1 / 43

SDSS and UKIDSS

SDSS and UKIDSS. Jon Loveday University of Sussex. Outline. Sloan Digital Sky Survey status UK Infrared Deep Sky Survey overview and status K -band luminosity function from matched SDSS-UKIDSS sample Future prospects. SDSS1 Survey Goals. Make definitive map of local universe

keely
Download Presentation

SDSS and UKIDSS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. SDSS and UKIDSS Jon Loveday University of Sussex

  2. Outline • Sloan Digital Sky Survey status • UK Infrared Deep Sky Survey overview and status • K-band luminosity function from matched SDSS-UKIDSS sample • Future prospects

  3. SDSS1 Survey Goals • Make definitive map of local universe • Image quarter-sky in five colours ugriz • Measure 50 million galaxy images to r~22 • Obtain spectra for 1 million galaxies and 100,000 quasars • SDSS1 ended June 2005, immediately followed by SDSS2 http://www.sdss.org

  4. SDSS2 - commenced July 2005 • Legacy survey • complete SDSS1 goals • SEGUE • Galactic structure • Supernovae • Repeated imaging of southern equatorial stripe

  5. SDSS Status (March 2006) • Unique area imaged (sq deg) • North: 7561 essentially completed 30 Jan 2006 • South: 739 • 210 million objects detected • Spectroscopy: 1819 plates inc spectra of • 697,757 galaxies • 93,083 QSOs • 253,261 stars

  6. Data Release 4 • Published July 2005 • Imaging area 6670 deg2 • Photometry of 180 million unique objects • Spectra of 849,920 objects over 4783 deg2: 565,715 galaxies 76,483 quasars 102,714 stars

  7. Imaging Spectroscopy

  8. Data Release 5 • Due summer 2006 • Imaging area 8000 deg2 • Photometry of 215 million unique objects • Spectra of 1,048,960 objects over 5740 deg2: 674,749 galaxies 90,611 quasars154,925 stars

  9. Imaging Spectroscopy

  10. SDSS Cosmological Highlights • Highest known redshift quasar (z = 6.4) • Large scale structure cosmological constraints • Galaxy properties and environment • Detection of baryon acoustic peak • More than 1000 publications using SDSS data, with 29,000 citations

  11. z=6.4 Quasar Gunn-PetersonTrough Fan et al 2003

  12. Cmbgg OmOl CMB + LSS WMAP only + SDSS Tegmark et al 2004

  13. UKIDSS • UK Infrared Deep Sky Survey • Consortium of most UK astronomy departments • UKIRT 3.8m telescope plus WFCAM (4x20482 Hawaii-II arrays, 0.21 deg2) • Etendue of 2.38 m2 deg2 largest of any IR camera until VISTA • zYJHK (1 ~ 2.5 ) near-IR filters • 5 surveys, 3 extragalactic • Significantly deeper than 2MASS

  14. UKIDSS (contd) • Observing started May 2005 • 7 year observing plan (~50% of UKIRT time) • Pipeline processing in Cambridge, archive in Edinburgh • No proprietary data period • Data immediately available to ESO members once verified • Rest of world 18 months later

  15. UKIDSS filters

  16. Why Near-IR? • 2 light traces mass in evolved stars - provides good estimate of stellar mass • Helps identify cool dwarf stars and high-z quasars (optical dropouts) • Less sensitive than optical light to dust reddening and type-dependent K-corrections

  17. Quasars vs dwarf stars T6 brown dwarfz =7 quasar

  18. UKIDSS Surveys

  19. Comparison with 2MASS Lawrence et al 2006 in prep

  20. UKIDSS Status http://apm14.ast.cam.ac.uk/status/wfcam/

  21. UKIDSS Early Data Release • Available to ESO community 2006 Feb 10 • ~1% of final sample, comparable to 2MASS

  22. Data Access • Via WFCAM Science Archive (Edinburgh) http://surveys.roe.ac.uk/wsa • Need to register with your community contact • SQL interface will be familiar to SDSS CAS users • NB: EDR data not all of final survey quality

  23. Early application of SDSS + UKIDSS • K-band luminosity function • UKIDSS K-band photometry • SDSS redshifts

  24. Current estimates Bell et al 2003Grey: Cole et al 2001

  25. K-band luminosity function • Use UKIDSS “EDR+” sample: includes areas of sky with incomplete filter coverage • Match UKIDSS EDR+ LAS with SDSS DR5 main sample galaxies (r < 17.7) • Tolerance 2 arcsec (nearly all matches within 1 arcsec) • Use Petrosian magnitudes

  26. Sky Coverage “EDR+” inc. areas with incomplete filter coverage

  27. Sky Coverage Matched with SDSS DR5 main galaxy target

  28. Sky Coverage Has redshift and K-band detection

  29. K-band Completeness LAS galaxies 16.0 SDSS matches 14.0

  30. r-K colours Completeness of matched sample (K=14) limited by SDSS r limit (17.77) and reddest r-K colour (~3.8)

  31. LF Estimate • Use complete sample (K < 14)  1287 galaxies (fewer than 50%) • K-corrections to z = 0.1 from template fit to SDSS ugriz using kcorrect v4 • STY, SWML estimators of (MK) - independent of density inhomogeneities

  32. Bivariate LF • Use entire matched sample by estimating SWML bivariate (Mr, MK) allowing for SDSS r flux limit (r < 17.7) • Sample size 3249 galaxies, but faintest galaxies will now be bluer than average • Integrate over Mr to obtain (MK) • Fit Schechter function by least squares

  33. Conclusions/Future Prospects • UKIDSS-SDSS K-band LF consistent with earlier estimates using 2MASS • Measurements will improve considerably with more data • UKIDSS Data Release 1 (DR1) due mid-2006 will have ~10 times as much data • Two year goals: • LAS half complete • DXS full depth in JK over 3.1 deg2 • UDS K = 22.8, J = 23.8

  34. Future Plans • Investigate type-dependence of K-band LF and its evolution • Comparison with optical distinguishes stellar mass accumulation with star formation history • Evolution to z ~ 0.3 with SDSS redshifts • Higher-redshift evolution using photometric redshifts

  35. Future Plans (2) • SDSS Southern stripe co-added data plus UKIDSS DXS excellent for photo-z • Possible volume-limited redshift survey using AAOmega • Clustering evolution of K-limited (stellar mass selected) samples • VISTA …

  36. Websites • http://www.sdss.org • http://www.ukidss.org • http://surveys.roe.ac.uk/wsa

More Related