The Carnegie Supernova Project

Wendy Freedman Carnegie Observatories

Cosmology 2007San Servolo, ItalyAugust 30, 2007

State of the Art (2007): Type Ia Supernovae

Riess et al. 2004

HST ACS data

Knop et al. 2003 Astier et al. 2006

Wood-Vasey et al. 2007 WLF et al. 2007

Carnegie Supernova Project: Primary Goals

1. Reduce systematics (reddening, calibration, K-corrections…)

2. I-band restframe Hubble diagram

=> observations in the near-IR (>1m)

“Y” , J bands

(To date only UBV restframe…)

Carnegie Supernova Project

Swope 1-meter Magellan 6.5-meterDupont 2.5-meter

Low z: High z:

•u’BVg’r’i’YJHK photometry• 2.5-meter spectroscopy

• YJ photometry • Magellan 6.5-meter

• C40 9 month campaigns over 5 years (1350 nights)• densely sampled photometry and spectroscopy 0 < z < 0.1• 100 SNe Ia, 100 SNe II

• ~100 SNe Ia at completion• observations near max• 0.2 < z < 0.8

Carnegie Supernova Project (CSP)

Chris Burns

Carlos Contreras

Gaston Folatelli

Wendy Freedman (PI, High z)

Mario Hamuy

Barry Madore

Nidia Morell

Eric Persson

Mark Phillips (PI, Low z)

Miguel Roth

Nick Suntzeff

Pamela Wyatt

Collaborators:Ray Carlberg, Chris Pritchet, Mark Sullivan, Kathy Perrett, Andy Howell (CFHT SN Legacy)Alex Filippenko, Weidong Li (LOSS)Nick Suntzeff (ESSENCE)Josh Friemann, Masao Sato (SDSS-II)

Dan Kelson, Eric Hsiaohttp://www.ociw.edu/csp/

• CFHT Legacy Survey • ESSENCE

CSP Collaborations

• LOTOSS (KAIT)• SN Factory

High z: Low z:

Intermediate z:

• SDSS-II

CSP followup and collaboration

Carnegie Supernova Project: Systematics

Nugent et al (2002)

1. Galactic reddening2. Host reddening3. Supernova Dust1. Reddening

2. K-corrections

3. Environment

4. Calibration**

Minimize effects due to:

Overview: WLF 2005, astro-ph/0411176

1. Galactic Extinction Law

Cardelli, Clayton and Mathis 1989

AB / E(B-V) = 4.1

AI / E(B-V) = 1.7

B

I

V

R V = AV / E(B-V)

AU / E(B-V) = 4.9U

2. Improved K-corrections

Eric HsiaoUniv. Victoriaastro-ph 0703529

Thesis:Improvement to Standard (Nugent)K-corrections

New spectra, at many epochs andincluding i-band coverage (includingCSP low-z data).

CSP {

Ca triplet

CSP Low z Targets

Low zsupernovae

Examples of CSP Low-z Light Curves

• SN 2006X• NGC 4321 (M100)• Type Ia• Spectra from du Pont and Magellan / LDSS2

Carnegie Supernova Project

Nidia Morell SN2006X

d149wcc4_11 (ESSENCE)

z ~ 0.3

c040117-14 (CFHT Legacy)

z ~ 0.6

Magellan High-z IR Observations: Two Examples

Target Template Difference

Carnegie Supernova Project: High z

SNLSSDSS-IIESSENCE

Redshift z

• 58 SN Ia

as of 3/07

• 41 with templates

16 with complete reductions, reddenings

Nu

mb

er

Carnegie Supernova Project: High z

Redshift

i’-bandlight curves: low z

High z:

• Observe pre- maximum

• Follow 3-7 epochs

Less than 10 days after maximum

• Gaps less than 5 days

1st peak

2nd peak

Carnegie Supernova Project: High z

z = 0.59

z = 0.43z = 0.52

z = 0.62

z = 0.62

ri: SNLSYJ: Magellan

z = 0.32

gri : SDSS-IIY: Magellan

.

.

JY

i

r

Y

i

r

g

C. Burns

Carnegie Supernova Project: High z

Y J• Use optical data to determine decline rates (m15(B) ).

• Use both optical and near-IR data to solve for reddening.

• Use YJ light curves to solve for the distance modulus.

Template light curves from Prieto et al. (2006) nearby sample

.

Carnegie Supernova Project: High z

Redshift

*PRELIMINARY*

16 Type Ia supernovae

First I-bandHubble diagramat z > 0.07

Magellan

Riess et al. goldAstier et al.

• small scatter at I• better than current low-z sample

Carnegie Supernova Project: Fisher-Matrix Constraints on

wo and

Current CSP (50 SN Ia)

100 SN Ia

150 SN Ia

Stage I SNLS (71 SN Ia)Astier et al(2006)

Chris BurnsWMAP plus H0 Key Project priors95% confidence contoursCSP Allows for k-correction and color errors**

Carnegie Supernova Project: Fisher-Matrix Constraints on

wo and

Current CSP (50 SN Ia)

100 SN Ia

150 SN Ia

Stage II SNLS (700 SN Ia)

Chris Burns

WMAP plus H0 Key Project priors95% confidence contours

Carnegie Supernova Project: High z

Assumption:• flat universe

*PRELIMINARY*maximum likelihood CSP+BAO:

M = 0.3 ± 0.1  w =  -0.9 ±  0.2

95% confidence

W = P /

SNe Ia & The GMT0.5 seeing

HST 1.5m

GMT AO

SNe studies are limited by

confusion

GMT AO will address this

GMT Science Working Group--P. McCarthy

The Giant Magellan Telescope (GMT)

Alt-az structure

Seven 8.4-m primary mirrors

• Cast borosilicate honeycomb

• 25.3-m enclosed diameter

• 24.5-m diffraction equivalent

• 21.5-m equivalent aperture

3.2-m adaptive Gregorian secondary mirror

GMT Institutions

• Australia

• Carnegie Observatories• Harvard University

• Smithsonian Astrophysical Observatory

• Texas A&M University• University of Arizona• University of Michigan• University of Texas, Austin

• + …OTHERS TBD

Summary

First restframe I-band Hubble diagram for 0.2 < z < 0.7 Dispersion lower than for UBV Lower sensitivity to reddening Improved K-corrections Preliminary Results: w = -0.9§ 0.2 (95% confidence) Final sample 4-5 times greater

• Low redshift : tests of systematics

• High redshift: I-band Hubble diagram

• “Local” calibration for JDEM