The SuperNovae Legacy Survey Overview and First results

Dominique Fouchez ( Centre de physique des Particules de Marseille/ IN2P3 )

On behalf of the SNLS Collaboration

Sino-French workshop on Dark universe Marseille, 23 Sep 2005

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

The SNLS : Overview and First results

• Introduction• Project overview• Current status and first results • Perspectives

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Introduction:The cosmological paradigm

• Today’s universe : Dark matter (30%) + Dark energy (70%)

• Dark energy: caracterised by Equation of State w=p/ w = w(z) In the following w =constant

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Introduction:The principle of the measure

• Hubble diagram of standard candles:– Standard candles– Redshift– Magnitude

• Standard Candle: Standardized Supernovae Ia

• Measure: with a magnitude precision of few 0.01

a precision of 0.1 for <w> will give first indication of Dark energy nature

p

w

z

m

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Project: a SuperNova Legacy Survey

• PRIMARY SCIENCE GOAL : Measurement of cosmological parameters– constraint <w> below the 0.1 precision

• ADDITIONAL GOALS : – Adressing all possible cosmological and astrophycical

issues from such large SN set : • SN rate• SN study, • galaxy formation etc…

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Project: Requirements

• 700 identified, localised, standardised and well measured high z SNIa

– Spectral identification of SN a maximum luminosity– Spectral redshift : from host galaxy and/or SN spectrum– Multicolor LC Photometry = g’,r’,i’,z’ – LC well sampled (~ 5 multicolor epochs per month)– Precise calibration :  few percent accuracy– depth, z=0.3-0.9 (i’ at max < 24.5 )– …

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Project: Requirements

• 700 identified, localised, standardised and well measured high z SNIa

– Spectral identification of SN a maximum luminosity– Spectral redshift : from host galaxy and/or SN spectrum– Multicolor LC Photometry = g’,r’,i’,z’ – LC well sampled (~ 5 multicolor epochs per month)– Precise calibration :  few percent accuracy– depth, z=0.3-0.9 (i’ at max < 24.5 )– …

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Project: Requirements

• 700 identified, localised, standardised and well measured high z SNIa

– Spectral identification of SN a maximum luminosity– Spectral redshift : from host galaxy and/or SN spectrum– Multicolor LC Photometry = g’,r’,i’,z’ – LC well sampled (~ 5 multicolor epochs per month)– Precise calibration :  few percent accuracy– depth, z=0.3-0.9 (i’ at max < 24.5 )– …

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Project: Requirements

• 700 identified, localised, standardised and well measured high z SNIa

– Spectral identification of SN a maximum luminosity– Spectral redshift : from host galaxy and/or SN spectrum– Multicolor LC Photometry = g’,r’,i’,z’ – LC well sampled (~ 5 multicolor epochs per month)– Precise calibration :  few percent accuracy– depth, z=0.3-0.9 (i’ at max < 24.5 )– …

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Project: Requirements

• 700 identified, localised, standardised and well measured high z SNIa

– Spectral identification of SN a maximum luminosity– Spectral redshift : from host galaxy and/or SN spectrum– Multicolor LC Photometry = g’,r’,i’,z’ – LC well sampled (~ 5 multicolor epochs per month)– Precise calibration :  few percent accuracy– depth, z=0.3-0.9 (i’ at max < 24.5 )– …

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Project: Requirements

• 700 identified, localised, standardised and well measured high z SNIa

– Spectral identification of SN a maximum luminosity– Spectral redshift : from host galaxy and/or SN spectrum– Multicolor LC Photometry = g’,r’,i’,z’ – LC well sampled (~ 5 multicolor epochs per month)– Precise calibration :  few percent accuracy– depth, z=0.3-0.9 (i’ at max < 24.5 )– …

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means

• Team : canadian-french+others (UK+US+Port.)

– about 60 collaborators

• Telescope : CFHT+VLT+Gemini• Time :

– about 250H/year in both photometric and spectroscopic observations

• Real time detection pipelines

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means: Telescopes & intruments

• Photometry– CFHT : 3.6 meters at Hawaii

megacam imager of 1 sq degree

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means: Telescopes & intruments

• Spectrocopy : 8m - class– VLT + FORS1– Gemini + GMOS– Others : KECK + LRIS

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means : Real time detection

• Principle of detection– Subtraction of each night (stacked images) on a reference

image to find individual detections

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means : Real time detection

• Principle of detection– Subtraction of each night (stacked images) on a reference

image to find individual detections– Construction of Lightcurve of candidates for all night all filter

at same sky position

days

- =

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means : Real time detection

• Principle of detection– Subtraction of each night (stacked images) on a reference

image to find individual detections– Construction of Lightcurve of candidates for all night all filter

at same sky position– SNIa photometric ranking : to select candidate for

spectroscopy follow up, based on multicolor lightcurve fit

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means : Real time detection

• Principle of detection– Subtraction of each night (stacked images) on a reference

image to find individual detections– Construction of Lightcurve of candidates for all night all filter

at same sky position– SNIa photometric ranking– Two independant real time pipeline (Can & F)

• crosscheck and robustness• Select candidate for spectro after each obs night Result in less than

24H • Dataflow stream : up to 30 Go input/night and up to 10 To output/year

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means : a fully automated pipeline

Detection on each stacked image

Real time science images (Elixir) provided by CFHT automatically trigger the start of the pipeline. Image stack + subtraction is done to produce individual detections detections are send to event database for selection.

Construction and selection of the candidated

• A manual stream (snlsdb), where a visual scanning is used to select and validate the snupernova candidates• An automated selection (ACE), based on neural network trained on image simulation, is used to select the good candidates (better than 90% efficient)

Merging with the other (canadian) pipeline

The output of the pipeline is directed to the common Canada/France candidate database (based at Toronto) A synchronisation of the database is performed each hour ( 90% agreement up to i’=24.5). The choice of candidate for spectro is made on the information collected by both French and canada pipeline

So far (july 2005) we registred about 3000 candidates, 1000 SN like and sent 330 of those to spectroscopy follow-up

No human intervention is necessary up to this stage to produce the candidate list.

Detection on each stacked image

Construction and selection of the candidates

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Means : a fully automated pipeline

Detection on each stacked image

Real time science images (Elixir) provided by CFHT automatically trigger the start of the pipeline. Image stack + subtraction is done to produce individual detections detections are send to event database for selection.

Construction and selection of the candidated

• A manual stream (snlsdb), where a visual scanning is used to select and validate the snupernova candidates• An automated selection (ACE), based on neural network trained on image simulation, is used to select the good candidates (better than 90% efficient)

Merging with the other (canadian) pipeline

The output of the pipeline is directed to the common Canada/France candidate database (based at Toronto) A synchronisation of the database is performed each hour ( 90% agreement up to i’=24.5). The choice of candidate for spectro is made on the information collected by both French and canada pipeline

So far (july 2005) we registred about 3000 candidates, 1000 SN like and sent 330 of those to spectroscopy follow-up

No human intervention is necessary up to this stage to produce the candidate list.

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Status: Real time lightcurves

A sample of lighcurves in each filter …

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Status: Spectroscopy

330 spectra analysed in quasi real time

190 Ia identified with template fitting Identification is performed by 2 fitting of SN database templates

(different type : Ia, Iapeculiar,Ic,IIP … and different phase) and galaxy templates.

Gemini VLT

with SN and Galaxy fitted

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Status: Survey progress

• Almost 2 years of running

May 2005

800 SN like 190 SNIa

2000 SN 700 SNIa

at the end of 2008

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Status: spectro redshift distribution

• Redshift distribution of SNIa : <z>= 0.6

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First Results : Cosmological parameters measurement

• 1 year of data : – 142 spectra

– 20 Type II SNe

– 9 AGN/QSO

– 91 Sne Ia• 10 miss references

• 6 only have 1 band

• Cosmo paramameters measurements = 5 Steps– Differential photometry

– Photometric calibration

– Lightcurve fit

– Cosmology fit

– Systematic uncertainties

75 usable SNIa events

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First result: Differential photometry

• Image model=constant galaxy+point source + sky background

Fit is performed independently On each exposure

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First Results: Lightcurve exemples

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First Results: Multi-color lightcurve fits

• SALT: Spectral adaptative lightcurve template• Model SNIa SED as a function of

– Phase (date wrt to B-band maximum)– Lambda (rest frame )– Stretch (dilatation of B-band phase axis)– Color (E(B-V) at B maximum)

• Color term and extinction

Model fitted on an independant

Sample of low z SNIa

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First results: SNLS Lightcurve fits

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First results: Photometric calibration

• Based on Landolt stars in ‘landolt magnitude system’• Low redshift sample : already in landolt magnitude• Produce calibrated stars in SN field • Checked observed vs synthetic color terms• Zero points at the percent level

metrics

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First results: Hubble diagram

B = m*B – M + (s-1) –c

45 low z + 71 SNLS ( outliers removed)

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First results: Cosmological parameter fits

• SNLS first year contours, combined with Baryon oscillation results (Eisenstein et al 2005)

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Data consistency and systematic studies

• Comparison SNLS/Nearby: stretch and color(Black) (Blue)

stretch color

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Data consistency and systematic studies

• SALT multi-band consistency U3 is the difference between measure in a third band and

expectation from SALT fit in two other band

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Data consistency and systematic studies

• Summary of error budget

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

First results: numbers

• For a flat CDM cosmology

• For a flat M,w cosmology,– Combined with Baryonic acoutic oscillation (Eisenstein 2005)

A better result than all ground-based SNe results

M=0.263 +- 0.042 (stat) +- 0.032 (syst)

M= 0.271 +- 0.021 (stat) +- 0.007 (syst)w = -1.023 +- 0.090 (stat) +- 0.054 (syst)

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Prospects :

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Prospects : error reduction

• The current status:– 71 high z SNIa :

• w> = 0.1 (stat) + 0.05 (syst)

Important to control the systematical errors for error budget

• The perspectives– Up to 700 high z SNIa

• Statistical error reduced

– Many analysis of systematical effect• Systematical error better controlled and reduced

• Both Statistical and systematical errors can be reduced at the end of the survey

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Prospects : Systematical errors control

• Systematical errors potential sources

– Calibration– K correction– Malmquist bias– Evolution– Dust– Extinction– Contamination– Gravitational lensing

• Control tools and analysis

- Calibration program- Multicolor lightcurves- Spectral line studies - Spectral evolution- IR data- UV studies- Classification/Sub-sample studies- Host galaxie morphology- MonteCarlo simulations- Type II analysis

- …

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Prospects : ultimate precision

• 5 years expectations : w> = 0.07 combined with low z SNe and weak lensing of CFHTLS

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Prospects: Other science

• Other science with 2000 Sne + 1000 spectra– SN rate

– SN IIP

../..

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Prospects: Other science

Type Ia ratesMetallicity

effectsType Ia

progenitorsRedshift evolution

Cosmology with Type II SNe

SN Ia UV properties

Properties of Dust

Type Ia rise times

Epoch of cosmic deceleration

Ia explosion mechanism

Ia Intrinsic Scatter

Benetti velocity diagram

High-stretch SNe Ia diversity

Core collapse SN rate

CMAGIC

Core collapse progenitors

Improved K-corrections

SN Ib/c-GRB connection

SN Ia peak-tail ratio

Ia metallicity cutoff

Ia geometric effects

II-P risetimeIR Hubble Diagram

Type IIn - Type Ia connection

AGN/SN Ia connection

Ia pseudo-EW correlations

Host galaxy properties

Unique SNeIa high velocity

componentsSN color-color

selection

SN Luminosity distribution

Cosmic star formation

history

Deflagration vs. detonation

Intrinsic Type Ia colors

Type II shock breakout

Stretch, MLCS, m15

improvements

Galactic chemical evolution

Are SNe Ia a one parameter

family?

Are there low-s SNe Ia at

high z?

Groundwork for future (JDEM,

LSST)

SNLS:Overview and First Results, Sino-French workshop, Marseille 2005

Conclusions

• The SNLS project is entering it’s most existing phase of producing new science results :

– Set up after first 2 years is well under control, in accordance to expectations : should achived designed goal after 5 years

– First year result competitive with previous cosmological parameters measurements with SNIa

• The SNLS is a second generation High z SNIa project– Very homegenous and complete dataset– Redondancy of multicolor lighcurve and spectroscopy– Systematical errors can be controlled and reduced

• The SNLS is a legacy survey– Many other studies, related to SNe science will be possible

• Many scientific results to come … Stay tuned !