1. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses SNLS – The SuperNova Legacy Survey Mark Sullivan (University of Toronto) on behalf of the SNLS collaboration http://cfht.hawaii.edu/SNLS/

2. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses The 5-year CFHT Legacy Survey… in 10 minutes Utilises Megacam, a 36CCD/1 sq deg imager Deep/SNLS component has: 202 nights over 5 years Repeat observations over four fields 5 epochs per field per month (10 visits/month) g’r’i’z’ observed on each epoch (tweaked to allow for moon) Hence rest-frame UBVR sampled every 3-4 days in the SN rest-frame Field Name Other data/surveys D1(02:26,-04) VIMOS, SWIRE, GALEX, XMM Deep D2(10:00,+02) COSMOS/ACS, VIMOS, SIRTF, GALEX, XMM etc. D3(14:19,+53) Groth Strip – ACS, DEEP-II, GALEX etc. D4(22:15,-18) XMM Deep

3. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Primary science goals Primary goal: Use SNe Ia to determine “w” Many other talks for details on how SNe Ia can help to constrain w SNLS Goal: 1000 SNe Ia (across all redshifts) Calibration goal: 1-2% photometric accuracy SNLS provides many consistency checks on the use of SNe Ia, e.g. SN colour evolution – multi-colour consistency check Detailed studies of spectral evolution (e.g. talk by P. Nugent + VLT/Gemini spectra) Collaboration with Carnegie to construct rest-frame I-band Hubble diagram (minimise dust extinction)

4. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Secondary goals – other SN science Type Ia/II SN rates  co-moving SF density (z), SNe Ia progenitor information SNe IIP as standard candles via expansion vel. Independent confirmation of accelerating Universe? Host galaxy studies (SNLS fields have a wealth of HST imaging + ugriz deep host photometry) In summary: a wealth of exciting SN science

5. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses How it works – I Raw Data PSFmatch/Search algorithms

6. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses How it works Data reduced in real-time by Elixir Two independent search pipelines PSF-match the “reference” and “epoch” images Subtract… … and search the difference images Real candidate PSFmatch errors from saturated objects easily rejected

7. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Detections ~90% agreement between the two pipelines to i’=24.5 As of May 2004, the database contains (over 4 fields): 222 AGN candidates 328 SN candidates (of all flavours…) 282 “repeatedly varying” stellar objects Even with ~120 hours/semester of 8-10m spectroscopic time, we cannot hope to follow all these candidates However – we have a wealth of real-time photometric information – unprecedented when compared to previous surveys

8. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Photometric pre-screening So, we use a SN photo-z technique to identify our priority candidates Performs a least-squares fit to 2-3 epochs of data over (phase,redshift,stretch,reddening) to a Ia spectral template Non-SNe Ia screened out (colour e.g. g’-r’, rise-time..) (conservative cuts) Identifies priority candidates for follow-up – especially valuable in poor weather conditions

9. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Photometric-redshift analysis (all spectroscopic redshifts from March  May 2004)

10. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Current status Survey “proper” commenced Aug 1, 2003 (pre-survey March  July 2003) Atrocious winter on Mauna Kea, some technical issues All observing is queue-scheduled – big advantage in poor weather conditions New priority agreements – SNLS has priority on time- critical nights

11. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Current status – typical light-curves Typical time-sampling from early (pre-survey and start of survey) SN discoveries (this shows real-time Elixir photometry only)

12. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses How many SNe will there be? Cumulative number of supernovae (to end April 2004)

13. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses How many SNe will there be? Cumulative number of supernovae to survey end

14. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses How many SNe will there be? Cumulative number of supernovae – with photometric typing and a host redshift

15. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Current status – N(z) Current spectroscopic N(z) (includes SNe from September 2003  April 2004) ~70 SNe Ia from an 8 month period

16. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Current status – N(z) Total predicted number of detected SNe (detection efficiency calculated by J. Guy)

17. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Current status – N(z) Total predicted number of spectroscopically followed SNe Distribution appears as expected to z=0.6

18. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Predicted cosmological constraints Constraints on w expected after 5 years based on current survey progress (Red indicates constraints using Ω M determination from CFHTLS “wide” )

19. Padua: 1604 → 2004 – Supernovae as cosmological lighthouses Want to know more? Check out these websites for all the details: Project overview, collaboration members, publications: http://cfht.hawaii.edu/SNLS/ Candidate database, real-time candidate lists: http://legacy.astro.utoronto.ca/ Also: see posters by A. Howell and S. Basa