5,281 research outputs found
HIFLUGCS: Galaxy cluster scaling relations between X-ray luminosity, gas mass, cluster radius, and velocity dispersion
We present relations between X-ray luminosity and velocity dispersion
(L-sigma), X-ray luminosity and gas mass (L-Mgas), and cluster radius and
velocity dispersion (r500-sigma) for 62 galaxy clusters in the HIFLUGCS, an
X-ray flux-limited sample minimizing bias toward any cluster morphology. Our
analysis in total is based on ~1.3Ms of clean X-ray XMM-Newton data and 13439
cluster member galaxies with redshifts. Cool cores are among the major
contributors to the scatter in the L-sigma relation. When the
cool-core-corrected X-ray luminosity is used the intrinsic scatter decreases to
0.27 dex. Even after the X-ray luminosity is corrected for the cool core, the
scatter caused by the presence of cool cores dominates for the low-mass
systems. The scatter caused by the non-cool-core clusters does not strongly
depend on the mass range, and becomes dominant in the high-mass regime. The
observed L-sigma relation agrees with the self-similar prediction, matches that
of a simulated sample with AGN feedback disregarding six clusters with <45
cluster members with spectroscopic redshifts, and shows a common trend of
increasing scatter toward the low-mass end, i.e., systems with sigma<500km/s. A
comparison of observations with simulations indicates an AGN-feedback-driven
impact in the low-mass regime. The best fits to the relations
for the disturbed clusters and undisturbed clusters in the observational sample
closely match those of the simulated samples with and without AGN feedback,
respectively. This suggests that one main cause of the scatter is AGN activity
providing feedback in different phases, e.g., during a feedback cycle. The
slope and scatter in the observed r500-sigma relation is similar to that of the
simulated sample with AGN feedback except for a small offset but still within
the scatter.Comment: 45 pages, 28 figures, A&A proof-version, high-resolution figures in
Appendix F can be found in the electronic version on the A&A we
Two-photon Lithography for 3D Magnetic Nanostructure Fabrication
Ferromagnetic materials have been utilised as recording media within data
storage devices for many decades. Confinement of the material to a two
dimensional plane is a significant bottleneck in achieving ultra-high recording
densities and this has led to the proposition of three dimensional (3D)
racetrack memories that utilise domain wall propagation along nanowires.
However, the fabrication of 3D magnetic nanostructures of complex geometry is
highly challenging and not easily achievable with standard lithography
techniques. Here, by using a combination of two-photon lithography and
electrochemical deposition, we show a new approach to construct 3D magnetic
nanostructures of complex geometry. The magnetic properties are found to be
intimately related to the 3D geometry of the structure and magnetic imaging
experiments provide evidence of domain wall pinning at a 3D nanostructured
junction
What is a Cool-Core Cluster? A Detailed Analysis of the Cores of the X-ray Flux-Limited HIFLUGCS Cluster Sample
We use the largest complete sample of 64 galaxy clusters (HIghest X-ray FLUx
Galaxy Cluster Sample) with available high-quality X-ray data from Chandra, and
apply 16 cool-core diagnostics to them, some of them new. We also correlate
optical properties of brightest cluster galaxies (BCGs) with X-ray properties.
To segregate cool core and non-cool-core clusters, we find that central cooling
time, t_cool, is the best parameter for low redshift clusters with high quality
data, and that cuspiness is the best parameter for high redshift clusters. 72%
of clusters in our sample have a cool core (t_cool < 7.7 h_{71}^{-1/2} Gyr) and
44% have strong cool cores (t_cool <1.0 h_{71}^{-1/2} Gyr). For the first time
we show quantitatively that the discrepancy in classical and spectroscopic mass
deposition rates can not be explained with a recent formation of the cool
cores, demonstrating the need for a heating mechanism to explain the cooling
flow problem. [Abridged]Comment: 45 pages, 19 figures, 7 tables. Accepted for publication in A&A.
Contact Person: Rupal Mittal ([email protected]
Sustained Release of Multiple Growth Factors from Injectable Polymeric System as a Novel Therapeutic Approach Towards Angiogenesis
The aim was to investigate that a bio-degradable alginate and poly lactide-co-glycolide (PLG) system capable of delivering growth factors sequentially would be superior to single growth factor delivery in promoting neovascularization and improving perfusion
Longitudinal double-spin asymmetry for inclusive jet production in p+p collisions at sqrt(s)=200 GeV
We report a new STAR measurement of the longitudinal double-spin asymmetry
A_LL for inclusive jet production at mid-rapidity in polarized p+p collisions
at a center-of-mass energy of sqrt(s) = 200 GeV. The data, which cover jet
transverse momenta 5 < p_T < 30 GeV/c, are substantially more precise than
previous measurements. They provide significant new constraints on the gluon
spin contribution to the nucleon spin through the comparison to predictions
derived from one global fit of polarized deep-inelastic scattering
measurements.Comment: 7 pages, 4 figures + 1 tabl
Longitudinal double-spin asymmetry and cross section for inclusive jet production in polarized proton collisions at sqrt(s) = 200 GeV
We report a measurement of the longitudinal double-spin asymmetry A_LL and
the differential cross section for inclusive midrapidity jet production in
polarized proton collisions at sqrt(s)=200 GeV. The cross section data cover
transverse momenta 5 < pT < 50 GeV/c and agree with next-to-leading order
perturbative QCD evaluations. The A_LL data cover 5 < pT < 17 GeV/c and
disfavor at 98% C.L. maximal positive gluon polarization in the polarized
nucleon.Comment: 6 pages, 3 figures. Minor changes from review process in Phys. Rev.
Lett. Plain text tables of data in STAR publications may be found at
http://www.star.bnl.gov/central/publications
Identified baryon and meson distributions at large transverse momenta from Au+Au collisions at GeV
Transverse momentum spectra of , and up to 12 GeV/c
at mid-rapidity in centrality selected Au+Au collisions at GeV are presented. In central Au+Au collisions, both and
show significant suppression with respect to binary scaling at
4 GeV/c. Protons and anti-protons are less suppressed than
, in the range 1.5 6 GeV/c. The and
ratios show at most a weak dependence and no significant
centrality dependence. The ratios in central Au+Au collisions approach
the values in p+p and d+Au collisions at 5 GeV/c. The results at high
indicate that the partonic sources of , and have
similar energy loss when traversing the nuclear medium.Comment: 6 pages, 4 figure
Forward Neutral Pion Transverse Single Spin Asymmetries in p+p Collisions at \sqrt{s}=200 GeV
We report precision measurements of the Feynman-x dependence, and first
measurements of the transverse momentum dependence, of transverse single spin
asymmetries for the production of \pi^0 mesons from polarized proton collisions
at \sqrt{s}=200 GeV. The x_F dependence of the results is in fair agreement
with perturbative QCD model calculations that identify orbital motion of quarks
and gluons within the proton as the origin of the spin effects. Results for the
p_T dependence at fixed x_F are not consistent with pQCD-based calculations.Comment: 6 pages, 4 figure
Neutral Kaon Interferometry in Au+Au collisions at sqrt(s_NN) = 200 GeV
We present the first statistically meaningful results from two-K0s
interferometry in heavy-ion collisions. A model that takes the effect of the
strong interaction into account has been used to fit the measured correlation
function. The effects of single and coupled channel were explored. At the mean
transverse mass m_T = 1.07 GeV, we obtain the values R = 4.09 +/- 0.46 (stat.)
+/- 0.31 (sys) fm and lambda = 0.92 +/- 0.23 (stat) +/- 0.13 (sys), where R and
lambda are the invariant radius and chaoticity parameters respectively. The
results are qualitatively consistent with m_T systematics established with
pions in a scenario characterized by a strong collective flow.Comment: 11 pages, 10 figure
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