of the intracluster medium (ICM) in 245 massive galaxy clusters selected from X-ray and Sunyaev-Zel'dovich (SZ) effect surveys, spanning redshifts $0<z<1.2$. Metallicities were measured in three different radial ranges, spanning cluster cores through their outskirts. We explore trends in these measurements as a function of cluster redshift, temperature, and surface brightness "peakiness" (a proxy for gas cooling efficiency in cluster centers). The data at large radii (0.5--1 $r_{500}$) are consistent with a constant metallicity, while at int…
The combination of gas-phase oxygen abundances and stellar metallicities can provide us with unique insights into the metal enrichment histories of galaxies. In this work, we compare the stellar and gas-phase metallicities measured within a 1$R_{e}$ aperture for a representative sample of 472 star-forming galaxies extracted from the SAMI Galaxy Survey. We confirm that the stellar and interstellar medium (ISM) metallicities are strongly correlated, with scatter $\sim$3 times smaller than that found in previous works, and that integrated stellar populations are generally more metal-poor than the…
Shocks and torques produced by non-axisymmetric structures such as spiral arms and bars may transport gas to galaxy central regions. We test this hypothesis by studying the dependence of concentration of CO luminosity ($C_{CO}$), molecular gas ($C_{mol}$), and star formation rate ($C_{SFR}$) in central $\sim$ 2 kpc on the $strength$ of non-axisymmetric disk structure using a sample of 57 disk galaxies selected from the EDGE-CALIFA survey. $C_{mol}$ is calculated using a CO-to-H$_2$ conversion factor that decreases with higher metallicity and higher stellar surface density. We find that $C_{mol…
Detailed observations of globular clusters (GCs) have revealed evidence of self-enrichment: some of the heavy elements that we see in stars today were produced by cluster stars themselves. Moreover, GCs have internal subpopulations with different elemental abundances, including, in some cases, in elements such as iron that are produced by supernovae. This paper presents a theoretical model for GC formation motivated by observations of Milky Way star forming regions and simulations of star formation, where giant molecular clouds fragment into multiple clumps which undergo star formation at slig…
Gas flows play a fundamental role in galaxy formation and evolution, providing the fuel for the star formation process. These mechanisms leave an imprint in the amount of heavy elements. Thus, the analysis of this metallicity signature provides additional constraint on the galaxy formation scenario. We aim to discriminate between four different galaxy formation models based on two accretion scenarios and two different star formation recipes. We address the impact of a bimodal accretion scenario and a strongly regulated star formation recipe. We present a new extension of the eGalICS model, whi…
We present an empirical relation between the cold gas surface density ($Σ_{\rm gas}$) and the optical extinction (${\rm A_V}$) in a sample of 103 galaxies from the Extragalactic Database for Galaxy Evolution (EDGE) survey. This survey provides CARMA interferometric CO observations for 126 galaxies included in the Calar Alto Legacy Integral Field Area (CALIFA) survey. The matched, spatially resolved nature of these data sets allows us to derive the $Σ_{\rm gas}$-${\rm A_V}$ relation on global, radial, and kpc (spaxel) scales. We determine ${\rm A_V}$ from the Balmer decrement (H$α$/H$β$). We fi…
Observations have revealed massive (logM*/Msun>11) galaxies that were already dead when the universe was only ~2 Gyr. Given the short time before these galaxies were quenched, their past histories and quenching mechanism(s) are of particular interest. In this paper, we study star formation histories (SFHs) of 24 massive galaxies at 1.6<z<2.5. A deep slitless spectroscopy + imaging data set collected from multiple Hubble Space Telescope surveys allows robust determination of their spectral energy distributions and SFHs with no functional assumption on their forms. We find that most of our massi…
Rapid, out of equilibrium metal enrichment indicated by a flat mass-metallicity relation at z~6 from NIRCam grism spectroscopy
Institute of Science and Technology Austria（奥地利科学技术学院）；National Astronomical Observatory of Japan（日本国立天文台）；Astronomy Centre, University of Sussex（萨塞克斯大学天文学中心）；Department of Physics, North Carolina State University（北卡罗来纳州立大学物理系）；Institute for Computational & Data Sciences, The Pennsylvania State University（宾夕法尼亚州立大学计算与数据科学研究所）；Institute for Gravitation and the Cosmos, The Pennsylvania State University（宾夕法尼亚州立大学引力与宇宙学研究所）；Department of Astronomy, University of Wisconsin-Madison（威斯康星大学麦迪逊分校天文学系）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）
Radial migration is defined as the change in guiding centre radius of stars and gas caused by gains or losses of angular momentum that result from gravitational interaction with non-axisymmetric structure. This has been shown to have significant impact on the metallicity distribution in galactic discs, and therefore affects the interpretation of Galactic archeology. We use a simulation of a Milky Way-sized galaxy to examine the effect of radial migration on the star and gas radial metallicity distribution. We find that both the star and gas component show significant radial migration. The stel…
The fate of metals ejected by young OB associations into the Interstellar Medium (ISM) is investigated numerically. In particular, we study the enrichment of the cold gas phase, which is the material that forms molecular clouds. Following previous work, the expansion and collision of two supershells in a diffuse ISM is simulated, in this case also introducing an advected quantity which represents the metals expelled by the young stars. We adopt the simplest possible approach, not differentiating between metals coming from stellar winds and those coming from supernovae. Even though the hot, dif…
Lithium abundance in most of the warm metal-poor main sequence stars shows a constant plateau (A(Li)~2.2 dex) and then the upper envelope of the lithium vs. metallicity distribution increases as we approach solar metallicity. Meteorites, which carry information about the chemical composition of the interstellar medium at the solar system formation time, show a lithium abundance A(Li)~3.26 dex. This pattern reflects the Li enrichment history of the interstellar medium during the Galaxy lifetime. After the initial Li production in Big Bang Nucleosynthesis, the sources of the enrichment include A…
