Leon V. E. Koopmans

Cross-correlation Study between the Cosmological 21-cm Signal and the kinetic Sunyaev-Zel'dovich effect (2009)

Jelic, Vibor, Zaroubi, Saleem, Aghanim, Nabila, Douspis, Marian, Koopmans, Leon V. E., Langer, Mathieu, ...

The Universe's Epoch of Reionization (EoR) can be studied using a number of observational probes that provide complementary or corroborating information. Each of these probes suffers from its own...

Non-parametric foreground subtraction for 21cm epoch of reionization experiments (2009)

Harker, Geraint, Zaroubi, Saleem, Bernardi, Gianni, Brentjens, Michiel A., De Bruyn, A. G., Ciardi, Benedetta, ...

An obstacle to the detection of redshifted 21cm emission from the epoch of reionization (EoR) is the presence of foregrounds which exceed the cosmological signal in intensity by orders of magnitude....

Strong gravitational lensing probes of the particle nature of dark matter (2009)

Moustakas, Leonidas A., Abazajian, Kevork, Benson, Andrew, Bolton, Adam S., Bullock, James S., Chen, Jacqueline, ...

There is a vast menagerie of plausible candidates for the constituents of dark matter, both within and beyond extensions of the Standard Model of particle physics. Each of these candidates may have...

The LOFAR EoR Data Model: (I) Effects of Noise and Instrumental Corruptions on the 21-cm Reionization Signal-Extraction Strategy (2009)

Labropoulos, Panagiotis, Koopmans, Leon V. E., Jelic, Vibor, Yatawatta, Sarod, Thomas, Rajat M., Bernardi, Gianni, ...

A number of experiments are set to measure the 21-cm signal of neutral hydrogen from the Epoch of Reionization (EoR). The common denominator of these experiments are the large data sets produced,...

The role of luminous substructure in the gravitational lens system MG 2016+112 (2009)

More, A., McKean, John P., More, Surhud, Porcas, Richard W., Koopmans, Leon V. E., Garrett, M. A.

MG 2016+112 is a quadruply imaged lens system with two complete images A and B and a pair of merging partial images in region C as seen in the radio. The merging images are found to violate the...

The role of luminous substructure in the gravitational lens system MG 2016+112 (2009)

More, A., McKean, John P., More, Surhud, Porcas, Richard W., Koopmans, Leon V. E., Garrett, M. A.

MG 2016+112 is a quadruply imaged lens system with two complete images A and B and a pair of merging partial images in region C as seen in the radio. The merging images are found to violate the...

Detection and extraction of signals from the epoch of reionization using higher order one-point statistics (2008)

Harker, Geraint J. A., Zaroubi, Saleem, Thomas, Rajat M., Jelic, Vibor, Labropoulos, Panagiotis, Mellema, Garrelt, ...

Detecting redshifted 21cm emission from neutral hydrogen in the early Universe promises to give direct constraints on the epoch of reionization (EoR). It will, though, be very challenging to extract...

Fast Large-Scale Reionization Simulations (2008)

Thomas, Rajat M., Zaroubi, Saleem, Ciardi, Benedetta, Pawlik, Andreas H., Labropoulos, Panagiotis, Jelic, Vibor, ...

We present an efficient method to generate large simulations of the Epoch of Reionization (EoR) without the need for a full 3-dimensional radiative transfer code. Large dark-matter-only simulations...

Crash-testing the CAULDRON code for joint lensing and dynamics analysis of early-type galaxies (2008)

Barnabe, Matteo, Nipoti, Carlo, Koopmans, Leon V. E., Vegetti, Simona, Ciotti, Luca

We apply the joint lensing and dynamics code for the analysis of early-type galaxies, CAULDRON, to a rotating N-body stellar system with dark matter halo which significantly violates the two major...

The Sloan Lens ACS Survey. V. The Full ACS Strong-Lens Sample (2008)

Bolton, Adam S., Burles, Scott, Koopmans, Leon V. E., Treu, Tommaso, Gavazzi, Raphael, Moustakas, Leonidas A., ...

We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens...

The Sloan Lens ACS Survey. VII. Elliptical Galaxy Scaling Laws from Direct Observational Mass Measurements (2008)

Bolton, Adam S., Treu, Tommaso, Koopmans, Leon V. E., Gavazzi, Raphael, Moustakas, Leonidas A., Burles, Scott, ...

We use a sample of 53 massive early-type strong gravitational lens galaxies with well-measured redshifts (ranging from z=0.06 to 0.36) and stellar velocity dispersions (between 175 and 400 km/s) from...

Foreground simulations for the LOFAR - Epoch of Reionization Experiment (2008)

Jelic, Vibor, Zaroubi, Saleem, Labropoulos, Panagiotis, Thomas, Rajat M., Bernardi, Gianni, Brentjens, Michiel A., ...

Future high redshift 21-cm experiments will suffer from a high degree of contamination, due both to astrophysical foregrounds and to non-astrophysical and instrumental effects. In order to reliably...

The Sloan Lens ACS Survey. VI: Discovery and analysis of a double Einstein ring (2008)

Gavazzi, Raphael, Treu, Tommaso, Koopmans, Leon V. E., Bolton, Adam S., Moustakas, Leonidas A., Burles, Scott, ...

We report the discovery of two concentric Einstein rings around the gravitational lens SDSSJ0946+1006, as part of the Sloan Lens ACS Survey. The main lens is at redshift zl=0.222, while the inner...

Two-dimensional kinematics of SLACS lenses: I. Phase-space analysis of the early-type galaxy SDSS J2321-097 at z=0.1 (2007)

Czoske, Oliver, Barnabe, Matteo, Koopmans, Leon V. E., Treu, Tommaso, Bolton, Adam S.

We present the first results of a combined VLT VIMOS integral-field unit and Hubble Space Telescope (HST)/ACS study of the early-type lens galaxy SDSS J2321-097 at z=0.0819, extending kinematic...

A More Fundamental Plane (2007)

Bolton, Adam S., Burles, Scott, Treu, Tommaso, Koopmans, Leon V. E., Moustakas, Leonidas A.

We combine strong-lensing masses with SDSS stellar velocity dispersions and HST-ACS effective (half-light) radii for 36 lens galaxies from the Sloan Lens ACS (SLACS) Survey to study the mass...

The Sloan Lens ACS Survey. IV: the mass density profile of early-type galaxies out to 100 effective radii (2007)

Gavazzi, Raphael, Treu, Tommaso, Rhodes, Jason D., Koopmans, Leon V. E., Bolton, Adam S., Burles, Scott, ...

We present a weak gravitational lensing analysis of 22 early-type strong lens galaxies, based on deep HST images obtained as part of the Sloan Lens ACS Survey. Using the most advanced techniques to...

A Unifying Framework for Self-consistent Gravitational Lensing and Stellar Dynamics Analyses of Early-Type Galaxies (2007)

Barnabe', Matteo, Koopmans, Leon V. E.

Gravitational lensing and stellar dynamics are two independent methods, based solely on gravity, to study the mass distributions of galaxies. Both methods suffer from degeneracies, however, that are...

The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample of Massive Early-Type Lens Galaxies (2005)

Bolton, Adam S., Burles, Scott, Koopmans, Leon V. E., Treu, Tommaso, Moustakas, Leonidas A.

The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected...

SDSSJ140228.22+632133.3: A New Spectroscopically Selected Gravitational Lens (2004)

Bolton, Adam S., Burles, Scott, Koopmans, Leon V. E., Treu, Tommaso, Moustakas, Leonidas A.

(abridged) We present Gemini integral-field unit (IFU) spectroscopy and Hubble Space Telescope (HST) F435W- and F814W-band images of a new four-image gravitational lens, SDSSJ140228.22+632133.3,...

Massive Dark-matter halos and Evolution of Early-type Galaxies to z=1 (2004)

Treu, Tommaso, Koopmans, Leon V. E.

(Shortened) The combination of lensing and stellar dynamics breaks the mass-anisotropy degeneracy and provides stringent constraints on the mass distribution in early-type (E/S0) galaxies out to z~1....

The internal structure of the lens PG1115+080: breaking degeneracies in the value of the Hubble Constant (2002)

Treu, Tommaso, Koopmans, Leon V. E.

We combine lensing, stellar kinematic and mass-to-light ratio constraints to build a two-component (luminous plus dark) mass model of the early-type lens galaxy in PG1115+080. We find a total mass...