1. H Stacked Images Reveal Large Numbers of PNe in the LMC
Warren Reid1
Quentin Parker1,2
1Macquarie University,
Sydney, Australia
2 Anglo-Australian Observatory

2. A Unique Set of Matching Images
Deep Ha and equivalent R-band images of the entire 25.sq.deg. central LMC
Monolithic, high quality Ha filter
High-resolution Tech-Pan film
SuperCOSMOS scanned and co-added exposures arcsec pixels after 15-bit digitized plate scanning. (SHASSA = 48 acrsec resolution WHAM = 1 degree resolution)
Depth reaches R-equivalent ~22 for Ha and R ~21.5 for Red
Advantages of the stacking process
IAM data
Red
9 x 15min Stack Hα
13 x 2hr Stack
New PN!

3. SuperCOSMOS scanned UKST Images
R-band, Tech-pan single exp.
R-band, Tech-pan stacked
R-band, IIIaF
Ha, Tech-pan single exp.
Ha, Tech-pan stacked

4. Colour combination of Red and Ha Stacked Images+ =
Red Stack
Ha Stack + =

5. Method of Image Analysis
16 x 1.25 sq.deg. image cells
Accurate WCS applied
Image colouring and Intensity matching
PSF matching on continuum sources
Diameters recorded
Magnitudes calibrated to bright photometry from the Tycho and Guide star Photometric catalogues. Faint calibrations are tied to CCD standards from:
Groom et.al. (1999, MNRAS, 306, 592)
Boyle et.al. (1995, MNRAS, 276, 33)
Stobie et.al. (1985, A&AS, 60, 503)
Large numbers of candidate PNe found

6. Previously Known PNe Re-identified
SMP 90
SMP 89
Mo 35
Mo 39
Mo37
Mo 36

7. RP 105, a newly discovered and confirmed PN with an elliptical halo

8. SMP 27
HST bb 9” x 12” image revealing outer structure

9. SMP27

10. HST image of the central PN scaled to the UKST image
SMP 93 with Extended Halo
HST image of the central PN scaled to the UKST image

11. 2dF Spectroscopic Follow-up
New PNe discovered from our survey and confirmed with 2dF on the AAT within a 1.25 square degree area
versus
Previously known PNe within the same area

12. Images and Spectra
PR 23
RP 25

13. Images and Spectra
RP 85
RP 92

15. Difference in Ha magnitude between Central PN and Central PN plus Halo
(with a sample of 71 PNe)
Difference in Ha Magnitude between Emission-line Star and Ha Spread Function
(with a sample of 39 ELS)

16. PNe halo radius beyond the Central PN vs
PNe halo radius beyond the Central PN vs. the difference in Ha magnitude between the central PN and the whole PN including the halo
Each diameter bucket contains an average magnitude for that Halo diameter

17. Newly Discovered PNe

18. Science Implications Comprehensive LMC PNe Luminosity Function
To understand evolutionary types in the LMC
To provide a probe into the structure and origin of the LMC
As a distance probe when applied to other Hubble-type Galaxies
Chemical Abundances and Ratios
Shells provide a tool to study ejected material, giving insight into precursor evolution
H-R Diagrams based on Diameters, Fluxes, Nebula Temperatures and Densities
Specific line ratios can be used in conjunction with photoionization modelling to determine stellar parameters
Parameters of AGB Halos
Initial to Final Mass Relation
An updated and comprehensive catalogue of LMC PNe

19. Conclusion
Thus far 6/16 image cells have been carefully analysed to extract the position, magnitude and dimensions of every possible emission source.
Detection rate increases 3-fold on the main bar
Each source is added to the database with an estimate as to it’s probability as a PNe or Emission-line star.
All previously known PNe have been re-identified independently.
Of 262 candidate sources observed using 2dF on the AAT from spectroscopic follow-up of candidates in 3 cells we find:
136 are confirmed PNe,
57 are Emission-line stars,
33 require longer exposure times
33 are non-detections.
From current estimates we expect to discover >1,000 new Pne within the 25 square degrees of the main LMC bar.
A 5-night run allocated with 2dF on the AAT in December 2004 will confirm most candidates.
A proposal to observe PNe for faint diagnostic lines on VLT/FLAMES is in.
A proposal to observe PN Halos for chemical abundances, velocities and densities on VLT using IFUs.

21. Known PN with HST bb Images superimposed to scale
SMP 88, Central PN dia = 1.5 arcsec. Halo dia = 8.1 arcsec
SMP 89, Central PN dia

22. DSS SuperCosmos
Stacked SuperCOSMOS

23. DSS SuperCOSMOS
Stacked SuperCOSMOS