pinecone/core-2020-05-10-deduplication huggingface dataset:
Observational Constraints on the ICM Temperature Enhancement by Cluster Mergers

We present results from a combined weak lensing and X-ray analysis of the merging cluster A1914 at a redshift of $z=0.1712$ based on $R_{\rm}$-band imaging data with Subaru/Suprime-Cam and archival Chandra X-ray data. Based on the weak-lensing and X-ray data we explore the relationships between cluster global properties, namely the gravitational mass, the bolometric X-lay luminosity and temperature, the gas mass and the gas mass fraction, as a function of radius. We found that the gas mass fractions within $r_{2500}$ and $r_{{\rm vir}}$ are consistent with the results of earlier X-ray cluster studies and of cosmic microwave background studies based on the WMAP observations, respectively. However, the observed temperature, $k_B T_{\rm ave}=9.6\pm0.3 {\rm keV}$, is significantly higher than the virial temperature, $k_B T_{\rm vir}=4.7\pm0.3 {\rm keV}$ derived from the weak lensing distortion measurement. The X-ray bolometric luminosity and temperature ($L_X-T$) relation is consistent with the $L_X-T$ relation derived by previous statistical X-ray studies of galaxy clusters. Such correlations among the global cluster properties are invaluable observational tools for studying the cluster merger physics. Our results demonstrate that the combination of X-ray and weak-lensing observations is a promising, powerful probe of the physical processes associated with cluster mergers as well as of their mass properties
Tracing the evolution in the iron content of the ICM

We present a Chandra analysis of the X-ray spectra of 56 clusters of galaxies at z>0.3, which cover a temperature range of 3>kT>15 keV. Our analysis is aimed at measuring the iron abundance in the ICM out to the highest redshift probed to date. We find that the emission-weighted iron abundance measured within (0.15-0.3)R_vir in clusters below 5 keV is, on average, a factor of ~2 higher than in hotter clusters, following Z(T)~0.88T^-(0.47)Z_o, which confirms the trend seen in local samples. We made use of combined spectral analysis performed over five redshift bins at 0.3>z>1.3 to estimate the average emission weighted iron abundance. We find a constant average iron abundance Z_Fe~0.25Z_o as a function of redshift, but only for clusters at z>0.5. The emission-weighted iron abundance is significantly higher (Z_Fe~0.4Z_o) in the redshift range z~0.3-0.5, approaching the value measured locally in the inner 0.15R_vir radii for a mix of cool-core and non cool-core clusters in the redshift range 0.1<z<0.3. The decrease in Z_Fe with redshift can be parametrized by a power law of the form ~(1+z)^(-1.25). The observed evolution implies that the average iron content of the ICM at the present epoch is a factor of ~2 larger than at z=1.2. We confirm that the ICM is already significantly enriched (Z_Fe~0.25Z_o) at a look-back time of 9 Gyr. Our data provide significant constraints on the time scales and physical processes that drive the chemical enrichment of the ICM
Chemical Gradients in Galaxy Clusters and the Multiple Ways of Making a Cold Front

Cold fronts were originally interpreted as being the result of subsonic/transonic motions of head-on merging substructures. This merger core remnant model is theoretically justified and hold relatively well for clusters that have clear signs of merging, such as 1E0657-56, but they do not work well for the increasing number of cold fronts found in clusters that do not show clear merging signs, such as A496. Here we report the results of a deeper observation of that cluster that allowed us to produce high quality maps of the gas parameters and to compare more closely the observations with the predictions given by different models for cold front formation. We found for the first time a ``cold arm'' characteristic of a flyby of a massive DM halo near the core of the cluster. The cold arm is accompanied by an enhanced SN II Fe mass fraction, inconsistent with the merger core remnant scenario
Beyond the Cool Core: The Formation of Cool Core Galaxy Clusters

Why do some clusters have cool cores while others do not? In this paper, cosmological simulations, including radiative cooling and heating, are used to examine the formation and evolution of cool core (CC) and non-cool core (NCC) clusters. Numerical CC clusters at z=0 accreted mass more slowly over time and grew enhanced cool cores via hierarchical mergers; when late major mergers occurred, the CCs survived the collisions. By contrast, NCC clusters of similar mass experienced major mergers early in their evolution that destroyed embryonic cool cores and produced conditions that prevent CC re-formation. We discuss observational consequences
AMR Simulations of the Cosmological Light Cone: SZE Surveys of the Synthetic Universe

We present preliminary results from simulated large sky coverage (~100 square degrees) Sunyaev-Zeldovich effect (SZE) cluster surveys using the cosmological adaptive mesh refinement N-body/hydro code Enzo. We have generated simulated light cones to match the resolution and sensitivity of current and future SZE instruments. These simulations are the most advanced calculations of their kind. The simulated sky surveys allow a direct comparison of large N-body/hydro cosmological simulations to current and pending sky surveys. Our synthetic surveys provide an indispensable guide for observers in the interpretation of large area sky surveys, and will develop the tools necessary to discriminate between models for cluster baryonic physics, and to accurately determine cosmological parameters
Modeling Chandra X-ray observations of Galaxy Clusters using Cosmological Simulations

X-ray observations of galaxy clusters potentially provide powerful cosmological probes if systematics due to our incomplete knowledge of the intracluster medium (ICM) physics are understood and controlled. In this paper, we study the effects of galaxy formation on the properties of the ICM and X-ray observable-mass relations using high-resolution self-consistent cosmological simulations of galaxy clusters and comparing their results with recent Chandra X-ray observations. We show that despite complexities of their formation and uncertainties in their modeling, clusters of galaxies both in observations and numerical simulations are remarkably regular outside of their cores, which holds great promise for their use as cosmological probes
Complex Physics in Cluster Cores: Showstopper for the Use of Clusters for Cosmology?

The influence of cool galaxy cluster cores on the X-ray luminosity--gravitational mass relation is studied with Chandra observations of 64 clusters in the HIFLUGCS sample. As preliminary results we find (i) a significant offset of cool core (CC) clusters to the high luminosity (or low mass) side compared to non-cool core (NCC) clusters, (ii) a smaller scatter of CC clusters compared to NCC clusters, (iii) a decreasing fraction of CC clusters with increasing cluster mass, (iv) a reduced scatter in the luminosity--mass relation for the entire sample if the luminosity is scaled properly with the central entropy. The implications of these results on the intrinsic scatter are discussed
A Heating Model for the Millennium Gas Run

The comparison between observations of galaxy clusters thermo-dynamical properties and theoretical predictions suggests that non-gravitational heating needs to be added into the models. We implement an internally self-consistent heating scheme into GADGET-2 for the third (and fourth) run of the Millennium gas project (Pearce et al. in preparation), a set of four hydrodynamical cosmological simulations with N=2(5x10^8) particles and with the same volume (L=500 h-1 Mpc) and structures as the the N-body Millennium Simulation (Springel et al. 2005). Our aim is to reproduce the observed thermo-dynamical properties of galaxy clusters
2dF-SDSS LRG and QSO (2SLAQ) Survey: Evolution of the Most Massive Galaxies

The 2dF-SDSS LRG and QSO (2SLAQ) survey is a new survey of distant Luminous Red Galaxies (LRGs) and faint quasars selected from the Sloan Digital Sky Survey (SDSS) multi-color photometric data and spectroscopically observed using the 2dF instrument on the Anglo-Australian Telescope (AAT). In total, the 2SLAQ survey has measured over 11000 LRG redshifts, covering 180deg^2 of SDSS imaging data, from 87 allocated nights of AAT time. Over 90% of these galaxies are within the range 0.45<z<0.7 and have luminosities consistent with >=3L*. When combined with the lower redshift SDSS LRGs, the evolution in the luminosity function of these LRGs is fully consistent with that expected from a simple passive (luminosity) evolution model. This observation suggests that at least half of the LRGs seen at z~0.2 must already have more than half their stellar mass in place by z~0.6, i.e., our observations are inconsistent with a majority of LRGs experiencing a major merger in the last 6 Gyrs. However, some "frosting" (i.e., minor mergers) has taken place with ~5% of LRGs showing some evidence of recent and/or on-going star-formation, but it only contributes ~1% of their stellar mass
Scalable N-body code for the modelling of early-type galaxies

Early-type galaxies exhibit a wealth of photometric and dynamical structures.
These signatures are fossil records of their formation and evolution processes.
In order to examine these structures in detail, we build models aimed at
reproducing the observed photometry and kinematics. The developed method is a
generalization of the one introduced by Syer and Tremaine (1996), consisting in
an N-body representation, in which the weights of the particles are changing
with time. Our code is adapted for integral-field spectroscopic data, and is
able to reproduce the photometric as well as stellar kinematic data of observed
galaxies. We apply this technique on SAURON data of early-type galaxies, and
present preliminary results on NGC 3377.Comment: 6 pages, 2 figures. Original version printed in the Proceedings of
  "Science perspective for 3D spectroscopy", 2005, Eds Kissler-Patig, Walsh,
  Roth, ES0, Springe
3D-Spectroscopy of extragalactic planetary nebulae as diagnostic probes for galaxy evolution

In addition to study extragalactic stellar populations in their integrated light, the detailed analysis of individual resolved objects has become feasible, mainly for luminous giant stars and for extragalactic planetary nebulae (XPNe) in nearby galaxies. A recently started project at the Astrophysical Institute Potsdam (AIP), called ``XPN--Physics'', aims to verify if XPNe are useful probes to measure the chemical abundances of their parent stellar population. The project involves theoretical and observational work packages
The Strong CP Problem and Axions

I describe how the QCD vacuum structure, necessary to resolve the $U(1)_A$
problem, predicts the presence of a P, T and CP violating term proportional to
the vacuum angle $\bar{\theta}$. To agree with experimental bounds, however,
this parameter must be very small $(\bar{\theta} \leq 10^{-9}$). After briefly
discussing some possible other solutions to this, so-called, strong CP problem,
I concentrate on the chiral solution proposed by Peccei and Quinn which has
associated with it a light pseudoscalar particle, the axion. I discuss in
detail the properties and dynamics of axions, focusing particularly on
invisible axion models where axions are very light, very weakly coupled and
very long-lived. Astrophysical and cosmological bounds on invisible axions are
also briefly touched upon.Comment: 14 pages, to appear in the Lecture Notes in Physics volume on Axions,
  (Springer Verlag
Axion Searches in the Past, at Present, and in the Near Future

Theoretical axion models state that axions are very weakly interacting
particles. In order to experimentally detect them, the use of colorful and
inspired techniques becomes mandatory. There is a wide variety of experimental
approaches that were developed during the last 30 years, most of them make use
of the Primakoff effect, by which axions convert into photons in the presence
of an electromagnetic field. We review the experimental techniques used to
search for axions and will give an outlook on experiments planned for the near
future.Comment: 38 pages, 26 figures and images, to appear in the Lecture Notes in
  Physics volume on Axions (Springer Verlag
Astrophysical Axion Bounds

Axion emission by hot and dense plasmas is a new energy-loss channel for
stars. Observational consequences include a modification of the solar
sound-speed profile, an increase of the solar neutrino flux, a reduction of the
helium-burning lifetime of globular-cluster stars, accelerated white-dwarf
cooling, and a reduction of the supernova SN 1987A neutrino burst duration. We
review and update these arguments and summarize the resulting axion
constraints.Comment: Contribution to Axion volume of Lecture Notes in Physics, 20 pages, 3
  figure
Axions and their Relatives

A review of the status of axions and axion-like particles is given. Special
attention is devoted to the recent results of the PVLAS collaboration, which
are in conflict with the CAST data and with the astrophysical constraints.
Solutions to the puzzle and the implications for new physics are discussed. The
question of axion-like particles being dark matter is also addressed.Comment: Updated version of an invited talk at the Axion Training (CERN,
  December 2005). To appear as a Lecture Notes in Physics (Springer-Verlag),
  edited by B. Beltran, M. Kuster and G. Raffel
A simulation-based study of TCP performance over an Optical Burst Switched backbone with 802.11 access

13th Open European Summer School and IFIP TC6.6 Workshop, EUNICE 2007, Enschede, The Netherlands, July 18-20, 2007. ProceedingsThe combined effect of optical and wireless subnetworks in an hypothetical future scenario where core networks have evolved to the still prototype Optical Burst Switching (OBS) technology is an open research issue. This paper studies this hybrid scenario, in the particular case of 802.11 access, by reviewing the key aspects of OBS and 802.11 with an impact on the performance of TCP, and makes a simulation-based assessment of the relative influence of  both  technologies over the effective end-to-end behaviour of TCP.This work has been partly supported by the EU under the IST e-Photon/One+ project (FP6-IST-027497) and by the Spanish CAPITAL project (TEC2004-05622-C04-03).Publicad
Enumerating Constrained Non-crossing Geometric Spanning Trees (Computing and Combinatorics)

Computing and combinatorics : 13th Annual International Conference, COCOON 2007 Banff, Canada, July 16-19, 2007 : proceedings : (Lecture notes in computer science ; 4598)Proc. of 13th Annual International Computing and Combinatorics Conference (COCOON 2007) LNCS 4598In this paper we present an algorithm for enumerating without repetitions all non-crossing geometric spanning trees on a given set of n points in the plane under edge inclusion constraints (i.e., some edges are required to be included in spanning trees). We will first prove that a set of all edge-constrained non-crossing spanning trees is connected via remove-add flips, based on the constrained smallest indexed triangulation which is obtained by extending the lexicographically ordered triangulation introduced by Bespamyatnikh. More specifically, we prove that all edge-constrained triangulations can be transformed to the smallest indexed triangulation among them by O(n 2) times of greedy flips. Our enumeration algorithm generates each output graph in O(n 2) time and O(n) space based on reverse search technique
Seed-Based Exclusion Method for Non-coding RNA Gene Search

International audienceGiven an RNA family characterized by conserved sequences and folding constraints, the problem is to search for all the instances of the RNA family in a genomic database. As seed-based heuristics have been proved very eﬃcient to accelerate the classical homology based search methods such as BLAST, we use a similar idea for RNA structures. We present an exclusion method for RNA search allowing for possible nucleotide insertion, deletion and substitution. It is based on a partition of the RNA stem-loops into consecutive seeds and a preprocessing of the target database. This algorithm can be used to improve time eﬃciency of current methods, and is guaranteed to ﬁnd all occurrences that contain at least one exact seed
An architecture for self-healing autonomous object groups

Jgroup/ARM is a middleware for developing and operating
dependable distributed Java applications. Jgroup integrates the distributed
object model of Java RMI with the object group paradigm, enabling
construction of replicated servers that offer dependable services
to clients. ARM aims to improve the dependability characteristics of
systems through fault treatment, focusing on operational aspects where
the gain in terms of improved dependability is likely to be the greatest.
ARM offers two core mechanisms: recovery from node, object and network
failures and distribution of replicas. ARM identifies failures and
reconfigures the system according to its dependability requirements.
This paper proposes an enhancement of the ARM framework in which
replica placement is performed in a distributed manner, eliminating the
need for a centralized manager with global information about all object
groups. Instead each autonomous object group handles their own replica
placement based on information from nodes. Assuming that multiple objects
groups are deployed in the system, this constitutes a distributed
replica placement scheme. This scheme enables the implementation of
self-healing object groups that can perform fault treatment on themselves.
Advantages of the approach: (a) no need to maintain global information
about all object groups which is costly and limits scalability, (b)
reduced infrastructure complexity, and (c) less communication overhead
Ultrafast peptide and protein dynamics by vibrational spectroscopy

Proteins are molecular machines with a well-defined 3D structure, and it is mainly the success of X-ray and NMR spectroscopic techniques that made the tremendous progress in structural biology happen. However, it is also clear that biomolecular processes generally involve conformational changes of proteins and enzymes. Mostly due to a lack of appropriate spectroscopic tools, much less is known about the dynamics of protein structures.\ud
Protein dynamics occurs on a large range of time scales, which can coarsely be related to various length scales: Dynamics of tertiary and quaternary structure extends from milliseconds to seconds and even longer, while formation of secondary structure has been observed between 50 ns and a few microseconds [1–12]. Nevertheless, several experiments have provided strong hints for the relevance of even faster processes from the observation of large instantaneous signals, which could not be time-resolved [2, 7, 13]. For example, Thompson et al. [5] estimated a “zipping time” for a 21-residue α-helix of 300 ps (i.e., the time for closing of subsequent hydrogen bonds, once an initial helix turn is formed), while Huang et al. [7] indirectly concluded that helix nucleation might occur on a subnanosecond time scale. Also molecular dynamics (MD) simulations suggest that peptides and proteins can undergo considerable structural changes within 1 ns or less [8–10, 14, 15]. Hummer et al. [16] found the formation of the first α-helical turn within 0.1–1 ns in work on helix nucleation in short Ala and Gly based peptides. Daura et al. [9, 17] simulated equilibrium folding/unfolding of a β-heptapeptide at the melting point and above to obtain statistics on the populations of the folded and unfolded states. Several folding/unfolding events were observed in a 50 ns trajectory, where the actual transitions from unfolded to folded conformations could be as fast as 50–100ps
Plasma polarization spectroscopy

Plasma Polarization Spectroscopy (PPS) is now becoming a standard diagnostic technique for working with laboratory plasmas. This new area needs a comprehensive framework, both experimental and theoretical. This book reviews the historical development of PPS, develops a general theoretical formulation to deal with this phenomenon, along with an overview of relevant cross sections, and reports on laboratory experiments so far performed. It also includes various facets that are interesting from this standpoint, e.g. X-ray lasers and effects of microwave irradiation. It also offers a timely discussion of instrumentation that is quite important in a practical PPS experiment
A higher abstraction level using first-class inheritance relations

Although classes are a fundamental concept in object-oriented programming, a class itself cannot be built using general purpose classes as building blocks in a practical manner. High-level concepts like associations, bounded values, graph structures, and infrastructure for event mechanisms which form the foundation of a class cannot be reused conveniently as components for classes. As a result, they are implemented over and over again. We raise the abstraction level of the language with a code inheritance relation for reusing general purpose classes as components for other classes. Features like mass renaming, first-class relations, high-level dependencies, component parameters, and indirect inheritance ensure that maximal reuse can be achieved with minimal effort. A case study shows a reduction of the code between 21% and 36%, while the closest competitor only reduces the size between 3% and 12%.status: publishe
Beyond Gross-Pitaevskii Mean Field Theory

A large number of effects related to the phenomenon of Bose-Einstein
Condensation (BEC) can be understood in terms of lowest order mean field
theory, whereby the entire system is assumed to be condensed, with thermal and
quantum fluctuations completely ignored. Such a treatment leads to the
Gross-Pitaevskii Equation (GPE) used extensively throughout this book. Although
this theory works remarkably well for a broad range of experimental parameters,
a more complete treatment is required for understanding various experiments,
including experiments with solitons and vortices. Such treatments should
include the dynamical coupling of the condensate to the thermal cloud, the
effect of dimensionality, the role of quantum fluctuations, and should also
describe the critical regime, including the process of condensate formation.
The aim of this Chapter is to give a brief but insightful overview of various
recent theories, which extend beyond the GPE. To keep the discussion brief,
only the main notions and conclusions will be presented. This Chapter
generalizes the presentation of Chapter 1, by explicitly maintaining
fluctuations around the condensate order parameter. While the theoretical
arguments outlined here are generic, the emphasis is on approaches suitable for
describing single weakly-interacting atomic Bose gases in harmonic traps.
Interesting effects arising when condensates are trapped in double-well
potentials and optical lattices, as well as the cases of spinor condensates,
and atomic-molecular coupling, along with the modified or alternative theories
needed to describe them, will not be covered here.Comment: Review Article (19 Pages) - To appear in 'Emergent Nonlinear
  Phenomena in Bose-Einstein Condensates: Theory and Experiment', Edited by
  P.G. Kevrekidis, D.J. Frantzeskakis and R. Carretero-Gonzalez (Springer
  Verlag
Experiments on Multidimensional Solitons

This article presents an overview of experimental efforts in recent years
related to multidimensional solitons in Bose-Einstein condensates. We discuss
the techniques used to generate and observe multidimensional nonlinear waves in
Bose-Einstein condensates with repulsive interactions. We further summarize
observations of planar soliton fronts undergoing the snake instability, the
formation of vortex rings, and the emergence of hybrid structures.Comment: review paper, to appear as Chapter 5b in "Emergent Nonlinear
  Phenomena in Bose-Einstein Condensates: Theory and Experiment," edited by P.
  G. Kevrekidis, D. J. Frantzeskakis, and R. Carretero-Gonzalez
  (Springer-Verlag