26 research outputs found
Free-floating molecular clumps and gas mixing: hydrodynamic aftermaths of the intraclusterinterstellar medium interaction
The interaction of gas-rich galaxies with the intra-cluster medium (ICM) of
galaxy clusters has a remarkable impact on their evolution, mainly due to the
gas loss associated with this process. In this work, we use an idealised,
high-resolution simulation of a Virgo-like cluster, run with RAMSES and with
dynamics reproducing that of a zoom cosmological simulation, to investigate the
interaction of infalling galaxies with the ICM. We find that the tails of ram
pressure stripped galaxies give rise to a population of up to more than a
hundred clumps of molecular gas lurking in the cluster. The number count of
those clumps varies a lot over time -- they are preferably generated when a
large galaxy crosses the cluster (M M), and their
lifetime ( Myr) is small compared to the age of the cluster. We
compute the intracluster luminosity associated with the star formation which
takes place within those clumps, finding that the stars formed in all of the
galaxy tails combined amount to an irrelevant contribution to the intracluster
light. Surprisingly, we also find in our simulation that the ICM gas
significantly changes the composition of the gaseous disks of the galaxies:
after crossing the cluster once, typically 20% of the cold gas still in those
disks comes from the ICM.Comment: 9 pages, 6 figures. Accepted for publication in MNRA
XMM-Newton temperature maps for five intermediate redshift clusters of galaxies
We have analyzed XMM-Newton archive data for five clusters of galaxies
(redshifts 0.223 to 0.313) covering a wide range of dynamical states, from
relaxed objects to clusters undergoing several mergers. We present here
temperature maps of the X-ray gas together with a preliminary interpretation of
the formation history of these clusters.Comment: 4 pages, 2 figs. Accepted for publication in the Proceedings of the
36th COSPAR Scientific Assembl
A New Method to Quantify X-ray Substructures in Clusters of Galaxies
We present a new method to quantify substructures in clusters of galaxies,
based on the analysis of the intensity of structures. This analysis is done in
a residual image that is the result of the subtraction of a surface brightness
model, obtained by fitting a two-dimensional analytical model (beta-model or
S\'ersic profile) with elliptical symmetry, from the X-ray image. Our method is
applied to 34 clusters observed by the Chandra Space Telescope that are in the
redshift range 0.02<z<0.2 and have a signal-to-noise ratio greater than 100. We
present the calibration of the method and the relations between the
substructure level with physical quantities, such as the mass, X-ray
luminosity, temperature, and cluster redshift. We use our method to separate
the clusters in two sub-samples of high and low substructure levels. We
conclude, using Monte Carlo simulations, that the method recuperates very well
the true amount of substructure for small angular core radii clusters (with
respect to the whole image size) and good signal-to-noise observations. We find
no evidence of correlation between the substructure level and physical
properties of the clusters such as mass, gas temperature, X-ray luminosity and
redshift. The scaling relations for the two sub-samples (high and low
substructure level clusters) are different (they present an off-set, i.e.,
given a fixed mass or temperature, low substructure clusters tend to be more
X-ray luminous), which is an important result for cosmological tests using the
mass-luminosity relation to obtain the cluster mass function, since they rely
on the assumption that clusters do not present different scaling relations
according to their dynamical state.Comment: 13 pages, 17 figures, accepted for publication in ApJ
(http://iopscience.iop.org/0004-637X/746/2/139/
Structure and dynamics of the supercluster of galaxies SC0028-0005
According to the standard cosmological scenario, superclusters are objects
that have just passed the turn around point and are collapsing. The dynamics of
very few superclusters have been analysed up to now. In this paper we study the
supercluster SC0028-0005, at redshift 0.22, identify the most prominent groups
and/or clusters that make up the supercluster, and investigate the dynamic
state of this structure. For the membership identification, we have used
photometric and spectroscopic data from SDSS-DR10, finding 6 main structures in
a flat spatial distribution. We have also used a deep multi-band observation
with MegaCam/CFHT to estimate de mass distribution through the weak-lensing
effect. For the dynamical analysis, we have determined the relative distances
along the line of sight within the supercluster using the Fundamental Plane of
early-type galaxies. Finally, we have computed the peculiar velocities of each
of the main structures. The 3D distribution suggests that SC0028-005 is indeed
a collapsing supercluster, supporting the formation scenario of these
structures. Using the spherical collapse model, we estimate that the mass
within ~Mpc should lie between 4 and . The
farthest detected members of the supercluster suggest that within ~Mpc
the density contrast is with respect to the critical density at
, implying a total mass of --,
most of which in the form of low-mass galaxy groups or smaller substructures.Comment: 12 pages, 9 figures, Accepted for publication in MNRA