The final product of galaxy evolution through cosmic time is the population of galaxies in the local universe. These galaxies are also those that can be studied in most detail, thus providing a stringent benchmark for our understanding of galaxy evolution. Through the huge success of spectroscopic single-fiber, statistical surveys of the Local Universe in the last decade, it has become clear, however, that an authoritative observational description of galaxies will involve measuring their spatially resolved properties over their full optical extent for a statistically significant sample. We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction. We summarize the survey goals and design, including sample selection and observational strategy. We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data. This survey is obtaining spatially resolved spectroscopic information of a diameter selected sample of ∼600 galaxies in the Local Universe (0.005 < z < 0.03). CALIFA has been designed to allow the building of two-dimensional maps of the following quantities: (a) stellar populations: ages and metallicities; (b) ionized gas: distribution, excitation mechanism and chemical abundances; and (c) kinematic properties: both from stellar and ionized gas components. CALIFA uses the PPAK integral field unit (IFU), with a hexagonal field-of-view of ∼1.3 , with a 100% covering factor by adopting a three-pointing dithering scheme. The optical wavelength range is covered from 3700 to 7000 Å, using two overlapping setups (V500 and V1200), with different resolutions: R ∼ 850 and R ∼ 1650, respectively. CALIFA is a legacy survey, intended for the community. The reduced data will be released, once the quality has been guaranteed. The analyzed data fulfill the expectations of the original observing proposal, on the basis of a set of quality checks and exploratory analysis: (i) the final datacubes reach a 3σ limiting surface brightness depth of ∼23.0 mag/arcsec 2 for the V500 grating data (∼22.8 mag/arcsec 2 for V1200); (ii) about ∼70% of the covered field-of-view is above this 3σ limit; (iii) the data have a blue-to-red relative flux calibration within a few percent in most of the wavelength range; (iv) the absolute flux calibration is accurate within ∼8% with respect to SDSS; (v) the measured spectral resolution is ∼85 km s −1 for V1200 (∼150 km s −1 for V500); (vi) the estimated accuracy of the wavelength calibration is ∼5 km s −1 for the V1200 data (∼10 km s −1 for the V500 data); (vii) the aperture matched CALIFA and SDSS spectra are qualitatively and quantitatively similar. Finally, we show that we are able to carry out all measurements indicated above, recovering the properties of the stellar populations, the ionized gas and the kinematics of both components. The associated maps illustrate the spatial variation of...

We studied the global and local M-Z relation based on the first data available from the CALIFA survey (150 galaxies). This survey provides integral field spectroscopy of the complete optical extent of each galaxy (up to 2−3 effective radii), with a resolution high enough to separate individual H ii regions and/or aggregations. About 3000 individual H ii regions have been detected. The spectra cover the wavelength range between [OII]3727 and [SII]6731, with a sufficient signal-to-noise ratio to derive the oxygen abundance and star-formation rate associated with each region. In addition, we computed the integrated and spatially resolved stellar masses (and surface densities) based on SDSS photometric data. We explore the relations between the stellar mass, oxygen abundance and star-formation rate using this dataset. We derive a tight relation between the integrated stellar mass and the gas-phase abundance, with a dispersion lower than the one already reported in the literature (σ Δlog (O/H) = 0.07 dex). Indeed, this dispersion is only slightly higher than the typical error derived for our oxygen abundances. However, we found no secondary relation with the star-formation rate other than the one induced by the primary relation of this quantity with the stellar mass. The analysis for our sample of ∼3000 individual H ii regions confirms (i) a local mass-metallicity relation and (ii) the lack of a secondary relation with the star-formation rate. The same analysis was performed with similar results for the specific star-formation rate. Our results agree with the scenario in which gas recycling in galaxies, both locally and globally, is much faster than other typical timescales, such like that of gas accretion by inflow and/or metal loss due to outflows. In essence, late-type/disk-dominated galaxies seem to be in a quasi-steady situation, with a behavior similar to the one expected from an instantaneous recycling/closed-box model.

VLT spectra of 14 luminous compact galaxies (LCGs) reveal strong metallic absorption line sytems as well as narrow and intense emission lines. Their gas extinction is found to be large (A V ∼ 1.5 mag) leading to an upward revision of their star formation rate (SFR) to an average value of ∼ 40 M ⊙ yr −1 . Large extinction values are also supported by the large rate of detection in one field observed by ISO. Gas metal abundances in LCGs have about half the solar value. LCG absorption spectra can be synthesized with a mix of a few Gyr old and relatively metal-rich (generally solar to over-solar values) stellar population and a younger stellar population (< 5×10 8 years) having a metal abundance similar to that of the gas.We argue that LCGs are the progenitors of present-day spiral bulges. LCGs have masses and light concentrations similar to those of present-day bulges. They could have been formed entirely during a period of a few Gyr prior to the epoch of their observations if the star formation has been sustained at the observed rate. As in present-day galactic bulges, LCG stars show a wide range of abundances. Thus, observing LCGs allows us to directly witness an important stage in the formation of a massive galaxy, the building of the bulge prior to that of the disk. The gas needed to feed the observed star formation is likely to be falling in from the outskirts of the galaxy, being tidally pulled out from interacting companion galaxies. An infall scenario naturally explains the gas metal abundance which is generally lower than that of the older stellar component. At least for the strongest star-forming LCGs, there is clear imaging evidence for the presence of companions. Some LCGs also show evidence for the beginning of a disk formation. If the above scenario holds for most LCGs, we estimate that at least 20% of present-day spiral galaxies have formed the bulk of their stars at relatively recent epochs, during the last 8-9 Gyr, at redshifts less than ∼ 1. Since they are heavily extincted, we predict their IR luminosities to be relatively large, around L IR =10 11 L ⊙ , i.e. near or slightly below the luminosities of the galaxies detected by ISO in the same redshift range. Taking into account the integrated IR luminosity of the LCG galaxy population can lead to a significant upward revision of the cosmic SFR density in the redshift range from 0.5 to 1.

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 × 10 −18 erg s −1 cm −2 Å −1 arcsec −2 at 5635 Å and 2.2 × 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 × 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.

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Abstract. We present a study of the star formation rate (SFR) for a sample of 16 distant galaxies detected by ISOCAM at 15 µm in the CFRS0300+00 and CFRS1400+52 fields. Their high quality and intermediate resolution VLT/FORS spectra have allowed a proper correction of the Balmer emission lines from the underlying absorption. Extinction estimates using the Hβ/Hγ and the Hα/Hβ Balmer decrement are in excellent agreement, providing a robust measurement of the instantaneous SFR based on the extinction-corrected Hα luminosity. Star formation has also been estimated exploiting the correlations between IR luminosity and those at MIR and radio wavelengths. Our study shows that the relationship between the two SFR estimates follow two distinct regimes: (1) for galaxies with SFR IR below ∼100 M /yr, the SFR deduced from Hα measurements is a good approximation of the global SFR and (2) for galaxies near ULIRG regime. The corrected Hα SFR understimated the SFR by a factor of 1.5 to 2. Our analyses suggest that heavily extincted regions completely hidden in optical bands (such as those found in Arp 220) contribute less than 20% of the global budget of star formation up to z = 1.

We present the study of a large sample of early-type dwarf galaxies in the Coma cluster observed with DEIMOS on the Keck II to determine their internal velocity dispersion. We focus on a subsample of 41 member dwarf elliptical galaxies for which the velocity dispersion can be reliably measured, 26 of which were studied for the first time. The magnitude range of our sample is −21 < M R < −15 mag. This paper (Paper I) focuses on the measurement of the velocity dispersion and their error estimates. The measurements were performed using penalized pixel fitting (PPXF) and using the calcium triplet absorption lines. We use Monte Carlo bootstrapping to study various sources of uncertainty in our measurements, namely statistical uncertainty, template mismatch and other systematics. We find that the main source of uncertainty is the template mismatch effect which is reduced by using templates with a range of spectral types.Combining our measurements with those from the literature, we study the Faber-Jackson relation (L ∝ σ α ) and find that the slope of the relation is α = 1.99 ± 0.14 for galaxies brighter than M R −16 mag. A comprehensive analysis of the results combined with the photometric properties of these galaxies is reported in Paper II.

Objectives To develop a high-performance, rapid semi-automated method (Sheffield TKV Tool) for measuring total kidney volume (TKV) from magnetic resonance images (MRI) in patients with autosomal dominant polycystic kidney disease (ADPKD). Methods TKV was initially measured in 61 patients with ADPKD using the Sheffield TKV Tool and its performance compared to manual segmentation and other published methods (ellipsoidal, mid-slice, MIROS). It was then validated using an external dataset of MRI scans from 65 patients with ADPKD. Results Sixty-one patients (mean age 45 ± 14 years, baseline eGFR 76 ± 32 ml/min/1.73 m 2 ) with ADPKD had a wide range of TKV (258–3680 ml) measured manually. The Sheffield TKV Tool was highly accurate (mean volume error 0.5 ± 5.3% for right kidney, − 0.7 ± 5.5% for left kidney), reproducible (intra-operator variability − 0.2 ± 1.3%; inter-operator variability 1.1 ± 2.9%) and outperformed published methods. It took less than 6 min to execute and performed consistently with high accuracy in an external MRI dataset of T2-weighted sequences with TKV acquired using three different scanners and measured using a different segmentation methodology (mean volume error was 3.45 ± 3.96%, n = 65). Conclusions The Sheffield TKV Tool is operator friendly, requiring minimal user interaction to rapidly, accurately and reproducibly measure TKV in this, the largest reported unselected European patient cohort with ADPKD. It is more accurate than estimating equations and its accuracy is maintained at larger kidney volumes than previously reported with other semi-automated methods. It is free to use, can run as an independent executable and will accelerate the application of TKV as a prognostic biomarker for ADPKD into clinical practice. Key Points • This new semi-automated method (Sheffield TKV Tool) to measure total kidney volume (TKV) will facilitate the routine clinical assessment of patients with ADPKD. • Measuring TKV manually is time consuming and laborious. • TKV is a prognostic indicator in ADPKD and the only imaging biomarker approved by the FDA and EMA. Electronic supplementary material The online version of this article (10.1007/s00330-018-5918-9) contains supplementary material, which is available to authorized users.