Mass-metallicity relation explored with CALIFA I. Is there a dependence on the star-formation rate?

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 Hii regions and/or aggregations. About 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 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 (σΔlog (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 Hii 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.
Nacional de Investigación y Desarrollo funding programs of the Spanish Ministerio de Ciencia e Innovación AYA2010-22111-C03-03 AYA2010-10904E
Ramon y Cajal project of the spanish Ministerio de Economía y Competitividad RyC-2011-07590
Academy of Sciences of the Czech Republic (ASCR Internal support program of international cooperation projects-PIPPMS) M100031241 M100031201
Czech Republic program for the long-term development of the research institution RVO67985815
Plan Nacional de Investigación y Desarrollo funding program AYA2010-15081
Consejo Nacional de Ciencia y Tecnología (CONACyT)
Spanish grant AYA2010-15169
Junta de Andalucía TIC114
Excellence Project P08-TIC-03531
Consejo Superior de Investigaciones Científicas (CSIC)
Junta para la Ampliación de Estudios
European Social Fund (ESF)
spanish programme of International Campus of Excellence Moncloa
Spanish PNAYA AYA2010-21887
Spanish Government CSD2006-00070 AYA2012-38491-C02-02
Autonomic Government of Andalusia P08-TIC-4075 TIC-126
Ciencia
Portuguese Foundation for Science and Technology
European Commission European Commission Joint Research Centre European Social Fund (ESF)
Portuguese Foundation for Science and Technology SFRH/BPD/66958/2009
National Science Foundation (NSF)