For refcode 2013A&A...555A..66L: Retrieve 124 NED objects in this reference. Please click here for ADS abstract
NED Abstract
Copyright by European Southern Observatory (ESO).
Reproduced by permission
2013A&A...555A..66L
A comprehensive picture of baryons in groups and clusters of galaxies
Lagana, T. F.; Martinet, N.; Durret, F.; Lima Neto, G. B.; Maughan, B.;
Zhang, Y.Y.
Abstract.
Aims: Based on XMMNewton, Chandra, and SDSS data, we investigate the
baryon distribution in groups and clusters and its use as a cosmological
constraint. For this, we considered a sample of 123 systems with
temperatures kT_500_ = 1.09.0 keV, total masses in the mass range M_500_
= (~10^13^4 x 10^15^)h_70_^1^ M_sun_, and redshifts 0.02 < z < 1.3.
Methods: The gas masses and total masses are derived from Xray data
under the assumption of hydrostatic equilibrium and spherical symmetry.
The stellar masses are based on SDSSDR8 optical photometric data. For the
37 systems out of 123 that had both optical and Xray data available, we
investigated the gas, stellar, and total baryon mass fractions inside
r_2500_ and r_500_ and the differential gas mass fraction within the
spherical annulus between r_2500_ and r_500_, as a function of total mass.
For the other objects, we investigated the gas mass fraction only.
Results: We find that the gas mass fraction inside r_2500_ and r_500_
depends on the total mass. However, the differential gas mass fraction
does not show any dependence on total mass for systems with M_500_ >
10^14^ M_sun_. The stellar mass fraction inside r_2500_ and r_500_
increases towards lowmass systems more steeply than the f_gas_ decrease
with total mass. Adding the gas and stellar mass fractions to obtain the
total baryonic content, we find it to increase with cluster mass, reaching
the WMAP7 value for clusters with M_500_ ~ 10^14^ M_sun_. This led us
to investigate the contribution of the intracluster light to the total
baryon budget for lower mass systems, but we find that it cannot account
for the difference observed.
Conclusions: The gas mass fraction dependence on total mass observed for
groups and clusters could be due to the difficulty of lowmass systems to
retain gas inside the inner region (r < r_2500_). Because of their
shallower potential well, nonthermal processes are more effective in
expelling the gas from their central regions outwards. Since the
differential gas mass fraction is nearly constant, it provides better
constraints for cosmology. Moreover, we find that the gas mass fraction
does not depend on redshift at a 2sigma level. Using our total f_b_
estimates, our results imply Omega_m_ < 0.55, and taking the highest
significant estimates for f_b_, Omega_m_ > 0.22.
Table 1 and Appendices are available in electronic form at
http://www.aanda.org
Key words: galaxies: clusters: general, cosmological parameters, galaxies:
clusters: intracluster medium
Retrieve 124 NED objects in this reference. Please click here for ADS abstract
