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We present the first angular clustering measurement of ultraviolet-selected galaxies at low redshift ($z \approx 0.1$) using data from the FOCA survey. We measure the galaxy autocorrelation function $\omega(\theta)$from three separate fields with $m_{\rm UV} <20.25$(AB). Assuming $\omega(\theta) = A_\omega \theta^{-\delta}$, we obtain $A_\omega = 2.9^{+1.9}_{-1.2} \times 10^{-2}$and $\delta=0.53^{+0.23}_{-0.26}$, as a best fit to the data, which yields a correlation length $r_0 = 3.2^{+0.8}_{-2.3}~h^{-1}$Mpc. This estimate is formally lower than those obtained from optically selected $L_\star$galaxy samples, although the difference is within errors.

Context.Dust attenuation curves in external galaxies are useful for studying their dust properties as well as interpreting their intrinsic spectral energy distributions. These functions are not very well known in the UV range whether at low or high redshift. In particular, the presence or absence of a UV bump at 2175 Å remains an open issue that has consequences on the interpretation of broad band colours of galaxies involving the UV range.

Context.The nearby universe remains the best laboratory to understand the physical properties of galaxies and is a reference for any comparison with high redshift observations. The all sky (or very large) surveys that have been performed from the ultraviolet (UV) to the far-infrared (far-IR) provide us with large datasets of very large wavelength coverage to perform a reference study.

The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) is a complete blind survey of the Virgo cluster covering  ~40 sq. deg in the far UV (FUV, λeff= 1539   Å, Δλ= 442   Å) and  ~120 sq. deg in the near UV (NUV, λeff= 2316   Å, Δλ= 1060   Å). The goal of the survey is to study the ultraviolet (UV) properties of galaxies in a rich cluster environment, spanning a wide luminosity range from giants to dwarfs, and regardless of prior knowledge of their star formation activity. The UV data will be combined with those in other bands (optical: NGVS; far-infrared – submm: HeViCS; HI: ALFALFA) and with our multizone chemo-spectrophotometric models of galaxy evolution to make a complete and exhaustive study of the effects of the environment on the evolution of galaxies in high density regions. We present here the scientific objectives of the survey, describing the observing strategy and briefly discussing different data reduction techniques. Using UV data already in-hand for the central 12 sq. deg we determine the FUV and NUV luminosity functions of the Virgo cluster core for all cluster members and separately for early- and late-type galaxies and compare it to the one obtained in the field and other nearby clusters (Coma, A1367). This analysis shows that the FUV and NUV luminosity functions of the core of the Virgo clusters are flatter (α~  −1.1) than those determined in Coma and A1367. We discuss the possible origin of this difference.

Aims. We explore spectral energy distributions (SEDs), star formation (SF), and dust extinction properties of galaxies in the Local Universe.Methods. The AKARI all-sky survey provided the first bright point source catalog detected at 90 μm. Beginning with this catalog, we selected galaxies by matching the AKARI sources with those in the IRAS point source catalog redshift survey. We measured the total GALEX FUV and NUV flux densities with a photometry software we specifically developed for this purpose. In a further step we matched this sample with the Sloan digital sky survey (SDSS) and 2 micron all sky survey (2MASS) galaxies. With this procedure we obtained a basic sample which consists of 776 galaxies. After removing objects whose photometry was contaminated by foreground sources (mainly in the SDSS), we defined the “secure sample” which contains 607 galaxies.Results. The sample galaxies have redshifts of $\la$0.15, and their 90-μm luminosities range from 106to 1012$L_\odot$, with a peak at 1010$L_\odot$. The SEDs display a large variety, especially more than four orders of magnitude at the mid-far-infrared (M-FIR), but if we sort the sample with respect to 90 μm, the average SED shows a coherent trend: the more luminous an SED at 90 μm, the redder the global SED becomes. The Mr- NUV – rcolor–magnitude relation of our sample does not show bimodality, and the distribution is centered on the green valley. We established formulae to convert the FIR luminosity from the AKARI bands to the total IR (TIR) luminosity LTIR. The luminosity related to the SF activity (LSF) is dominated by LTIReven if we take into account the FIR emission from dust heated by old stars. At a high SF rate (SFR) (>20 $M_\odot$yr-1), the fraction of the directly visible SFR, SFRFUV, decreases. We also estimated the FUV attenuation AFUVfrom the FUV-to-TIR luminosity ratio. We examined the LTIR/LFUV-UV slope (FUV – NUV) relation. The majority of the sample has LTIR/LFUVratios five to ten times lower than expected from the local starburst relation, while some luminous IR and all the ultraluminous IR galaxies of this sample have higher LTIR/LFUVratios. We found the attenuation indicator LTIR/LFUVcorrelated to the stellar mass of galaxies, $M_*$, but not with a specific SFR, SFR/$M_*$.Conclusions. Together, these results show that the AKARI survey gives a representative sample of the local SF galaxies which will be a comprehensive local standard of their various properties to be compared with, for instance, high-zSF galaxies.

Aims. We explore spectral energy distributions (SEDs), star formation (SF), and dust extinction properties of galaxies in the Local Universe.