119 research outputs found
Stellar Population gradients in galaxy discs from the CALIFA survey
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 the
effective radius of the disc, the slope of the stellar population gradients
does not correlate with the mass or with the morphological type of the
galaxies. Contrary to this, the values of both age and metallicity at 2.5
scale-lengths correlate with the central velocity dispersion in a similar
manner to the central values of the bulges, although bulges show, on average,
older ages and higher metallicities than the discs. One of the goals of the
present paper is to test the theoretical prediction that non-linear coupling
between the bar and the spiral arms is an efficient mechanism for producing
radial migrations across significant distances within discs. The process of
radial migration should flatten the stellar metallicity gradient with time and,
therefore, we would expect flatter stellar metallicity gradients in barred
galaxies. However, we do not find any difference in the metallicity or age
gradients in galaxies with without bars. We discuss possible scenarios that can
lead to this absence of difference.Comment: 24 pages, 17 figures, accepted for publication in A&
CALIFA : a diameter-selected sample for an integral field spectroscopy galaxy survey
JMA acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild).We describe and discuss the selection procedure and statistical properties of the galaxy sample used by the Calar Alto Legacy Integral Field Area (CALIFA) survey, a public legacy survey of 600 galaxies using integral field spectroscopy. The CALIFA "mother sample" was selected from the Sloan Digital Sky Survey (SDSS) DR7 photometric catalogue to include all galaxies with an r-band isophotal major axis between 45 '' and 79 : 2 '' and with a redshift 0 : 005 M-r > -23 : 1 and over a stellar mass range between 10(9.7) and 10(11.4) M-circle dot. In particular, within these ranges, the diameter selection does not lead to any significant bias against - or in favour of - intrinsically large or small galaxies. Only below luminosities of M-r = -19 (or stellar masses <10(9.7) M-circle dot) is there a prevalence of galaxies with larger isophotal sizes, especially of nearly edge-on late-type galaxies, but such galaxies form <10% of the full sample. We estimate volume-corrected distribution functions in luminosities and sizes and show that these are statistically fully compatible with estimates from the full SDSS when accounting for large-scale structure. For full characterization of the sample, we also present a number of value-added quantities determined for the galaxies in the CALIFA sample. These include consistent multi-band photometry based on growth curve analyses; stellar masses; distances and quantities derived from these; morphological classifications; and an overview of available multi-wavelength photometric measurements. We also explore different ways of characterizing the environments of CALIFA galaxies, finding that the sample covers environmental conditions from the field to genuine clusters. We finally consider the expected incidence of active galactic nuclei among CALIFA galaxies given the existing pre-CALIFA data, finding that the final observed CALIFA sample will contain approximately 30 Sey2 galaxies.Peer reviewe
The Mass-Metallicity relation explored with CALIFA: I. Is there a dependence on the star formation rate?
We present the results on the study of 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 enough resolution to separate
individual HII regions and/or aggregations. Nearly 3000 individual HII
regions have been detected. The spectra cover the wavelength range between
[OII]3727 and [SII]6731, with a sufficient signal-to-noise to derive the oxygen
abundance and star-formation rate associated with each region. In addition, we
have 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 smaller than the one already reported in
the literature (0.07 dex). Indeed, this
dispersion is only slightly larger than the typical error derived for our
oxygen abundances. However, we do not find any secondary relation with the
star-formation rate, other than the one induced due to the primary relation of
this quantity with the stellar mass. We confirm the result using the 3000
individual HII regions, for the corresponding local relations.
Our results agree with the scenario in which gas recycling in galaxies, both
locally and globally, is much faster than other typical timescales, 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.Comment: 19 Pages, 8 figures, Accepted for Publishing in Astronomy and
Astrophysics (A&A
Water mass age and ageing driving chromophoric dissolved organic matter in the dark global ocean
Research articleThe omnipresence of chromophoric dissolved organic matter (CDOM) in the open ocean
enables its use as a tracer for biochemical processes throughout the global overturning circulation. We
made an inventory of CDOM optical properties, ideal water age (τ), and apparent oxygen utilization (AOU)
along the Atlantic, Indian, and Pacific Ocean waters sampled during the Malaspina 2010 expedition. A water
mass analysis was applied to obtain intrinsic, hereinafter archetypal, values of τ, AOU, oxygen utilization rate
(OUR), and CDOM absorption coefficients, spectral slopes and quantum yield for each one of the 22 water
types intercepted during this circumnavigation. Archetypal values of AOU and OUR have been used to trace
the differential influence of water mass aging and aging rates, respectively, on CDOM variables. Whereas the
absorption coefficient at 325nm (a325) and the fluorescence quantum yield at 340nm (Φ340) increased, the
spectral slope over the wavelength range 275–295nm (S275–295) and the ratio of spectral slopes over the
ranges 275–295nm and 350–400nm (SR) decreased significantly with water mass aging (AOU). Combination
of the slope of the linear regression between archetypal AOU and a325 with the estimated global OUR
allowed us to obtain a CDOM turnover time of 634 ± 120 years, which exceeds the flushing time of the
dark ocean (>200 m) by 46%. This positive relationship supports the assumption of in situ production and
accumulation of CDOM as a by-product of microbial metabolism as water masses turn older. Furthermore,
our data evidence that global-scale CDOM quantity (a325) is more dependent on aging (AOU), whereas CDOM
quality (S275–295, SR, Φ340) is more dependent on aging rate (OUR).Versión del editor4,785
Stellar populations of bulges at low redshift
This chapter summarizes our current understanding of the stellar population
properties of bulges and outlines important future research directions.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen
E., Peletier R., Gadotti D., Springer Publishing. 34 pages, 12 figure
Integral Field Spectroscopy of a sample of nearby galaxies. I. Sample, Observations and Data Reduction
Aims: Integral Field Spectroscopy (IFS) is a powerful approach for the study
of nearby galaxies since it enables a detailed analysis of their resolved
physical properties. Here we present the sample of nearby galaxies selected to
exploit the two dimensional information provided by the IFS. Methods: We
observed a sample of 48 galaxies from the Local Universe with the PPAK Integral
Field Spectroscopy unit (IFU), of the PMAS spectrograph, mounted at the 3.5m
telescope at Calar Alto Observatory (Almeria, Spain). Two different setups were
used during these studies (low -V300- and medium -V600- resolution mode)
covering a spectral range of around 3700-7000 Angs. We developed a full
automatic pipeline for the data reduction, that includes an analysis of the
quality of the final data products. We applied a decoupling method to obtain
the ionised gas and stellar content of these galaxies, and to derive the main
physical properties of the galaxies. To asses the accuracy in the measurements
of the different parameters, we performed a set of simulations to derive the
expected relative errors obtained with these data. In addition, we extracted
two aperture, central and integrated spectra, from the datacubes. The main
properties of the stellar populations and ionised gas of these galaxies and an
estimate of their relative errors are derived from those spectra, as well as
from the whole datacubes. Results: The comparison of the central spectrum
extracted from the datacubes and the SDSS spectrum for those galaxies in common
shows a good agreement between the derived values from both samples. We find
differences in the properties of galaxies when comparing a central and an
integrated spectra, showing the effects of the extracted aperture in the
interpretation of the data. Finally, we present two dimensional maps of some of
the main properties derived with the decoupling procedure.Comment: 17 pages, 20 figures, accepted for publication in A&
CALIFA, the Calar Alto Legacy Integral Field Area survey III. Second public data release
CALIFA is the first legacy survey being performed at Calar Alto. The CALIFA collaboration would like to thank the IAA-CSIC and MPIA-MPG as major partners of the observatory, and CAHA itself, for the unique access to telescope time and support in manpower and infrastructures. The CALIFA collaboration thanks also the CAHA staff for the dedication to this project. R.G.B., R.G.D., and E.P. are supported by the Spanish Ministerio de Ciencia e Innovacion under grant AYA2010-15081. S.Z. is supported by the EU Marie Curie Integration Grant "SteMaGE" Nr. PCIG12-GA-2012-326466 (Call Identifier: FP7-PEOPLE-2012 CIG). J.F.B. acknowledges support from grants AYA2010-21322-C03-02 and AIB-2010-DE-00227 from the Spanish Ministry of Economy and Competitiveness (MINECO), as well as from the FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA grant agreement number 289313. Support for L.G. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC12009, awarded to The Millennium Institute of Astrophysics, M.A.S.L.G. also acknowledges support by CONICYT through FONDECYT grant 3140566. A.G. acknowledges support from the FP7/2007-2013 under grant agreement n. 267251 (AstroFIt). J.M.G. acknowledges support from the Fundacao para a Ciencia e a Tecnologia (FCT) through the Fellowship SFRH/BPD/66958/2009 from FCT (Portugal) and research grant PTDC/FIS-AST/3214/2012. RAM was funded by the Spanish programme of International Campus of Excellence Moncloa (CEI). J.M.A. acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild). I.M., J.M. and A.d.O. acknowledge the support by the projects AYA2010-15196 from the Spanish Ministerio de Ciencia e Innovacion and TIC 114 and PO08-TIC-3531 from Junta de Andalucia. AMI acknowledges support from Agence Nationale de la Recherche through the STILISM project (ANR-12-BS05-0016-02). M.M. acknowledges financial support from AYA2010-21887-C04-02 from the Ministerio de Economia y Competitividad. P.P. is supported by an FCT Investigador 2013 Contract, funded by FCT/MCTES (Portugal) and POPH/FSE (EC). P.P. acknowledges support by FCT under project FCOMP-01-0124-FEDER-029170 (Reference FCT PTDC/FIS-AST/3214/2012), funded by FCT-MEC (PIDDAC) and FEDER (COMPETE). T.R.L. thanks the support of the Spanish Ministerio de Educacion, Cultura y Deporte by means of the FPU fellowship. PSB acknowledges support from the Ramon y Cajal program, grant ATA2010-21322-C03-02 from the Spanish Ministry of Economy and Competitiveness (MINECO). C.J.W. acknowledges support through the Marie Curie Career Integration Grant 303912. V.W. acknowledges support from the European Research Council Starting Grant (SEDMorph P.I. V. Wild) and European Career Re-integration Grant (Phiz-Ev P.I.V. Wild). Y.A. acknowledges financial support from the Ramon y Cajal programme (RyC-2011-09461) and project AYA2013-47742-C4-3-P, both managed by the Ministerio de Economia y Competitividad, as well as the "Study of Emission-Line Galaxies with Integral-Field Spectroscopy" (SELGIFS) programme, funded by the EU (FP7-PEOPLE-2013-IRSES-612701) within the Marie-Sklodowska-Curie Actions scheme. We thank the referee David Wilman for very useful comments that improved the presentation of the paper.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 lowresolution 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 200 : 4. In total, the second data
release contains over 1.5 million spectra.Instituto de Salud Carlos III
Spanish Government
AYA2010-15081
AYA2010-15196European Union (EU)
PCIG12-GA-2012-326466Spanish Ministry of Economy and Competitiveness (MINECO)
AYA2010-21322-C03-02
AIB-2010-DE-00227FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA
289313Ministry of Economy, Development, and Tourism's Millennium Science Initiative
IC12009Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)
CONICYT FONDECYT
3140566Fundacao para a Ciencia e a Tecnologia (FCT) from FCT (Portugal)
SFRH/BPD/66958/2009Spanish programme of International Campus of Excellence Moncloa (CEI)European Research Council (ERC)Junta de Andalucia
TIC 114
PO08-TIC-3531French National Research Agency (ANR)
ANR-12-BS05-0016-02Spanish Government
AYA2010-21887-C04-02FCT Investigador Contract - FCT/MCTES (Portugal)European Commission Joint Research Centre
European Social Fund (ESF)FCT - FCT-MEC (PIDDAC)
FCOMP-01-0124-FEDER-029170
FCT PTDC/FIS-AST/3214/2012European Union (EU)Spanish Ministerio de Educacion, Cultura y Deporte by FPURamon y Cajal program from the Spanish Ministry of Economy and Competitiveness (MINECO)
ATA2010-21322-C03-02European Union (EU)
303912European Career Re-integration GrantSpanish Government
RyC-2011-09461
AYA2013-47742-C4-3-PEuropean Union (EU)
FP7-PEOPLE-2013-IRSES-612701PTDC/FIS-AST/3214/2012Science & Technology Facilities Council (STFC)
ST/K000985/
Integral field spectroscopy of a sample of nearby galaxies: II. Properties of the H ii regions
In this work we analyze the spectroscopic properties of a large number of H
ii regions, \sim2600, located in 38 galaxies. The sample of galaxies has been
assembled from the face-on spirals in the PINGS survey and a sample described
in M\'armol-Queralt\'o (2011, henceforth Paper I). All the galaxies were
observed using Integral Field Spectroscopy with a similar setup, covering their
optical extension up to \sim2.4 effective radii within a wavelength range from
\sim3700 to \sim6900{\AA}. We develop a new automatic procedure to detect H ii
regions, based on the contrast of the H{\alpha} intensity maps. Once detected,
the procedure provides us with the integrated spectra of each individual
segmented region. A well-tested automatic decoupling procedure has been applied
to remove the underlying stellar population, deriving the main proper- ties of
the strongest emission lines in the considered wavelength range (covering from
[O ii] {\lambda}3727 to [S ii] {\lambda}6731). A final catalogue of the
spectroscopic properties of these regions has been created for each galaxy. In
the current study we focused on the understanding of the average properties of
the H ii regions and their radial distributions. We find that the gas-phase
oxygen abundance and the H{\alpha} equivalent width present negative and
positive gradient, respectively. The distribution of slopes is statistically
compatible with a random Gaussian distribution around the mean value, if the
radial distances are measured in units of the respective effective radius. No
difference in the slope is found for galaxies of different morphologies:
barred/non-barred, grand-design/flocculent. Therefore, the effective radius is
a universal scale length for gradients in the evolution of galaxies. Other
properties have a larger variance across each object.Comment: 29 pages, 13 figures, accepted for publishing in Astronomy and
Astrophysics (A&A
The CALIFA survey across the Hubble sequence Spatially resolved stellar population properties in galaxies
Various different physical processes contribute to the star formation and stellar mass assembly histories of galaxies. One important approach to
understanding the significance of these different processes on galaxy evolution is the study of the stellar population content of today’s galaxies
in a spatially resolved manner. The aim of this paper is to characterize in detail the radial structure of stellar population properties of galaxies
in the nearby universe, based on a uniquely large galaxy sample, considering the quality and coverage of the data. The sample under study was
drawn from the CALIFA survey and contains 300 galaxies observed with integral field spectroscopy. These cover a wide range of Hubble types,
from spheroids to spiral galaxies, while stellar masses range from M? ∼ 109
to 7 × 1011 M . We apply the fossil record method based on spectral
synthesis techniques to recover the following physical properties for each spatial resolution element in our target galaxies: the stellar mass surface
density (µ?), stellar extinction (AV ), light-weighted and mass-weighted ages (hlog ageiL, hlog ageiM), and mass-weighted metallicity (hlog Z?iM).
To study mean trends with overall galaxy properties, the individual radial profiles are stacked in seven bins of galaxy morphology (E, S0, Sa, Sb,
Sbc, Sc, and Sd). We confirm that more massive galaxies are more compact, older, more metal rich, and less reddened by dust. Additionally, we
find that these trends are preserved spatially with the radial distance to the nucleus. Deviations from these relations appear correlated with Hubble
type: earlier types are more compact, older, and more metal rich for a given M?, which is evidence that quenching is related to morphology, but
not driven by mass. Negative gradients of hlog ageiL are consistent with an inside-out growth of galaxies, with the largest hlog ageiL gradients in
Sb–Sbc galaxies. Further, the mean stellar ages of disks and bulges are correlated and with disks covering a wider range of ages, and late-type
spirals hosting younger disks. However, age gradients are only mildly negative or flat beyond R ∼ 2 HLR (half light radius), indicating that star
formation is more uniformly distributed or that stellar migration is important at these distances. The gradients in stellar mass surface density depend
mostly on stellar mass, in the sense that more massive galaxies are more centrally concentrated. Whatever sets the concentration indices of galaxies
obviously depends less on quenching/morphology than on the depth of the potential well. There is a secondary correlation in the sense that at the
same M? early-type galaxies have steeper gradients. The µ? gradients outside 1 HLR show no dependence on Hubble type. We find mildly negative
hlog Z?iM gradients, which are shallower than predicted from models of galaxy evolution in isolation. In general, metallicity gradients depend on
stellar mass, and less on morphology, hinting that metallicity is affected by both – the depth of the potential well and morphology/quenching.
Thus, the largest hlog Z?iM gradients occur in Milky Way-like Sb–Sbc galaxies, and are similar to those measured above the Galactic disk. Sc
spirals show flatter hlog Z?iM gradients, possibly indicating a larger contribution from secular evolution in disks. The galaxies from the sample
have decreasing-outward stellar extinction; all spirals show similar radial profiles, independent from the stellar mass, but redder than E and S0.
Overall, we conclude that quenching processes act in manners that are independent of mass, while metallicity and galaxy structure are influenced
by mass-dependent processes.CALIFA is the first legacy survey carried out at Calar Alto.
The CALIFA collaboration would like to thank the IAA-CSIC and MPIA-MPG
as major partners of the observatory, and CAHA itself, for the unique access
to telescope time and support in manpower and infrastructures. We also thank
the CAHA staff for the dedication to this project. Support from the Spanish
Ministerio de Economía y Competitividad, through projects AYA2010-15081 (PI
R.G.D.), and Junta de Andalucía FQ1580 (PI R.G.D.), AYA2010-22111-C03-03,
and AYA2010-10904E (S.F.S.). We also thank the Viabilidad, Diseño, Acceso y
Mejora funding program, ICTS-2009-10, for funding the data acquisition of this
project. R.C.F. thanks the hospitality of the IAA and the support of CAPES and
CNPq. R.G.D. acknowledges the support of CNPq (Brazil) through Programa
Ciencia sem Fronteiras (401452/2012-3). A.G. acknowledges support from
EU FP7/2007-2013 under grant agreement n.267251 (AstroFIt) and from the
EU Marie Curie Integration Grant “SteMaGE” Nr. PCIG12-GA-2012-326466.
C.J.W. acknowledges support through the Marie Curie Career Integration Grant
303912. E.P. acknowledges support from the Guillermo Haro program at
INAOE. Support for L.G. is provided by the Ministry of Economy, Development,
and Tourism’s Millennium Science Initiative through grant IC120009, awarded
to The Millennium Institute of Astrophysics, MAS. L.G. acknowledges support by CONICYT through FONDECYT grant 3140566. J.I.P. acknowledges
financial support from the Spanish MINECO under grant AYA2010-21887-
C04-01 and from Junta de Andalucía Excellence Project PEX2011-FQM7058.
I.M., J.M. and A.d.O. acknowledge support from the project AYA2013-42227-P.
RAM is funded by the Spanish program of International Campus of Excellence
Moncloa (CEI). J.M.A. acknowledges support from the European Research
Council Starting Grant (SEDmorph; P.I. V. Wild
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