The "main sequence of galaxies" − defined in terms of the total star formation rate ψ vs. the total stellar mass M * − is a well-studied tight relation that has been observed at several wavelengths and at different redshifts. All earlier studies have derived this relation from integrated properties of galaxies. We recover the same relation from an analysis of spatially-resolved properties, with integral field spectroscopic (IFS) observations of 306 galaxies from the CALIFA survey. We consider the SFR surface density in units of log(M ⊙ yr −1 Kpc −2 ) and the stellar mass surface density in units of log(M ⊙ Kpc −2 ) in individual spaxels which probe spatial scales of 0.5-1.5 Kpc. This local relation exhibits a high degree of correlation with small scatter (σ = 0.23 dex), irrespective of the dominant ionisation source of the host galaxy or its integrated stellar mass. We highlight: (i) the integrated star formation main sequence formed by galaxies whose dominant ionisation process is related to star formation, for which we find a slope of 0.81 ±0.02; (ii) the spatially-resolved relation obtained with the spaxel analysis, we find a slope of 0.72 ±0.04; (iii) for the integrated main sequence we identified also a sequence formed by galaxies that are dominated by an old stellar population, which we have called the retired galaxies sequence.

We demonstrate the existence of a local mass, metallicity, star formation relation using spatially resolved optical spectroscopy of H ii regions in the local universe. One of the projections of this distribution-the local mass-metallicity relation-extends over a wide range in this parameter space: three orders of magnitude in mass and a factor of eight in metallicity. We explain the new relation as the combined effect of the differential distributions of mass and metallicity in the disks of galaxies, and a selective star formation efficiency. We use this local relation to reproduce-with a noticeable agreement-the mass-metallicity relation seen in galaxies, and conclude that the latter is a scale-up integrated effect of a local relation, supporting the inside-out growth and downsizing scenarios of galaxy evolution.

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.

Context. We present the largest catalogue of HI single dish observations of isolated galaxies to date, as part of the multi-wavelength compilation being performed by the AMIGA project (Analysis of the interstellar Medium in Isolated GAlaxies). Despite numerous studies of the HI content of galaxies, no revision focused on the HI scaling relations of the most isolated L * galaxies has been made since . Aims. The AMIGA sample has been demonstrated to be almost "nurture free", therefore, by creating scaling relations for the HI content of these galaxies we will define a metric of HI normalcy in the absence of interactions. Methods. The catalogue comprises of our own HI observations with Arecibo, Effelsberg, Nançay and GBT, and spectra collected from the literature. In total we have measurements or constraints on the HI masses of 844 galaxies from the Catalogue of Isolated Galaxies (CIG). The multi-wavelength AMIGA dataset includes a revision of the B-band luminosities (LB), optical diameters (D25), morphologies, and isolation. Due to the large size of the catalogue, these revisions permit cuts to be made to ensure isolation and a high level of completeness, which was not previously possible. With this refined dataset we fit HI scaling relations based on luminosity, optical diameter and morphology. Our regression model incorporates all the data, including upper limits, and accounts for uncertainties in both variables, as well as distance uncertainties. Results. The scaling relation of HI mass with D25 is in good agreement with that of , but our relation with LB is considerably steeper. This disagreement is attributed to the large uncertainties in the luminosities, which introduce a bias when fitting with ordinary least squares regression (as was done in previous works), and the different morphology distributions of the samples. We find that the main effect of morphology on the D25-relation is to increase the intercept towards later types, while for the LB-relation it is to flatten the slope. These trends were not evident in previous works due to the small number of detected early-type galaxies. Applying our relations to HI detected galaxies in the Virgo cluster we find that although the typical HI-deficiency is only ∼0.3 dex, the tail of the distribution extends over an order of magnitude beyond that of the AMIGA sample. These results are in general agreement with previous studies of HI-deficiency in the Virgo cluster. Conclusions. The HI scaling relations of the AMIGA sample define an up-to-date metric of the HI content of almost "nurture free" galaxies. These relations allow the expected HI mass, in the absence of interactions, of an individual galaxy to be predicted to within 0.25 dex (for typical measurement uncertainties). These relations are thus suitable for use as statistical measures of the impact of interactions on the neutral gas content of galaxies.

Context. Detecting cosmic ray hits (cosmics) in fiber-fed integral-field spectroscopy (IFS) data of single exposures is a challenging task because of the complex signal recorded by IFS instruments. Existing detection algorithms are commonly found to be unreliable in the case of IFS data, and the optimal parameter settings are usually unknown a priori for a given dataset. Aims. The Calar Alto legacy integral field area (CALIFA) survey generates hundreds of IFS datasets for which a reliable and robust detection algorithm for cosmics is required as an important part of the fully automatic CALIFA data reduction pipeline. Such a new algorithm needs to be tested against the performance of the commonly used algorithms L.A.Cosmic and DCR. General recommendations for the usage and optimal parameter settings of each algorithm have not yet been systematically studied for fiber-fed IFS datasets to guide users in their choice. Methods. We developed a novel algorithm, PyCosmic, which combines the edge-detection algorithm of L.A.Cosmic with a pointspread function convolution scheme. We generated mock data to compute the efficiency of different algorithms for a wide range of characteristic fiber-fed IFS datasets using the Potsdam Multi-Aperture Spectrophotometer (PMAS) and the VIsible MultiObject Spectrograph (VIMOS) IFS instruments as representative cases. Results. PyCosmic is the only algorithm that achieves an acceptable detection performance for CALIFA data. We find that PyCosmic is the most robust tool with a detection rate of 90% and a false detection rate 5% for any of the tested IFS data. It has one less free parameter than the L.A.Cosmic algorithm. Only for strongly undersampled IFS data does L.A.Cosmic exceed the performance of PyCosmic by a few per cent. DCR never reaches the efficiency of the other two algorithms and should only be used if computational speed is a concern. Thus, PyCosmic appears to be the most versatile cosmics detection algorithm for IFS data. It is implemented in the new CALIFA data reduction pipeline as well as in recent versions of the multi-instrument IFS pipeline P3D. Although PyCosmic has been optimized for IFS data, we have also successfully applied it to longslit data and anticipate that good results will be achieved with imaging data.

Using images from Sloan Digital Sky Survey Data Release 8, we have re-examined the morphology of 719 galaxies from the Analysis of the interstellar Medium in Isolated GAlaxies (AMIGA) project, a sample consisting of the most isolated galaxies that have yet been identified. The goal is to further improve the classifications of these galaxies by examining them in the context of the Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system, which includes recognition of features that go beyond the original de Vaucouleurs point of view. Our results confirm previous findings that isolated galaxies are found across the complete revised Hubble sequence, with intermediate to late-type (Sb-Sc) spirals being relatively more common. Elmegreen Arm Classifications are also presented, and show that more than 50% of the 514 spirals in the sample for which an arm class could be judged are grand design (AC 8,9,12). The visual bar fraction for the sample is ≈50%, but only 16% are classified as stronglybarred (SB). The dominant family classification is SA (nonbarred), the dominant inner variety classification is (s) (pure spiral), and the dominant outer variety classification is no outer ring, pseudoring, or lens. The Kolmogorov-Smirnov test is used to check for potential biases in the morphological interpretations, and for any possible relation between rings, bars, and arm classes with local environment and far-infrared excess. The connection between morphology and stellar mass is also examined for a subset of the sample.

We present integral field spectroscopic observations of the quadruple-lensed QSO SDSS 1004+4112 taken with the fiber system INTEGRAL at the William Herschel Telescope on 2004 January 19. In May 2003 a blueward enhancement in the high ionization lines of SDSS 1004+4112A was detected and then faded. Our observations are the first to note a second event of similar characteristics less than one year after. Although initially attributed to microlensing, the resemblance among the spectra of both events and the absence of microlensing-induced changes in the continuum of component A are puzzling. The lack of a convincing explanation under the microlensing or intrinsic variability hypotheses makes the observed enhancements particularly relevant, calling for close monitoring of this object.

Context. The basic properties of galaxies can be affected by both nature (internal processes) or nurture (interactions and effects of environment). Deconvolving the two effects is an important current effort in astrophysics. Observed properties of a sample of isolated galaxies should be mainly the result of internal (natural) evolution. It follows that nurture-induced galaxy evolution can only be understood through a comparative study of galaxies in different environments. Aims. We take a first look at SDSS (g − r) colors of galaxies in the AMIGA sample, which consists of many of the most isolated galaxies in the local Universe. This alerted us at the same time to the pitfalls of using automated SDSS colors. Methods. We focused on median values for the principal morphological subtypes found in the AMIGA sample (E/S0 and Sb-Sc) and compared them with equivalent measures obtained for galaxies in denser environments. Results. We find a weak tendency for AMIGA spiral galaxies to be redder than objects in close pairs. We find no clear difference when we compared this with galaxies in other (e.g. group) environments. However, the (g − r) color of isolated galaxies shows a Gaussian distribution, as might be expected assuming nurture-free evolution. We find a smaller median absolute deviation in colors for isolated galaxies compared to both wide and close pairs. The majority of the deviation on median colors for spiral subtypes is caused by a color-luminosity correlation. Surprisingly, isolated and non-isolated early-type galaxies show similar (g − r). We see little evidence for a green valley in our sample because most spirals redder than (g − r) = 0.7 have spurious colors. Conclusions. The redder colors of AMIGA spirals and lower color dispersions for AMIGA subtypes -compared with close pairsare likely caused by a more passive star formation in very isolated galaxies.