Evaluation of 6dF Data

1. Evaluation of 6dF Data Lesa Moore Macquarie University Honours Project 2003 Supervisor: Quentin Parker MU/AAO

2. Goals of Honours Project • Independent evaluation of results from 6dFDR and RUNZ • Comparison analysis using IRAF dofibers, line measurements, xcsao and emsao • Test 6dFDR and RUNZ for accuracy and systematic errors by comparison with IRAF results • Test 6dFDR and RUNZ for repeatability • Report to survey team with results and recommendations

3. Target and Observed Fields One field studied to date My first field!!

4. Field Details • 0924m30 • Observed 20/3/2002 • Reflection gratings 600V: 4000-5600Å; 316R: 5500-8500Å • 109 spectra, 28 parked fibres, 13 skies

5. Batch-Mode Reduction • 6dFDR, RUNZ on separate V, R and spliced VR data using 6dFDR arc-line lists (see later!) • IRAF dofibers on V, R data using my own arc-line lists (NIST Atomic Spectra Database:http://physics.nist.gov/cgi-bin/AtData/lines_form) • IRAF xcsao on R grating data only • No heliocentric correction applied (raw redshifts only)

6. Comparison Spectra - 1 IRAF data not flux-calibrated

7. Comparison Spectra - 2 IRAF data not flux-calibrated

8. Signal-to-noise comparison(mean for 109 galaxies) Data from: IRAF - measured in splot; RUNZ - 0924Rcom.sdfz.zlog

9. Problems encountered • Discovered HgCdNe line list has too few Ne, extra Ar and miscellaneous lines • High-dispersion data: only 13 good arc lines in HgCdHe line list: - 6dFDR throws away 3 worst lines - can’t afford this! • Heliocentric correction incorrectly applied, correct on: /net/aaowfi/data1/will/runz/runz6df_may03

10. Arc spectrum R - HgCdNe

11. R-arc line-identification compared (subset of 10 fibres) Data from: IRAF – arcapid.t.ms; 6dFDR – arclist006.dat On 108 spectra, mean rms IRAF 0.1816; 6dFDR 0.1539

12. IRAF 6dFDR • Line lists and matched lines in dispersion functions • Red: neon lines to be added • Blue: 6dfdr desert

13. Arc spectrum R - HgCdNe

14. Arc spectrum V - HgCdHe • Not enough lines in high-dispersion data to be used for Dn-s measurements? • Even with extra lines from NIST ASD, still only 16 good lines

15. IRAF R 57 Agreement: batch x-cor results • V data, R data and VR data compared • Dz ≤ 0.0005 (150 km/s) out of 109 spectra RUNZ R RUNZ V 45 43 69 78 RUNZ VR

16. RUNZ-VR misidentifications 11/109 V 21/109; R 28/109 z = ~ 0.09

17. R data: 109 galaxies - r-h plots from both x-correlations- “disagrees” are low S/N spectra Data from: IRAF – xcsao.log; RUNZ – read from display (r writes to log)

18. Mean uncertainty in x-correlation 109 galaxies Data from: IRAF – xcsao.log; RUNZ – verr from 0924Rcom.sdfz.zlog IRAF uses 12 templates, RUNZ uses 8 templates

19. X-correlation R data 57 well-matched galaxies Error bars are x-correlation uncertainties

20. X-correlation R data All 109 galaxies

21. Line Measurements – 9 galaxies

22. Summary Results • S/N appears higher in RUNZ than in IRAF • Line lists should be reviewed • 6dFDR should have “retain all lines” option • Update all versions of RUNZ to do heliocentric correction properly • Can’t batch-process – still need to check for misidentifications • Disagreements between methods and gratings on low S/N data not a matter of concern • X-cor uncertainty could be quoted on RUNZ screen display and should be mentioned in online database • May reduce uncertainty by including more templates for RUNZ • Overall z values concur in cases of proper identification • … and keep in mind …

23. Results from these analyses are preliminary! • Many more fields will be studied • VPH grating data will be compared with reflection grating data • Repeatability of measurements will be tested on repeat observation if possible

24. Thanks • Anglo-Australian Observatory • Wide-Field Astronomy Unit, Edinburgh • Macquarie University • 6df Galaxy Survey Team (37 members) • Will Saunders, AAO • Quentin Parker, MU/AAO