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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, concentration, and the relationship of these properties with those of the host galaxy. We also estimate that the amount of Halpha emission that arises from the diffuse ionized gas is about 15-30% of the total Halpha flux for a typical UCM galaxy. This percentage seems to be independent of the Hubble type. Conversely, we found that an `average UCM galaxy harbours a star formation event with 30% of its Halpha luminosity arising from a nuclear component. The implications of these results for higher-redshift studies are discussed, including the effects of galaxy size and the depth of the observations. A correlation between the SFR and the Balmer decrement is observed, but such correlation breaks down for large values of the extinction. Finally, we recalculate the Halpha luminosity function and star formation rate density of the local Universe using the new imaging data. Our results point out that, on average, spectroscopic observations detected about one third of the total emission-line flux of a typical UCM galaxy. The new values obtained for the Halpha luminosity density and the star formation rate density of the local Universe are 10^(39.3+/-0.2) erg s-1 Mpc-3, and rho_SFR=0.016^(+0.007)_(-0.004) Mass_sun yr-1 Mpc-3 (H_0=50 km s-1 Mpc-1, Omega_M=1.0, Lambda=0). The corresponding values for the `concordance cosmology (H_0=70 km s-1 Mpc-1, Omega_M=0.3, Lambda=0.7) are 10^(39.5+/-0.2) erg s-1 Mpc-3 rho_SFR=0.029^(+0.008)_(-0.005) Mass_sun yr-1 Mpc-3.
The [CII] 158um fine-structure line is the brightest emission line observed in local star-forming galaxies. As a major coolant of the gas-phase interstellar medium, [CII] balances the heating, including that due to far-ultraviolet photons, which heat
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 comp
This paper presents the first results of an Halpha imaging survey of galaxies in the central regions of the A2151 cluster. A total of 50 sources were detected in Halpha. The morphologies of the 43 H$alpha$ selected galaxies range from grand design sp
We present new near-infrared J and K imaging data for 67 galaxies from the Universidad Complutense de Madrid survey used to determine the SFR density of the local universe by Gallego et al. (1995). This is a sample of local star-forming galaxies with
Submillimeter excess emission has been reported at 500 microns in a handful of local galaxies, and previous studies suggest that it could be correlated with metal abundance. We investigate the presence of an excess submillimeter emission at 500 micro