Snls the good the bad and the ugly
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CFHTLS SN Survey. SNLS The Good, the Bad, and the Ugly. Chris Pritchet U. Victoria ( SNLS West ). Some history …. Riess et al. 1998 Perlmutter et al. 1998. MegaCam – 1 deg x 1 deg. “Size matters …”. Anon. MegaCam at CFHT.

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SNLS The Good, the Bad, and the Ugly

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Snls the good the bad and the ugly

CFHTLS SN Survey

SNLS The Good, the Bad, and the Ugly

Chris Pritchet

U. Victoria (SNLS West)

Dark Energy Tucson 2004


Some history

Some history …

Riess et al. 1998

Perlmutter et al. 1998

Dark Energy Tucson 2004


Snls the good the bad and the ugly

MegaCam – 1 deg x 1 deg

“Size matters …”

Anon.

Dark Energy Tucson 2004


Megacam at cfht

MegaCam at CFHT

  • 40 x (2048 x 4612) chips (~ 400Megapixels)

  • good blue response

Dark Energy Tucson 2004


Megacam at cfht1

MegaCam at CFHT

Dark Energy Tucson 2004


Cfht legacy survey

XMM deep

VIMOS

SWIRE

GALEX

Cosmos/ACS

VIMOS

SIRTF

XMM …

Groth strip

Deep2

ACS …

XMM deep

CFHT Legacy Survey

470 nights (dark-grey) over 5 years (2003-2008)

  • SNLS - Deep (“SNe + galaxy evolution”)

    • 202 nights over 5 years

    • four 1 deg² fields (0226-04, 1000+02, 1419+53, 2215-18)

  • repeated observations in ugriz filters (360-950nm)

  • depth i’>24.5 (S/N=8, 1 hr); r’ > 28 in final stacked image

  • superb image quality (0.5-0.6 arcsec expected)

  • queue scheduling, excellent temporal sampling

  • ~1000 SNeIa over 5 yrs

  • spectroscopic followup plan (VLT, Gemini, Keck, Magellan)

  • Very Wide(“KBO”)

    • 1300 deg², +-2 deg from ecliptic,

    • short exposures

  • Wide (“lensing’)

    • 172 deg² in 3 patches

Dark Energy Tucson 2004


The team s

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 + …

Dark Energy Tucson 2004


Goals of sn observations 1 cosmology

Goals of SN observations – 1.Cosmology

  • Λ, w=P/ρ

  • from Type Ia SNe (exploding white dwarfs)

P = wr, ρ(a) ~ a -3(1+w)

w = 0 matter w = -1 L w = 1/3 radiation

a(z)  w !

Linder 2002

relative to

w = -0.7 model

Dark Energy Tucson 2004


Science goals

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

Dark Energy Tucson 2004


Expected precision on w m w l w

Expected precision on Wm, WL, w

Pain 2004

1000 up to z=0.9

Flat

Flat, dWm=0.03

Dark Energy Tucson 2004


2 sfr z type ii sne core collapse

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

Dark Energy Tucson 2004


Snls the good the bad and the ugly

  • 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 2002

Perlmutter et al 1998

Dark Energy Tucson 2004


The stacks

The Stacks

Dark Energy Tucson 2004


Snls current status

SNLS - Current Status

  • First SN discovered Mar 2003

  • Survey underway officially since Aug 2003

Mar 2003 Feb 2003 diff

Dark Energy Tucson 2004


Snls the good the bad and the ugly

  • 2 real time detection pipelines

    working well - Ca-Fr agree

    to i’=+24

  • psfmatch2 at work

diff 1999-2000

1999 2000

6hr I band 100''×100''

Dark Energy Tucson 2004


Detections

Detections

  • 143 in 03B (candidates)

  • 80-90% overlap Ca-Fr to i’=24

Dark Energy Tucson 2004


Reliability of faint detections

Reliability of Faint Detections

What fraction of i’=24.5 detections are real?

Answer: of 45 objects i’>24.5:

  • 2 psfmatch errors

  • 2 other/unknown

  • others (89%) showed real light variations (though not necessarily SNe)

Dark Energy Tucson 2004


Detections vs radius deg

Detections vs radius [deg]

R [deg]

R [deg]

Dark Energy Tucson 2004


I detections vs seeing

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

Dark Energy Tucson 2004


Spectral successes

Spectral successes

  • Getting the spectroscopy time in the first place!

  • working scheme for coordination of telescopes

Dark Energy Tucson 2004


Snls the good the bad and the ugly

Dark Energy Tucson 2004


Spectral successes1

Spectral successes

  • Getting the spectroscopy time in the first place!

  • working scheme for coordination of telescopes

  • Nod & shuffle at Gemini

Dark Energy Tucson 2004


Nod and shuffle gemini gmos

Nod and Shuffle – Gemini+GMOS

Dark Energy Tucson 2004


Spectral successes2

Spectral successes

  • Toronto program for predicting type/phase

  • Getting the spectroscopy time in the first place!

  • working scheme for coordination of telescopes

  • Nod & shuffle at Gemini

Dark Energy Tucson 2004


Spec z photo z

+ SNIa  SNII AGN

Spec-z / Photo-z

Spec confirmed

Slight over-estimate in photo-z, indicating that photometry is systematically faint

But this should be improved once we switch to Elixir

Sullivan, Howell et al 2004

Uses only two epochs of SNaproc photometry!

Dark Energy Tucson 2004


Pre screening candidates agn

Pre-screening candidates – AGN

blue = AGN

red = Ia

green = II

AGN

what comes out of fitting code without knowing the true z

Dark Energy Tucson 2004


Pre screening candidates sn agn

Pre-screening candidates – SN/AGN?

purple = AGN

red = Ia

green = II

(from spec)

SN/AGN?

Dark Energy Tucson 2004


Spectra statistics

Spectra Statistics

Dark Energy Tucson 2004


Z 0 84 composite 4

z=0.84 composite (4)

Dark Energy Tucson 2004


Recent light curves

Recent Light Curves

Perlmutter 2004

z=0.4-0.7

Dark Energy Tucson 2004


Light curves

Light curves

Howell, Sullivan et al 2004

0.270

0.497

0.93

z

0.695

0.87

Dark Energy Tucson 2004


June 2003 i 1 hr c030622 07

June 2003 i’ 1 hr (c030622-07)

Sainton 2004

z=0.281 SN Iap t=-7d

Dark Energy Tucson 2004


Snls the good the bad and the ugly

R6D4-9 = c030903-1

i’max= 24.05

z=0.95

time

Dark Energy Tucson 2004


Rudimentary hubble diagram

Rudimentary Hubble diagram

ΛCDM

  • Absolute calibration unknown

  • Relative filter-to-filter calibration not yet confirmed

  • Bias to brighter objects at higher-redshift

  • Preliminary photometry

EdS

= wrong z, not Ia

Howell, Sullivan et al 2004

Dark Energy Tucson 2004


Web pages

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/

Dark Energy Tucson 2004


6 issues

6. Issues

“The Dirty Dozen”

Dark Energy Tucson 2004


Ls vs pi

r’ i’ , less g’z’

LS vs. PI

  • weather

  • instrument failures

  • engineering

  • validation rate

  • seeing

  • focus overheads

Dark Energy Tucson 2004


Snls the good the bad and the ugly

  • LS Deep - i’ and z’

Dark Energy Tucson 2004


Snls the good the bad and the ugly

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?

  • Image Quality - corrector problems

    4. 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”

  • Dark Energy Tucson 2004


    Conclusions

    Conclusions

    • “The Ugly”:

      • less data than hoped for in 2003B

      • less g’z’

  • “The Bad”:

    • IQ – natural seeing and corrector

    • calibration/photometry issues to solve

  • “The Good”:

    • team

    • detection pipelines

    • spectroscopy

    • “ugly” and “bad” mostly understood and preventable in 2004A

  • Dark Energy Tucson 2004


    Snls the good the bad and the ugly

    --

    Dark Energy Tucson 2004


    Snls the good the bad and the ugly

    Dark Energy Tucson 2004


    Snls the good the bad and the ugly

    Dark Energy Tucson 2004


    Snls the good the bad and the ugly

    Dark Energy Tucson 2004


    Snls the good the bad and the ugly

    Dark Energy Tucson 2004


    Snls the good the bad and the ugly

    Dark Energy Tucson 2004


    Snls the good the bad and the ugly

    Dark Energy Tucson 2004


    Telescope aperture vs focal plane area

    Telescope Aperture vs. Focal Plane Area

    total area in 3m+ telescopes [m2]

    total CCD area [Megapix]

    Dark Energy Tucson 2004


    Real fits

    “Real” fits

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

    Howell, Sullivan et al 2004

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

    Dark Energy Tucson 2004


    Real fits1

    “Real” fits

    Moving up in redshift

    Coverage is still good

    Howell, Sullivan et al 2004

    Dark Energy Tucson 2004


    Real fits2

    “Real” fits

    Intermediate redshift

    Howell, Sullivan et al 2004

    Dark Energy Tucson 2004


    Real fits3

    “Real” fits

    …and higher redshift…

    Howell, Sullivan et al 2004

    Dark Energy Tucson 2004


    Real fits4

    “Real” fits

    And “high” redshift.

    Photometry is much nosier. Peak in i is about 24.2

    Howell, Sullivan et al 2004

    Dark Energy Tucson 2004


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