Lensing clusters with EUCLID from VIS and NISP expected performances

Massimo Meneghetti

INAF-OABO

A large cluster dataset

• EUCLID is expected to find of order of 60000 galaxy clusters in the zrange 0.2-2.

• About 50000 of them will have >15 galaxies per sq. arcmin detectable in their background.

• These galaxies will be distorted by the gravitational lensing effects of the foreground clusters.

• Occasionally, they will appear as multiple image systems and/or gravitational arcs.

• A lot of cluster science, cosmology with galaxy clusters…

How do we expect to see the lensingclusters with EUCLID?

Using the code SkyLens(Meneghetti et al. 2006; 2011) we can simulate how EUCLID will be able to observe lensing clusters.

In the image: a massive galaxy cluster at z=0.29, resulting from hydro-N-body simulations, observed for 4x540s in the Riz band…

…and in the Y band (4x70s)

Clusters @z>1 with EUCLID

• cluster at z=1.04

• mass is 5x1014 h-1 Msun

• cluster at z=1.04

• mass is 5x1014 h-1 Msun

Combining different datasets:EUCLID + ground based data

DES:

g,r,i,z

Y

J

H

Photo-z from EUCLID + ground based data

SED fitting using the software BPZ (Benitez et al.)

z_inp=1.3

z_phot=1.29

F. Bellagamba et al., submitted to MNRAS

Cluster mass profiles

Accurate mass measurements!

And still missing the SL constraints…

KSBf90 code to measure shear

How many arcs will be seen by EUCLID?Giocoli et al. 2011; Boldrin et al. 2011 in prep.

• Use the MOKA code to produce ~370000 mock clusters for carefully sampling the strong lensing cross section in mass and redshift in LCDM:

– triaxial DM halo

– follow c-M relation by Zhao et al. (2009)

– BCG

– substructures

– adiabatic contraction

• Use mass function to produce light cones, reproducing the expected abundance of clusters in redshiftbins from z=0 to z=2

How many arcs will be seen by EUCLIDGiocoli et al. 2011, in prep; Boldrin et al. 2011 in prep.

• Use SkyLens to derive the redshift distribution of sources above a certain surface brightness limit

• Combine it with the lensingcross sections…

• We finally derive the number of giant arcs that EUCLID is likely to see...

• We can also estimate the cosmic variance (scatter in triaxiality, substructure content, concentrations, etc.) by making multiple realizations of the survey which will be operated by EUCLID.

Detection of SL features(arcfinders by Cabanac et al. & Seidel et al.)

Conclusions

• EUCLID will deliver excellent-quality observations of lensing effects by galaxy clusters…

• High density of background sources up to z=1, sharp imaging, thousands of SL lensing features

• These will allow, for example, to measure cluster mass profiles with high accuracy… M,c,slope

• Many other applications: high-z galaxies through magnification effects, arc statistics,…