The Dark Energy Survey DES

1
The Dark Energy Survey (DES)

• Sarah Bridle, UCL
• On behalf of the DES Collaboration

2
The Dark Energy Survey

• Study Dark Energy using
• 4 complementary techniques
• I. Cluster Counts
• II. Weak Lensing
• III. Baryon Acoustic Oscillations
• IV. Supernovae
• Two multi-band surveys
• 5000 deg2 g, r, i, z
• 40 deg2 repeat (SNe)
• Build new 3 deg2 camera
• and data management system
• Survey 2010-2015 (525 nights)
• Response to NOAO AO

Blanco 4-meter at CTIO
300,000,000 photometric redshifts
3
The Dark Energy Survey

• Study Dark Energy using
• 4 complementary techniques
• I. Cluster Counts
• II. Weak Lensing
• III. Baryon Acoustic Oscillations
• IV. Supernovae
• Two multi-band surveys
• 5000 deg2 g, r, i, z
• 40 deg2 repeat (SNe)
• Build new 3 deg2 camera
• and data management system
• Survey 2010-2015 (525 nights)
• Response to NOAO AO

Blanco 4-meter at CTIO
300,000,000 photometric redshifts
4
The DES Collaboration
Fermilab J. Annis, H. T. Diehl, S. Dodelson, J.
Estrada, B. Flaugher, J. Frieman, S. Kent, H.
Lin, P. Limon, K. W. Merritt, J. Peoples, V.
Scarpine, A. Stebbins, C. Stoughton, D. Tucker,
W. Wester University of Illinois at
Urbana-Champaign C. Beldica, R. Brunner, I.
Karliner, J. Mohr, R. Plante, P. Ricker, M.
Selen, J. Thaler University of Chicago J.
Carlstrom, S. Dodelson, J. Frieman, M. Gladders,
W. Hu, S. Kent, R. Kessler, E. Sheldon, R.
Wechsler Lawrence Berkeley National Lab N. Roe,
C. Bebek, M. Levi, S. Perlmutter University of
Michigan R. Bernstein, B. Bigelow, M. Campbell,
D. Gerdes, A. Evrard, W. Lorenzon, T. McKay, M.
Schubnell, G. Tarle, M. Tecchio NOAO/CTIO T.
Abbott, C. Miller, C. Smith, N. Suntzeff, A.
Walker CSIC/Institut d'Estudis Espacials de
Catalunya (Barcelona) F. Castander, P. Fosalba,
E. Gaztañaga, J. Miralda-Escude Institut de
Fisica d'Altes Energies (Barcelona) E.
Fernández, M. Martínez CIEMAT (Madrid) C. Mana,
M. Molla, E. Sanchez, J. Garcia-Bellido University
College London O. Lahav, D. Brooks, P. Doel, M.
Barlow, S. Bridle, S. Viti, J. Weller University
of Cambridge G. Efstathiou, R. McMahon, W.
Sutherland University of Edinburgh J. Peacock
University of Portsmouth R. Crittenden, R.
Nichol, R. Maartnes, W. Percival University of
Sussex A. Liddle, K. Romer
plus postdocs and students
5

The Dark Energy Survey UK Consortium (I)
PPARC funding O. Lahav (PI), P. Doel, M.
Barlow, S. Bridle, S. Viti, J. Weller (UCL),
R. Nichol (Portsmouth), G. Efstathiou, R.
McMahon, W. Sutherland (Cambridge) J. Peacock
(Edinburgh) Submitted a proposal to PPARC
requesting 1.7M for the DES optical design.
In March 2006, PPARC Council announced that
it will seek participation in DES. PPARC
already approved 220K for current RD. (II)
SRIF3 funding R. Nichol, R. Crittenden, R.
Maartens, W. Percival (ICG Portsmouth) K.
Romer, A. Liddle (Sussex) Funding the optical
glass blanks for the UCL DES optical work These
scientists will work together through the UK DES
Consortium. Other DES proposals are under
consideration by US and Spanish funding
agencies.

6
The Dark Energy Survey Camera DECam
DECam will replace the prime focus cage
4m Blanco telescope
7
Expected performance of DECAM, Blanco, and CTIO
site
8
DeCamOptical Lay Out
C1
C2
C3
C4
C5
978mm
Filter
1870mm
9
(No Transcript)
10
(No Transcript)
11
i zenith 0
12
DES and VISTA synergy
DES (griz)
DESVISTA(JK)
VISTA J (lt21) and K (lt19) would improve photo-z
by a factor of 2 for zgt 1
F. Abdalla, M. Banerji, OL, H. Lin, et al.
13
DES Forecasts Power of Multiple Techniques

w(z) w0wa(1a) 68 CL
Assumptions Clusters ?80.75, zmax1.5, WL
mass calibration BAO lmax300 WL
lmax1000 (no bispectrum) Statisticalphoto-z
systematic errors only Spatial curvature,
galaxy bias marginalized, Planck CMB
prior Factor 4.6 improvement over Stage II

DETF Figure of Merit inverse area of ellipse

14
DES Forecast Constraints
DETF FoM

• DESStage II combined Factor 4.6 improvement
  over Stage II combined
• Consistent with DETF range for Stage III DES-like
  project
• Large uncertainties in systematics remain, but
  FoM is robust to uncertainties
• in any one probe, and we havent made use of
  all the information