Dark Energy Tucson 2004 SNLS The Good, the Bad, and the Ugly Chris Pritchet SNLS West U. Victoria...

Dark Energy Tucson 2004Dark Energy Tucson 2004

SNLS The Good, the Bad, and the Ugly

Chris PritchetU. Victoria (SNLS WestSNLS West)

CFHTLS SN Survey


Some history …

Riess et al. 1998Riess et al. 1998Perlmutter et al. 1998Perlmutter et al. 1998


““Size matters Size matters …”…” Anon.

MegaCam – 1 deg x 1 degMegaCam – 1 deg x 1 deg


MegaCam at CFHT

40 x (2048 x 4612) chips (~ 400Megapixels) good blue response


MegaCam at CFHT


CFHT Legacy Survey

470 nights (dark-grey) over 5 years (2003-2008)470 nights (dark-grey) over 5 years (2003-2008) SNLS - Deep SNLS - Deep (“SNe + galaxy evolution”)(“SNe + galaxy evolution”)

202 nights over 5 years202 nights over 5 years four 1 degfour 1 deg² ² fields (0226-04, 1000+02, 1419+53, 2215-18)fields (0226-04, 1000+02, 1419+53, 2215-18)

XMM deepVIMOSSWIREGALEX

Cosmos/ACSVIMOSSIRTFXMM …

Groth stripDeep2ACS …

XMM deep

repeated observations in ugriz filters (360-950nm)repeated observations in ugriz filters (360-950nm)depth i’>24.5 (S/N=8, 1 hr); r’ > 28 in final stacked imagedepth i’>24.5 (S/N=8, 1 hr); r’ > 28 in final stacked imagesuperb image quality (0.5-0.6 arcsec expected)superb image quality (0.5-0.6 arcsec expected)queue scheduling, excellent temporal samplingqueue scheduling, excellent temporal sampling~1000 SNeIa over 5 yrs~1000 SNeIa over 5 yrsspectroscopic followup plan (VLT, Gemini, Keck, Magellan)spectroscopic followup plan (VLT, Gemini, Keck, Magellan)

Wide (“lensing’) 172 deg² in 3 patches

Very Wide (“KBO”) 1300 deg², +-2 deg from ecliptic, short exposures


The Team(s)

France: R. Pain (CB Chair), P. Astier, J. Rich …

Canada - U. Toronto: R. Carlberg, A. Howell, T. Merrall,K. Perrett, M. Sullivan

Canada - U. Victoria: C. Pritchet (SN Coordinator), D. Balam,D. Neill (Aug 2004)

US: S. Perlmutter + …

UK: I. Hook + …


Goals of SN observations – 1.1. CosmologyCosmology Λ, w=P/ρ from Type Ia SNe (exploding white dwarfs)

P = wρ(a) ~ a -3(1+w) w = 0 matter

w = -1 w = 1/3 radiation

a(z) w !

Linder 2002 relative to

w = -0.7 model


Science goals

beat down intrinsic dispersion (±0.1–0.2 mag per SN) as N1/2

goal: ±0.01 mag error in a z bin


Expected precision on m, , w

Flat

Flat, m=0.03

1000 up to z=0.9

Pain 2004Pain 2004


2. SFR(z) – Type II SNe (core collapse)SFR(z) – Type II SNe (core collapse)

IaIa IIII

progenitorprogenitor 1 or 2 white dwarfs

massive star

mechanismmechanism mass transfer or merger

core collapse

progenitor progenitor ageage

~1010 yr ~107 yr

evolution evolution with zwith z

little (1+z) 2-4 :


Other applications

SNeII cosmology: v(exp) gives intrinsic luminosity

galaxy evolution, correlation functions (deep stacked images)

variable AGN’s

other variable objects

SN properties vs galaxy properties

rates Sullivan et al 2002Perlmutter et al 1998


The Stacks


SNLS - Current Status First SN discovered Mar 2003 Survey underway officially since Aug 2003

Mar 2003 Feb 2003 diff


2 real time detection pipelines working well - Ca-Fr agree to i’=+24

psfmatch2 at work

diff 1999-20001999 2000 6hr I band 100''×100''


Detections

143 in 03B (candidates) 80-90% overlap Ca-Fr to

i’=24


Reliability of Faint Detections

What fraction of i’=24.5 detections are real?What fraction of i’=24.5 detections are real?

AnswerAnswer:: of 45 objects i’>24.5:45 objects i’>24.5:

• 2 psfmatch errors• 2 other/unknown• others (89%) showed real light variations (though

not necessarily SNe)


Detections vs radius [deg]

R [deg]

R [deg]


i’ detections vs. seeing

Complex!

(# of new detections) ~ (# nights elapsed since last detections)

Normalize # by dt before comparing with seeing

median ~0.4 SNe/night/field


Spectral successes

working scheme for coordination of working scheme for coordination of telescopestelescopes

Getting the spectroscopy time in the first Getting the spectroscopy time in the first place!place!


Spectral successes

working scheme for coordination of telescopes

Nod & shuffle at GeminiNod & shuffle at Gemini

Getting the spectroscopy time in the first place!


Nod and Shuffle – Gemini+GMOS


Spectral successes

Toronto program for predicting type/phaseToronto program for predicting type/phase

working scheme for coordination of telescopes

Nod & shuffle at Gemini

Getting the spectroscopy time in the first place!


Spec-z / Photo-z

Slight over-estimate in photo-z, indicating that

photometry is systematically faint

But this should be improved once we switch

to Elixir

Uses only two epochs of SNaproc photometry!

Sullivan, Howell et al 2004

+ SNIa SNII AGN�Spec confirmed


Pre-screening candidates – AGN

AGN

what comes out of fitting code without knowing the true z

blue = AGN

red = Ia

green = II


Pre-screening candidates – SN/AGN?

SN/AGN?

purple = AGN

red = Ia

green = II

(from spec)


Spectra Statistics


z=0.84 composite (4)


Recent Light Curves

Perlmutter 2004

z=0.4-0.7


Light curves

Howell, Sullivan et al 2004

0.270

0.497

0.695

0.87

0.93z


June 2003 i’ 1 hr (c030622-07)

z=0.281 SN Iap t=-7d

Sainton 2004


R6D4-9 = c030903-1

time

i’max= 24.05z=0.95


Rudimentary Hubble diagram

Absolute calibration unknownRelative filter-to-filter calibration not yet confirmedBias to brighter objects at higher-redshiftPreliminary photometry


= wrong z, not Ia

EdS

ΛCDM


Web pages

www.cfht.hawaii.edu/CFHTLS http://legacy.astro.utoronto.ca – photometry,

spectroscopy, finder charts, light curves, calendar, …

http://makiki.cfht.hawaii.edu:872/sne/

http://www.cfht.hawaii.edu/CFHTLS/







http://legacy.astro.utoronto.ca/

















6. Issues

““The Dirty Dozen”The Dirty Dozen”


LS LS vsvs. PI. PI

Program Allocated Validated % validated

DeepL01+L04 138 hr 91 hr 66%

WideL02+L05 110 hr 40 hr 36%

Very-Wide L03+L06 71 hr 21 hr 30%

Total LSTotal LS 318 hr318 hr 152 hr152 hr 48%48%

PIPI 375 hr375 hr 185 hr185 hr 49%49%

•weather•instrument failures •engineering•validation rate•seeing•focus overheads

r’ i’ , less g’z’r’ i’ , less g’z’


LS Deep - i’ and z’


2. Scheduling Issues – 2. Scheduling Issues – QSO has worked well, but …

how to handle demands of other surveys in bad weather? how to get more g’z’ in bad weather?

3.3. Image Quality - Image Quality - corrector problems

4. Calibration4. Calibration

• how achievable is 0.01 mag precision?• zeropoints – esp.in colour (matching k-corr’s at

different redshifts)• uniformity across array• variation in colour terms (esp u* and z’)• CFHT preprocessing pipeline (“Elixir”)• “phase closure”


Conclusions

““The Ugly”:The Ugly”: • less data than hoped for in 2003B• less g’z’

““The Bad”:The Bad”: • IQ – natural seeing and corrector• calibration/photometry issues to solve

““The Good”:The Good”:• team• detection pipelines• spectroscopy • ““ugly” and “bad” mostly understood and preventable ugly” and “bad” mostly understood and preventable

in 2004Ain 2004A


--


Telescope Aperture vs. Focal Plane Area

total CCD area [Megapix]

total area in 3m+ telescopes [m2]


Light-curve coverage at low redshift encompasses up to 15 epochs

French and Canadian photometry not yet completely consistent, should be improved once we switch to Elixir.


“Real” fits


“Real” fits

Moving up in redshift

Coverage is still good



“Real” fits

Intermediate redshift



“Real” fits

…and higher redshift…



“Real” fits

And “high” redshift.

Photometry is much nosier. Peak in i is

about 24.2


Dark Energy Tucson 2004 SNLS The Good, the Bad, and the Ugly Chris Pritchet SNLS West U. Victoria...

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