1 / 21

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:.

bernard-peck
Download Presentation

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

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. 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

More Related