M. Rego

The Current Star Formation Rate of the Local Universe

The Universidad Complutense de Madrid (UCM) survey is a long-term project aimed at finding and analyzing star-forming galaxies detected by their Hα emission in Schmidt objective-prism plates. The instrumental setup limits the volume of the universe surveyed to a redshift z ≲ 0.045. So far we have discovered several hundred emission-line galaxies (ELGs) undergoing star formation at a wide range of levels. Analyzing a complete sample of ELGs from the UCM survey, we have computed the Hα luminosity function for the star-forming galaxies in the surveyed volume of the universe. A Schechter function provides a good fit to the H_α luminosity function with the following parameters: α = -1.3 ± 0.2, L^*(H_α) = 10^42.15±0.08 ergs s^-1, and φ^* = 10^-3.2±0.2 Mpc^3 for H_0 = 50 km s^-1 Mpc^-1. Integrating over the full range of luminosities, we obtain an H_α luminosity density of 10^39.1±0.2 ergs s^-1 Mpc^-3. Using the H_α emission as a star formation rate (SFR) estimator, this translates into a SFR density for the local universe of 0.013_−0.005^+0.007 M_☉ yr^-1 Mpc^-3 in star-forming galaxies with EW(H_α + [N_II]) > 10 A and z lesssim 0.045 for a Scalo initial mass function. This is the first observational determination of this quantity, which will provide a direct test of current galaxy formation and evolution models.

Spectroscopic properties and luminosity distribution of the Universidad Complutense de Madrid survey galaxies

A spectroscopic analysis of the entire sample of Hα emission-line galaxies (ELGs) contained in lists 1 and 2 of the Universidad Complutense de Madrid (UCM) objective-prism survey is presented. A significant fraction (59%) of star-forming galaxies with low-ionization or high-extinction properties has been found. This kind of ELG is only incompletely detected in the blue or in other ELG surveys. We have found evidence for evolution among some of the different ELG classes. A comparison between the populations detected by the Case, Kiso, University of Michigan, and UCM surveys is presented. We conclude that a deep Hα survey is better able to sample all the ages, evolutionary stages, and luminosities of currently star-forming galaxies than other surveys using blue emission lines or colors. Finally, the luminosity and spatial distributions of the UCM galaxies are determined. The contribution of the newly found, currently star-forming ELGs provides new clues to galaxy evolution and has to be taken into account when trying to consider the density of ELGs and total star formation rate in the universe.

The [O [CSC]ii[/CSC]] λ3727 Luminosity Function of the Local Universe

The measurement of the Star Formation Rate density of the Universe is of prime importance in understanding the formation and evolution of galaxies. The [OII]3727 emission line flux, easy to measure up to z~1.4 within deep redshift surveys in the optical and up to z~5.4 in the near infrared, offers a reliable means of characterizing the star formation properties of high-z objects. In order to provide the high-z studies with a local reference, we have measured total [OII]3727 fluxes for the well analyzed local sample of star-forming galaxies from the Universidad Complutense de Madrid Survey. This data is used to derive the [OII]3727 luminosity function for local star-forming galaxies. When compared with similar luminosity densities published for redshift up to z~1, the overall evolution already observed in the star formation activity of the Universe is confirmed.The measurement of the star formation rate density of the universe is of prime importance in understanding the formation and evolution of galaxies. The [O II] ƛ3727 emission-line flux, easy to measure up to z ≈ 1.4 within deep redshift surveys in the optical and up to z ≈ 5/4 in the near-infrared, offers a reliable means of characterizing the star formation properties of high-z objects. In order to provide the high-z studies with a local reference, we have measured total [O II] ƛ3727 fluxes for the well-analyzed local sample of star-forming galaxies from the Universidad Complutense de Madrid Survey. These data are used to derive the [O II] ƛ3727 luminosity function for local star-forming galaxies. When compared with similar luminosity densities published for redshift up to z ≈ 1, the overall evolution already observed in the star formation activity of the universe is confirmed.

Barium and iron abundances in red giants

An intermediate-dispersion abundance analysis has been carried out on a sample of 21 barium and 14 comparison stars. The excess of barium over iron has been used as the most representative indicator of peculiarity. These excesses are higher in the peculiar stars than in the nonpeculiar stars. Particularly interesting is the case of HD 67447, included in the comparison stars, with an excess Ba/Fe abundance = 1.61, probably a new barium star. A trend indicating a possible anticorrelation between barium overabundance and metallicity favors the suggestion that the barium strong group is older than the barium weak one. 36 refs.

Survey of emission-line galaxies: Universidad Complutense de Madrid list

A low-dispersion objective-prism survey for low-redshift emission-line galaxies (ELGs) is being carried out by the University Complutense de Madrid with the Schmidt telescope at the German-Spanish Observatory of Calar Alto (Almeria, Spain). A 4° full aperture prism, which provides a dispersion of 1950 A mm^-1, and IIIaF emulsion combination has been used to search for ELGs selected by the presence of H_α emission in their spectra. Our survey has proved to be able to recover objects already found by similar surveys with different techniques and, what is more important, to discover new objects not previously cataloged. A compilation of descriptions and positions, along with finding charts when necessary, is presented for 160 extragalactic emission-line objects. This is the first list, which contains objects located in a region of the sky covering 270 deg^2 in 10 fields near α = 0^h and δ = 20°.

Erratum: “The Current Star Formation Rate of the Local Universe” (ApJ, 455, L1 [1995])

The Universidad Complutense de Madrid (UCM) Survey is a long-term project aiming at finding and analysing star-forming galaxies detected by their H

UCM 2257+2438, a new narrow-line seyfert 1 galaxy

\alpha

IRAS observations of H-alpha selected emission-line galaxies

emission in Schmidt objective-prism plates. The instrumental set-up limits the volume of the Universe surveyed to a redshift

NEW EMISSION-LINE GALAXIES IDENTIFIED FROM AN OBJECTIVE PRISM SURVEY*

z\lesssim0.045

Iron abundances in G dwarfs

. So far we have discovered several hundred emission-line galaxies (ELGs) undergoing star formation at a wide range of levels. Analyzing a complete sample of ELGs from the UCM survey we have computed the H