C.D.S. - SIMBAD4 rel 1.7 - 2021.02.26CET02:16:52

2005A&A...443..793G - Astronomy and Astrophysics, volume 443, 793-804 (2005/12-1)

Projection effects in cluster mass estimates: the case of MS2137-23.


Abstract (from CDS):

We revisit the mass properties of the lensing cluster of galaxies MS2137-23 and assess the mutual agreement between cluster mass estimates based on strong/weak lensing, X-rays and stellar dynamics. We perform a thorough elliptical lens modelling using arcs and their counter-images in the range 20≲R≲100kpc and weak lensing (100≲R≲1000kpc). We confirm that the dark matter distribution is consistent with an NFW profile (Navarro et al., 1997ApJ...490..493N) with high concentration c∼11.7±0.6. We further analyse stellar kinematics data with a detailed modelling of the line-of-sight velocity distribution (LOSVD) of stars in the cD galaxy and quantify the small bias due to the non-Gaussian shape of the LOSVD. After correction, the NFW lens model is unable to properly fit kinematical data and is a factor of ∼2 more massive than suggested by X-rays analysis. The discrepancy between projected (lensing) and tridimensional (X-rays, dynamics) mass estimates is studied by assuming prolate (triaxial) halos with the major axis oriented toward the line-of-sight. This model well explains the high concentration and the misalignement between stellar and dark matter components (Δψ∼13°). We then calculate the systematic and statistical uncertainties in the relative normalization between the cylindric M2(<r) and spherical M3(<r) mass estimates for triaxial halos. These uncertainties prevent any attempt to couple 2D and 3D constraints without undertaking a complete tridimensional analysis. Such asphericity/projection effects should be a major concern for comparisons between lensing and X-rays/dynamics mass estimates.

Abstract Copyright:

Journal keyword(s): cosmology: dark matter - galaxies: clusters: individual: MS2137 - galaxies: elliptical and lenticular, cD - gravitational lensing - galaxies: kinematics and dynamics - galaxies: clusters: general

Simbad objects: 2

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Number of rows : 2

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
1 ACO 1689 ClG 13 11 29.5 -01 20 28           ~ 1036 0
2 ClG 2137-2353 ClG 21 40 12.8 -23 39 27     18.5     ~ 352 0

    Equat.    Gal    SGal    Ecl

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