A Detailed Study of the Mass Distribution of the Galaxy Cluster RXC J2248.7-4431

In this work we use strong gravitational lensing techniques to constrain the total mass distribution of the galaxy cluster RXC J2248.7-4432 (RXC J2248, zlens = 0.348), also known as Abell S1063, observed within the Cluster Lensing And Supernova survey with Hubble (CLASH). Thanks to its strong lensing efficiency and exceptional data quality from the VIsible Multi-Object Spectrograph (VIMOS) and Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope, we can build a parametric model for the total mass distribution. Using the positions of the multiple images generated by 7 multiply-lensed background sources with measured spectroscopic redshifs, we find that the best-fit parametrisation for the cluster total mass distribution is composed of an elliptical pseudo-isothermal mass distribution with a significant core for the overall cluster halo, and of truncated pseudo-isothermal mass profiles for the cluster galaxies. This model is capable to predict the positions of the multiple images with an unprecedented precision of 48 0".3. We also show that varying freely the cosmological parameters of the \u39bCDM model, our strong lensing model can constrain the underlying geometry of the universe via the angular diameter distances between the lens and the sources and the observer and the sources

Joining X-Ray to Lensing: An Accurate Combined Analysis of MACS J0416.1-2403

We present a novel approach for a combined analysis of X-ray and gravitational lensing data and apply this technique to the merging galaxy cluster MACS J0416.1-2403. The method exploits the information on the intracluster gas distribution that comes from a fit of the X-ray surface brightness and then includes the hot gas as a fixed mass component in the strong-lensing analysis. With our new technique, we can separate the collisional from the collision-less diffuse mass components, thus obtaining a more accurate reconstruction of the dark matter distribution in the core of a cluster. We introduce an analytical description of the X-ray emission coming from a set of dual pseudo-isothermal elliptical mass distributions, which can be directly used in most lensing softwares. By combining Chandra observations with Hubble Frontier Fields imaging and Multi Unit Spectroscopic Explorer spectroscopy in MACS J0416.1-2403, we measure a projected gas-to-total mass fraction of approximately 10% at 350 kpc from the cluster center. Compared to the results of a more traditional cluster mass model (diffuse halos plus member galaxies), we find a significant difference in the cumulative projected mass profile of the dark matter component and that the dark matter over total mass fraction is almost constant, out to more than 350 kpc. In the coming era of large surveys, these results show the need of multiprobe analyses for detailed dark matter studies in galaxy clusters

Anatomische Auswirkungen des mechanisch-biologischen Schaelschutzes auf das Holz der Fichte

TIB: AC 8195+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

CLASH-VLT: constraints on f(R) gravity models with galaxy clusters using lensing and kinematic analyses

We perform a maximum likelihood kinematic analysis of the two dynamically relaxed galaxy clusters MACS J1206.2-0847 at z=0.44 and RXC J2248.7-4431 at z=0.35 to determine the total mass profile in modified gravity models, using a modified version of the MAMPOSSt code of Mamon, Biviano and Bou&apose. Our work is based on the kinematic and lensing mass profiles derived using the data from the Cluster Lensing And Supernova survey with Hubble (hereafter CLASH) and the spectroscopic follow-up with the Very Large Telescope (hereafter CLASH-VLT). We assume a spherical Navarro-Frenk-White (NFW hereafter) profile in order to obtain a constraint on the fifth force interaction range λ for models in which the dependence of this parameter on the environment is negligible at the scale considered (i.e. λ=const) and fixing the fifth force strength to the value predicted in f(R) gravity. We then use information from lensing analysis to put a prior on the other NFW free parameters. In the case of MACSJ 1206 the joint kinematic+lensing analysis leads to an upper limit on the effective interaction range λ=0.14 mpc at Δχ2=2.71. This is consequence of the slight difference between the lensing and kinematic data, appearing in GR for this cluster, that could in principle be explained in terms of modifications of gravity. We discuss the impact of systematics and the limits of our analysis as well as future improvements of the results obtained. This work has interesting implications in view of upcoming and future large imaging and spectroscopic surveys, that will deliver lensing and kinematic mass reconstruction for a large number of galaxy clusters

An excess of small-scale gravitational lenses observed in galaxy clusters

Cold dark matter (CDM) constitutes most of the matter in the Universe. The interplay between dark and luminous matter in dense cosmic environments, such as galaxy clusters, is studied theoretically using cosmological simulations. Observations of gravitational lensing are used to characterize the properties of substructures-the small-scale distribution of dark matter-in clusters. We derive a metric, the probability of strong lensing events produced by dark-matter substructure, and compute it for 11 galaxy clusters. The observed cluster substructures are more efficient lenses than predicted by CDM simulations, by more than an order of magnitude. We suggest that systematic issues with simulations or incorrect assumptions about the properties of dark matter could explain our results

Zentrale Lebensereignisse von Frauen Veraenderungen im Lebensverlaufsmuster in den letzten 30 Jahren

StBA Wiesbaden(282) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Subjectivity of the social documentary

Diplomová práce pojednává o subjektivitě sociálního dokumentu. Dále práce obsahuje aspekty (nejen) fotografického obrazu, různé přístupy při interpretaci a analýze fotografií. V závěru teoretické práce je začleněna úvaha o budoucnosti sociálního dokumentu. Praktická část se snaží dokázat subjektivitu dokumentu.Katedra výtvarné kulturyObhájenoDiploma thesis discusses subjectivity of a social documentary photography. Furthermore, paper includes aspects of (not just phtotgraphic) image, different approaches in the interpretation and analysis of photographs. Reflection essay about future of a social document photography is included in the end of a theoretical part. Practical part struggles to prove subjectivity of a document

VLT/MUSE spectroscopic obs. of MACS J1149.5+2223

VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'The story of supernova "Refsdal" told by MUSE.' (bibcode: 2016ApJ...822...78G

Clues on the presence and segregation of very massive stars in the Sunburst Lyman-continuum cluster at z=2.37

We report on the identification of very massive stars (VMS, mass $> 100$ \msun) possibly segregated in the center of the young massive star cluster at $z$=2.37 hosted in the {\tt Sunburst} lensed galaxy. Such a result is based on two pieces of evidence: (1) the VLT/MUSE spectra of several multiple images of the same star cluster show key spectral signatures of VMS, like the \heii broad emission, \nivblue emission and \niv P-Cygni profile. In particular, \heii is broad ($\sim1610\pm300$\kms) with an equivalent width of 3Å and shows an asymmetric profile. Such features require an extremely young ($\sim2.5$ Myr) stellar population component with masses of the stars exceeding 100~\msun. Assuming a Salpeter IMF and BPASS models for normal massive stars, the observed spectral features require $\sim$400 VMS; (2) the same star cluster is detected at S/N~$\sim100$ in the LyC domain ($\lambda < 900$Å). The LyC emission emerges from a region with a radius at least 2 times smaller than what is observed at 1700Å~(independently from magnification) and is located in the center of the cluster. In absolute scales, after de-lensing, the effective radii are R$_{\tt eff}[{\tt LyC}]\sim4.7 \pm 1.5$ pc and R$_{\tt eff}[1700]= 7.8 \pm 1.4$ pc. The LyC radiation is mainly produced by hot and massive stars, implying that their spatial distribution (including VMS) is preferentially more confined in the central parts of the cluster. Approximately 400 VMS hosted by a cluster of $\sim 10^7$\msun are producing $\sim$15% of the escaping LyC photons, while the rest is produced from other massive early-type stars