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The [OII]3727 emission line is frequently used as an indicator of the star formation rate (SFR) despite its complex dependence on metallicity and excitation conditions. We have analysed the properties of the [OII] and Halpha emission lines for a complete sample of local Halpha-selected galaxies, the Universidad Complutense de Madrid (UCM) survey. We find a large scatter in the [OII]/Halpha line ratios, although the scatter in the extinction-corrected [OII]^0/Halpha^0 ratio is considerably smaller. We also find that the [OII]/Halpha ratios are reasonably well correlated with the absolute B- and K-band magnitudes and with EW([OII]). However, the extinction-corrected [OII]^0/Halpha^0 ratio is largely independent of these quantities, indicating that extinction is the main driver of the correlations. These correlations allow us to statistically predict--with varying degrees of accuracy--the observed and extinction-corrected Halpha fluxes from the observed [OII] flux using the information contained in EW([OII]) and/or the absolute magnitudes, but extreme caution is needed to make sure that the sample selection effects are correctly taken into account.
We use the data for the Hbeta emission-line, far-ultraviolet (FUV) and mid-infrared 22 micron continuum luminosities to estimate star formation rates <SFR> averaged over the galaxy lifetime for a sample of about 14000 bursting compact star-forming ga
We study the relations between gas-phase metallicity ($Z$), local stellar mass surface density ($Sigma_*$), and the local star formation surface density ($Sigma_{rm SFR}$) in a sample of 1120 star-forming galaxies from the MaNGA survey. At fixed $Sig
To compute the SFR of galaxies from the rest-frame UV it is essential to take into account the obscuration by dust. To do so, one of the most popular methods consists in combining the UV with the emission from the dust itself in the IR. Yet, differen
(Abridged) The observational determination of the behaviour of the star formation rate (SFR) with look-back time or redshift has two main weaknesses: 1- the large uncertainty of the dust/extinction corrections, and 2- that systematic errors may be in
We present a photometric study of the Halpha emission in the Universidad Complutense de Madrid (UCM) Survey galaxies. This work complements our previously-published spectroscopic data. We study the location of the star-forming knots, their intensity,