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Weak lensing results from the HST COSMOS survey
with
Nick Scoville, Roberto Abraham,Masaru Ajiki, Justin Alpert, Herve
Aussel, Josh Barnes, Andrew Blain,Daniela Calzetti, Peter Capak, John
Carlstrom, Chris Carilli, Andrea Cimatti,Andrea Comastri, Marcella Corollo,
Emannuel Daddi, Richard Ellis, Martin Elvis,Amr El Zant, Shawn Ewald, Mike Fall, Alexis
Finoguenov, Alberto Franceschini, MauroGiavalisco, Richard Griffiths, Gigi Guzzo, Gunther Hasinger, Catherine Heymans, Chris Impey, Jean-
Paul Kneib, Karel Nel, Jeyhan Kartaltepe, Jin Koda,Anton Koekemoer, Lisa Kewley, Alexie Leauthaud,
Olivier LeFevre, Ingo Lehmann, Simon Lilly, Thorsten Lisker,Charles Liu, Henry McCracken, Yannick Mellier, Satoshi
Miyazaki, Bahram Mobasher, Takashi Murayama, Colin Norman,Alex Refregier, Alvio Renzini, Jason Rhodes, Mike Rich, Dimitra
Rigopoulou, Dave Sanders, Shunji Sasaki, Dave Schminovich, EvaSchinnerer, Marco Scodeggio, Kartik Sheth, Patrick Shopbell, Jason Surace, Yoshi Taniguchi, James Taylor, Dave Thompson, Neil Tyson,
Meg Urry, Ludovic Van Waerbeke, Paolo Vettolani, Simon White, Lin Yan
COSMOS(cosmic evolution survey)
Richard Massey
The view from Hubble
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Hubble Space Telescope data
http://irsa.ipac.caltech.edu/Missions/cosmos.html
Largest ever HST survey• 577 contiguous ACS pointings• 1.6 square degrees in IF814W band (VSDSS at z=1)• Depth IF814W
Multicolour followup of COSMOS fieldP. Capak et al. (ApJ 2007), B. Mobasher et al. (ApJ 2007)
Δz/(1+z)= 0.05 , 0.15
X-ray
Radio
N. Scoville et al. (ApJ 2007)Large-scale distribution of baryonic material
Large-scale distribution of baryonic material
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Galaxy number density Weighted by stellar mass
Large-scale distribution of baryonic material
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Nick Scoville
Deflection of light rays
ESA/Hubble (M. Kornmesser & L. L. Christensen)
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NASA and A. Fruchter (STScI)Strong lensing
Spot the difference
Intrinsic galaxy shapes Gravitationally lensed galaxy shapes
• Each tick mark shows the averaged ellipticity of >100 galaxies• Density of resolved galaxies sets the resolution of a mass map• 71 galaxies/arcmin2 from space• ~20 galaxies/arcmin2 from ground
COSMOS mass mapGravitational lensing convergence ∝ projected mass
• Largest ever survey with HST• 1.6 square degrees in IF814W band• Depth IF814W
B-mode check for residual systematicsR. Massey et al. (Nature 2007)
z=0.3
z=0.5
z=0.7
Redshift tomography (palaeocosmology)
3D dark matter map
z=0.5
z=0.7
z=1
z=0.3Right ascension
Dec
linat
ion
NASA, ESA and R. Massey (California Institute of Technology)
z=0
3D dark matter map animation
ESA/Hubble (M. Kornmesser & L. L. Christensen)
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Statistical analysis of 3D mass distributionR. Massey et al. (ApJ 2007), J. Lesgourgues et al. (arXiv:0705.0533)
z=0.7
Shear-shear correlation function
z=0.5
z=0.3
Cosmological parameter constraints
WMAP
SDSSLyα forest
COSMOS3D weak lensing
VHS Lyα forest
Am
ount
of p
ower
Angular scale on sky
Growth of structure over cosmic timeR. Massey et al. (ApJ 2007)
Frac
tion
of m
ass
on s
mal
l sca
les
Redshift-distance relationJames Taylor et al. (in prep)
Cum
ulat
ive
shea
r sig
nal
Redshift
Cum
ulat
ive
shea
r sig
nal
Redshift
Cum
ulat
ive
shea
r sig
nal
Redshift
Well-know shape as a function ofangular diameter distancefrom simple lens geometry
Comparison with baryons
Weak lensingmass contours(HST)
Extended x-rayemission (XMM-Newton)
Sensitivity fallswith redshift!
Galaxy numberdensity(Subaru/CFHT)
Galaxy stellarmass(Subaru/CFHT)
R. Massey et al. (Nature 2007)
Mass vs light tomography (z~0.3)~19Mpc × 19Mpc
R. Massey et al. (Nature 2007)
Mass vs light tomography (z~0.5)~26Mpc × 26Mpc
R. Massey et al. (Nature 2007)
Mass vs light tomography (z~0.7)~31Mpc × 31Mpc
R. Massey et al. (Nature 2007)
“Bullet” cluster 1E0657-56
400 kpc
Doug Clowe, Marusa Bradac et al. (Astrophysical Journal 2006)
Largest particle accelerator in the Universe
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Future prospects
© NASA
Weak lensing signal is really weak.
Animations show 0-10% shear in 1% steps (real signal is ~2%).
Real imageSimulated imageR. Massey et al. (MNRAS 2004)Shear TEsting Programme (STEP) simulations
Shear TEsting Programme (STEP) resultsC. Heymans et al. (MNRAS 2006)R. Massey et al. (MNRAS 2007)
Shapelets basis functions
Trun
cati
on o
f hi
ghsp
atia
l fre
quen
cies
http://www.astro.caltech.edu/~rjm/shapelets
0 2 4 6 8NN
MM
8
6
4
2
0
-2
-4
-6
-8
ConclusionsRemarkably fast progress since first statistical detections of cosmic shearin 2000. Gravitational lensing is now a major tool in cosmology.
We can now compare the large-scale distribution of baryons to that ofmass. In general, baryonic structures are built inside a dark matterscaffold. Discrepancies on small scales reveal the different(e.g. non-interacting) properties of dark matter.
Statistical analyses of the mass distribution constraincosmological parameters, trace the growth of structure,and measure the expansion history of the universe.
Could not have been done from the ground.Imaging from space (+photozs) is essentialfor high resolution mass reconstructionand redshift tomography over widertimescales. The untimely failure of ACSis heartbreaking. Hubble provides aunique proof of concept for ambitious,dedicated missions in the future.
Y|Ç
Radial mass profile
Face-on bulletJames Jee et al. (Astrophysical Journal 2007))
Two clustersalong line of sight
Face-on bullet
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NASA, ESA and M. J. Jee (Johns Hopkins University)
In and out of the shadow of the Earth
© NASA© NASA
PSF variation
HST’s thermal “breathing” affects both size and ellipticity of PSF
Effective focus changes by• 3μm per orbit• 12μm in ~days
J. Rhodes (ApJ 2007), J. Jee (ApJ 2005)
PSF variationJ. Rhodes (ApJ 2007)
HST is really simple
1
© Hergé
Charge Transfer (in)EfficiencySTIS image, courtesy Paul Bristow
Trailing during CCD readout creates a spurious, coherent ellipticity.Affects photometry, astrometry and morphology of faint galaxies.
CCD readout register
Effect of CTE trailing on the mass map
Ground versus space
Ground vs space (mass maps)
Using 71 galaxies per arcmin2
SPACE GROUND
R. Massey et al. (Nature 2007), M. Kasliwal et al. (Proc. AAS 2007)
Ground vs space (B-mode/noise in mass maps)R. Massey et al. (Nature 2007), M. Kasliwal et al. (Proc. AAS 2007)
SPACE GROUND
Using 71 galaxies per arcmin2
Ground vs space (cluster detection over z range)M. Kasliwal et al. (Proc. AAS 2007)
SPACE
GROUND
SPACE
GROUND
Redshift 0.73 Redshift 0.93
Redshift 0.22Redshift 0.35
SPACEGROUND SPACE
GROUND
Lensing sensitivity with redshift
Resolved background galaxies
Redshift
Foreground lensing sensitivity
1/r2