Star formation efficiency in galaxy clusters
Abstract
Context: The luminous material in clusters of galaxies exists in two forms: the visible galaxies and the X-ray emitting intra-cluster medium. The hot intra-cluster gas is the major observed baryonic component of clusters, about six times more massive than the stellar component. The mass contained within visible galaxies is approximately 3% of the dynamical mass.
Aims: Our aim was to analyze both baryonic components, combining X-ray and optical data of a sample of five galaxy clusters (Abell 496, 1689, 2050, 2631 and 2667), within the redshift range 0.03 < {z} < 0.3. We determined the contribution of stars in galaxies and the intra-cluster medium to the total baryon budget.
Methods: We used public XMM-Newton data to determine the gas mass and to obtain the X-ray substructures. Using the optical counterparts from SDSS or CFHT we determined the stellar contribution.
Results: We examine the relative contribution of galaxies, intra-cluster light and intra-cluster medium to baryon budget in clusters through the stellar-to-gas mass ratio, estimated with recent data. We find that the stellar-to-gas mass ratio within r500 (the radius within which the mean cluster density exceeds the critical density by a factor of 500), is anti-correlated with the ICM temperature, which range from 24% to 6% while the temperature ranges from 4.0 to 8.3 keV. This indicates that less massive cold clusters are more prolific star forming environments than massive hot clusters.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 2008
- DOI:
- 10.1051/0004-6361:20079168
- arXiv:
- arXiv:0804.1102
- Bibcode:
- 2008A&A...485..633L
- Keywords:
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- galaxies: clusters: general;
- X-rays: galaxies: clusters;
- galaxies: luminosity function;
- mass function;
- Astrophysics
- E-Print:
- A&