1,487 research outputs found
A radial mass profile analysis of the lensing cluster MS2137-23
We reanalyze the strong lens modeling of the cluster of galaxies MS2137-23
using a new data set obtained with the ESO VLT. We found the photometric
redshifts of the two main arc systems are both at z=1.6. After subtraction of
the central cD star light of the HST image we found that only one object lying
underneath has the expected properties of the fifth image associated to the
tangential arc. We improve the previous lens modelings of the central dark
matter distribution of the cluster, using an isothermal model with a core (IS)
and the NFW-like model with a cusp. Without the fifth image, the arc properties
together with the shear map profile are equally well fit by the and by an IS
and a sub-class of generalized-NFW mass profiles having inner slope power index
in the range 0.7<alpha<1.2. Adding new constrains provided by the fifth image
favors IS profiles that better predict the fifth image properties. A model
including cluster galaxy perturbations or the the stellar mass distribution
does not change our conclusions but imposes the M/L_I of the cD stellar
component is below 10 at a 99% confidence level.
Using our new detailed lensing model together with Chandra X-ray data and the
cD stellar component we finally discuss intrinsic properties of the
gravitational potential. Whereas X-ray and dark matter have a similar shape at
various radius, the cD stellar isophotes are twisted by 13 deg. The sub-
arc-second azimuthal shift we observe between the radial arc position and the
predictions of elliptical models correspond to what is expected from a mass
distribution twist. This shift may result from a projection effect of the cD
and the cluster halos, thus revealing the triaxiality of the system.Comment: Final version accepted in A&
- …