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
*Plots show full hemisphere (360 deg, Celestial equator to SCP)
Top: targets selected from catalogues (NIR and optical imaging surveys)
*Targets plot shows density scale (number of objects per square degree)
*Zone of avoidance – the Milky Way
Bottom: Observed fields as at April 2003 – circles are 6 degrees in diameter
*Gratings have been changed since the commencement of the survey
*Key: Green reflection gratings, grey transmission gratings
*The field I’ve been studying (first of many) is
centred at 9h 24m
17,000 square degrees per hemisphere
4,000 square degrees in zone of avoidance
Adaptive tiling algorithm – allows for varying number density of targets (overlap, some fields need to be observed twice)
Over 1000 fields
My first field!!

4. Field Details 0924m30 Observed 20/3/2002
Reflection gratings V: Å; R: Å
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:
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)
RUNZ R
RUNZ V
9.4253
RUNZ VR
8.8476
IRAF R
3.4753
Data from: IRAF - measured in splot; RUNZ Rcom.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: dFDR 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)
IRAF
6dFDR
# lines in line list 61 46
mean rms
of disp function
0.1930
0.1584
mean # lines fitted
39.5
29.5
Data from: IRAF – arcapid.t.ms; 6dFDR – arclist006.dat
On 108 spectra, mean rms IRAF ; 6dFDR

12. Line lists and matched lines in dispersion functions
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. Even with extra lines from NIST ASD, still only 16 good lines
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. Agreement: batch x-cor results
V data, R data and VR data compared
Dz ≤ (150 km/s) out of 109 spectra
RUNZ R
RUNZ V 45
IRAF R 57 43 69 78
RUNZ VR

16. RUNZ-VR misidentifications 11/109

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
RUNZ R
± 79 km/s
(z ± )
RUNZ V
± 84 km/s
RUNZ VR
± 59 km/s
(z ± )
IRAF R
± 41 km/s
(z ± )
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