- ID:
- ivo://CDS.VizieR/J/MNRAS/383/183
- Title:
- CaII triplet of RGB from VLT/FLAMES obs.
- Short Name:
- J/MNRAS/383/183
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We demonstrate that low-resolution CaII triplet (CaT) spectroscopic estimates of the overall metallicity ([Fe/H]) of individual red giant branch (RGB) stars in two nearby dwarf spheroidal galaxies (dSphs) agree to +/-0.1-0.2dex with detailed high-resolution spectroscopic determinations for the same stars over the range -2.5<[Fe/H]<-0.5. For this study, we used a sample of 129 stars observed in low- and high-resolution modes with VLT/FLAMES in the Sculptor and Fornax dSphs. We also present the data-reduction steps we used in our low-resolution analysis and show that the typical accuracy of our velocity and CaT [Fe/H] measurement is ~2km/s and 0.1dex, respectively. We conclude that CaT[Fe/H] relations calibrated on globular clusters can be applied with confidence to RGB stars in composite stellar populations over the range -2.5<[Fe/H]<-0.5.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/130/2666
- Title:
- Ca4227 indices in early-type galaxies
- Short Name:
- J/AJ/130/2666
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated the abundance of calcium in early-type galaxies by measuring the strength of the CaI {lambda}4227 absorption line in their integrated spectra. The database used is the large sample of early-type galaxy integrated spectra in Caldwell and coworkers (2003AJ....125.2891C). We have measured Ca abundances from the CaI {lambda}4227 feature both by using the Lick Ca4227 index and by defining a new index, Ca4227_r_, that avoids the CN4216 molecular band in the continuum on the blueward side of the line.
- ID:
- ivo://CDS.VizieR/J/ApJ/765/94
- Title:
- Calibration of the mid-IR Tully-Fisher relation
- Short Name:
- J/ApJ/765/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Distance measures on a coherent scale around the sky are required to address the outstanding cosmological problems of the Hubble constant and of departures from the mean cosmic flow. The correlation between galaxy luminosities and rotation rates can be used to determine the distances to many thousands of galaxies in a wide range of environments potentially out to 200Mpc. Mid-infrared (3.6{mu}m) photometry with the Spitzer Space Telescope is particularly valuable as a source of luminosities because it provides products of uniform quality across the sky. From a perch above the atmosphere, essentially the total magnitude of targets can be registered in exposures of a few minutes. Extinction is minimal and the flux is dominated by the light from old stars, which is expected to correlate with the mass of the targets. In spite of the superior photometry, the correlation between mid-infrared luminosities and rotation rates extracted from neutral hydrogen profiles is slightly degraded from the correlation found with I-band luminosities. A color correction recovers a correlation that provides comparable accuracy to that available at the I band (~20% 1{sigma} in an individual distance) while retaining the advantages identified above. Without color correction, the relation between linewidth and [3.6] magnitudes is M^b,i,k,a^_[3.6]_=-20.34-9.74(logW^i^_mx_-2.5). This description is found with a sample of 213 galaxies in 13 clusters that define the slope and 26 galaxies with Cepheid or tip of the red giant branch distances that define the zero point. A color-corrected parameter M_c[3.6]_ is constructed that has reduced scatter: M_c[3.6]_=-20.34-9.13(logW_mx_^i^-2.5). Consideration of the seven calibration clusters beyond 50Mpc, outside the domain of obvious peculiar velocities, provides a preliminary Hubble constant estimate of H_0_=74+/-4km/s.M/pc.
- ID:
- ivo://CDS.VizieR/J/ApJ/533/744
- Title:
- Calibration of the Tully-Fischer relation
- Short Name:
- J/ApJ/533/744
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The correlation between the luminosities and rotation velocities of galaxies can be used to estimate distances to late-type galaxies. It is an appropriate moment to reevaluate this method given the great deal of new information available. The major improvements described here include: (1) the template relations can now be defined by large, complete samples, (3) the samples are drawn from a wide range of environments, (3) the relations are defined by photometric information at the B, R, I, and K' bands, (4) the multiband information clarifies problems associated with internal reddening, (5) the template zero points are defined by 24 galaxies with accurately known distances, and (6) the relations are applied to 12 clusters scattered across the sky and out to velocities of 8000km/s.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A47
- Title:
- CALIFA color/metallicity gradients connections
- Short Name:
- J/A+A/585/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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. Sloan Digital Sky Survey (SDSS) g'- and r'-band surface brightness, (g'-r') color, and ionized-gas oxygen abundance profiles for 324 galaxies within the Calar Alto Legacy Integral Field Area (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 one single exponential (Type I). The analysis of the color gradients at both sides of this break shows a U-shaped profile for most Type II galaxies with an average minimum (g'-r') color of ~0.5mag and an ionized-gas metallicity flattening associated with it only in the case of low-mass galaxies. Comparatively, more massive systems show a rather uniform negative metallicity gradient. The correlation between metallicity flattening and stellar mass for these systems results in p-values as low as 0.01. Independent of the mechanism having shaped the outer light profiles of these galaxies, stellar migration or a previous episode of star formation in a shrinking star-forming disk, it is clear that the imprint in their ionized-gas metallicity was different for low- and high-mass Type II galaxies. In the case of Type III disks, a positive correlation between the change in color and abundance gradient is found (the null hypothesis is ruled out with a p-value of 0.02), with the outer disks of Type III galaxies with masses <=10^10^M_{sun}_ showing a weak color reddening or even a bluing. This is interpreted as primarily due to a mass downsizing effect on the population of Type III galaxies that recently experienced an enhanced inside-out growth.
436. CALIFA DR2
- ID:
- ivo://CDS.VizieR/J/A+A/576/A135
- Title:
- CALIFA DR2
- Short Name:
- J/A+A/576/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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 3.5m 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{AA} with a spectral resolution of 6.0{AA} (FWHM); and (ii) a medium-resolution V1200 setup covering the wavelength range 3650-4840{AA} with a spectral resolution of 2.3{AA} (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 2.4". In total, the second data release contains over 1.5 million spectra.
- ID:
- ivo://CDS.VizieR/J/MNRAS/491/3562
- Title:
- CALIFA ETGs spatially resolved stellar pop.
- Short Name:
- J/MNRAS/491/3562
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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 <~2Re, as a function of radius and stellar-mass surface density {mu}*. We study in detail the dependence of profiles on galaxies' global properties, including velocity dispersion {sigma}_e_, stellar mass, morphology. ETGs are universally characterized by strong, negative metallicity gradients (~-0.3dex per Re) within 1Re, which flatten out moving towards larger radii. A quasi-universal local {mu}*-metallicity relation emerges, which displays a residual systematic dependence on {sigma}_e_, whereby higher {sigma}_e_ implies higher metallicity at fixed {mu}*. Age profiles are typically U-shaped, with minimum around 0.4Re, asymptotic increase to maximum ages beyond ~1.5Re, and an increase towards the centre. The depth of the minimum and the central increase anticorrelate with {sigma}_e_. A possible qualitative interpretation of these observations is a two-phase scenario. In the first phase, dissipative collapse occurs in the inner 1Re, establishing a negative metallicity gradient. The competition between the outside-in quenching due to feedback-driven winds and some form of inside-out quenching, possibly caused by central AGN feedback or dynamical heating, determines the U-shaped age profiles. In the second phase, the accretion of ex-situ stars from quenched and low-metallicity satellites shapes the flatter stellar population profiles in the outer regions.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A70
- Title:
- CALIFA face-on spiral galaxies oxygen
- Short Name:
- J/A+A/587/A70
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measured the gas abundance profiles in a sample of 122 face-on spiral galaxies observed by the CALIFA survey and included all spaxels whose line emission was consistent with star formation. This type of analysis allowed us to improve the statistics with respect to previous studies, and to properly estimate the oxygen distribution across the entire disc to a distance of up to 3-4 disc effective radii (r_e_). We confirm the results obtained from classical HII region analysis. In addition to the general negative gradient, an outer flattening can be observed in the oxygen abundance radial profile. An inner drop is also found in some cases. There is a common abundance gradient between 0.5 and 2.0r_e_ of {alpha}_O/H_=-0.075dex/r_e_ with a scatter of {sigma}=0.016dex/r_e_ when normalising the distances to the disc effective radius. By performing a set of Kolmogorov-Smirnov tests, we determined that this slope is independent of other galaxy properties, such as morphology, absolute magnitude, and the presence or absence of bars. In particular, barred galaxies do not seem to display shallower gradients, as predicted by numerical simulations. Interestingly, we find that most of the galaxies in the sample with reliable oxygen abundance values beyond ~2 effective radii (57 galaxies) present a flattening of the abundance gradient in these outer regions. This flattening is not associated with any morphological feature, which suggests that it is a common property of disc galaxies. Finally, we detect a drop or truncation of the abundance in the inner regions of 27 galaxies in the sample; this is only visible for the most massive galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/604/A4
- Title:
- CALIFA galaxies observational hints
- Short Name:
- J/A+A/604/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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. 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 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). We analyse 214 spiral galaxies from the CALIFA survey covering different SB profiles. We make use of GASP2D and SDSS data to characterise their light distribution and obtain colour profiles. The stellar age and metallicity profiles are computed using a methodology based on full-spectrum fitting techniques (pPXF, GANDALF, and STECKMAP) to the IFS CALIFA data. 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 and type III the shallowest, with type I galaxies displaying an intermediate behaviour. These results are consistent with a scenario in which radial migration is more efficient for type III galaxies than for type I systems with type II galaxies presenting the lowest radial migration efficiency. In such scenario, radial migration mixes the stellar content flattening the radial stellar properties and shaping different SB profiles. However, in sight of these results we cannot further quantify its importance in shaping spiral galaxies, and other processes such as recent star formation or satellite accretion might play a role.
- ID:
- ivo://CDS.VizieR/J/A+A/595/A62
- Title:
- CALIFA galaxies O/H and N/O slopes
- Short Name:
- J/A+A/595/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of the integrated properties of star-forming galaxies is central to understand their formation and evolution. Some of these properties are extensive and therefore their analysis require totally covering and spatially resolved observations. Among these properties, metallicity can be defined in spiral discs by means of integral field spectroscopy (IFS) of individual HII regions. The simultaneous analysis of the abundances of primary elements, as oxygen, and secondary, as nitrogen, also provides clues about the star formation history and the processes that shape the build-up of spiral discs. Our main aim is to analyse simultaneously O/H and N/O abundance ratios in HII regions in different radial positions of the discs in a large sample of spiral galaxies to obtain the slopes and the characteristic abundance ratios that can be related to their integrated properties. We analysed the optical spectra of individual selected HII regions extracted from a sample of 350 spiral galaxies of the CALIFA survey. We calculated total O/H abundances and, for the first time, N/O ratios using the semi-empirical routine HII-CHI-MISTRY, which, according to Perez-Montero (2014MNRAS.441.2663P), is consistent with the direct method and reduces the uncertainty in the O/H derivation using [NII] lines owing to the dispersion in the O/H-N/O relation. Then we performed linear fittings to the abundances as a function of the de-projected galactocentric distances.
