Results of the GREAT08 Challenge: An image analysis competition for cosmological lensing (2009)
Bridle, Sarah, Balan, Sreekumar T., Bethge, Matthias, Gentile, Marc, Harmeling, Stefan, Heymans, Catherine, ...
We present the results of the GREAT08 Challenge, a blind analysis challenge to infer weak gravitational lensing shear distortions from images. The primary goal was to stimulate new ideas by...
Handbook for the GREAT08 Challenge: An image analysis competition for cosmological lensing (2008)
Bridle, Sarah, Shawe-Taylor, John, Amara, Adam, Applegate, Douglas, Balan, Sreekumar T., Berge, Joel, ...
The GRavitational lEnsing Accuracy Testing 2008 (GREAT08) Challenge focuses on a problem that is of crucial importance for future observations in cosmology. The shapes of distant galaxies can be used...
Lensing signals in the Hubble Ultra-Deep Field using all 2nd order shape deformations (2006)
Irwin, John, Shmakova, Marina, Anderson, Jay
The long exposure times of the HST Ultra-Deep Field plus the use of an empirically derived position-dependent PSF, have enabled us to measure a cardioid/displacement distortion map coefficient as...
Observation of small scale structure using sextupole lensing (2005)
Weak gravitational lensing seeks to determine shear by measuring induced quadrupole (elliptical) shapes in background galaxy images. Small impact parameter (a few kpc) gravitational lensing by...
Brane Inflation, Solitons and Cosmological Solutions: I (2005)
Chen, Pisin, Dasgupta, Keshav, Narayan, K., Shmakova, Marina, Zagermann, Marco
In this paper we study various cosmological solutions for a D3/D7 system directly from M-theory with fluxes and M2-branes. In M-theory, these solutions exist only if we incorporate higher derivative...
Current Observational Constraints on Cosmic Doomsday (2004)
Wang, Yun, Kratochvil, Jan Michael, Linde, Andrei, Shmakova, Marina
In a broad class of dark energy models, the universe may collapse within a finite time t_c. Here we study a representative model of dark energy with a linear potential, V(\phi)=V_0(1+\alpha\phi)....
Testing the Cosmological Constant as a Candidate for Dark Energy (2003)
Kratochvil, Jan, Linde, Andrei, Linder, Eric V., Shmakova, Marina
It may be difficult to single out the best model of dark energy on the basis of the existing and planned cosmological observations, because many different models can lead to similar observational...
Observations of cluster substructure using weakly lensed sextupole moments (2003)
Since dark matter clusters and groups may have substructure, we have examined the sextupole content of Hubble images looking for a curvature signature in background galaxies that would arise from...
Observational Bounds on Cosmic Doomsday (2003)
Kallosh, Renata, Kratochvil, Jan, Linde, Andrei, Linder, Eric V., Shmakova, Marina
Recently it was found, in a broad class of models, that the dark energy density may change its sign during the evolution of the universe. This may lead to a global collapse of the universe within the...
On Branes and Oriented B-fields (2003)
Dasgupta, Keshav, Shmakova, Marina
Novel theories appear on the world-volume of branes by orienting B fields along various directions of the branes. We review some of the earlier developments and explore many new examples of these...
Supergravity, Dark Energy and the Fate of the Universe (2002)
Kallosh, Renata, Linde, Andrei, Prokushkin, Sergey, Shmakova, Marina
We propose a description of dark energy and acceleration of the universe in extended supergravities with de Sitter (dS) solutions. Some of them are related to M-theory with non-compact internal...
Gauged Supergravities, de Sitter Space and Cosmology (2001)
Kallosh, Renata, Linde, Andrei, Prokushkin, Sergey, Shmakova, Marina
We have studied scalar potentials V of gauged N=8,4,2 supergravities in d=4. Extrema of these potentials may correspond to de Sitter, anti de Sitter and Minkowski vacua. All de Sitter extrema that we...
Domain Walls with Strings Attached (2001)
Kallosh, Renata, Prokushkin, Sergey, Shmakova, Marina
We have constructed a bulk & brane action of IIA theory which describes a pair of BPS domain walls on S_1/Z_2, with strings attached. The walls are given by two orientifold O8-planes with coincident...
Excision of singularities by stringy domain walls (2001)
Kallosh, Renata, Mohaupt, Thomas, Shmakova, Marina
We study supersymmetric domain walls on S1/Z2 orbifolds. The supergravity solutions in the bulk are given by the attractor equation associated with Calabi–Yau (CY) spaces and have a naked...
Domain walls with strings attached (2001)
Kallosh, Renata, Prokushkin, Sergey, Shmakova, Marina
We have constructed a bulk & brane action of IIA theory which describes a pair of BPS domain walls on S-1/Z(2), with strings attached. The walls are given by two orientifold O8-planes with coincident...
Domain Walls, Black Holes, and Supersymmetric Quantum Mechanics (2001)
Behrndt, Klaus, Gukov, Sergei, Shmakova, Marina
Supersymmetric solutions, such as BPS domain walls or black holes, in four- and five-dimensional supergravity theories with eight supercharges can be described by effective quantum mechanics with a...
Excision of Singularities by Stringy Domain Walls (2000)
Kallosh, Renata, Mohaupt, Thomas, Shmakova, Marina
We study supersymmetric domain walls on S_1/Z_2 orbifolds. The supergravity solutions in the bulk are given by the attractor equation associated with Calabi-Yau spaces and have a naked space-time...
Supersymmetric Multiple Basin Attractors (1999)
Kallosh, Renata, Linde, Andrei, Shmakova, Marina
We explain that supersymmetric attractors in general have several critical points due to the algebraic nature of the stabilization equations. We show that the critical values of the cosmological...
One-loop corrections to the D3 brane action (1999)
We calculate one-loop corrections to the effective Lagrangian for the D3 brane. We perform the gauge-fixing of the kappa-symmetric Born-Infeld D3 brane action in the flat background using Killing...
We have found the entropy of N=2 extreme black holes associated with general Calabi-Yau moduli space. We show that for arbitrary d_{ABC} and black hole charges the entropy-area formula depends on...
STU Black Holes and String Triality (1996)
Behrndt, Klaus, Kallosh, Renata, Rahmfeld, Joachim, Shmakova, Marina, Wong, Wing Kai
We find double-extreme black holes associated with the special geometry of the Calabi-Yau moduli space with the prepotential F=STU. The area formula is STU-moduli independent and has ${[SL(2,Z)]}^3$...
Freezing of Moduli by N=2 Dyons (1996)
Kallosh, Renata, Shmakova, Marina, Wong, Wing Kai
In N=2 ungauged supergravity we have found the most general double-extreme dyonic black holes with arbitrary number n_v of constant vector multiplets and n_h of constant hypermultiplets. They are...