Calibration of the galaxy cluster M{500}-Y{X} relation with XMM-Newton
Abstract
The quantity Y_X, the product of the X-ray temperature TX and gas mass M_g, has recently been proposed as a robust low-scatter mass indicator for galaxy clusters. Using precise measurements from XMM-Newton data of a sample of 10 relaxed nearby clusters, spanning a YX range of 1013-1015 M_⊙ keV, we investigate the M500-YX relation. The M500-YX data exhibit a power law relation with slope α = 0.548 ± 0.027, close to the self-similar value (3/5) and independent of the mass range considered. However, the normalisation is ~20% below the prediction from numerical simulations including cooling and galaxy feedback. We discuss two effects that could contribute to the normalisation offset: an underestimate of the true mass due to the hydrostatic equilibrium assumption used in X-ray mass estimates, and an underestimate of the hot gas mass fraction in the simulations. A comparison of the functional form and scatter of the relations between various observables and the mass suggest that YX may indeed be a better mass proxy than TX or M_g,500.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 2007
- DOI:
- 10.1051/0004-6361:20078541
- arXiv:
- arXiv:0709.1561
- Bibcode:
- 2007A&A...474L..37A
- Keywords:
-
- cosmology: observations;
- cosmology: dark;
- matter;
- galaxies: clusters: general;
- galaxies: intergalactic;
- medium;
- X-rays: galaxies: clusters;
- Astrophysics
- E-Print:
- 4 pages, 2 figures, accepted for publication in A&