Issue |
A&A
Volume 570, October 2014
|
|
---|---|---|
Article Number | A9 | |
Number of page(s) | 9 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361/201321748 | |
Published online | 07 October 2014 |
Reconstructing the projected gravitational potential of galaxy clusters from galaxy kinematics
1
Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische
Astrophysik,
Philosophenweg 12,
69120
Heidelberg,
Germany
e-mail:
Sarli@uni-heidelberg.de
2
INAF – Osservatorio Astronomico di Bologna, via Ranzani 1,
40127
Bologna,
Italy
3
INFN – Sezione di Bologna , viale Berti Pichat 6/2,
40127
Bologna,
Italy
Received:
22
April
2013
Accepted:
23
July
2014
We have developed a method for reconstructing the two-dimensional, projected gravitational potential of galaxy clusters from observed line-of-sight velocity dispersions of cluster galaxies. It is the second in an intended series of papers aiming at a unique reconstruction method for cluster potentials that combine lensing, X-ray, Sunyaev-Zel’dovich and kinematic data. The observed galaxy velocity dispersions are deprojected using the Richardson-Lucy algorithm. The obtained radial velocity dispersions are then related to the gravitational potential by using the tested assumption of a polytropic relation between the effective galaxy pressure and the density. Once the gravitational potential is obtained in three dimensions, projection along the line of sight yields the two-dimensional potential. For simplicity we adopt spherical symmetry and a known profile for the anisotropy parameter of the galaxy velocity dispersions. We tested the method with a numerically simulated galaxy cluster and the galaxies identified therein and performed the reconstruction for three different lines of sight. We extracted a projected velocity-dispersion profile from the simulated cluster and passed it through our algorithm, showing that the deviation between the true and the reconstructed gravitational potential is ≲10% within ≈ 1.5 h-1 Mpc from the cluster centre.
Key words: dark matter / galaxies: clusters: general / galaxies: kinematics and dynamics / gravitational lensing: strong / gravitational lensing: weak
© ESO, 2014
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