Issue |
A&A
Volume 369, Number 1, April I 2001
|
|
---|---|---|
Page(s) | 1 - 15 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361:20010030 | |
Published online | 15 April 2001 |
Cluster mass profiles from weak lensing II
1
IAEF der Universität Bonn, Auf Dem Hügel 71, Bonn, Germany
2
MPA, Karl-Schwarzschild Str 1, Garching bei München, Germany
Corresponding author: L. J. King, lindsay@astro-uni.bonn.de
Received:
4
October
2000
Accepted:
22
December
2000
When a cluster gravitationally lenses faint background galaxies, its
tidal gravitational field distorts their shapes (shear effect) and its
magnification effect changes the observed number density. In
Schneider et al. ([CITE]) we developed likelihood
techniques to compare the constraints on cluster mass profiles
that can be obtained using the shear and magnification information.
This work considered circularly symmetric power-law
models for clusters at fairly low redshifts where
the redshift distribution of source galaxies could be neglected.
Here this treatment is extended
to encompass NFW profiles which are a good description of clusters from
cosmological N-body simulations, and NFW clusters at higher redshifts
where the influence of various scenarios for the knowledge of the
redshift distribution are examined. Since in reality the overwhelming
majority of clusters have ellipsoidal rather than spherical profiles,
the singular isothermal ellipsoid (SIE) is investigated. We also
briefly consider the impact of substructure on such a likelihood analysis.
In general, we find that the shear information provides a better
constraint on the NFW profile under consideration, so this becomes the
focus of what follows. The ability to
differentiate between the NFW and power-law profiles strongly depends
on the size of the data field, and on the number density of galaxies
for which an ellipticity can be measured. Combining Monte Carlo
simulations with likelihood techniques is a very suitable way to
predict whether profiles will be distinguishable, given the
field of view and depth of the observations.
For higher redshift NFW profiles, there is very little reduction
1.5% ) in the dispersion of parameter estimates when
spectroscopic redshifts, as opposed to photometric redshift estimates,
are available for the galaxies used in the lensing analysis.
Key words: dark matter / gravitational lensing / large-scale structure of Universe / galaxies: clusters: general / methods: statistical
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.