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The 6dF Galaxy Redshift Survey: Status Report and Data Release 2

100,000 REDSHIFTS. The 6dF Galaxy Redshift Survey: Status Report and Data Release 2. Heath Jones ANU/AAO. Will Saunders AAO. Mike Read Edinburgh. Matthew Colless AAO. The 6dF Galaxy Survey:.

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The 6dF Galaxy Redshift Survey: Status Report and Data Release 2

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  1. 100,000 REDSHIFTS The 6dF Galaxy Redshift Survey:Status Report and Data Release 2 Heath Jones ANU/AAO Will Saunders AAO Mike Read Edinburgh Matthew Colless AAO

  2. The 6dF Galaxy Survey: • The 6dFGS is designed to be the first of a new generation of combined z+v-surveys, combining… • NIR-selected redshift survey of the local universe • Peculiar velocity survey using FP distances • Additional redshift surveys of other ‘interesting’ source samples.

  3. The 6dF Galaxy Survey: • The 6dFGS is designed to be the first of a new generation of combined z+v-surveys, combining… • NIR-selected redshift survey of the local universe • Peculiar velocity survey using FP distances • Additional redshift surveys of other ‘interesting’ source samples. • Survey strategy… • survey whole southern sky with |b|>10° • primary z-survey: 2MASS galaxies to Ktot<12.75 • secondary samples: H<13, J<13.75, r<15.6, b<16.75 • 11 additional samples: radio, X-ray, IRAS… • v-survey: ~15,000 brightest early-type galaxies

  4. Selection in the NIR (J,H,K) minimizes extinction effects of extinction - galaxies can be selected over |b|>10° Advantages - NIR selection

  5. Advantages - NIR selection • Selection in the NIR (J,H,K) minimizes extinction effects of extinction - galaxies can be selected over |b|>10°. Cole et al (2001) • NIR luminosity is very closely correlated with total stellar mass, and so yields the stellar mass function. log (Mstars/h-2M)

  6. Advantages - Sky Coverage • Selection in the NIR (J,H,K) minimizes extinction effects of extinction - galaxies can be selected over |b|>10°. 2dFGRS • NIR luminosity is very closely correlated with total stellar mass, and so yields the stellar mass function. • The 6dFGS has 8x the sky coverage of the 2dFGRS and twice the coverage of SDSS. SDSS

  7. Advantages - NIR selection • Selection in the NIR (J,H,K) minimizes extinction effects of extinction - galaxies can be selected over |b|>10°. • NIR luminosity is very closely correlated with total stellar mass, and so yields the stellar mass function. • The 6dFGS has 8x the sky coverage of the 2dFGRS and twice the coverage of SDSS. • Traditionally, most redshift surveys have been optically selected and therefore favoured late-type galaxies. In contrast, the NIR selection of 6dFGS is biased towards the redder early-type galaxies needed for the Peculiar Velocity Survey.

  8. Number of Tiled Sources Number of Sources on Sky • Target allocation 92% or better for the primary and secondary samples. Target Allocation

  9. Target allocation 92% or better for the primary and secondary samples. • Additional target samples extend science and fully exploit survey: • 2MASS NIR sky survey • DENIS NIR sky survey • SuperCosmos galaxy catalogs • ROSAT All-Sky Survey (RASS) • HI Parkes Sky Survey (HIPASS) • IRAS Faint Source Catalog (FSC) • NVSS and SUMSS radio surveys • Hamburg-ESO QSO survey Target Allocation

  10. DR 2: 0 % 5 % 7 % 77 % 11% <1% V grating: dl = 5 – 6 A • Q=1 - spectra of no value • Q=2 - possible z value • Q=3 - likely z value • Q=4 - z value beyond doubt • Q=5 - textbook example • Q=1 - spectra of no value • Q=2 - possible z value • Q=3 - acceptable z value • Q=4 - z value beyond doubt • Q=5 - textbook example R grating: dl = 9 – 12 A • Q=6 - Galactic source

  11. 6dFGS The Observing/Redshifting Cycle • Preparation, observing, reducing follows the lunar cycle

  12. 6dFGS The Observing/Redshifting Cycle TELESCOPE Mt STROMLO • Preparation, observing, reducing follows the lunar cycle • Redshifting takes place in the following lunation • Survey results are updated/reported ~6 weeks after observation

  13. 6dFGS Online Database: • Searchable using either SQL query commands or a WWW form • Each source has its own multi-extension FITS file, including 6dF spectrum, brJHK imaging, redshift and photometric information • The different target catalogues are also online, fully searchable and inter-linked http://www-wfau.roe.ac.uk/6dFGS/ DR2 6dFGS 2nd Data Release: April 2005 • Jan 2002 – October 2004 for public release  89211 spectra; 83014 unique redshifts; 936 fields • 36540 more redshifts (37163 more spectra) than DR1

  14. Recalibrated br SUPERCosmos photometry (BMAG, RMAG) and the preservation of the old selection magnitudes (BMAGSEL, RMAGSEL): Around7% have disparate irreconcilable proximity and mag rankings Around 1% have no br match at all What’s New Since DR1 • Data and database structure largely unchanged since DR1 • Recent introduction of a QSO template for redshifting (~Aug 05 onwards) • Introduction of Q=6 for confirmed Galactic spectra (formerly Q=2)

  15. Number-Redshift Distribution • Median z for 6dFGS (z=0.05) is roughly half that of 2dFGRS and SDSS • When complete, the population of 6dFGS galaxies at low redshifts will be on a par with the other surveys

  16. 2MASS Redshift Maps: ~90k redshifts

  17. 547 fields 595 fields 422 fields 6df Survey Sky Coverage • 1564 fields over southern sky with |b| >10 = 17000 • Observing strategy has been to cover the sky in thirds: (1) central strip; (2) equatorial strip; (3) southern polar cap.

  18. 6dF+ ZCAT +2dF… Number of Galaxy Redshifts Per Unit Area Number of Galaxy Redshifts 6df + Failures + Remaining Per Unit Area Survey Sky Coverage • 1564 fields over southern sky with |b|>10 = 17000 • Observing strategy has been to cover the sky in thirds: (1) central strip; (2) equatorial strip; (3) southern polar cap. • 1375 fields observed to date – 936 fields from January 02 to October 04 constituting the Second Data Release

  19. Survey Sky Coverage DR 2 (2005) DR 1 (2004)

  20. Breakdown of spectra extragalactic (85 %) stellar (3 %) HII regions,PNe (1%) failures (11 %) 80% of fields > 80% complete Number of 6dF Galaxy z’s per field 90% of fields > 60% Number of 6dF Galaxy Redshifts + Redshift Failures per field Field Completeness

  21. 6dFGS Home  http://www.aao.gov.au/local/www/6df/ • 6dFGS Database http://www-wfau.roe.ac.uk/6dFGS/ MOVED ! 6dFGS Second Data Release: Summary • Jan 2002 – October 2004  89211 spectra; 83014 unique redshifts; 936 fields • Definitive 6dF Survey Paper (DR1):  Jones et al (2004), MNRAS355, 747 • DR2 paper Jones et al, PASA

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