The “Fundamental Metallicity Relation” in CALIFA, SDSS-IV MaNGA and high-z galaxies. (arXiv:1811.06015v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Cresci_G/0/1/0/all/0/1">Giovanni Cresci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mannucci_F/0/1/0/all/0/1">Filippo Mannucci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Curti_M/0/1/0/all/0/1">Mirko Curti</a>
Metallicity of local galaxies is tightly related not only to stellar mass,
i.e. the Mass-Metallicity (MZ) Relation, but also to star formation rate (SFR)
through the so-called Fundamental Metallicity Relation (FMR), with more active
galaxies showing lower metallicities Z at fixed mass. Interestingly, the
relation does not evolve with redshift, with high-z galaxies up to z~2.5
following the same FMR defined by SDSS locally. However, FMR with different
shapes have been proposed for local galaxies, and the existence of a FMR and
the role of the SFR has been recently questioned by some authors, who do not
confirm the dependence of the residuals of the MZ relation on SFR in their
datasets, both locally and at high-z. In this paper we first discuss the
different parameterisations of this M*-Z-SFR relation that appeared in the
literature, to understand the origin of their different shapes. We then
re-analysed data from CALIFA and SDSS-IV MaNGA surveys, which were used to
suggest no dependency of metallicity on SFR in local galaxies. Contrary to
those claims, we find that those datasets are instead fully consistent with the
FMR predictions, with the expected dependency on SFR at fixed mass. Finally, we
analysed those high-z data whose consistency with the FMR was questioned. While
an internal dependency on SFR among the sub-samples is difficult to detect at
high-z due to the limited dynamic range sampled in the three parameters and to
the intrinsic scatter and uncertainties of such small samples, all these
datasets are compatible with the FMR defined locally by SDSS galaxies,
confirming the no evolution of the FMR in these data up to z~2.3
Metallicity of local galaxies is tightly related not only to stellar mass,
i.e. the Mass-Metallicity (MZ) Relation, but also to star formation rate (SFR)
through the so-called Fundamental Metallicity Relation (FMR), with more active
galaxies showing lower metallicities Z at fixed mass. Interestingly, the
relation does not evolve with redshift, with high-z galaxies up to z~2.5
following the same FMR defined by SDSS locally. However, FMR with different
shapes have been proposed for local galaxies, and the existence of a FMR and
the role of the SFR has been recently questioned by some authors, who do not
confirm the dependence of the residuals of the MZ relation on SFR in their
datasets, both locally and at high-z. In this paper we first discuss the
different parameterisations of this M*-Z-SFR relation that appeared in the
literature, to understand the origin of their different shapes. We then
re-analysed data from CALIFA and SDSS-IV MaNGA surveys, which were used to
suggest no dependency of metallicity on SFR in local galaxies. Contrary to
those claims, we find that those datasets are instead fully consistent with the
FMR predictions, with the expected dependency on SFR at fixed mass. Finally, we
analysed those high-z data whose consistency with the FMR was questioned. While
an internal dependency on SFR among the sub-samples is difficult to detect at
high-z due to the limited dynamic range sampled in the three parameters and to
the intrinsic scatter and uncertainties of such small samples, all these
datasets are compatible with the FMR defined locally by SDSS galaxies,
confirming the no evolution of the FMR in these data up to z~2.3
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