SDSS Supernova Survey

Josh Frieman

Fermilab and University of Chicago

Jan. 12, 2005 AAS 2

SDSS and SDSS II

• SDSS I: April 2000-June 2005• SDSS II: July 2005-2008 (contingent on funding):

• Legacy Survey (complete northern survey) ~106 redshifts

• SEGUE (low-latitude survey of Milky Way)

see posters 64.09, 114.03, 142.04

• Supernova Survey

see poster 114.04 by H. Lampeitl

and 71.04 by S. Krughoff

Jan. 12, 2005 AAS 3

Fermilab: Jen Adelman-McCarthy, Fritz DeJongh, Juan Estrada, Hubert Lampeitl,

John Marriner, Chris Stoughton, Doug Tucker

U. Chicago: Ben Dilday, Rick Kessler, Erin Sheldon, Don York, Gary Kilper,

Mark Subbarao

U. Washington: Andy Becker, Gajus Miknaitis, Craig Hogan

Portsmouth: Bob Nichol, Bruce Bassett

NMSU/APO: Jon Holtzman, Bill Ketzeback, Jack Dembicky, Russet

McMillan, John Barentine, Scot Kleinman, Howard Brewington, Mike Harvanek,

Atsuko Nitta, Stephanie Snedden, Dan Long, Jerzy Krzesinski, Peter Newman

Princeton: Dave Johnston, Jim Gunn

U. Pittsburgh: Andy Connolly, Simon Krughoff, Ryan Scranton

JPG: Mamoru Doi, Naoki Yasuda, Naohiro Takanashi

Stanford: Roger Romani, Masao Sako, Jared Kaplan, Roger Blandford, Steve Kahn

Ohio State: Darren Depoy, Jennifer Marshall

STScI: Adam Riess LBNL: Lifan Wang

U. Texas: Peter Hoeflich SF State: Dennis Lamenti

SDSS SN Collaborators

Date SDSS Supernovae 4

a(t)

Expansion

History of

the Universe

Jan. 12, 2005 AAS 5

Type Ia Supernovae & CosmologyAdvantages:• small dispersion in peak brightness (standard candles)• single objects (simpler than galaxies) • can be observed over wide redshift range (bright)

Challenges/Systematic concerns:• dust extinction in host galaxy• chemical composition variations/evolution• evolution of progenitor population• photometric calibration• Malmquist bias• environmental differences• K correction uncertainties

Need new

SN surveys for

statistics and

systematics

Jan. 12, 2005 AAS 6

Tonry etal ‘03

0.3, 0.70.3, 0.0

1.0, 0.0

Brightnessrelative toemptyUniverse:(m= =0)

m

Compiled Supernovae Ia Sample

`Gold’ sample of ~150 SNe included only 5 between

z = 0.1-0.3; SDSS naturally fills this gap

Jan. 12, 2005 AAS 7

The SDSS SN Program• Repeat ugriz imaging of ~2.5ox100o deg. region along celestial

equator for three 3-month runs (Sept-Nov. ‘05-’07): 310<RA<50• Frame subtraction in SDSS gri SN Ia selection in 24 hrs• Follow-up spectroscopy for SN typing, redshift (other telescopes)• Multi-epoch spectrophotometry for improved K-corrections • Follow-up NIR imaging for host extinction & properties• Obtain ~200 high-quality, densely sampled SN Ia light-curves in

the redshift desert z = 0.05 – 0.35 (exposure time 55 sec on 2.5m telescope; limits g~r~22.2 in `good’ seeing)

• 5-band photometry, large survey volume also allow selection of unusual type II, Ibc, etc., for further study

• Rapid release of candidates and data

Jan. 12, 2005 AAS 8

Science Goals

• Probe Dark Energy in z regime less sensitive to evolution than deeper surveys

• Study SN Ia systematics (critical for SN cosmology) with high photometric accuracy

• Search for additional parameters to reduce Ia dispersion• Determine SN/SF rates/properties vs. z, environment• Rest-frame u-band templates for z >1 surveys• Study feasibility of cosmology with SN colors • Database of Type II and other SN light-curves

Jan. 12, 2005 AAS 9

Monte Carlo Data

Dis

tanc

e m

odul

us

Simulated

redshift

distribution

and photometric

errors for

completed

SDSS SN sample

(here assumed

=0.7=1–m

H0=72)

Jan. 12, 2005 AAS 10

Fall 2004: Early Science & Test Run• Imaging: 20 nights of SDSS 2.5m scheduled every other night late Sept.-mid

Nov., covered half the survey area: ~1/2 the nights were useable.• Follow-up spectroscopy: ARC 3.5m, HET 9.2m• Follow-up imaging (during/after run): NMSU 1m, ARC 3.5m• Science Goal: ~10 well-measured SN Ia light-curves with confirmed

spectroscopic types and redshifts. • Yield: 16 confirmed Ia’s: 0.05<z<0.32 with z = 0.15, 5 Type II, 1 luminous Type Ic • Engineering goals met:• Rapid processing and selection of candidates in g,r (48 hours) • Coordinated follow-up observations • Study detection efficiency and photometric accuracy under varying conditions

Jan. 12, 2005 AAS 11

SN Ia z=0.0513

3 epochs of spectroscopy

Jan. 12, 2005 AAS 12

Preliminary

u+0.25

g

r–0.75

i–2

z–3.25

13

14

15

16

17

18

19

20

21

Mag

nitu

de

Jan. 12, 2005 AAS 13

SN 83: Observed vs. Synthetic Light-curves (preliminary)

Jan. 12, 2005 AAS 14

•• Highest redshift Ia from this sample:

• z=0.32

•• Luminous Ia: Mr ~ –20

•• Cross-correlation analysis yields

• best-fit Ia spectral templates

• separated by 2 days, in excellent

agreement with data

Jan. 12, 2005 AAS 15

Type II

Type Ic

Jan. 12, 2005 AAS 16

SDSS II SN Follow-up

• Spectroscopy: SN typing, redshift, multi-epoch spectrophotometry• NIR imaging: extinction/reddening and lightcurves

• Spectroscopy: ARC 3.5m, HET, MDM 2.4m (new high-throughput spectrograph), Subaru, SALT?, Gemini?• NIR imaging: Liverpool Telescope, Carnegie Supernova Project, Calar Alto • Optical imaging: NMSU 1m, ARC 3.5m, …

Jan. 12, 2005 AAS 17

Conclusions

SDSS SN Survey: SDSS 2.5m, ~200 SNe, z = 0.05-0.35,

Sept-Nov. 2005-7, fill in the redshift desert

Successful early science and test run Fall 2004: results out soon

In combination with WMAP CMB data, the SDSS SN survey

should determine the Dark Energy equation of state parameter

w to ~10-15% statistical accuracy (assuming w constant) and

provide new insight into SN Ia systematics.

Combining SDSS SN data with that of deeper on-going surveys

(ESSENCE, CFHTLS, z=0.3-0.8) should lead to improved

cosmological constraints, due to broader redshift leverage.