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Dark Energy in the Supernova Legacy Survey. Mark Sullivan (University of Toronto). http://legacy.astro.utoronto.ca/. Victoria Group Chris Pritchet, Don Neill, Dave Balam. French Group Reynald Pain (PI), Pierre Astier, Julien Guy, Nicolas Regnault, Jim Rich, Stephane Basa, Dominique Fouchez. - PowerPoint PPT Presentation
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Dark Energy in the Supernova Dark Energy in the Supernova Legacy SurveyLegacy Survey
Mark Sullivan (University of Toronto)Mark Sullivan (University of Toronto)
http://legacy.astro.utoronto.ca/
Toronto Group
Ray Carlberg, Mark Sullivan, Andy Howell, Kathy Perrett,
Alex Conley
French Group
Reynald Pain (PI), Pierre Astier, Julien Guy, Nicolas Regnault,
Jim Rich, Stephane Basa, Dominique Fouchez
UK
Gemini PI: Isobel Hook
Victoria Group
Chris Pritchet, Don Neill, Dave Balam
USA
LBL: Saul Perlmutter
CIT: Richard Ellis
Plus: Many students and associate members throughout the world
AAS Calgary June 2006AAS Calgary June 2006
SNLS: Vital StatisticsSNLS: Vital Statistics202n/5 year rolling SN survey202n/5 year rolling SN survey
Uses “Megacam” 36CCD 1 sq. deg. Uses “Megacam” 36CCD 1 sq. deg. imager on the CFHTimager on the CFHT
Observe in griz every 4Observe in griz every 4thth night in night in Grey/Dark timeGrey/Dark time
Typical seeing: 0.5-0.6 arcsecTypical seeing: 0.5-0.6 arcsec
Depth i’>24.5 (S/N=8) in 1 hrDepth i’>24.5 (S/N=8) in 1 hr
4 survey fields; 2 always available:4 survey fields; 2 always available:
Queue scheduling – and the highest queue priority – offers Queue scheduling – and the highest queue priority – offers protection from weatherprotection from weather
D1 (02:26,-04)D1 (02:26,-04) VIMOS, SWIRE, GALEX, XMM DeepVIMOS, SWIRE, GALEX, XMM Deep
D2 (10:00,+02)D2 (10:00,+02) COSMOS: ACS, Spitzer, GALEX, XMM etc.COSMOS: ACS, Spitzer, GALEX, XMM etc.
D3 (14:19,+53)D3 (14:19,+53) Groth Strip: – ACS, DEEP-II, GALEX etc.Groth Strip: – ACS, DEEP-II, GALEX etc.
D4 (22:15,-18)D4 (22:15,-18) GALEX, XMM DeepGALEX, XMM Deep
AAS Calgary June 2006AAS Calgary June 2006
OrganisationOrganisationCFHT-LS CFHT-LS (imaging) – 2003-2008(imaging) – 2003-2008
DEEPDEEP WIDEWIDE
Galaxy studiesGalaxy studies
Time sequenced dataset Time sequenced dataset (202n over 5 years)(202n over 5 years)
Cosmic shearCosmic shear
ClustersClustersSNLSSNLS collaborationcollaboration
Data-processingData-processing
Major Spectroscopic ProgramMajor Spectroscopic Program
Gemini (Canada/UK/USA)Gemini (Canada/UK/USA)
120 hrs/yr (60:40:20)120 hrs/yr (60:40:20)
VLT (France/Other Euros)VLT (France/Other Euros)
120 hrs/yr120 hrs/yr
Keck (through LBL)Keck (through LBL)
40 hrs/yr40 hrs/yr
Cosmological analysesCosmological analyses
Magellan near-IR study (Freedman et Magellan near-IR study (Freedman et al.)al.)
Rest-frame I-band Hubble diagramRest-frame I-band Hubble diagramKeck SN Ia UV study (Ellis/Sullivan et Keck SN Ia UV study (Ellis/Sullivan et
al.)al.)
LRIS high-S/N - metallicity through UV LRIS high-S/N - metallicity through UV lineslines
Testing accuracy of k-corrections in Testing accuracy of k-corrections in the UVthe UV
SN IIP study (Nugent/Sullivan/Ellis et SN IIP study (Nugent/Sullivan/Ellis et al.)al.)
Using SNe IIP as standard candlesUsing SNe IIP as standard candles
Independent Hubble diagram to z=0.5Independent Hubble diagram to z=0.5
AAS Calgary June 2006AAS Calgary June 2006
Current StatusCurrent Status
Survey has now been running for 3 yearsSurvey has now been running for 3 years
Nearly 300 spectroscopically confirmed SNe IaNearly 300 spectroscopically confirmed SNe Ia ““On track” for 500 by survey endOn track” for 500 by survey end
AAS Calgary June 2006AAS Calgary June 2006
Rolling Light-curvesRolling Light-curves
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Redshift distributionRedshift distribution
Redshift range: 0.08<z<1.06
SNLS-03D4agSNLS-03D4ag
AAS Calgary June 2006AAS Calgary June 2006
Typical light-curvesTypical light-curves
z = 0.91
z = 0.36
Rolling search: Lightcurves are
equally well-sampled at all phases
AAS Calgary June 2006AAS Calgary June 2006
Cosmological ConstraintsCosmological Constraints
AAS Calgary June 2006AAS Calgary June 2006
First-Year SNLS Hubble Diagram
First Year Results (Astier et al. 2006)First Year Results (Astier et al. 2006)
Intrinsic disp.: 0.13 ± 0.02
Low-z: 0.15 ±0.02
SNLS: 0.12 ± 0.02
Assuming flatness, w=-1: ΩM = 0.263 ± 0.042
AAS Calgary June 2006AAS Calgary June 2006
Dark energy: SNLS + BAODark energy: SNLS + BAO
Assuming flatness:
ΩM = 0.271 ± 0.021
w=-1.023 ± 0.087
AAS Calgary June 2006AAS Calgary June 2006
Dark energy: SNLS + WMAPDark energy: SNLS + WMAP
066.0085.0984.0w
021.0029.0M 719.0
Spergel et al. (2006)
AAS Calgary June 2006AAS Calgary June 2006
Coming soon…Coming soon…
The first year SNLS dataset provides the best SN The first year SNLS dataset provides the best SN sample for measuring “w”sample for measuring “w”
This sample is only 10-15% of the final sampleThis sample is only 10-15% of the final sample
Third Year cosmological analysis:Third Year cosmological analysis: Data collection complete in 2 monthsData collection complete in 2 months SN sample 4-5 times largerSN sample 4-5 times larger Improved “z” data will make the higher-redshift SNe Improved “z” data will make the higher-redshift SNe
more cosmologically powerful than in Year 1more cosmologically powerful than in Year 1 Results should be ready in the FallResults should be ready in the Fall
AAS Calgary June 2006AAS Calgary June 2006
Where Next?Where Next?
AAS Calgary June 2006AAS Calgary June 2006
Current status – Current status – and where nextand where next??First year:First year: NN~~70; w=-1.0270; w=-1.02 w: ±0.09 (stat) (RED)w: ±0.09 (stat) (RED) w: ±0.055 (sys) (BLUE)w: ±0.055 (sys) (BLUE)
Third Year:Third Year: N~250-300N~250-300
End-of-survey:End-of-survey: N~500-600N~500-600 ±~0.05 (stat)±~0.05 (stat) ±??? (sys)±??? (sys)
Substantial effort needs to be invested not only in “N”, but in reducing systematics
AAS Calgary June 2006AAS Calgary June 2006
Potential Systematics in measuring wPotential Systematics in measuring wPhotometric zeropointsPhotometric zeropoints
Mismatches to local SNe observationsMismatches to local SNe observations
Contamination by non-SNe IaContamination by non-SNe Ia Spectroscopy is criticalSpectroscopy is critical
K-correctionsK-corrections U and near-UV uncertain - U and near-UV uncertain - see poster 13.04 by Eric Hsiaosee poster 13.04 by Eric Hsiao
ExtinctionExtinction Effective REffective RBB;; Dust evolution; Grey dustDust evolution; Grey dust
Redshift evolution in the mix of SNeRedshift evolution in the mix of SNe ““Population drift”Population drift”
Evolution in SN propertiesEvolution in SN properties Light-curves/Colors/LuminositiesLight-curves/Colors/Luminosities
More “mundane”
More “scientifically interesting”
?White Dwarf
Many competing models for:Many competing models for:• Nature of progenitor system – the Nature of progenitor system – the
“second star”“second star”• Single versus double degenerateSingle versus double degenerate• Young versus old progenitorYoung versus old progenitor• Explosion mechanism?Explosion mechanism?• Mass transfer mechanism?Mass transfer mechanism?
AAS Calgary June 2006AAS Calgary June 2006
SNLS work on understanding SNe IaSNLS work on understanding SNe Ia
Relationship with environment (Sullivan et al. 2006)Relationship with environment (Sullivan et al. 2006) SN explode in galaxies with different ages/metallicitiesSN explode in galaxies with different ages/metallicities Population “drift”? – galaxy mix evolves with redshiftPopulation “drift”? – galaxy mix evolves with redshift
Evolution in SN propertiesEvolution in SN properties Rise-time analysis (Conley et al. 2006)Rise-time analysis (Conley et al. 2006)
High signal/noise UV spectroscopy (Ellis/Sullivan et al.)High signal/noise UV spectroscopy (Ellis/Sullivan et al.) Progenitor metallicity mostly affects the UV – Evolution?Progenitor metallicity mostly affects the UV – Evolution? Improved U-band k-correctionsImproved U-band k-corrections
Relationship with environment (Sullivan et al. 2006)Relationship with environment (Sullivan et al. 2006) SN explode in galaxies with different ages/metallicitiesSN explode in galaxies with different ages/metallicities Population “drift”? – galaxy mix evolves with redshiftPopulation “drift”? – galaxy mix evolves with redshift
Evolution in SN propertiesEvolution in SN properties Rise-time analysis (Conley et al. 2006)Rise-time analysis (Conley et al. 2006)
High signal/noise UV spectroscopy (Ellis/Sullivan et al.)High signal/noise UV spectroscopy (Ellis/Sullivan et al.) Progenitor metallicity mostly affects the UV – Evolution?Progenitor metallicity mostly affects the UV – Evolution? Improved U-band k-correctionsImproved U-band k-corrections
AAS Calgary June 2006AAS Calgary June 2006
Evolution in Ia properties with z?Evolution in Ia properties with z?
Riess et al. 1999 rise time of low-z and high-z SNe different by 5.8.
Limitations:
•Inhomogeneous data
•No early-time data
Conley et al. find low-z and high-z SNLS risetimes consistent at 1
Conley et al. 2006, AJ, submitted
tr: rise time
AAS Calgary June 2006AAS Calgary June 2006
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CFHT u*g’r’i’z’ imaging via the CFHT u*g’r’i’z’ imaging via the Legacy program. (UofT seeing Legacy program. (UofT seeing limit stacks)limit stacks)
PEGASE2 is used to fit SED PEGASE2 is used to fit SED templates to the optical data.templates to the optical data.
Recent star-formation rate, Recent star-formation rate, and total stellar mass are and total stellar mass are estimated. estimated.
Sources classified based on Sources classified based on their specific star-formation their specific star-formation rate.rate.
CFHT u*g’r’i’z’ imaging via the CFHT u*g’r’i’z’ imaging via the Legacy program. (UofT seeing Legacy program. (UofT seeing limit stacks)limit stacks)
PEGASE2 is used to fit SED PEGASE2 is used to fit SED templates to the optical data.templates to the optical data.
Recent star-formation rate, Recent star-formation rate, and total stellar mass are and total stellar mass are estimated. estimated.
Sources classified based on Sources classified based on their specific star-formation their specific star-formation rate.rate.
Optical Typing of SNe Ia hostsOptical Typing of SNe Ia hosts
AAS Calgary June 2006AAS Calgary June 2006
SNLS: SN rate as a function of sSFRSNLS: SN rate as a function of sSFRUse specific star-
formation rate (SFR per unit
mass) to classify the SNLS SNIa
hosts
Per unit stellar mass, SNe are at least an order of magnitude more common in more vigorously star-forming galaxies
SNLS “passive” galaxies
125 Host Galaxies at
z<0.75
Low-redshift data from Mannucci et al. 2005
AAS Calgary June 2006AAS Calgary June 2006
““A+B” ModelA+B” Model
SFRBMAt stellarIaSNR
Scannapieco & Bildsten (2005) and Mannucci et al. Scannapieco & Bildsten (2005) and Mannucci et al. (2005): Two component model(2005): Two component model
PromptPrompt: P=B @ t=0 and P=0 at all other times: P=B @ t=0 and P=0 at all other times
DelayedDelayed: P=A constant with time: P=A constant with time
AAS Calgary June 2006AAS Calgary June 2006
Mannucci et al. 2006 – P(t)Mannucci et al. 2006 – P(t)
“Delayed”
“Prompt”
““A+B” essentially A+B” essentially approximates the details of approximates the details of
the SNIa delay-time the SNIa delay-time probability distributionprobability distribution
AAS Calgary June 2006AAS Calgary June 2006
Mix will evolve with redshift…Mix will evolve with redshift…
Relative mix Relative mix evolves evolves stronglystrongly
with redshiftwith redshift
“B” component
“A” component
“A+B” total
Neill et al. (2006) SNLS
SNIa rate
SFRBMAt stellarIaSNR
AAS Calgary June 2006AAS Calgary June 2006
Light-curve width / host-typeLight-curve width / host-type
Light-curveLight-curve widthwidth is a key is a key parameter for standardizing parameter for standardizing SNe Ia as calibrateable SNe Ia as calibrateable candlescandles
We use the “stretch” We use the “stretch” technique (e.g. Perlmutter et technique (e.g. Perlmutter et al. 1997)al. 1997)
Stretch is known to depend Stretch is known to depend on environment locally:on environment locally:
e.g. Riess et al. (1999), e.g. Riess et al. (1999), Hamuy et al. (1995;2000)Hamuy et al. (1995;2000)
AAS Calgary June 2006AAS Calgary June 2006
Stretch/EnvironmentStretch/Environment
Stretch
Fainter SNe Brighter SNe
AAS Calgary June 2006AAS Calgary June 2006
Further evidence for A+B?Further evidence for A+B?
All star-forming galaxies
Star-forming galaxies plus “mass-scaled”
passive
All star-forming galaxies MINUS
passive
AAS Calgary June 2006AAS Calgary June 2006
Other environmental differences?Other environmental differences?
(Conley et al. 2006, AJ submitted)(Conley et al. 2006, AJ submitted)
No evidence for gross differences
between light-curves in passive
and active galaxies
AAS Calgary June 2006AAS Calgary June 2006
Cosmological effects?Cosmological effects?
“First-year” SNLS dataset plus low-z
classified by morphology
More to come in the third year
analyses…
Black – passive
Red – active
AAS Calgary June 2006AAS Calgary June 2006
Spectral UV evolution studiesSpectral UV evolution studies
Possible metallicity clues in the far-UV spectrumPossible metallicity clues in the far-UV spectrum Address concerns over systematics?Address concerns over systematics?
Little is known in the UV at z=0Little is known in the UV at z=0 Atmosphere precludes observationsAtmosphere precludes observations Space-based time is hard to come bySpace-based time is hard to come by
Try at intermediate redshift – where a guaranteed supply Try at intermediate redshift – where a guaranteed supply of SNe (SNLS) removes scheduling problemsof SNe (SNLS) removes scheduling problems
Keck-I/LRIS campaign (PI: Ellis) using LRIS-BKeck-I/LRIS campaign (PI: Ellis) using LRIS-B
~25 high-quality (S/N) spectra down to rest-frame 2800A~25 high-quality (S/N) spectra down to rest-frame 2800A
Lentz et al. (2000)
Varying metallicity changes line
blanketing in the UV
AAS Calgary June 2006AAS Calgary June 2006
Mean z=0.5 UV spectrumMean z=0.5 UV spectrum
Ellis, Sullivan et al.
Preliminary
AAS Calgary June 2006AAS Calgary June 2006
SummarySummary
SNLS is a mature survey – 8-10 new SNe Ia confirmed SNLS is a mature survey – 8-10 new SNe Ia confirmed every monthevery month
With nearly 300 SNe Ia in hand, the survey will have With nearly 300 SNe Ia in hand, the survey will have around 500 by the scheduled finish in 2008around 500 by the scheduled finish in 2008
11stst year SNLS dataset is the most uniform, well year SNLS dataset is the most uniform, well understood, and statistically powerful SN Ia data setunderstood, and statistically powerful SN Ia data set
SNLS data is currently the best SN Ia dataset to SNLS data is currently the best SN Ia dataset to combine with either BAO or WMAP data to measure combine with either BAO or WMAP data to measure dark energy.dark energy.
AAS Calgary June 2006AAS Calgary June 2006
SummarySummary
The challenge now is the control of systematics:The challenge now is the control of systematics: SNe Ia know and “care” about their environmentSNe Ia know and “care” about their environment Light-curve width depends on age of the progenitor Light-curve width depends on age of the progenitor
populationpopulation Evidence for wide-range of delay-times, or two progenitors Evidence for wide-range of delay-times, or two progenitors
– relative mix evolves with redshift?– relative mix evolves with redshift?
The final SNLS data set will be essential for constraining The final SNLS data set will be essential for constraining systematics for next generation projects like the LSST or systematics for next generation projects like the LSST or NASA’s JDEM.NASA’s JDEM.