Justin Vandenbroucke (KIPAC, Stanford / SLAC) for the Fermi LAT collaboration
The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31,...
-
Upload
edwin-joseph -
Category
Documents
-
view
216 -
download
1
Transcript of The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31,...
![Page 1: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/1.jpg)
The LSST andExperimental Cosmology at KIPAC
David L. BurkeSLAC/KIPAC
SLAC HEP SeminarOctober 31, 2006
![Page 2: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/2.jpg)
Outline
• Experimental Cosmology
• Gravitational Lensing
• KIPAC Activities
• The Large Synoptic Survey Telescope
![Page 3: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/3.jpg)
Elements of Cosmology
Space and Time
The Big Bang and inflation.
Homogeneous, isotropic, expanding universe.
Matter and Energy
Particles and quantum interactions.
Mass and General Relativity.
What we see in the laboratory. What we see
in the sky.
![Page 4: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/4.jpg)
What We See in the Sky
3000 1080 ~15 0Redshift z =
![Page 5: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/5.jpg)
The Expanding Universe
Hubble 1929-1934
Isotropic linear distance-velocity relation,
“Hubble Parameter” H0.
Perlmutter/Reiss 1998
Non-linear distance-redshift relation,
Dark Energy and the Cosmological Constant
Z = 0 21
![Page 6: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/6.jpg)
Matter in the Universe
Geller/Huchra 1989Large Scale Structure
Rubin/Ford 1980Galaxy Rotation Curves
Dark Matter and Evolution of Structure
The “Great Wall”
![Page 7: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/7.jpg)
Cosmic Microwave Background
Penzias/Wilson 1964 Mather/Smoot 1992 Wilkison 2006
Best FitCDMSeeds fertilized by
cold dark matter grow into large scale structure.
“CDM Model”
![Page 8: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/8.jpg)
Concordance and Discord
Is the universe really flat?
What is the dark matter? Is it just one thing?
What is driving the acceleration of the universe?
What is inflation?
Can general relativity be reconciled with quantum mechanics?
![Page 9: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/9.jpg)
Experimental Cosmology
CMB and Baryon Oscillations – dA(z) and H(z).
Supernovae – dL(z).
Galaxies and clusters – dA(z), H(z), and Cl(z).
Gravitational lensing – dA(z) and Cl(z).
![Page 10: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/10.jpg)
Elements of General Relativity(Sean Carroll, SSI2005, http://pancake.uchicago.edu/~carroll/notes )
[Geodesic Equation] [Einstein Equation]
The metric g, that defines transformation of distances in coordinate space to the
distances in physical space we can measure, must satisfy these equations.
Homogeneous, isotropic, flat, expanding universe:
g = -1 0 0 00 a(t) 0 0
0 0 a(t) 0 0 0 0 a(t)
More generally:Curvature of space.
“Size” of space relative to time.Gravitational potential (weak)
d2 = dt2 – a2(t) · dx2
![Page 11: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/11.jpg)
E = 1.74 arc-sec
Newton, Einstein, and Eddington
Soldner 1801
Einstein 1915
Eddington 1919 “between 1.59 and 1.86 arc-sec”
![Page 12: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/12.jpg)
Propagation of Light Rays
There can be several (or even an infinite number of) geodesics along which light travels from the source to the observer.
Displaced and distorted images.
Multiple images.
Time delays in appearances of images.
Observables are sensitive to cosmic distances and to the structure of energy and matter (near) line-of-sight.
![Page 13: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/13.jpg)
A complete Einstein ring.
Strong Lensing
Galaxy at z =1.7 multiply imaged by a cluster at z = 0.4.
Multiply imaged quasar (with time delays).
![Page 14: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/14.jpg)
Propagation of a Bundle of Light
Central Ray0
ξi
ξj
ξ ( )
Bundle of rays each labeled by angle with respect to the central ray as they pass an observer at the origin.
Linear approximation,
and = 0 case,
ξ () = D ()
D () = dA()
angular diameter distance
2-dimensional vector
![Page 15: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/15.jpg)
Weak Lensing Approximation
If distances are large compared to region of significant gravitational potential , the deflection of a ray can be localized to a plane – the “Born” approximation.
Unless the source, the lens, and the observer are tightly aligned (Schwarzschild radius), the deflection will be small,
And the actual position of the source can be linearly related to the image position,
(Einstein)
![Page 16: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/16.jpg)
Distorted Image
Source
ξi
ξj
Convergence and Shear
“Convergence” and “shear” determine the magnification and shape (ellipticity) of the image.
Distortion matrix
with the co-moving coordinate along the geodesic, and a function of angular diameter distances.
( )
![Page 17: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/17.jpg)
Simulation courtesy of S. Colombi (IAP, France).
Weak Lensing of Distant Galaxies
Sensitive to cosmological distances, large-scale structure of matter, and the nature of gravitation.
Source galaxies are also lenses for other galaxies.
![Page 18: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/18.jpg)
Observables and Survey Strategy
Galaxies are not round!
g ~ 30%
The cosmic signal is 1%.
Must average a large number of source galaxies.
Signal is the gradient of , with zero curl.
“B-Mode” must be zero.
![Page 19: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/19.jpg)
Ellipticity (Shear) Measurements
16 arc-sec
2000 Galaxies 200 Stars
WHT Bacon, Refregier, and Ellis (2000)
i i/2
![Page 20: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/20.jpg)
Instrumental PSF and Tracking
Mean ellipticity ~ 0.3%.
Images of stars are used to determine smoothed corrections.
Bacon, Refregier, and Ellis (2000)
![Page 21: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/21.jpg)
Weak Lensing Results
Discovery (2000 – 2003) 1 sq deg/survey 30,000 galaxies/survey
CFHT Legacy Survey (2006) 20 sq deg (“Wide”) 1,600,000 galaxies
“B-Mode”
Requires Dark Energy (w0 < -0.4 at 99.7% C.L.)
![Page 22: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/22.jpg)
Shear-Shear Correlations andTomography
Maximize fraction of the sky covered, and reach
zs ~ 3 to optimize
sensitivity to dark energy.
Two-point covariance computed as ensemble average over large fraction of the sky
ξ2() = < e(r) e(r+)>.
Fourier transform to get
power spectrum C(l).
Tomography
– spectra at differing zs.
zs = 1
CDM with only linear structure growth.
0.22 1’
![Page 23: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/23.jpg)
Experimental and Computational Cosmology at KIPAC
Cosmic microwave background. (Church)
First objects, formation of galaxies. (Abel, Wechsler)
Clusters of galaxies and intergalactic medium. (Allen)
Supernovae. (Romani)
Gravitational lensing. (Allen, Burchat, Burke, Kahn)
![Page 24: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/24.jpg)
Cosmic Microwave Background
Temperature
Polarization
WMAP QUaD
High resolution observations of CMB with QUaD at the South Pole.
Also studies of the Sunyaev-Zeldovich effect in galaxy clusters in combination with X-ray cluster investigations.
![Page 25: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/25.jpg)
Supernovae with SDSS II
Fall 2005
160 1a SNe
SDSS 2.5m
Hobby-Eberly9.2m
Taking data through 2007.
Complete the magnitude-redshift distribution.
![Page 26: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/26.jpg)
Formation of Galaxies and Clusters
Observations, theory, and simulations. New techniques and exploiting best available data.
Complementary constraints from different methods: eg direct distance measures, growth of structure and geometric.
Allen et al. Rapetti et al.
![Page 27: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/27.jpg)
Gravitational Lensing by Clusters
Measurements of baryonic and dark matter in galaxy clusters from multi-wavelength observations (X-ray and gravitational lensing).
Gravitational potentials of baryonic and dark matter in clusters.
Separation of baryonic and dark matter in merging systems.
Allen et al. Bradac et al.
![Page 28: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/28.jpg)
Large Synoptic Survey Telescope(Burchat, Burke, Kahn, Schindler)
8.4m Primary-TertiaryMonolithic Mirror
3.5° Photometric Camera
3.4m Secondary Mirror
![Page 29: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/29.jpg)
The LSST Mission
Photometric survey of half the sky ( 20,000 square degrees).
Multi-epoch data set with return to each point on the sky approximately every 4 nights for up to 10 years.
Prompt alerts (within 60 seconds of detection) to transients.
Fully open source and data.
Deliverables
Archive 3 billion galaxies with photometric redshifts to z = 3.
Detect 250,000 Type 1a supernovae per year (with photo-z < 0.8).
![Page 30: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/30.jpg)
Cosmology with LSST
o Weak lensing of galaxies to z = 3. Two and three-point shear correlations in linear and non-linear
gravitational regimes.
o Supernovae to z = 1. Lensed supernovae and measurement of time delays.
o Galaxies and cluster number densities as function of z. Power spectra on very large scales k ~ 10-3 h Mpc-1.
o Baryon acoustic oscillations. Power spectra on scales k ~ 10-1 h Mpc-1.
Simultaneously in one data set.
![Page 31: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/31.jpg)
LSST Site
Cerro Pachón
Gemini Southand SOAR
LSST Site
![Page 32: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/32.jpg)
Telescope Optics
Polychromatic diffraction energy collection
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 80 160 240 320
Detector position ( mm )
Imag
e di
amet
er (
arc-
sec
)
U 80% G 80% R 80% I 80% Z 80% Y 80%
U 50% G 50% R 50% I 50% Z 50% Y 50%
Paul-Baker Three-Mirror Optics
8.4 meter primary aperture.
3.5° FOV with f/1.23 beam and 0.20” plate scale.
![Page 33: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/33.jpg)
Camera and Focal Plane Array
Filters and Shutter
Focal Plane Array3.2 Giga pixels
~ 2mWavefront Sensors and
Fast Guide Sensors
“Raft” of nine 4kx4k CCDs.
0.65m Diameter
![Page 34: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/34.jpg)
Aperture and Field of View
Primary mirror diameter
Field of view
KeckTelescope
0.2 degrees10 m
3.5 degrees
LSST
![Page 35: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/35.jpg)
Optical Throughput – Eténdue AΩ
0
40
80
120
160
200
240
280
320
Ete
nd
ue
(m
2 de
g2 )
LSST PS4 PS1 Subaru CFHT SDSS MMT DES 4m VST VISTAIR
All facilities assumed operating100% in one survey
![Page 36: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/36.jpg)
LSST Postage Stamp(10-4 of Full LSST FOV)
Exposure of 20 minutes on 8 m Subaru telescope. Point spread width 0.52 arc-sec (FWHM). Depth r < 26 AB.
Field contains about 10 stars and 100 galaxies useful for analysis.
1 arc-minute
LSST will see each point on the sky in each optical filter this well every 6-12 months.
![Page 37: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/37.jpg)
Optical Filter Bands
Transmission – atmosphere, telescope, and detector QE.
![Page 38: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/38.jpg)
Photometric Measurement of Redshifts – “Photo-z’s”
Galaxy Spectral Energy Density (SED)
Moves right larger z.Moves left smaller z.
“Balmer Break”
![Page 39: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/39.jpg)
Photo-z Calibration
Calibrate with 20,000 spectroscopic redshifts.
Need to calibrate bias and width to 10% accuracy to reach desired precision
Simulation of 6-band photo-z.
z 0.05 (1+z)
Simulation photo-z calibration.
z 0.03 (1+z)
![Page 40: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/40.jpg)
Shear Power Spectra Tomography
Linear regime Non-linear regime
CDM
1
0.22
![Page 41: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/41.jpg)
Precision on Dark Energy Parameters
Measurements have different systematic limits.
Combination is significantly better than any individual measurement.
DETF Goal
![Page 42: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/42.jpg)
Weighing Neutrinos
Free streaming of massive neutrinos suppresses large scale structure within the horizon distance at the time the neutrinos freeze out.
The suppression depends on the sum of the neutrino masses,
m
Hu, Eisenstein, and Tegmark 1998
m = 0.2
h = 0.65
P
![Page 43: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/43.jpg)
Present Status and Forecast
Present atmospheric value:
m322 = 1.9 – 3.0 10-3 eV2 (90%CL),
or Σm > 0.044 eV.
Forecast for LSST (contours):
Σm 0.020 eV (statistical).
Hannastad, Tu, and Wong (2006)
Goobar, Hannestad, Mörtsell, Tu (2006)
CDM
Present Limits
14 3 2
![Page 44: The LSST and Experimental Cosmology at KIPAC David L. Burke SLAC/KIPAC SLAC HEP Seminar October 31, 2006.](https://reader035.fdocuments.in/reader035/viewer/2022062722/56649f295503460f94c428bc/html5/thumbnails/44.jpg)
Project Milestones and Schedule
2006 Site SelectionConstruction Proposals (NSF and DOE).
2007-2009 Complete Engineering and DesignLong-Lead Procurements
2010-2012 Construction
2013 First Light and Commissioning