The Local Universe Survey (LUS)

1. The Local Universe Survey (LUS)

2. LUS • LUS aims to study the formation and evolution of galaxies • Determine the spatial distribution of the properties of the ionised gas and recent star formation • Determine the spatial distribution of the properties of the evolved stellar populations • Local Universe Galaxies carry themselves the memory of its formation and evolution (e.g. Heavens et al., Nature 2004; R. González Delgado, this morning talk!)

3. LUS: The Goals • Trace the star formation history of individual galaxies in the sample • Produce high-resolution BPT-diagram analysis • Map the metallicity/age distribution in disc galaxies • Study Compact Star Clusters in the nuclear and circumnuclear regions of normal galaxies • Study Feedback: the interaction between massive stars and the ISM • Detect and quantify the diffuse ionized gas in the sample galaxies • Study Star-formation in low-density environments

4. The Sample • All galaxies inside a volume of 3.5 Mpc • Plus all irregulars and spirals within a volume of 11 Mpc • Plus a sample of Virgo Galaxies • 224 Galaxies in Total

5. LUS strategy • Map the sample galaxies in both a number of selected emission lines plus continuum • The lines selected are Lick indices motivated • Use Galex, SDSS, 2Mass & Spitzer BB photometry • The logistics is dictated by the need to cover most relevant lines and continuum feature sparing observing time • Use the OSIRIS TF and BB for the observation • Preliminary results show that to achieve our goals we require narrow band images with photometric accuracy < 5% ...

6. What we have so far

7. M101

8. M101 region Hα

9. M101 region SII

10. The LUS Pipeline (IRAF based) • Pre-reduction: bias, flat, and trim • Each chip treated individually • Cosmic Ray and Bad Pixel Masking (pending) • Alignment of the images: geomap, geotran and imcombine • Create a Weight image by combining 1 – 0 fake images using the same dithering pattern as for the real images • PSF-Matching before stacking (pending) • Astrometry and creation of a single image: ccxymatch, ccmap, imcombine, mkpattern, ccsetwcs, wregister (applied to the images and the weight)

11. Example: NGC 5949

12. LUS Pipeline: Step II • Flux calibrate using the S3 Method: • Select isolated SLOAN stars • Use the SEGUE spectroscopic data base to fit the observed SEDs (http://segue.uchicago.edu/) • Use best Spectra to find the conversion between counts and flux in the NB TF images

13. NGC 5949 Hα Image (λc=6572 Å, Δλ=12 Å) SLOAN Id K factor J152726.30+644617.1 1.67239e-17 J152731.33+644205.4 1.34703e-17 J152737.48+644402.0 1.56477e-17 J152738.39+644750.6 1.64536e-17 J152739.92+644643.4 1.56409e-17 J152744.18+644339.9 1.61065e-17 J152748.74+644825.6 1.53437e-17 J152825.81+644514.3 1.52459e-17 J152834.75+644643.5 1.60957e-17 < K Factor > = (1.56 +- 0.095)e-17 erg s-1cm-2/count s-1 Photometric Error~ 6%!

14. Full Monochromatic Ha Image of M101 - SW

15. Summary • LUS intends to disentangle the individual history of each galaxy of a large sample of local galaxies • Each galaxy carries its history in its stellar populations • Using the large FoV of OSIRIS and its TF capability • So far we are working with preliminary data & optimising the strategy • Depend heavily on the availability of the Blue TF • Preliminary data looks promising