sdss supernova survey josh frieman fermilab and university of chicago
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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.
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