Date post: | 11-Jan-2016 |
Category: |
Documents |
Upload: | claribel-flowers |
View: | 213 times |
Download: | 0 times |
30/6/09Unity of the Universe1
Michael Drinkwater for the team
Australia: Blake, Brough, Colless, Couch, Croom, Davis, Glazebrook, Jelliffe, Jurek, Li, Pimbblet, Poole,
Pracy, Sharp, WisniosikiU.S.A.: Foster, Gladders, Madore,
Martin, Small, Wyder Canada: Gilbank, Woods, Yee
The WiggleZ Dark Energy Survey
30/6/092 Unity of the Universe
1. Motivation2. Design &
Progress3. Large Scale
Structure Results
4. Other Results
1. Motivation
30/6/09Unity of the Universe3
Need to sample around redshift z=0.6 when acceleration starts
Survey aims:Measure BAO
scale to 2% in a sample of 240,000 galaxies at 0.3<z<0.9
Measure w to 10% to independently validate constant dark energy model
Motivation
30/6/09Unity of the Universe4
2. Design & Progress
30/6/09Unity of the Universe5
GALEX satellite imagingUV-selected galaxiesMedium Imaging Survey
extendedNUV < 22.8
Optical imaging: r < 22.5SDSS (North)RCS2 survey on CFHT
(South)AAT’s new AAOmega fibre
spectrograph220-night large projectMeasure 240,000 redshiftsStar forming galaxiesEmission line redshifts in
short 1-hour exposures
Example spectra
30/6/09Unity of the Universe6
Quality = 5 (high)Redshift z=0.57R = 21.4 mag
Quality = 3 (acceptable)Redshift z=0.86R = 21.2 mag
Survey coverage
30/6/09Unity of the Universe7
Design Improvements
30/6/09Unity of the Universe8
New spectrograph beam splitterMoved spectra
100 nm to the red
More reliable redshifts
Optical Colour SelectionIncreased
median redshift to zmed=0.6
Survey Status
30/6/09Unity of the Universe9
Progress Observations ¾ done Scheduled to run 2006 to 2010 August Over 140,000 galaxies measured Have doubled the number of known
z>0.5 galaxies from the two largest existing surveys (DEEP2 & VIMOS)
Galaxies in the 15-hour WiggleZ field… to 3.3 Gpc distance
3. Large scale clustering results
30/6/09Unity of the Universe10
The 2dF control system…
WiggleZ power spectrum
30/6/09Unity of the Universe11 By Chris Blake
5% accuracy indk = 0.01 bins
Linear model isgood fit to k = 0.3
WiggleZ power spectrum
30/6/09Unity of the Universe12 By Chris Blake
Divided by reference model with BAO signal removed.
Model divided by reference
Model convolved with survey window
Cosmological Parameters
30/6/09Unity of the Universe13 By Chris Blake
Predicted final sensitivity
30/6/09Unity of the Universe14 By Tamara Davis
Predicted precision in measurement of (wconst, ΩM) combined with supernovae
4. Other results
30/6/09Unity of the Universe15
Small scale clustering (Blake et al. 2009)UV luminosity function (Russell Jurek’s PhD)Growth of structure (Carlos Contreras’ PhD)Super starburst galaxies (Emily Wisnioski’s
PhD)Future work
Neutrino massGalaxy bispectrumGenus statisticHomogeneity scale of Universe (vs LTB
models)
Small scale clustering
30/6/09Unity of the Universe16 By Chris Blake
Small scale clustering
30/6/09Unity of the Universe17 By Chris Blake
The UV galaxy luminosity function
N=9356 (photo-z)
N=1869 N=1039
N=2976
WiggleZN=47,747
30/6/0918 Unity of the Universe
Russell Jurek’s PhD
First ever sample of bright end of UV luminosity function
30/6/09Unity of the Universe19 Russell Jurek’s PhD
MN
UV
-18
-
20
-
22
0.2 0.6 1.0 redshift (z) 0
.01
0.0
2
0
.03
Fract
ion
of
un
ivers
al st
ar
form
ati
on
den
sity
• WiggleZ galaxies have the highest SF at any redshift• Their contribution peaks at z≈0.6
UV contribution to star formation
Growth of structure
30/6/09Unity of the Universe20
Super starburst galaxies
30/6/09Unity of the Universe21
Neutrino Mass
30/6/09Unity of the Universe22 By Chris Blake
Advantage of WiggleZGalaxies less
strongly clustered than LRGs
Higher redshift
Better power spectrum measurementHave many
more Fourier scales before it goes non linear
Non-linear growthof structure
Summary
30/6/09Unity of the Universe23
Aims of WiggleZSurvey the largest ever
volume of the z>0.5 Universe
240,000 galaxies in 1 Gpc3
Measure BAO scale to 2%Measure constant w to
10%BAO not measured until
observations finish 2010 May
Many other science applications
The technology behind WiggleZ: 2dF positioning fibres on the AAT
2dF on a bad day
30/6/09Unity of the Universe24
Note the special error message: “Too many errors.”