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

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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

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on s

mal

l sca

les

Redshift-distance relationJames Taylor et al. (in prep)

Cum

ulat

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shea

r sig

nal

Redshift

Cum

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shea

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Redshift

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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

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http://www.astro.caltech.edu/~rjm/shapelets

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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

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