For a few years now, cosmology has a standard model. By this term, we mean a consistent theoretical background which is at the same time simple and broad enough to offer coherent explanations for the...
Weak gravitational lensing (2009)
Matthias Bartelmann, Peter Schneider, Matthias Bartelmann, Peter Schneider
Lensed CMB temperature and polarization maps from the Millennium Simulation (2009)
Carbone, Carmelita, Baccigalupi, Carlo, Bartelmann, Matthias, Matarrese, Sabino, Springel, Volker
Kosmologie heute: Stand und Perspektiven (2009)
Studium Generale Wintersemester 2008/2009: Galileis erster Blick durchs Fernrohr und die Folgen heute, 26. Januar 2009 Prof. Matthias Bartelmann, Zentrum für Astronomie der Universität Heidelberg...
Lensed CMB temperature and polarization maps from the Millennium Simulation (2008)
Carbone, Carmelita, Baccigalupi, Carlo, Bartelmann, Matthias, Matarrese, Sabino, Springel, Volker
We have constructed the first all-sky CMB temperature and polarization lensed maps based on a high-resolution cosmological N-body simulation, the Millennium Simulation (MS). We have exploited the...
Full-sky maps for gravitational lensing of the cosmic microwave background (2008)
Carbone, Carmelita, Springel, Volker, Baccigalupi, Carlo, Bartelmann, Matthias, Matarrese, Sabino
We use the large cosmological Millennium Simulation (MS) to construct the first all-sky maps of the lensing potential and the deflection angle, aiming at gravitational lensing of the CMB, with the...
Deconvolution with Shapelets (2008)
Melchior, Peter, Andrae, Rene, Maturi, Matteo, Bartelmann, Matthias
We seek to find a shapelet-based scheme for deconvolving galaxy images from the PSF which leads to unbiased shear measurements. Based on the analytic formulation of convolution in shapelet space, we...
Comparisons between isothermal and NFW mass profiles for strong-lensing galaxy clusters (2008)
Shu, Chenggang, Zhou, Binglu, Bartelmann, Matthias, Comerford, Julia M., Mellier, Yannick
While both isothermal and NFW-based mass models for galaxy clusters are widely adopted in strong-lensing studies, they cannot easily be distinguished based solely on observed positions of arcs and...
Impact of early dark energy on the Planck SZ cluster sample (2008)
Waizmann, Jean-Claude, Bartelmann, Matthias
Context. One science goal of the upcoming Planck mission is to perform a full-sky cluster survey based on the Sunyaev-Zel'dovich (SZ) effect, which leads to the question of how such a survey would be...
Angrick, Christian, Bartelmann, Matthias
Context. While the halo mass function is theoretically a very sensitive measure of cosmological models, masses of dark-matter halos are poorly defined, global, and unobservable quantities. Aims. We...
Full-sky maps for gravitational lensing of the cosmic microwave background (2008)
Carbone, Carmelita, Springel, Volker, Baccigalupi, Carlo, Bartelmann, Matthias, Matarrese, Sabino
SPH simulations of magnetic fields in galaxy clusters (2007)
Klaus Dolag Matthias, Matthias Bartelmann, Harald Lesch
. We perform cosmological, hydrodynamic simulations of magnetic fields in galaxy clusters. The computational code combines the special-purpose hardware Grape for calculating gravitational...
High-Redshift Quasars Lensed By Spiral Galaxies (2007)
Given its extraordinary spatial resolution and sensitivity, the projected Next Generation Space Telescope (NGST) is likely to detect a large number of high-redshift QSOs lensed by spiral galaxies....
The Core Structure of Galaxy Clusters from Gravitational Lensing (2007)
Liliya Williams And, Julio F. Navarro, Matthias Bartelmann
We examine gravitational lensing constraints on the structure of galaxy clusters and compare them with the results of cosmological N-body simulations of cluster formation in cold dark matter (CDM)...
Arcs from a Universal Dark-Matter Halo Profile (2007)
. Navarro, Frenk, & White have recently found numerically that the density profile of dark-matter halos can be described by a universal two-parameter function over a broad range of halo masses....
Aperture Multipole Moments from Weak Gravitational Lensing (2007)
Peter Schneider, Matthias Bartelmann
The projected mass of a gravitational lens inside (circular) apertures can be derived from the measured shear inside an annulus which is caused by the tidal field of the deflecting mass distribution....
Maximum Likelihood Cluster Reconstruction (2007)
Matthias Bartelmann, Ramesh Narayan, Stella Seitz, Peter Schneider
We present a novel method to reconstruct the mass distribution of galaxy clusters from their gravitational lens effect on background galaxies. The method is based on a least-x 2 fit of the...
A Comparison of X-ray and Strong Lensing Properties of Simulated X-ray Clusters (2007)
Matthias Bartelmann, Matthias Steinmetz
We use gas-dynamical simulations of galaxy clusters to compare their X-ray and strong lensing properties. Special emphasis is laid on mass estimates. The cluster masses range between 6 \Theta 10 14 M...
Entropy-regularized Maximum-Likelihood cluster mass reconstruction (2007)
Stella Seitz, Peter Schneider, Matthias Bartelmann
We present a new method for reconstructing two-dimensional mass maps of galaxy clusters from the image distortion of background galaxies. In contrast to most previous approaches, which directly...
Meneghetti, Massimo, Melchior, Peter, Grazian, Andrea, De Lucia, Gabriella, Dolag, Klaus, Bartelmann, Matthias, ...
We present a newly developed code that allows simulations of optical observations of galaxy fields with a variety of instruments. The code incorporates gravitational lensing effects and is targetted...
Maio, Umberto, Dolag, Klaus, Meneghetti, Massimo, Moscardini, Lauro, Yoshida, Naoki, Baccigalupi, Carlo, ...
We present the first hydrodynamic N-body simulations of primordial gas clouds responsible for the reionisation process in dark energy cosmologies. We compare the cosmological constant scenario with a...
Full-sky maps for gravitational lensing of the CMB (2007)
Carbone, Carmelita, Springel, Volker, Baccigalupi, Carlo, Bartelmann, Matthias, Matarrese, Sabino
We use the large cosmological Millennium Simulation (MS) to construct the first all-sky maps of the lensing potential and the deflection angle, aiming at gravitational lensing of the CMB, with the...
Die Enträtselung des Universums (2007)
Studium Generale Vorlesung im WiSe 2007-2008; Dienstag, 06. November 2007
Mignone, Claudia, Bartelmann, Matthias
Aims: In view of the substantial uncertainties regarding the possible dynamics of the dark energy, we aim at constraining the expansion rate of the universe without reference to a specific Friedmann...
Probing the dynamical state of galaxy clusters (2007)
Puchwein, Ewald, Bartelmann, Matthias
We show how hydrostatic equilibrium in galaxy clusters can be quantitatively probed combining X-ray, SZ, and gravitational-lensing data. Our previously published method for recovering...
Testing the reliability of weak lensing cluster detections (2007)
Pace, Francesco, Maturi, Matteo, Meneghetti, Massimo, Bartelmann, Matthias, Moscardini, Lauro, Dolag, Klaus
We study the reliability of dark-matter halo detections with three different linear filters applied to weak-lensing data. We use ray-tracing in the multiple lens-plane approximation through a large...
Arcfinder: An algorithm for the automatic detection of gravitational arcs (2006)
Seidel, Gregor, Bartelmann, Matthias
We present an efficient algorithm designed for and capable of detecting elongated, thin features such as lines and curves in astronomical images, and its application to the automatic detection of...
Arc sensitivity to cluster ellipticity, asymmetries and substructures (2006)
Meneghetti, Massimo, Argazzi, Rodolfo, Pace, Francesco, Moscardini, Lauro, Dolag, Klaus, Bartelmann, Matthias, ...
We investigate how ellipticity, asymmetries and substructures separately affect the ability of galaxy clusters to produce strong lensing events, i.e. gravitational arcs, and how they influence the...
Schaefer, Bjoern Malte, Bartelmann, Matthias
The PLANCK-mission is the most sensitive all-sky submillimetric mission currently being planned and prepared. Special emphasis is given to the observation of clusters of galaxies by their thermal...
Applications of gravitational lensing in cosmology (2005)
Gravitational lensing originates from the deflection of light by masses, irrespective of their physical state or composition. Since it appears inescapable that most of the matter in the universe is...
Three-dimensional reconstruction of the intra-cluster medium (2005)
Puchwein, Ewald, Bartelmann, Matthias
We propose and test a new method based on Richardson-Lucy deconvolution to reconstruct three-dimensional gas density and temperature distributions in galaxy clusters from combined X-ray and thermal...
Mass Distributions of HST Galaxy Clusters from Gravitational Arcs (2005)
Comerford, Julia M., Meneghetti, Massimo, Bartelmann, Matthias, Schirmer, Mischa
Although N-body simulations of cosmic structure formation suggest that dark matter halos have density profiles shallower than isothermal at small radii and steeper at large radii, whether observed...
A simulation pipeline for the Planck mission (2005)
Reinecke, Martin, Dolag, Klaus, Hell, Reinhard, Bartelmann, Matthias, Ensslin, Torsten
We describe an assembly of numerical tools to model the output data of the Planck satellite. These start with the generation of a CMB sky in a chosen cosmology, add in various foreground sources,...
Horesh, Assaf, Ofek, Eran O., Maoz, Dan, Bartelmann, Matthias, Meneghetti, Massimo, Rix, Hans-Walter
We compare the statistical properties of giant gravitationally lensed arcs produced in matched simulated and observed cluster samples. The observed sample consists of 10 X-ray selected clusters at...
Non-linear Structure Formation in Cosmologies with Early Dark Energy (2005)
Bartelmann, Matthias, Doran, Michael, Wetterich, Christof
We argue that a few per cent of "Early Dark Energy" can be detected by the statistics of nonlinear structures. The presence of Dark Energy during linear structure formation is natural in models where...
Detection of Cosmic Magnification with the Sloan Digital Sky Survey (2005)
Scranton, Ryan, Menard, Brice, Richards, Gordon T., Nichol, Robert C., Myers, Adam D., Jain, Bhuvnesh, ...
We present an 8 sigma detection of cosmic magnification measured by the variation of quasar density due to gravitational lensing by foreground large scale structure. To make this measurement we used...
The impact of gas physics on strong cluster lensing (2005)
Puchwein, Ewald, Bartelmann, Matthias, Dolag, Klaus, Meneghetti, Massimo
Previous studies of strong gravitational lensing by galaxy clusters neglected the potential impact of the intracluster gas. Here, we compare simulations of strong cluster lensing including gas...
Schaefer, Bjoern Malte, Bartelmann, Matthias
Dark matter currents in the large-scale structure give rise to gravitomagnetic terms in the metric, which affect the light propagation. Corrections to the weak lensing power spectrum due to these...
Evolution of dark-matter haloes in a variety of dark-energy cosmologies (2005)
Bartelmann, Matthias, Dolag, Klaus, Perrotta, Francesca, Baccigalupi, Carlo, Moscardini, Lauro, Meneghetti, Massimo, ...
Constraints on dark energy models from galaxy clusters with multiple arcs (2005)
Meneghetti, Massimo, Jain, Bhuvnesh, Bartelmann, Matthias, Dolag, Klaus
Strong lensing by cluster-sized halos in dark energy cosmologies (2005)
Meneghetti, Massimo, Bartelmann, Matthias, Dolag, Klaus, Perrotta, Francesca, Baccigalupi, Carlo, Moscardini, Lauro, ...
Constraints on dark energy from strong gravitational lensing by galaxy clusters (2005)
Meneghetti, Massimo, Baccigalupi, Carlo, Bartelmann, Matthias, Dolag, Klaus, Moscardini, Lauro, Perrotta, Francesca, ...
Horesh, Assaf, Ofek, Eran O., Maoz, Dan, Bartelmann, Matthias, Meneghetti, Massimo, Rix, Hans-Walter
We compare the statistical properties of giant gravitationally lensed arcs produced in matched simulated and observed cluster samples. The observed sample consists of 10 X-ray-selected clusters at...
Strong lensing by cluster-sized halos in dark energy cosmologies (2005)
Meneghetti, Massimo, Bartelmann, Matthias, Dolag, Klaus, Perrotta, Francesca, Baccigalupi, Carlo, Moscardini, Lauro, ...
Applications of gravitational lensing in cosmology (2005)
Gravitational lensing originates from the deflection of light by masses, irrespective of their physical state or composition. Since it appears inescapable that most of the matter in the universe is...
Constraints on Dark Energy Models from Galaxy Clusters with Multiple Arcs (2004)
Meneghetti, Massimo, Jain, Bhuvnesh, Bartelmann, Matthias, Dolag, Klaus
We make an exploratory study of how well dark energy models can be constrained using lensed arcs at different redshifts behind cluster lenses. Arcs trace the critical curves of clusters, and the...
Hamana, Takashi, Bartelmann, Matthias, Yoshida, Naoki, Pfrommer, Christoph
We investigate statistical distributions of differences in gravitational-lensing deflections between two light rays, the so-called lensing excursion angles. A probability distribution function of the...
Schaefer, Bjoern Malte, Pfrommer, Christoph, Bartelmann, Matthias, Springel, Volker, Hernquist, Lars
All-sky thermal and kinetic Sunyaev-Zel'dovich (SZ) maps are presented for assessing how well the PLANCK-mission can find and characterise clusters of galaxies, especially in the presence of primary...
Schaefer, Bjoern Malte, Pfrommer, Christoph, Hell, Reinhard, Bartelmann, Matthias
The PLANCK mission is the most sensitive all-sky CMB experiment currently planned. The High Frequency Instrument (HFI) will be especially suited for observing clusters of galaxies by their thermal...
Strong lensing by cluster-sized haloes in dark-energy cosmologies (2004)
Meneghetti, Massimo, Bartelmann, Matthias, Dolag, Klaus, Moscardini, Lauro, Perrotta, Francesca, Baccigalupi, Carlo, ...
We study the efficiency of numerically simulated galaxy clusters for producing strong gravitational lensing events in different dark-energy cosmologies with constant and time-variable equation of...
A catalog of compact groups of galaxies in the SDSS commissioning data (2004)
Lee, Brian C., Allam, Sahar S., Tucker, Douglas L., Annis, James, Johnston, David E., Scranton, Ryan, ...
The impact of cluster mergers on arc statistics (2004)
Torri, Elena, Menneghetti, Massimo, Bartelmann, Matthias, Moscardini, Lauro, Rasia, Elena, Tormen, Giuseppe
A catalog of compact groups of galaxies in the SDSS commissioning data (2004)
Lee, Brian C., Allam, Sahar S., Tucker, Douglas L., Annis, James, Johnston, David E., Scranton, Ryan, ...
A catalog of compact groups of galaxies in the SDSS commissioning data (2004)
Lee, Brian C., Allam, Sahar S., Tucker, Douglas L., Annis, James, Johnston, David E., Scranton, Ryan, ...
Compact groups (CGs) of galaxies-relatively poor groups of galaxies in which the typical separations between members is of the order of a galaxy diameter-offer an exceptional laboratory for the study...
Numerical study of halo concentrations in dark-energy cosmologies (2004)
Dolag, Klaus, Bartelmann, Matthias, Perrotta, Francesca, Baccigalupi, Carlo, Moscardini, Lauro, Meneghetti, Massimo, ...
We study the concentration parameters, their mass dependence and redshift evolution, of dark-matter halos in different dark-energy cosmologies with constant and time-variable equation of state, and...
Do arcs require flat halo cusps? (2003)
Bartelmann, Matthias, Meneghetti, Massimo
It was recently claimed that several galaxy clusters containing radial and tangential gravitational arcs and having a measured velocity-dispersion profile for the brightest cluster galaxy had to have...
A catalog of compact groups of galaxies in the RSDSS commissioning data (2003)
Lee, Brian C., Allam, Sahar S., Tucker, Douglas L., Annis, James, Blanton, Michael R., Johnston, David E., ...
Compact groups (CGs) of galaxies -- relatively poor groups of galaxies in which the typical separations between members is of the order of a galaxy diameter -- offer an exceptional laboratory for the...
The impact of cluster mergers on arc statistics (2003)
Torri, Elena, Meneghetti, Massimo, Bartelmann, Matthias, Moscardini, Lauro, Rasia, Elena, Tormen, Giuseppe
We study the impact of merger events on the strong lensing properties of galaxy clusters. Previous lensing simulations were not able to resolve dynamical time scales of cluster lenses, which arise on...
Numerical study of halo concentrations in dark-energy cosmologies (2003)
Dolag, Klaus, Bartelmann, Matthias, Perrotta, Francesca, Baccigalupi, Carlo, Moscardini, Lauro, Meneghetti, Massimo, ...
We study the concentration parameters, their mass dependence and redshift evolution, of dark-matter halos in different dark-energy cosmologies with constant and time-variable equation of state, and...
Arc statistics with realistic cluster models (2003)
Meneghetti, Massimo, Bartelmann, Matthias, Moscardini, Lauro, Rasia, Elena, Tormen, Giuseppe, Torri, Elena
Arc statistics is known to be a powerful cosmological tool. Numerical lensing simulations show that orders of magnitude differences in the number of {\em giant} arcs on the whole sky are expected in...
Numerical Methods in Gravitational Lensing (2003)
Most problems in gravitational lensing require numerical solutions. The most frequent types of problems are (1) finding multiple images of a single source and classifying the images according to...
cD galaxy contribution to the strong lensing cross sections of galaxy clusters (2003)
Meneghetti, Massimo, Bartelmann, Matthias, Moscardini, Lauro
We perform ray-tracing simulations evaluating the effect of a cD galaxy on the strong lensing properties of five galaxy cluster halos obtained from N-body simulations. The cD galaxy is modelled using...
Cluster cross-sections for strong lensing: analytic and numerical lens models (2003)
Meneghetti, Massimo, Bartelmann, Matthias, Moscardini, Lauro
CD galaxy contribution to the strong lensing cross-sections of galaxy clusters (2003)
Menneghetti, Massimo, Bartelmann, Matthias, Moscardini, L.auro
Probing intracluster magnetic fields with cosmic microwave background polarization (2003)
Ohno, Hiroshi, Takada, Masahiro, Dolag, Klaus, Bartelmann, Matthias, Sugiyama, Naoshi
Arc statistics in cosmological models with dark energy (2003)
Bartelmann, Matthias, Meneghetti, Massimo, Perrotta, Francesca, Baccigalupi, Carlo, Moscardini, Lauro
We investigate how the probability of the formation of giant arcs in galaxy clusters is expected to change in cosmological models dominated by dark energy with an equation of state p=w rho c^2...
Improving the Accuracy of Cosmic Magnification Statistics (2002)
Menard, Brice, Hamana, Takashi, Bartelmann, Matthias, Yoshida, Naoki
The systematic magnification of background sources by the weak gravitational-lensing effects of foreground matter, also called cosmic magnification, is becoming an efficient tool both for measuring...
Stacking Clusters in the ROSAT All-Sky Survey (2002)
Bartelmann, Matthias, White, Simon D. M.
Ongoing and planned wide-area surveys at optical and infrared wavelengths should detect a few times 10^5 galaxy clusters, roughly 10% of which are expected to be at redshifts >~ 0.8. We investigate...
Arc Statistics in Cosmological Models with Dark Energy (2002)
Bartelmann, Matthias, Meneghetti, Massimo, Perrotta, Francesca, Baccigalupi, Carlo, Moscardini, Lauro
We investigate how the probability of the formation of giant arcs in galaxy clusters is expected to change in cosmological models dominated by dark energy with an equation of state p=w rho c^2...
Measuring Omega_0 with higher-order Quasar-Galaxy Correlations induced by Weak Lensing (2002)
Menard, Brice, Bartelmann, Matthias, Mellier, Yannick
Via the magnification bias, gravitational lensing by large-scale structures causes angular cross-correlations between distant quasars and foreground galaxies on angular scales of arc minutes and...
Strong and weak lensing by galaxy clusters (2002)
I present an overview of strong and weak gravitational lensing by galaxy clusters. After briefly introducing the principles of gravitational lensing, I discuss the main lessons learned from lensing...
Halo Concentrations and Weak-Lensing Number Counts in Dark Energy Cosmologies (2002)
Bartelmann, Matthias, Perrotta, Francesca, Baccigalupi, Carlo
We study the effects of a dark energy component with equation of state p=w rho with constant w >= -1 on the formation of Cold Dark Matter (CDM) haloes. We find two main effects: first, haloes form...
Probing Intracluster Magnetic Fields with Cosmic Microwave Background Polarization (2002)
Ohno, Hiroshi, Takada, Masahiro, Dolag, Klaus, Bartelmann, Matthias, Sugiyama, Naoshi
Intracluster magnetic fields with $ \sim \mu G $ strength induce Faraday rotation on the cosmic microwave background (CMB) polarization. Measurements of this effect can potentially probe the detailed...
Cosmological Information from Quasar-Galaxy Correlations induced by Weak Lensing (2002)
Menard, Brice, Bartelmann, Matthias
The magnification bias of large-scale structures, combined with galaxy biasing, leads to a cross-correlation of distant quasars with foreground galaxies on angular scales of the order of arc minutes...
Evolution and structure of magnetic fields in simulated galaxy clusters (2002)
Dolag, Klaus, Bartelmann, Matthias, Lesch, Harald
We use cosmological magneto-hydrodynamic simulations to study the evolution of magnetic fields in galaxy clusters in two different cosmological models, a standard-CDM and a $\Lambda$-CDM model. We...
Cluster cross sections for strong lensing: analytic and numerical lens models (2002)
Meneghetti, Massimo, Bartelmann, Matthias, Moscardini, Lauro
The statistics of gravitationally lensed arcs was recognised earlier as a potentially powerful cosmological probe. However, while fully numerical models find orders of magnitude difference between...
Sloan Digital Sky Survey: Early data release (2002)
Stoughton, Chirs, Lupton, Rpbert H., Bernardi, Mariangela, Blanton, Michael R., Burles, Scott, Castander, Francsico J., ...
The Sloan Digital Sky Survey (SDSS) is an imaging and spectroscopic survey that will eventually cover approximately one-quarter of the celestial sphere and collect spectra of 10 6 galaxies, 100,000...
Clustering properties of galaxy clusters in present and future surveys (2002)
Moscardini, Lauro, Matarese, Sabino, Andreani, Paola, Bartelmann, Matthias, Mo, Houjun
Sloan Digital Sky Survey: Early Data Release (2002)
Stoughton, Chris, Lupton, Robert H., Bernardi, Mariangela, Blanton, Michael R., Burles, Scott, Castander, Francisco J., ...
Newberg, Heidi Jo, Yanny, Brian, Rockosi, Connie, Grebel, Eva K., Rix, Hans-Walter, Brinkmann, Jon, ...
Halo concentrations and weak-lensing number counts in dark energy cosmologies (2002)
Bartelmann, Matthias, Perrotta, Francesca, Baccigalupi, Carlo
We study the effects of a dark energy component with equation of state p=w rho with constant w >= -1 on the formation of Cold Dark Matter (CDM) haloes. We find two main effects: first, haloes form...
Gravitational lensing of extended high-redshift sources by dark matter haloes (2002)
Perrotta, Francesca, Baccigalupi, Carlo, Bartelmann, Matthias, De Zotti, Gianfranco, Granato, Gian Luigi
Sloan Digital Sky Survey: early data release (2002)
Stoughton, Chris, Lupton, Robert H., Bernardi, Mariangela, Blanton, Michael R., Burles, Scott M., Castander, Francisco J., ...
The Sloan Digital Sky Survey (SDSS) is an imaging and spectroscopic survey that will eventually cover approximately one-quarter of the celestial sphere and collect spectra of ≈ 106 galaxies,...
Sloan Digital Sky Survey: early data release (2002)
Stoughton, Chris, Lupton, Robert H., Bernardi, Mariangela, Blanton, Michael R., Burles, Scott M., Castander, Francisco J., ...
The Sloan Digital Sky Survey (SDSS) is an imaging and spectroscopic survey that will eventually cover approximately one-quarter of the celestial sphere and collect spectra of ≈ 106 galaxies,...
Predicting the clustering properties of galaxy clusters detectable for the Planck satellite (2001)
Moscardini, Lauro, Bartelmann, Matthias, Matarrese, Sabino, Andreani, Paola
We study the clustering properties of the galaxy clusters detectable for the Planck satellite due to their thermal Sunyaev-Zel'dovich effect. We take the past light-cone effect and the redshift...
Cluster detection from surface-brightness fluctuations in SDSS data (2001)
Bartelmann, Matthias, White, Simon D. M.
Galaxy clusters can be detected as surface brightness enhancements in smoothed optical surveys. This method does not require individual galaxies to be identifiable, and enables clusters to be...
The Evolution of Magnetic Fields in Galaxy Clusters (2001)
Bartelmann, Matthias, Dolag, Klaus, Lesch, Harald
Cosmological simulations of magnetic fields in galaxy clusters show that remarkable agreement between simulations and observations of Faraday rotation and radio haloes can be achieved assuming that...
Constraining cosmological models using arc statistics in future SZ cluster surveys (2001)
Meneghetti, Massimo, Bartelmann, Matthias, Moscardini, Lauro
Upcoming wide-area surveys in the submillimetre regime will allow the construction of complete galaxy cluster samples through their thermal Sunyaev-Zel'dovich effect. We propose an analytic method to...
Weak-Lensing Halo Numbers and Dark-Matter Profiles (2001)
Bartelmann, Matthias, King, Lindsay, Schneider, Peter
Integral measures of weak gravitational lensing by dark-matter haloes, like the aperture mass, are sensitive to different physical halo properties dependent on the halo mass density profile. For...
Gravitational lensing: effects of cosmology and of lens and source profiles (2001)
Perrotta, Francesca, Baccigalupi, Carlo, Bartelmann, Matthias, De Zotti, Gianfranco, Granato, Gian Luigi
We present detailed calculations of the magnification distribution, including both weak and strong lensing, using very recent solutions of the Dyer-Roeder (1973) equation for light propagation in a...
The temperature-mass relation in magnetized galaxy clusters (2001)
Dolag, Klaus, Evrard, August, Bartelmann, Matthias
We use cosmological, magneto-hydrodynamic simulations of galaxy clusters to quantify the dynamical importance of magnetic fields in these clusters. The set-up of initial magnetic field strengths at...
Lensing by Lyman Limit Systems: Determining the Mass to Gas Ratio (2001)
Maller, Ariyeh, Kolatt, Tsafrir, Bartelmann, Matthias, Blumenthal, George R.
We present a new method to determine the total mass-to-neutral gas ratio in Lyman-limits systems. The method exploits the relation between the neutral hydrogen column density and the magnification of...
Giant cluster arcs as a constraint on the scattering cross-section of dark matter (2000)
Meneghetti, Massimo, Yoshida, Naoki, Bartelmann, Matthias, Moscardini, Lauro, Springel, Volker, Tormen, Giuseppe, ...
We carry out ray tracing through five high resolution simulations of a galaxy cluster to study how its ability to produce giant gravitationally lensed arcs is influenced by the collision...
Lensing Sunyaev-Zel'dovich Clusters (2000)
Full-sky microwave surveys like the upcoming Planck satellite mission will detect of order 10^4 galaxy clusters through their thermal Sunyaev-Zel'dovich effect. I investigate the properties of the...
Cluster galaxies: contribution to the arc statistics (2000)
Meneghetti, Massimo, Bolzonella, Micol, Bartelmann, Matthias, Moscardini, Lauro, Tormen, Giuseppe
We present the results of a set of numerical simulations aiming at evaluating the effects of cluster galaxies on the arc statistics. At this goal we use nine different galaxy clusters obtained from...
Weak Gravitational Lensing (1999)
Bartelmann, Matthias, Schneider, Peter
We review theory and applications of weak gravitational lensing. After summarising Friedmann-Lemaitre cosmological models, we present the formalism of gravitational lensing and light propagation in...
Cluster deprojection with joint lensing, X-ray, and Sunyaev-Zeldovich data (1999)
Reblinsky, Katrin, Bartelmann, Matthias
We propose a new cluster deprojection algorithm for recovering cluster structure along the line of sight (los) based on the Richardson-Lucy (RL) algorithm, which recovers a nonnegative theoretical...
High-redshift quasars lensed by spiral galaxies (1999)
Given its extraordinary spatial resolution and sensitivity, the projected Next Generation Space Telescope (NGST) is likely to detect a large number of high-redshift QSOs lensed by spiral galaxies....
Effects of cluster galaxies on arc statistics (1999)
Meneghetti, Massimo, Bolzonella, Micol, Bartelmann, Matthias, Moscardini, Lauro, Tormen, Giuseppe
We present the results of a set of numerical simulations evaluating the effect of cluster galaxies on arc statistics. We perform a first set of gravitational lensing simulations using three...
SPH simulations of magnetic fields in galaxy clusters (proceedings) (1999)
Dolag, Klaus, Bartelmann, Matthias, Lesch, Harald
We perform cosmological, hydrodynamic simulations of magnetic fields in galaxy clusters. The computational code combines the special-purpose hardware Grape for calculating gravitational interaction,...
SPH simulations of magnetic fields in galaxy clusters (1999)
Dolag, Klaus, Bartelmann, Matthias, Lesch, Harald
We perform cosmological, hydrodynamic simulations of magnetic fields in galaxy clusters. The computational code combines the special-purpose hardware Grape for calculating gravitational interaction,...
The Core Structure of Galaxy Clusters from Gravitational Lensing (1999)
Williams, Liliya L. R., Navarro, Julio F., Bartelmann, Matthias
We examine gravitational lensing constraints on the structure of galaxy clusters and compare them with the results of cosmological N-body simulations of cluster formation in cold dark matter (CDM)...
Power spectrum from weak-shear data (1999)
Bartelmann, Matthias, Schneider, Peter
We demonstrate that the aperture mass as a measure for cosmic shear closely approximates (to better than ~5%) the scaled and shifted power spectrum of the projected mass density. This cosmological...
Projection effects in mass-selected galaxy-cluster samples (1999)
Reblinsky, Katrin, Bartelmann, Matthias
Selection of galaxy clusters by mass is now possible due to weak gravitational lensing effects. It is an important question then whether this type of selection reduces the projection effects...
Entropy-regularized Maximum-Likelihood cluster mass reconstruction (1998)
Seitz, Stella, Schneider, Peter, Bartelmann, Matthias
We present a new method for reconstructing two-dimensional mass maps of galaxy clusters from the image distortion of background galaxies. In contrast to most previous approaches, which directly...
Lectures on gravitational lensing (1998)
Ramesh Narayan, Matthias Bartelmann
These lectures give an introduction to Gravitational Lensing. We discuss lensing by point masses, lensing by galaxies, and lensing by clusters and larger-scale structures in the Universe. The...
Effects of Disks on Gravitational Lensing by Spiral Galaxies (1997)
Bartelmann, Matthias, Loeb, Abraham
Gravitational lensing of a quasar by a spiral galaxy should often be accompanied by damped Lyman-alpha absorption and dust extinction due to the intervening gaseous disk. In nearly edge-on...
Bartelmann, Matthias, Huss, Andreas, Colberg, Joerg M., Jenkins, Adrian, Pearce, Frazer R.
The gravitational lens effect of galaxy clusters can produce large arcs from source galaxies in their background. Typical source redshifts of ~ 1 require clusters at z ~ 0.3 for arcs to form...
Gravitational lensing of type Ia supernovae by galaxy clusters (1997)
Kolatt, Tsafrir S., Bartelmann, Matthias
We propose a method to remove the mass sheet degeneracy that arises when the mass of galaxy clusters is inferred from gravitational shear. The method utilizes high-redshift standard candles that...
Arc statistics with realistic cluster potentials. IV. Clusters in different cosmologies (1997)
Bartelmann, Matthias, Huss, Andreas, Colberg, Joerg M., Jenkins, Adrian, Pearce, Frazer R.
We use numerical simulations of galaxy clusters in different cosmologies to study their ability to form large arcs. The cosmological models are: Standard CDM (SCDM; Omega_0=1, Omega_Lambda=0); tauCDM...
Resolving the line-of-sight structure of galaxy clusters by combining X-ray and lensing data (1997)
Bartelmann, Matthias, Kolatt, Tsafrir S.
The projected gravitational potential of galaxy clusters is reflected in both their X-ray emission and their imprint on the images of background sources due to their gravitational lensing effects....
Effects of Dust on Gravitational Lensing by Spiral Galaxies (1997)
Perna, Rosalba, Loeb, Abraham, Bartelmann, Matthias
Gravitational lensing of an optical QSO by a spiral galaxy is often counteracted by dust obscuration, since the line-of-sight to the QSO passes close to the center of the galactic disk. The dust in...
QSO-galaxy correlations due to weak lensing in arbitrary Friedmann-Lemaitre cosmologies (1997)
Dolag, Klaus, Bartelmann, Matthias
We calculate the angular cross-correlation function between background QSOs and foreground galaxies induced by the weak lensing effect of large-scale structures. Results are given for arbitrary...
Aperture Multipole Moments from Weak Gravitational Lensing (1996)
Schneider, Peter, Bartelmann, Matthias
The projected mass of a gravitational lens inside (circular) apertures can be derived from the measured shear inside an annulus which is caused by the tidal field of the deflecting mass distribution....
Lectures on Gravitational Lensing (1996)
Narayan, Ramesh, Bartelmann, Matthias
These lectures give an introduction to Gravitational Lensing. We discuss lensing by point masses, lensing by galaxies, and lensing by clusters and larger-scale structures in the Universe. The...
A Comparison of X-ray and Strong Lensing Properties of Simulated X-ray Clusters (1996)
Bartelmann, Matthias, Steinmetz, Matthias
We use gas-dynamical simulations of galaxy clusters to compare their X-ray and strong lensing properties. Special emphasis is laid on mass estimates. The cluster masses range between 6 x 10^14 solar...
Arcs from a Universal Dark-Matter Halo Profile (1996)
Navarro, Frenk, \& White have recently found numerically that the density profile of dark-matter halos can be described by a universal two-parameter function over a broad range of halo masses. The...
Reanalysis of the association of high-redshift 1-Jansky quasars with IRAS galaxies (1996)
Bartsch, Armin, Schneider, Peter, Bartelmann, Matthias
We develop a new statistical method to reanalyse angular correlations between background QSOs and foreground galaxies that are supposed to be a consequence of dark matter inhomogeneities acting as...
Maximum-Likelihood Cluster Recontruction (1996)
Bartelmann, Matthias, Narayan, Ramesh, Seitz, Stella, Schneider, Peter
We present a novel method to recontruct the mass distribution of galaxy clusters from their gravitational lens effect on background galaxies. The method is based on a least-chisquare fit of the...
Lectures on Gravitational Lensing (1996)
Ramesh Narayan, Matthias Bartelmann
Contents 1 Introduction 1 2 Lensing by Point Masses in the Universe 4 2.1 Basics of Gravitational Lensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.1 Effective Refractive Index...
GRAVITATIONAL LENSING OF QUASARS BY THEIR DAMPED LYMAN-ALPHA ABSORBERS (1995)
Bartelmann, Matthias, Loeb, Abraham
Damped Lyman-alpha absorbers are believed to be associated with galactic disks. We show that gravitational lensing can therefore affect the statistics of these systems. First, the magnification bias...
Bartelmann, Matthias, Narayan, Ramesh
We propose a new technique, which we call the lens parallax method, to determine simultaneously the redshift distribution of the faint blue galaxies and the mass distributions of foreground clusters...
Cluster mass estimates from weak lensing (1994)
The reliability of cluster lens reconstruction techniques based on weak lensing is studied in terms of the accuracy of their reproduction of the total cluster mass as a function of distance from the...
Narayan, Ramesh, Bartelmann, Matthias
We propose a new technique, which we call the lens parallax method, to determine simultaneously the redshift distribution of the faint blue galaxies and the mass distribution of foreground clusters...
Gravitational Lensing and the Mass Distribution of Clusters (1994)
Bartelmann, Matthias, Narayan, Ramesh
We review and discuss information on the mass distribution of galaxy clusters obtained from gravitational lensing.
It is shown in this paper that deviations of galaxy cluster lenses from spherical symmetry can render mass estimates for galaxy clusters based on the formation of large arcs systematically to high....
Bartelmann, Matthias, Steinmetz, Matthias, Weiss, Achim
We construct a sample of numerical models for clusters of galaxies and employ these to investigate their capability of imaging background sources into long arcs. Emphasis is laid on the statistics of...
Cosmological Parameters from Angular Correlations between Qsos and Galaxies (1994)
The angular two-point correlation function between background QSOs and foreground galaxies induced by gravitational lensing is derived. It is shown that the shape of this correlation function depends...
Diffuse X-Ray Emission Around High-Redshift, Radio-Loud Qsos (1994)
Bartelmann, Matthias, Schneider, Peter, Hasinger, Guenther
We announce the detection of correlations on angular scales of $\ga10'$ between optically bright, high-redshift, radio-loud QSOs with diffuse X-ray emission seen by ROSAT in the {\it All-Sky Survey}....
On the spin parameter of dark-matter haloes (1994)
Steinmetz, Matthias, Bartelmann, Matthias
The study by White (1984) on the growth of angular momentum in dark haloes is extended towards a more detailed investigation of the spin parameter $\lambda\equiv L\sqrt{E}/{G M^{2.5}}$. Starting from...
Yusa, Keisuke, Song, Wei, Bartelmann, Matthias, Harada, Shinji
Human immunodeficiency virus type 1 (HIV-1) heterogeneity contributes to the emergence of drug-resistant virus, escape from host defense systems, and/or conversion of the cellular tropism. To...
Yusa, Keisuke, Song, Wei, Bartelmann, Matthias, Harada, Shinji
Human immunodeficiency virus type 1 (HIV-1) heterogeneity contributes to the emergence of drug-resistant virus, escape from host defense systems, and/or conversion of the cellular tropism. To...