Search

We apply a population-orbit superposition metho1d to 16 galaxies in the Fornax cluster observed with MUSE/VLT in the context of the Fornax3D project. By fitting the luminosity distribution, stellar kinematics, and age and metallicity maps simultaneously, we obtained the internal stellar orbit distribution, as well as the age and metallicity distribution of stars on different orbits for each galaxy. Based on the model, we decompose each galaxy into a dynamically cold disk (orbital circularity -z - 0:8) and a dynamically hot nondisk component (orbital circularity -z < 0:8), and obtain the surface-brightness, age, and metallicity radial profiles of each component. The galaxy infall time into the cluster is strongly correlated with galaxy cold-disk age with older cold disks in ancient infallers. We quantify the infall time tinfall of each galaxy with its cold-disk age using a correlation calibrated with TNG50 cosmological simulations. For galaxies in the Fornax cluster, we found that the luminosity fraction of cold disk in galaxies with tinfall > 8 Gyr are a factor of ~4 lower than in more recent infallers while controlling for total stellar mass. Nine of the 16 galaxies have spatially extended cold disks, and most of them show positive or zero age gradients; stars in the inner disk are ~2-5 Gyr younger than that in the outer disk, in contrast to the expectation of inside-out growth. Our results indicate that the assembly of cold disks in galaxies is strongly affected by their infall into clusters, by either removal of gas in outer regions or even tidally stripping or heating part of the pre-existing disks. Star formation in outer disks can stop quickly after the galaxy falls into the cluster, while star formation in the inner disks can last for a few Gyrs more, building the positive age gradient measured in cold disks. [ABSTRACT FROM AUTHOR]

We study the evolution of kinematically defined stellar discs in 10 Fornax-like clusters identified in the TNG50 run from the IllustrisTNG suite of cosmological simulations. We considered disc galaxies with present-day stellar mass M ⋆ ≥ 3 × 108 M⊙ and follow their evolution since first entering their host cluster. Very few stellar discs survive since falling in such dense environments, ranging from 40 per cent surviving to all being disrupted. Such survival rates are consistent with what reported earlier for the two more massive, Virgo-like clusters in TNG50. In absolute terms, however, the low number of present-day disc galaxies in Fornax-like clusters could be at odds with the presence of three edge-on disc galaxies in the central regions of the actual Fornax cluster, as delineated by the Fornax3D survey. When looking at the Fornax analogues from random directions and with the same selection function of Fornax3D, the probability of finding three edge-on disc galaxies in any one Fornax-like cluster in TNG50 is rather low, albeit not impossible. We also compared the stellar-population properties near the equatorial plane derived from integral-field spectroscopy for the three edge-ons in Fornax to similar line-of-sight integrated values for present-day disc galaxies in TNG50. For one of these, the very old and metal-rich stellar population of its disc cannot be matched by any the disc galaxies in TNG50, including objects in the field. We discuss possible interpretations of these findings, while pointing to future studies on passive cluster spirals as a way to further test state-of-the-art cosmological simulations. [ABSTRACT FROM AUTHOR]

Variations of the stellar initial mass function (IMF) in external galaxies have been inferred from a variety of independent probes. Yet the physical conditions causing these variations remain largely unknown. In this work, we explore new spatially resolved measurements of the IMF for three edge-on lenticular galaxies in the Fornax cluster. We utilize existing orbit-based dynamical models in order to fit the new IMF maps within an orbital framework. We find that, within each galaxy, the high-angular momentum disc-like stars exhibit an IMF which is rich in dwarf stars. The centrally concentrated pressure-supported orbits exhibit similarly dwarf-rich IMF. Conversely, orbits at large radius which have intermediate angular momentum exhibit IMF which are markedly less dwarf-rich relative to the other regions of the same galaxy. Assuming that the stars which reside, in the present-day, on dynamically hot orbits at large radii are dominated by accreted populations, we interpret these findings as a correlation between the dwarf-richness of a population of stars, and the mass of the host in which it formed. Specifically, deeper gravitational potentials would produce more dwarf-rich populations, resulting in the relative deficiency of dwarf stars which originated in the lower mass accreted satellites. The central and high-angular momentum populations are likely dominated by in situ stars, which were formed in the more massive host itself. There are also global differences between the three galaxies studied here, of up to ∼0.3 dex in the IMF parameter ξ. We find no local dynamical or chemical property which alone can fully account for the IMF variations. [ABSTRACT FROM AUTHOR]

Keywords: errata; addenda; galaxies: general; galaxies: statistics; galaxies: stellar content; galaxies: structure EN errata addenda galaxies: general galaxies: statistics galaxies: stellar content galaxies: structure 2746 2752 7 01/24/22 20220215 NES 220215 This is an erratum to the paper 'Resolving the age bimodality of galaxy stellar populations on kpc scales' (2017, MNRAS, 468, 1902-1916). Errata, addenda, galaxies: general, galaxies: statistics, galaxies: stellar content, galaxies: structure. [Extracted from the article]

The center of the Sagittarius dwarf spheroidal galaxy (Sgr dSph) hosts a nuclear star cluster (NSC), M54, which is the only galaxy nucleus that can be resolved into individual stars at optical wavelengths. It is thus a key target for understanding the formation of NSCs and their relation to globular clusters (GCs). We present a large Multi-Unit Spectroscopic Explorer data set that covers M54 out to ∼2.5 half-light radius, from which we extracted the spectra of ∼6600 cluster member stars. We use these data in combination with Hubble Space Telescope photometry to derive age and metallicity for each star. The stellar populations show a well-defined age–metallicity relation, implying an extended formation history for the central region of Sgr dSph. We classify these populations into three groups, all with the same systemic velocity: young metal-rich (YMR; 2.2 Gyr, [Fe/H] = −0.04); intermediate-age metal-rich (IMR; 4.3 Gyr, [Fe/H] = −0.29); and old metal-poor (OMP; 12.2 Gyr, [Fe/H] = −1.41). The YMR and OMP populations are more centrally concentrated than the IMR population, which are likely stars of the Sgr dSph. We suggest that the OMP population is the result of accretion and merging of two or more old and metal-poor GCs dragged to the center by dynamical friction. The YMR is consistent with being formed by in situ star formation in the nucleus. The ages of the YMR population suggest that it may have been triggered into forming when the Sgr dSph began losing its gas during the most recent interaction with the Milky Way, ∼3 Gyr ago. [ABSTRACT FROM AUTHOR]

The 31 brightest galaxies (mB ≤ 15 mag) inside the virial radius of the Fornax cluster were observed from the centres to the outskirts with the Multi Unit Spectroscopic Explorer on the Very Large Telescope. These observations provide detailed high-resolution maps of the line-of-sight kinematics, line strengths of the stars, ionised gas reaching 2–3 Re for 21 early-type galaxies, and 1–2 Re for 10 late-type galaxies. The majority of the galaxies are regular rotators, with eight hosting a kinematically distinct core. Only two galaxies are slow rotators. The mean age, total metallicity, and [Mg/Fe] abundance ratio in the bright central region inside 0.5 Re and in the galaxy outskirts are presented. Extended emission-line gas is detected in 13 galaxies, most of them are late-type objects with wide-spread star formation. The measured structural properties are analysed in relation to the galaxies' position in the projected phase space of the cluster. This shows that the Fornax cluster appears to consist of three main groups of galaxies inside the virial radius: the old core; a clump of galaxies, which is aligned with the local large-scale structure and was accreted soon after the formation of the core; and a group of galaxies that fell in more recently. [ABSTRACT FROM AUTHOR]

The stellar initial mass function (IMF) regulates the baryonic cycle within galaxies, and is a key ingredient for translating observations into physical quantities. Although it was assumed to be universal for decades, there is now growing observational evidence showing that the center of massive early-type galaxies hosts a larger population of low-mass stars than is expected based on observations from the Milky Way. Moreover, these variations in the IMF have been found to be related to radial metallicity variations in massive galaxies. We present here a two-dimensional stellar population analysis of the massive lenticular galaxy FCC 167 (NGC 1380) as part of the Fornax3D project. Using a newly developed stellar population fitting scheme, we derive a full two-dimensional IMF map of an early-type galaxy. This two-dimensional analysis allows us go further than a radial analysis, showing how the metallicity changes along a disk-like structure while the IMF follows a distinct, less disky distribution. Thus, our findings indicate that metallicity cannot be the sole driver of the observed radial IMF variations. In addition, a comparison with the orbital decomposition shows suggestive evidence of a coupling between stellar population properties and the internal dynamical structure of FCC 167, where metallicity and IMF maps seem to track the distribution of cold and warm orbits, respectively. [ABSTRACT FROM AUTHOR]

Nuclear star clusters hosted by dwarf galaxies exhibit similar characteristics to high-mass, metal complex globular clusters. This type of globular clusters could, therefore, be former nuclei from accreted galaxies. M54 resides in the photometric center of the Sagittarius dwarf galaxy, at a distance where resolving stars is possible. M54 offers the opportunity to study a nucleus before the stripping of their host by the tidal field effects of the Milky Way. We use a MUSE data set to perform a detailed analysis of over 6600 stars. We characterize the stars by metallicity, age, and kinematics, identifying the presence of three stellar populations: a young metal-rich (YMR), an intermediate-age metal-rich (IMR), and an old metal-poor (OMP). The evidence suggests that the OMP population is the result of accretion of globular clusters in the center of the host, while the YMR population was born in-situ in the center of the OMP population. [ABSTRACT FROM AUTHOR]

We have used deep MUSE observations to perform a stellar-kinematic and population analysis of FCC 153 and FCC 177, two edge-on S0 galaxies in the Fornax cluster. The geometrical definition of the different structural components of these two galaxies allows us to describe the nature of their thick disks. These are both old, relatively metal poor and [Mg/Fe]-enhanced, and their star formation history (SFH) reveals a minor younger component whose chemical properties suggest its later accretion. Moreover, the outer regions of these geometrically defined thick disks show higher values of metallicity and lower values of [Mg/Fe]. These stars probably formed in the thin-disk region and they were dynamically heated to form the flares present in these two galaxies. We propose different formation scenarios for the three populations of these thick disks: in-situ formation, accretion and disk heating. A clear distinction in age is found between the metal poor and [Mg/Fe]-enhanced thick disks (old, ∼12 − 13 Gyr), and the metal rich and less [Mg/Fe]-enhanced thin disks (young, ∼4 − 5 Gyr). These two galaxies show signs of relatively recent star formation in their thin disks and nuclear regions. While the thin disks show more continuous SFHs, the nuclei display a rather bursty SFH. These two galaxies are located outside of the densest region of the Fornax cluster where FCC 170 resides. This other edge-on S0 galaxy has recently been studied, and we have compared and discussed our results with this previous study. The differences between these three galaxies, at different distances from the cluster center, suggest that the environment can have a strong effect on the galaxy evolutionary path. [ABSTRACT FROM AUTHOR]

We present and discuss the stellar kinematics and populations of the S0 galaxy FCC 170 (NGC 1381) in the Fornax cluster, using deep MUSE data from the Fornax 3D survey. We show the maps of the first four moments of the stellar line-of-sight velocity distribution and of the mass-weighted mean stellar age, metallicity, and [Mg/Fe] abundance ratio. The high-quality MUSE stellar kinematic measurements unveil the structure of this massive galaxy: a nuclear disk, a bar seen as a boxy bulge with a clear higher-velocity-dispersion X shape, a fast-rotating and flaring thin disk and a slower rotating thick disk. Whereas their overall old age makes it difficult to discuss differences in the formation epoch between these components, we find a clear-cut distinction between metal-rich and less [Mg/Fe]-enhanced populations in the thin-disk, boxy-bulge and nuclear disk, and more metal-poor and [Mg/Fe]-enhanced stars in the thick disk. Located in the densest region of the Fornax cluster, where signs of tidal stripping have been recently found, the evolution of FCC 170 might have been seriously affected by its environment. We discuss the possibility of its "preprocessing" in a subgroup before falling into the present-day cluster, which would have shaped this galaxy a long time ago. The thick disk displays a composite star formation history, as a significant fraction of younger stars co-exist with the main older thick-disk population. The former subpopulation is characterized by even lower-metallicity and higher-[Mg/Fe] values, suggesting that these stars formed later and faster in a less chemically evolved satellite, which was subsequently accreted. Finally, we discuss evidence that metal-rich and less [Mg/Fe]-enhanced stars were brought in the outer parts of the thick disk by the flaring of the thin disk. [ABSTRACT FROM AUTHOR]

Galaxies continuously reprocess their interstellar material. We can therefore expect changing dust grain properties in galaxies that have followed different evolutionary pathways. Determining the intrinsic dust grain mix of a galaxy helps in reconstructing its evolutionary history. Early-type galaxies occasionally display regular dust lanes in their central regions. Owing to the relatively simple geometry and composition of their stellar bodies, these galaxies are ideal to disentangle dust mix variations from geometric effects. We therefore modelled the various components of such a galaxy (FCC 167). We reconstructed its recent history and investigated the possible fate of the dust lane. Observations from MUSE and the Atacama Large Millimeter/submillimeter Array (ALMA) reveal a nested interstellar medium structure. An ionised-gas disc pervades the central regions of FCC 167, including those occupied by the main dust lane. Inward of the dust lane, we also find a disc/ring of cold molecular gas where stars are forming and HII regions contribute to the ionised-gas emission. Further in, the gas ionisation points towards an active galactic nucleus and the fuelling of a central supermassive black hole from its surrounding ionised and molecular reservoir. Observational constraints and radiative transfer models suggest the dust and gas are distributed in a ring-like geometry and the dust mix lacks small grains. The derived dust destruction timescales from sputtering in hot gas are short, and we conclude that the dust must be strongly self-shielding and clumpy or will quickly be eroded and disappear. Our findings show how detailed analyses of individual systems can complement statistical studies of dust-lane ETGs. [ABSTRACT FROM AUTHOR]

The stellar velocity ellipsoid (SVE) in galaxies can provide important information on the processes that participate in the dynamical heating of their disc components (e.g. giant molecular clouds, mergers, spiral density waves, and bars). Earlier findings suggested a strong relation between the shape of the disc SVE and Hubble type, with later-type galaxies displaying more anisotropic ellipsoids and early types being more isotropic. In this paper, we revisit the strength of this relation using an exhaustive compilation of observational results from the literature on this issue. We find no clear correlation between the shape of the disc SVE and morphological type, and show that galaxies with the same Hubble type display a wide range of vertical-toradial velocity dispersion ratios. The points are distributed around a mean value and scatter of σz/σ R =0.7±0.2.With the aid of numerical simulations, we argue that different mechanisms might influence the shape of the SVE in the same manner and that the same process (e.g. mergers) does not have the same impact in all the galaxies. The complexity of the observational picture is confirmed by these simulations, which suggest that the vertical-to-radial axis ratio of the SVE is not a good indicator of the main source of disc heating. Our analysis of those simulations also indicates that the observed shape of the disc SVE may be affected by several processes simultaneously and that the signatures of some of them (e.g. mergers) fade over time. [ABSTRACT FROM AUTHOR]

Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal of this Letter is to determine if the mass assembly of the different components leaves an imprint in their stellar populations allowing the estimation the time of bar formation and its evolution. To this aim, we use integral field spectroscopy to derive the stellar age distributions, SADs, along the bar and disc of NGC 6032. The analysis clearly shows different SADs for the different bar areas. There is an underlying old (≥12 Gyr) stellar population for the whole galaxy. The bulge shows star formation happening at all times. The inner bar structure shows stars of ages older than 6 Gyr with a deficit of younger populations. The outer bar region presents an SAD similar to that of the disc. To interpret our results, we use a generic numerical simulation of a barred galaxy. Thus, we constrain, for the first time, the epoch of bar formation, the buckling instability period and the posterior growth from disc material. We establish that the bar of NGC 6032 is old, formed around 10 Gyr ago while the buckling phase possibly happened around 8 Gyr ago. All these results point towards bars being long-lasting even in the presence of gas. [ABSTRACT FROM AUTHOR]

Context. According to numerical simulations, stars are not always kept at their birth galactocentric distances but they have a tendency to migrate. The importance of this radial migration in shaping galactic light distributions is still unclear. However, if radial migration 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 in the light distribution and radial stellar content by comparing the inner colour, age, and metallicity gradients for galaxies with different SB profiles. We define these inner parts, avoiding the bulge and bar regions and up to around three disc scale lengths (type I, pure exponential) or the break radius (type II, downbending; type III, upbending). Methods. We analysed 214 spiral galaxies from the CALIFA survey covering different SB profiles. We made use of GASP2D and SDSS data to characterise the light distribution and obtain colour profiles of these spiral galaxies. The stellar age and metallicity profiles were computed using a methodology based on full-spectrum fitting techniques (pPXF, GANDALF, and STECKMAP) to the Integral Field Spectroscopic CALIFA data. Results. The distributions of the colour, stellar age, and stellar metallicity gradients in the inner parts for galaxies displaying different SB profiles are unalike as suggested by Kolmogorov-Smirnov and Anderson-Darling tests. We find a trend in which type II galaxies show the steepest profiles of all, type III show the shallowest, and type I display an intermediate behaviour. Conclusions. These results are consistent with a scenario in which radial migration is more efficient for type III galaxies than for type I systems, where type II galaxies present the lowest radial migration efficiency. In such a scenario, radial migration mixes the stellar content, thereby flattening the radial stellar properties and shaping different SB profiles. However, in light of these results we cannot further quantify the importance of radial migration in shaping spiral galaxies, and other processes, such as recent star formation or satellite accretion, might play a role. [ABSTRACT FROM AUTHOR]

Galaxies in the local Universe are known to follow bimodal distributions in the global stellar population properties. We analyse the distribution of the local average stellar population ages of 654 053 sub-galactic regions resolved on ~1 kpc scales in a volume-corrected sample of 394 galaxies, drawn from the Calar Alto Legacy Integral Field Area (CALIFA) DR3 integral-field-spectroscopy survey and complemented by Sloan Digital Sky Survey (SDSS) imaging. We find a bimodal local-age distribution, with an old and a young peak primarily due to regions in early-type galaxies and star-forming regions of spirals, respectively. Within spiral galaxies, the older ages of bulges and interarm regions relative to spiral arms support an internal age bimodality. Although regions of higher stellar mass surface density, μ*, are typically older, μ* alone does not determine the stellar population age and a bimodal distribution is found at any fixed μ*. We identify an 'old ridge' of regions of age ~9 Gyr, independent of μ*, and a 'young sequence' of regions with age increasing with μ* from 1-1.5 to 4-5 Gyr. We interpret the former as regions containing only old stars, and the latter as regions where the relative contamination of old stellar populations by young stars decreases as μ* increases. The reason why this bimodal age distribution is not inconsistent with the unimodal shape of the cosmic-averaged star formation history is that (i) the dominating contribution by young stars biases the age low with respect to the average epoch of star formation, and (ii) the use of a single average age per region is unable to represent the full time extent of the star formation history of 'young sequence' regions. [ABSTRACT FROM AUTHOR]

In a previous paper, we assembled a collection of medium-resolution spectra of 35 carbon stars, covering optical and near-infrared wavelengths from 400 to 2400 nm. The sample includes stars from the Milky Way and the Magellanic Clouds, with a variety of (J - Ks) colors and pulsation properties. In the present paper, we compare these observations to a new set of high-resolution synthetic spectra, based on hydrostatic model atmospheres. We find that the broad-band colors and the molecular-band strengths measured by spectrophotometric indices match those of the models when (J - Ks) is bluer than about 1.6, while the redder stars require either additional reddening or dust emission or both. Using a grid of models to fit the full observed spectra, we estimate the most likely atmospheric parameters Teff, log(g), [Fe/H] and C/O. These parameters derived independently in the optical and near-infrared are generally consistent when (J - Ks) < 1.6. The temperatures found based on either wavelength range are typically within ±100 K of each other, and log(g) and [Fe/H] are consistent with the values expected for this sample. The reddest stars ((J - Ks) > 1.6) are divided into two families, characterized by the presence or absence of an absorption feature at 1.53 μm, generally associated with HCN and C2H2. Stars from the first family begin to be more affected by circumstellar extinction. The parameters found using optical or near-infrared wavelengths are still compatible with each other, but the error bars become larger. In stars showing the 1.53 μm feature, which are all large-amplitude variables, the effects of pulsation are strong and the spectra are poorly matched with hydrostatic models. For these, atmospheric parameters could not be derived reliably, and dynamical models are needed for proper interpretation. [ABSTRACT FROM AUTHOR]

In this Paper, we describe how we use stellar dynamics information to constrain the shape of the stellar initial mass function (IMF) in a sample of 27 early-type galaxies from the CALIFA survey.We obtain dynamical and stellar mass-to-light ratios, ♈dyn and ♈*, over a homogenous aperture of 0.5 Re.We use the constraint♈dyn ♈* to test two IMF shapes within the framework of the extended MILES stellar population models. We rule out a single power-law IMF shape for 75 per cent of the galaxies in our sample. Conversely, we find that a double power-law IMF shape with a varying high-mass end slope is compatible (within 1σ) with 95 per cent of the galaxies. We also show that dynamical and stellar IMF mismatch factors give consistent results for the systematic variation of the IMF in these galaxies. [ABSTRACT FROM AUTHOR]

Deep observations of the dwarf elliptical (dE) galaxy NGC 1396 (MV = -16.60, Mass ∼4 × 108 M☉), located in the Fornax cluster, have been performed with the Very Large Telescope/Multi Unit Spectroscopic Explorer spectrograph in the wavelength region from 4750 to 9350 Å. In this paper, we present a stellar population analysis studying chemical abundances, the star formation history (SFH) and the stellar initial mass function (IMF) as a function of galactocentric distance. Different, independent ways to analyse the stellar populations result in a luminosity-weighted age of ∼6 Gyr and a metallicity [Fe/H]∼ -0.4, similar to other dEs of similar mass.We find unusually overabundant values of [Ca/Fe]∼+0.1, and underabundant Sodium, with [Na/Fe] values around -0.1, while [Mg/Fe] is overabundant at all radii, increasing from ∼+ 0.1 in the centre to ∼+ 0.2 dex. We notice a significant metallicity and age gradient within this dwarf galaxy. To constrain the stellar IMF of NGC 1396, we find that the IMF of NGC 1396 is consistent with either a Kroupa-like or a topheavy distribution, while a bottom-heavy IMF is firmly ruled out. An analysis of the abundance ratios, and a comparison with galaxies in the Local Group, shows that the chemical enrichment history of NGC 1396 is similar to the Galactic disc, with an extended SFH. This would be the case if the galaxy originated from a Large Magellanic Cloud-sized dwarf galaxy progenitor, which would lose its gas while falling into the Fornax cluster. [ABSTRACT FROM AUTHOR]

The CALIFA team has recently found that the stellar angular momentum and concentration of late-type spiral galaxies are incompatible with those of lenticular galaxies (S0s), concluding that fading alone cannot satisfactorily explain the evolution from spirals into S0s. Here we explore whether major mergers can provide an alternative way to transform spirals into S0s by analysing the spiral-spiral major mergers from the GalMer database that lead to realistic, relaxed S0-like galaxies. We find that the change in stellar angular momentum and concentration can explain the differences in the λRe-R90/R50 plane found by the CALIFA team. Major mergers thus offer a feasible explanation for the transformation of spirals into S0s. [ABSTRACT FROM AUTHOR]

This paper describes the Second Public Data Release (DR2) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. The data for 200 objects are made public, including the 100 galaxies of the First Public Data Release (DR1). Data were obtained with the integral-field spectrograph PMAS/PPak mounted on the 3.5 m telescope at the Calar Alto observatory. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the wavelength range 3745-7500 Å with a spectral resolution of 6.0 Å (FWHM); and (ii) a medium-resolution V1200 setup covering the wavelength range 3650-4840 Å with a spectral resolution of 2.3 Å (FWHM). The sample covers a redshift range between 0.005 and 0.03, with a wide range of properties in the color-magnitude diagram, stellar mass, ionization conditions, and morphological types. All the cubes in the data release were reduced with the latest pipeline, which includes improved spectrophotometric calibration, spatial registration, and spatial resolution. The spectrophotometric calibration is better than 6% and the median spatial resolution is 2". 004. In total, the second data release contains over 1.5 million spectra. [ABSTRACT FROM AUTHOR]

Context. Ionized gas kinematics provide important clues to the dynamical structure of galaxies and hold constraints to the processes driving their evolution. Aims. The motivation of this work is to provide an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of the CALIFA survey for including kinematical criteria in their selection of targets for specific studies. From the first 200 galaxies observed by CALIFA survey in its two configurations, we present the two-dimensional kinematic view of the 177 galaxies satisfaying a gas content/detection threshold. Methods. After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component for each spectrum in the CALIFA data cubes for different emission lines (namely, [O ii] λλ3726, 3729, [OIII] λλ4959, 5007, Hα+[N II] λλ6548, 6584, and [SII]λλ6716, 6730). The main kinematic parameters measured on the plane of the sky were directly derived from the radial velocities with no assumptions on the internal prevailing motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [OIII] λλ4959, 5007 emission line profiles. Results. At the velocity resolution of CALIFA, most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. Thirty-five percent of the objects present evidence of a displacement between the photometric and kinematic centers larger than the original spaxel radii. Only 17% of the objects in the sample exhibit kinematic lopsidedness when comparing receding and approaching sides of the velocity fields, but most of them are interacting galaxies exhibiting nuclear activity (AGN or LINER). Early-type (E+S0) galaxies in the sample present clear photometric-kinematic misaligments. There is evidence of asymmetries in the emission line profiles in 117 out of the 177 analyzed galaxies, suggesting the presence of kinematically distinct gaseous components located at different distances from the optical nucleus. The kinematic decoupling between the dominant and secondary component/s suggested by the observed asymmetries in the profiles can be characterized by a limited set of parameters. Conclusions. This work constitutes the first determination of the ionized gas kinematics of the galaxies observed in the CALIFA survey. The derived velocity fields, the reported kinematic distortions/peculiarities and the identification of the presence of several gaseous components in different regions of the objects might be used as additional criteria for selecting galaxies for specific studies. [ABSTRACT FROM AUTHOR]

We present 80 stellar and ionised gas velocity maps from the Calar Alto Legacy Integral Field Area (CALIFA) survey in order to characterise the kinematic orientation of non-interacting galaxies. The study of galaxies in isolation is a key step towards understanding how fast-external processes, such as major mergers, affect kinematic properties in galaxies. We derived the global and individual (projected approaching and receding sides) kinematic position angles (PAs) for both the stellar and ionised gas line-of-sight velocity distributions. When compared to the photometric PA, we find that morpho-kinematic differences are smaller than 22 degrees in 90% of the sample for both stellar and nebular components and that internal kinematic misalignments are generally smaller than 16 degrees. We find a tight relation between the global stellar and ionised gas kinematic PA consistent with circular-flow pattern motions in both components (~90% of the sample has differences smaller than 16 degrees). This relation also holds, generally in barred galaxies across the bar and galaxy disc scales. Our findings suggest that even in the presence of strong bars, both the stellar and the gaseous components tend to follow the gravitational potential of the disc. As a result, kinematic orientation can be used to assess the degree of external distortions in interacting galaxies. [ABSTRACT FROM AUTHOR]

We have studied the radial structure of the stellar mass surface density (μ*) and stellar population age as a function of the total stellar mass and morphology for a sample of 107 galaxies from the CALIFA survey. We applied the fossil record method based on spectral synthesis techniques to recover the star formation history (SFH), resolved in space and time, in spheroidal and disk dominated galaxies with masses from 109 to 1012 M☉. We derived the half-mass radius, and we found that galaxies are on average 15% more compact in mass than in light. The ratio of half-mass radius to half-light radius (HLR) shows a dual dependence with galaxy stellar mass; it decreases with increasing mass for disk galaxies, but is almost constant in spheroidal galaxies. In terms of integrated versus spatially resolved properties, we find that the galaxy-averaged stellar population age, stellar extinction, and μ* are well represented by their values at 1 HLR. Negative radial gradients of the stellar population ages are present in most of the galaxies, supporting an inside-out formation. The larger inner (⩽1 HLR) age gradients occur in the most massive (1011 M☉) disk galaxies that have the most prominent bulges; shallower age gradients are obtained in spheroids of similar mass. Disk and spheroidal galaxies show negative μ* gradients that steepen with stellar mass. In spheroidal galaxies, μ* saturates at a critical value (~7☉×102 M/pc2 at 1 HLR) that is independent of the galaxy mass. Thus, all the massive spheroidal galaxies have similar local μ at the same distance (in HLR units) from the nucleus. The SFH of the regions beyond 1 HLR are well correlated with their local μ*, and follow the same relation as the galaxy-averaged age and μ*; this suggests that local stellar mass surface density preserves the SFH of disks. The SFH of bulges are, however, more fundamentally related to the total stellar mass, since the radial structure of the stellar age changes with galaxy mass even though all the spheroid dominated galaxies have similar radial structure in μ*. Thus, galaxy mass is a more fundamental property in spheroidal systems, while the local stellar mass surface density is more important in disks. [ABSTRACT FROM AUTHOR]

Context. Galaxies, which often contain ionised gas, sometimes also exhibit a so-called low-ionisation nuclear emission line region (LINER). For 30 years, this was attributed to a central mass-accreting supermassive black hole (more commonly known as active galactic nucleus, AGN) of low luminosity, making LINER galaxies the largest AGN sub-population, which dominate in numbers over higher luminosity Seyfert galaxies and quasars. This, however, poses a serious problem. While the inferred energy balance is plausible, many LINERs clearly do not contain any other independent signatures of an AGN. Aims. Using integral field spectroscopic data from the CALIFA survey, we compare the observed radial surface brightness profiles with what is expected from illumination by an AGN. Methods. Essential for this analysis is a proper extraction of emission lines, especially weak lines, such as Balmer Hβ lines, which are superposed on an absorption trough. To accomplish this, we use the GANDALF code, which simultaneously fits the underlying stellar continuum and emission lines. Results. For 48 galaxies with LINER-like emission, we show that the radial emission-line surface brightness profiles are inconsistent with ionisation by a central point-source and hence cannot be due to an AGN alone. Conclusions. The most probable explanation for the excess LINER-like emission is ionisation by evolved stars during the short but very hot and energetic phase known as post-AGB. This leads us to an entirely new interpretation. Post-AGB stars are ubiquitous and their ionising effect should be potentially observable in every galaxy with the gas present and with stars older than ∼1 Gyr unless a stronger radiation field from young hot stars or an AGN outshines them. This means that galaxies with LINER-like emission are not a class defined by a property but rather by the absence of a property. It also explains why LINER emission is observed mostly in massive galaxies with old stars and little star formation [ABSTRACT FROM AUTHOR]

We present the first public data release (DR1) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. It consists of science-grade optical datacubes for the first 100 of eventually 600 nearby (0:005 < z < 0:03) galaxies, obtained with the integral-field spectrograph PMAS/PPak mounted on the 3.5 m telescope at the Calar Alto observatory. The galaxies in DR1 already cover a wide range of properties in color-magnitude space, morphological type, stellar mass, and gas ionization conditions. This offers the potential to tackle a variety of open questions in galaxy evolution using spatially resolved spectroscopy. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the nominal wavelength range 3745-7500 Å with a spectral resolution of 6.0 Å (FWHM), and (ii) a medium-resolution V1200 setup covering the nominal wavelength range 3650-4840 Å with a spectral resolution of 2.3 Å (FWHM). We present the characteristics and data structure of the CALIFA datasets that should be taken into account for scientific exploitation of the data, in particular the effects of vignetting, bad pixels and spatially correlated noise. The data quality test for all 100 galaxies showed that we reach a median limiting continuum sensitivity of 1.0 x 10-18 erg s-1 cm-2 Å-1 arcsec-2 at 5635 Å and 2.2 x 10-18 erg s-1 cm-2 Å-1 arcsec-2 at 4500 Å for the V500 and V1200 setup respectively, which corresponds to limiting r and g band surface brightnesses of 23:6 mag arcsec-2 and 23:4 mag arcsec??2, or an unresolved emission-line flux detection limit of roughly 1 × 10-17 erg s-1 cm-2 arcsec-2 and 0:6 x 10-17 erg s-1 cm-2 arcsec-2, respectively. The median spatial resolution is 3″,7, and the absolute spectrophotometric calibration is better than 15% (1σ). We also describe the available interfaces and tools that allow easy access to this first public CALIFA data at http://califa.caha.es/DR1. [ABSTRACT FROM AUTHOR]

Context. The rest-frame near-IR spectra of intermediate age (1-2 Gyr) stellar populations are dominated by carbon based absorption features offering a wealth of information. Yet, spectral libraries that include the near-IR wavelength range do not sample a sufficiently broad range of ages and metallicities to allow for accurate calibration of stellar population models and thus the interpretation of the observations. Aims. In this paper we investigate the integrated J- and H-band spectra of six intermediate age and old globular clusters in the Large Magellanic Cloud (LMC). Methods. The observations for six clusters were obtained with the SINFONI integral field spectrograph at the ESO VLT Yepun telescope, covering the J (1.09-1.41 μm) and H-band (1.43-1.86 μm) spectral range. The spectral resolution is 6.7Å in J and 6.6Å in H-band (FWHM). The observations were made in natural seeing, covering the central 24" × 24" of each cluster and in addition sampling the brightest eight red giant branch and asymptotic giant branch (AGB) star candidates within the clusters' tidal radii. Targeted clusters cover the ages of ∼1.3Gyr (NGC1806, NGC2162), 2Gyr (NGC2173) and ∼13Gyr (NGC 1754, NGC 2005, NGC2019). Results. H-band C2 and K-band 12CO(2-0) feature strengths for the LMC globular clusters are compared to the models of Maraston (2005). C2 is reasonably well reproduced by the models at all ages, while 12CO(2-0) shows good agreement for older (age ⩾ 2 Gyr) populations, but the younger (1.3 Gyr) globular clusters do not follow the models. We argue that this is due to the fact that the empirical calibration of the models relies on only a fewMilkyWay carbon star spectra, which show different 12CO(2-0) index strengths than the LMC stars. The C2 absorption feature strength correlates strongly with age. It is present essentially only in populations that have 1-2Gyr old stars, while its value is consistent with zero for older populations. The distinct spectral energy distribution observed for the intermediate age globular clusters in the J- and H-bands agrees well with the model predictions of Maraston for the contribution from the thermally pulsing AGB phase. Conclusions. In this pilot project we present an empirical library of six LMC globular cluster integrated near-IR spectra that are useful for testing stellar population models in this wavelength regime. We show that the H-band C2 absorption feature and the J-, H-band spectral shape can be used as an age indicator for intermediate age stellar populations in integrated spectra of star clusters and galaxies. [ABSTRACT FROM AUTHOR]

NGC 2146, a nearby luminous infrared galaxy, presents evidence for outflows along the disk minor axis in all gas phases (ionized, neutral atomic, and molecular). We present an analysis of the multi-phase, starburst-driven superwind in the central 5 kpc as traced in spatially resolved spectral line observations, using far-IR Herschel PACS spectroscopy, to probe the effects on the atomic and ionized gas, and optical integral field spectroscopy to examine the ionized gas through diagnostic line ratios. We observe an increased ∼250 km s–1 velocity dispersion in the [O I] 63 μm, [O III] 88 μm, [N II] 122 μm, and [C II] 158 μm fine-structure lines that is spatially coincident with high excitation gas above and below the disk. We model this with a slow ∼200 km s–1 shock and trace the superwind to the edge of our field of view 2.5 kpc above the disk. We present new SOFIA 37 μm observations to explore the warm dust distribution, and detect no clear dust entrainment in the outflow. The stellar kinematics appear decoupled from the regular disk rotation seen in all gas phases, consistent with a recent merger event disrupting the system. We consider the role of the superwind in the evolution of NGC 2146 and speculate on the evolutionary future of the system. Our observations of NGC 2146 in the far-IR allow an unobscured view of the wind, crucial for tracing the superwind to the launching region at the disk center, and provide a local analog for future ALMA observations of outflows in high-redshift systems. [ABSTRACT FROM AUTHOR]