Cluster Lensing, and Axions Search

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Cluster Lensing, and Axions Search

• Jean-Paul KNEIB
• Laboratoire dAstrophysique de Marseille, France
• D. Grin, G. Covone, E.Jullo, M. Kamionkovski, A.
  Blain,
• and many others

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Outline
MACSJ1149.52233
OII _at_ Z1.55
C
B

• Strong Weak Lensing
• Axion search
• Future prospects

A
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Lensing Theory in brief
CFHT 1990
Z_cluster0.375 Z_arc0.725 (Soucail et al 1988)
Lens
Observer
Source
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Strong Lensing Mass Reconstruction

• Not many constraints gt Parameterized mass
  distribution,
• Galaxy scale mass components are essential gt
• Galaxies are included using scaling relations
  (FJ, FP) and represent with their DM halos 10
  of the total mass

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Lensing Equations

• Amplification Matrix (lens mapping distortion)
• ? convergence
• ???????? shear vector
• Reduced shear (what we can measure)

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Weak Lensing

• Morphometry and shear measurement

b
a
Lensing equation for image moments
?
Lensing equation for ellipticity vectors
Ellipticity distribution
Ellipticity vector
?
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Measuring Weak Shear

• In the weak regime,the shape of galaxies are
  linearly modified by the gravitational shear
• The average of galaxy shape is an unbiased
  estimator of the gravitational shear
• Error on shear is a function of intrinsic shape,
  measurement error and number of galaxies

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Coupling Strong Weak Lensing
Absolute central mass, and inner slope
relative total mass and slope
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Cluster Mass reconstruction
Multi-scale mass reconstruction are necessary.
Different possible implementation wavelet or
using blobs. The latter can combine easily
strongweak lensing data using MCMC
techniques Useful to cope with complex shape and
add external priors
Marshall 2006
Simulation data
Shear field
Implementation in www.oamp.fr/cosmology/lenstool
/
Jullo et al 2007
Atomic Inference
Classical 2D single scale reconstruction
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An example from spaceCl00241654 HST wide
field sparse mosaic

• 76 orbits, 38 pointings
• Probe regions up to 5Mpc
• Aim learn cluster physics of clusters by
  comparing with other mass estimates X-ray,
  dynamics

Czoske et al 2002, Treu et al 2003, Kneib et al
2003, Moran et al 2007, Natarajan et al 2007
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0024 Shear Profile
SIS fitting strong lensing data

• Extrapolate strong lensing models at large scale
• Rule out SIS model
• NFW (with large c20) or Power-law are favored
• Large c unexpected!
• Line of sight alignment/merger?
• Very old structure?
• Baryon contribution?
• Background galaxy selection?

NFW fitting strong And weak lensing
3 Mpc
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Deep Spectrocopy on Abell 1689
Richard et al 2006

• Broadhurst et al 2005 found 30 multiple image
  systems,3 with spec-z. high concentration c14
• Now we have
• 21 systems with spectro-z out of 37 identified
  multiple image systems.

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StrongWeak lensing
Abell 1689 weak lensing vs. strong lensing model
Limousin et al 2007

• background source selection is critical to
  measure acurate mass
• Photo-z selection gives similar results to strong
  lensing
• Improved lensing constraints, revised
  concentration c7

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Bullet ClusterDirect Evidence of Dark Matter
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More Lensing Clusters !Snapshot with ACSMACS
Ebeling et al (cycle 1415) LOCUSS Smith et
al (cycle 15)

• List of 124 MACS(zgt0.3), 150 LOCUSS (0.15ltzlt0.3)
  clusters to be observed with HST/ACS in SNAP
  mode in F606W half an orbit
• Aim at finding effective lensing clusters and
  strongly distorted arcs (statistics and magnified
  sources)
• 34 clusters observed - almost half of them show
  obvious strong lensing!!! gt could expect 100
  new strong lensing clusters in 2 years
  (providing ACS works well).
• Will give a comprehensive (lensing) view of X-ray
  luminous clusters gt2x1044 erg/s

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MACS Snapshot ACSEbeling et al (GO 10491)
First Strong Lensing IDs
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LOCUSS Snapshot ACSSmith et al (GO 10881)
First Strong Lensing IDs
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Axion search with IFU observations
Grin et al 2007

• Abell 2667 z0.228

Abell 2390 z0.233
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Axions Decay

• Axions decay to 2 photons via 2 possible
  channels
• Axions couple to neutral pions, then these pions
  decays to photons pairs, or
• Axions couple directly to std-model fermions,
  which then couple to photon pairs
• Axions lifetime is define by

E/N depends on the axion models, hence the
uncertainty on the coupling factor. Important to
constrain this factor.
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Axion Decay Line

• The rest-frame wavelenght of the axion decay line
  is

The observed line-width is
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IFU observations
Grin et al 2007

• Model predicts line intensity as a function of ?
• Investigating the 2D spectrum as a function of
  the mass density derived by the lens model allows
  to put a constrain the coupling factor as a
  function of the axion mass.

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Axions constraints
Grin et al 2007
Sensitivity prediction for a higher redshift
(z1.2) cluster

• A2390/A2267 constraints

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Conclusion

• Lensing is a simple and precise probe of the
  total matter
• Merging cluster show direct evidence of the
  existence of DM
• Cluster integral field spectroscopic observation
  can probe axion decays, and put constraints on
  the axion coupling factor as a function of mass.

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The End