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DESpec survey strategy : realistic mock catalogue and target selection

DESpec survey strategy : realistic mock catalogue and target selection. Stephanie Jouvel , Filipe Abdalla , Huan Lin, James Annis , Richard Kron 22 jun 2011. PLAN : Investigate DESpec survey strategy. Build realistic Mock Catalogues of the DES + VISTA survey

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DESpec survey strategy : realistic mock catalogue and target selection

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  1. DESpec survey strategy :realistic mock catalogueand target selection Stephanie Jouvel, Filipe Abdalla, Huan Lin, James Annis, Richard Kron 22 jun 2011

  2. PLAN : Investigate DESpec survey strategy • Build realistic Mock Catalogues of the DES + VISTA survey • Derive spectrograph/fibers sensitivities for ground-based observation • Investigate redshift distribution and galaxy density for DESpec science • Which tragetting strategy ? What criterion in photoz or color-color space ?

  3. Galaxy Properties from Deep Surveys the COSMOS survey 2deg2 (representative)‏ 30 photometric bands from UV to IR with HST, Galex, Spitzer, Subaru, VLA, NOAO HST/ACS I band observation: galaxy sizes & shapes zCosmos spectroscopic survey Koekemoer et al. 2007 • the VVDS “Deep” survey • VIMOS/VLT deep spectroscopic survey on ~0.5 sq.deg • ~9000 spectra from 0<z<5 down to IAB ~24 (magnitude selected)‏ Le fèvre et al. 2005

  4. Building Mock Catalogues Use this catalogue COSMOS Mock catalogue GOODS Luminosity Function catalogue COSMOS catalogue (position, size, photometry)‏ 1 million galaxies Simulated Catalogue based on GOODS LF(z,type)‏ GOODS LF from Dahlen et al. 2005 Jouvel et al. 2009 Photoz, SED, emission lines COSMOS size distribution, emission lines - Realistic redshift distribution, - Realistic size distribution, - Emission line fluxes catalogue COSMOS photoz from Ilbert et al. 2009 Photometry in DE mission filter sets + Photometric errors Jouvel et al 2010 DE Forecast Stephanie Jouvel

  5. COSMOS Mock Catalog (CMC)‏ Construction using the properties of the COSMOS-ACS WL catalog using : - realistic photometric redshift distribution 30 photometric bands calibrated with spectroscopic redshift : > zCOSMOS bright (I~22 AB) > zCOSMOS faint (I~25 AB) > MIPS-spectro-z sample - best-fit template from this photoz distribution - galaxy size measured by Sextractor from Leauthaud et al 2007 Validation of the CMC using : - GOODS N&S visible - UDF visible + jhband - VVDS Ks band + spectro-z - GOODS-MUSIC Ks band

  6. COSMOS Mock Catalogue(CMC) • We want precision cosmology • Need for realistic mock catalogues to test photoz codes : • Realistic redshift distribution • Impacts DE FoM from WL • - Realistic distribution of galaxy • sizes in redshift and magnitude • => Realistic noise distribution impact photoz results • Emission line catalogue • Create spectroscopic catalogue to study photoz calibration Stephanie Jouvel

  7. COSMOS Mock Catalog (CMC)‏ : Validation Validation of the redshift distribution and emission line fluxes using the VVDS-DEEP I~24 AB (Lamareille et al 2008)‏ Emission line prediction : Kennicutt et al. 1998 : UV-OII relation Jouvel et al. 2009

  8. Spectroscopic Success Rate (SSR) :Validation using VVDS SSR : galaxy rate for which we will be able to measure a redshift Validation : reproducing the VVDS SSR Jouvel et al. 2009

  9. PhotoZ Calibration Survey (PZCS): Spectroscopic Success Rate (SSR)‏ In the context of the JDEM survey we simulated different spectroscopic surveys : WIDE NIR photometric calibration (BAO–RD survey)‏ • template • calibration: • DEEP-visible-NIR • DEEP-NIR Jouvel et al. 2009

  10. SSR Forecast for PZCS • Forecast : • DEEP-NIR • space survey (PZCS)‏ DEEP-NIR : I~27 0.5<z<3.5 35gal/arcmin2 Jouvel et al. 2009

  11. SSR forecast for PZCS Forecast : DEEP-visible-NIR space survey (PZCS)‏ DEEP-vis-NIR : I~27 0<z<3.5 60gal/arcmin2 Jouvel et al. 2009

  12. SSR Forecast for PZCS Forecast : WIDE-NIR space survey (BAO like)‏ WIDE-NIR : H ~22 0.5<z<1.5 5gal/arcmin2 Jouvel et al. 2009

  13. DESpec survey strategy : 1. Mock catalogue and photoz

  14. DES+VISTA photometric redshift ANNz training with 10000 galaxies Le Phare with COSMOS templates

  15. DESpec survey strategy : 2. Target selection

  16. Line sensitivities from Huan Lin - Sensitivities for 30 mins exposure time on 2 arcsec ø fibers (70% light fraction) - Resolution R=2500 at 0.9um. - Calculation include DES throughput + sky noise and atmospheric lines from Hanuschik (2003)

  17. Redshift distribution from em lines • Redshift distribution of emission line galaxies selected with : • I (DES) < 23 • 1 < photoz < 2 • at least one em line detected at 5 sigma • Photoz with Le Phare (template fitting method) u DES+VISTA • Can we select the emission line galaxies based on DES+VISTA photometry only ? Total of roughly 12000 gal/deg2

  18. Multidimensional method based on NN selection

  19. Use of NN to select em line galaxies • We assign a value of : • 1 for targetted em line galaxies • 0 for non targetted galaxies • We then use ANNz and train a NN on a sample of 10000 galaxies from the CMC (DES+VISTA) • Results for i(DES) < 24

  20. Which ANNz selection criterion ? • Fig : Cumulated nbr galaxies/deg2 fct ANNz target probability • We suggest a selection criterion of 0.8 yielding to : • 7500 emission line galaxies / deg2 i(DES)<24 • and a contamination of 800 gal/deg2 i(DES)<24 0.8

  21. Which ANNz selection criterion ? • Solid : percentage of galaxies for which we will measure a redshift/total nbr gal & Dashed : SSR fct ANNz target probability • We suggest a selection criterion of 0.8 yielding to : • 7500 emission line galaxies / deg2 i(DES)<24 • and a contamination of 800 gal/deg2 i(DES)<24

  22. Redshift distribution of ANNz sel 0.8

  23. Redshift distribution / em lines gal

  24. Redshift distribution / em lines gal

  25. Redshift distribution / em lines gal

  26. Line sensitivities from Huan Lin 0.6-1um - Sensitivities for 30 mins exposure time on 2 arcsec ø fibers (70% light fraction) - Resolution R=2500 at 0.9um. - Calculation include DES throughput + sky noise and atmospheric lines from Hanuschik (2003)

  27. Use of NN to select em line galaxies • We assign a value of : • 1 for targetted em line galaxies • 0 for non targetted galaxies • We then use ANNz and train a NN on a sample of 10000 galaxies from the CMC (DES+VISTA) • Results for i(DES) < 24 Using Huan Lin sensitivities cut between 0.6-1um

  28. Which ANNz selection criterion ? • Fig : Cumulated nbr galaxies/deg2 fct ANNz target probability • We suggest a selection criterion of 0.8 yielding to : • 7500 emission line galaxies / deg2 i(DES)<24 • and a contamination of 800 gal/deg2 i(DES)<24 Using Huan Lin sensitivities cut between 0.6-1um 0.8

  29. Which ANNz selection criterion ? • Solid : percentage of galaxies for which we will measure a redshift/total nbr gal & Dashed : SSR fct ANNz target probability • We suggest a selection criterion of 0.8 yielding to : • 7500 emission line galaxies / deg2 i(DES)<24 • and a contamination of 800 gal/deg2 i(DES)<24 Using Huan Lin sensitivities cut between 0.6-1um

  30. Redshift distribution of ANNz sel 0.8 Using Huan Lin sensitivities cut between 0.6-1um

  31. Photoz for the NN target galaxies

  32. Can we do color-color cut ? g-r vs r-i r-i vs i-z It looks difficult to select the OII line in a coloc-color cut. We need a higher dimensional kind of cut such as photoz codes can provide

  33. Conclusion • We simulated a DES+VISTA catalogue using the CMC which include emission line fluxes. • Huan Lin derived a fiber sensitivities including all instruments troughput and sky noise including astmospheric lines for a DESpec instrument. • Using Huan Lin sensitivities we can select emission line galaxies from DES+VISTA photometry using ANNz. • We suggest a selection criterion of 0.8 with a yield of 8000gal/deg2 for i(DES)<24 and a success rate of 93% or 5000gal/deg2 i(DES)<23 and a success rate of 95% (to verify). • A color-color cut does not seem the optimal solution to select target for DESpec.

  34. COSMOS Mock Catalog (CMC): Validation Jouvel et al. 2009

  35. COSMOS Mock Catalogue(CMC) • We want precision cosmology • Need for realistic mock catalogues to test photoz codes : • Realistic redshift distribution • Impacts DE FoM from WL • - Realistic distribution of galaxy • sizes in redshift and magnitude • => Realistic noise distribution impact photoz results • Emission line catalogue • Create spectroscopic catalogue to study photoz calibration Stephanie Jouvel

  36. Emission lines • z = 0 H-a 6563 A Ly-a 1215 A OII 3726-3729 A doublet H-b 4861 A OIII 4959A and 5007A • z~2.5 : Ly-a 4250 OII 13000 • z~3.5 : Ly-a 5460

  37. Results from CMC : Photoz calibration • work with Gary Bernstein • as part of the SNAP-WL group • Simulation of spectroscopic survey using forecast survey sensitivities for :optical/+NIR surveys, SHALLOW or DEEP. • => No photoz calibration possible for z<0.5 & z>1.6 galaxies. • => Need of visible + NIR spectroscopy to cover the whole redshift range of future photometric surveys. Jouvel et al. 2009 Stephanie Jouvel

  38. Photoz : Need for spectroscopic calibration Successful method to remove systematic trends • u* +0.019 • g’ -0.079 • r’ -0.002 • i’ 0 • Z’ -0.008 Importance of the zero-point calibration Further improvement of the templates Ilbert et al.2006

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