Tommaso Treu

The Lick AGN Monitoring Project: Photometric Light Curves and Optical Variability Characteristics (2009)

Walsh, Jonelle L., Minezaki, Takeo, Bentz, Misty C., Barth, Aaron J., Baliber, Nairn, Li, Weidong, ...

The Lick AGN Monitoring Project targeted 13 nearby Seyfert 1 galaxies with the intent of measuring the masses of their central black holes using reverberation mapping. The sample includes 12 galaxies...

Dry mergers and the formation of early-type galaxies: constraints from lensing and dynamics (2009)

Nipoti, Carlo, Treu, Tommaso, Bolton, Adam S.

Dissipationless (gas-free or "dry") mergers have been suggested to play a major role in the formation and evolution of early-type galaxies, particularly in growing their mass and size without...

Direct Observation of Cosmic Strings via their Strong Gravitational Lensing Effect: II. Results from the HST/ACS Image Archive (2009)

Morganson, Eric, Marshall, Phil, Treu, Tommaso, Schrabback, Tim, Blandford, Roger D.

We have searched 4.5 square degrees of archival HST/ACS images for cosmic strings, identifying close pairs of similar, faint galaxies and selecting groups whose alignment is consistent with...

The Lick AGN Monitoring Project: Broad-Line Region Radii and Black Hole Masses from Reverberation Mapping of Hbeta (2009)

Bentz, Misty C., Walsh, Jonelle L., Barth, Aaron J., Baliber, Nairn, Bennert, Nicola, Canalizo, Gabriela, ...

We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05)...

Two-dimensional kinematics of SLACS lenses: II. Combined lensing and dynamics analysis of early-type galaxies at z = 0.08 - 0.33 (2009)

Barnabe, Matteo, Czoske, Oliver, Koopmans, Leon, Treu, Tommaso, Bolton, Adam, Gavazzi, Raphael

We present the first detailed analysis of the mass and dynamical structure of a sample of six early-type lens galaxies, selected from the Sloan Lens ACS Survey, in the redshift range 0.08 < z < 0.33....

The Survival of Dark Matter Halos in the Cluster Cl 0024+16 (2009)

Natarajan, Priyamvada, Kneib, Jean-Paul, Smail, Ian, Treu, Tommaso, Ellis, Richard, Moran, Sean, ...

Theories of structure formation in a cold dark matter dominated universe predict that massive clusters of galaxies assemble from the hierarchical merging of lower mass subhalos. Exploiting strong and...

The Nature of Dusty Starburst Galaxies in a Rich Cluster at z = 0.4: The Progenitors of Lenticulars? (2009)

Geach, James E., Smail, Ian, Moran, Sean M., Treu, Tommaso, Ellis, Richard S.

We present the results of a Spitzer Infrared Spectrograph survey of 24 μm selected luminous infrared galaxies (LIRGs, LIR > 10^11 L☉) in the rich cluster Cl 0024+16 at z = 0.4. Optically, these...

Enhanced lensing rate by clustering of massive galaxies: newly discovered systems in the SLACS fields (2008)

Newton, Elisabeth R., Marshall, Philip J., Treu, Tommaso

[Abridged] We exploit the clustering of massive galaxies to perform a high efficiency imaging search for gravitational lenses. Our dataset comprises 44 fields imaged by the Hubble Space Telescope...

First Results from the Lick AGN Monitoring Project: The Mass of the Black Hole in Arp 151 (2008)

Bentz, Misty C., Walsh, Jonelle L., Barth, Aaron J., Baliber, Nairn, Bennert, Nicola, Canalizo, Gabriela, ...

We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 13 nearby (z < 0.05)...

The nature of dusty starburst galaxies in a rich cluster at z=0.4: the progenitors of lenticulars? (2008)

Geach, J. E., Smail, Ian, Moran, Sean M., Treu, Tommaso, Ellis, Richard S.

We present the results of a Spitzer Infrared Spectrograph (IRS) survey of 24um-selected luminous infrared galaxies (LIRGs, L_IR > 10^11 L_sun) in the rich cluster Cl0024+16 at z=0.4. Optically, these...

Revealing the properties of dark matter in the merging cluster MACSJ0025.4-1222 (2008)

Bradač, Maruša, Allen, Steven W., Treu, Tommaso, Ebeling, Harald, Massey, Richard, Morris, R. Glenn, ...

We constrain the physical nature of dark matter using the newly identified massive merging galaxy cluster MACSJ0025.4-1222. As was previously shown by the example of the Bullet Cluster (1E0657-56),...

The evolutionary history of galactic bulges : photometric and spectroscopic studies of distant spheroids in the GOODS fields (2008)

MacArthur, Lauren A., Ellis, Richard S., Treu, Tommaso, U, Vivian, Bundy, Kevin, Moran, Sean

We report on the first results of a new study aimed at understanding the diversity and evolutionary history of distant galactic bulges in the context of now well-established trends for pure...

The Sloan Lens ACS Survey. I. a large spectroscopically selected sample of massive early-type lens galaxies (2008)

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

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

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...

Separating baryons and dark matter in cluster cores: A full two-dimensional lensing and dynamic analysis of Abell 383 and MS 2137-23 (2008)

Sand, David J., Treu, Tommaso, Ellis, Richard S., Smith, Graham P., Kneib, Jean-Paul

We utilize existing data for the galaxy clusters MS 2137–23 and Abell 383 to present improved measures of the distribution of dark and baryonic material in the clusters' central regions. Our...

Late-time observations of SN2006gy: Still Going Strong (2008)

Smith, Nathan, Foley, Ryan J., Bloom, Joshua S., Li, Weidong, Filippenko, Alexei V., Gavazzi, Raphael, ...

Owing to its extremely high luminosity and long duration, SN2006gy radiated more energy in visual light than any other known SN. Two hypotheses to explain its high luminosity -- that it was powered...

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...

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

Gavazzi, Raphael, Treu, Tommaso, Koopmans, Leon, Bolton, Adam, Moustakas, Leonidas, 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...

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

Gavazzi, Raphael, Treu, Tommaso, Koopmans, Leon, Bolton, Adam, Moustakas, Leonidas, 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...

Dark Matter and Baryons in the Most X-ray Luminous and Merging Galaxy Cluster RX J1347.5-1145 (2007)

Bradač, Maruša, Schrabback, Tim, Erben, Thomas, McCourt, Michael, Million, Evan, Mantz, Adam, ...

The galaxy cluster RX J1347-1145 is one of the most X-ray luminous and most massive clusters known. Its extreme mass makes it a prime target for studying issues addressing cluster formation and...

The survival of dark matter halos in the cluster Cl0024+16 (2007)

Natarajan, Priyamvada, Kneib, Jean-Paul, Smail, Ian, Treu, Tommaso, Ellis, Richard, Moran, Sean, ...

Theories of structure formation in a cold dark matter dominated Universe predict that massive clusters of galaxies assemble from the hierarchical merging of lower mass subhalos. Exploiting strong and...

AMUSE-Virgo I. Super-massive black holes in low-mass spheroids (2007)

Gallo, Elena, Treu, Tommaso, Jacob, Jeremy, Woo, Jong-Hak, Marshall, Phil, Antonucci, Robert

We present the first results from the AGN Multiwavelength Survey of Early-type galaxies in the Virgo cluster (AMUSE-Virgo). This large program targets 100 early-type galaxies with the Advanced CCD...

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...

The Evolutionary History of Galactic Bulges: Photometric and Spectroscopic Studies of Distant Spheroids in the GOODS Fields (2007)

MacArthur, Lauren A., Ellis, Richard S., Treu, Tommaso, U, Vivian, Bundy, Kevin, Moran, Sean M.

We report on the first results of a new study aimed at understanding the diversity and evolutionary history of distant galactic bulges in the context of now well-established trends for pure...

Direct Observation of Cosmic Strings via their Strong Gravitational Lensing Effect: I. Predictions for High Resolution Imaging Surveys (2007)

Gasparini, Maria Alice, Marshall, Phil, Treu, Tommaso, Morganson, Eric, Dubath, Florian

We use current theoretical estimates for the density of long cosmic strings to predict the number of strong gravitational lensing events in astronomical imaging surveys as a function of angular...

Comparing and calibrating black hole mass estimators for distant active galactic nuclei (2007)

McGill, Kathryn L., Woo, Jong-Hak, Treu, Tommaso, Malkan, Matthew A.

Black hole mass is a fundamental property of active galactic nuclei (AGNs). In the distant universe, black hole mass is commonly estimated using the MgII, Hbeta, or Halpha emission line widths and...

The Fundamental Plane of Bulges at Intermediate Redshift (2007)

MacArthur, Lauren A., Ellis, Richard S., Treu, Tommaso

We report on a new study aimed at understanding the diversity and evolutionary properties of distant galactic bulges in the context of well-established trends for pure spheroidal galaxies. Bulges...

The dynamical distinction between elliptical and lenticular galaxies in distant clusters: further evidence for the recent origin of S0 galaxies (2007)

Moran, Sean M., Loh, Boon Liang, Ellis, Richard S., Treu, Tommaso, Bundy, Kevin, MacArthur, Lauren A.

We examine resolved spectroscopic data obtained with the Keck II telescope for 44 spheroidal galaxies in the fields of two rich clusters, Cl 0024+16 (z = 0.40) and MS 0451-03 (z = 0.54) and contrast...

The Mass Assembly History of Spheroidal Galaxies: Did Newly Formed Systems Arise via Major Mergers? (2007)

Bundy, Kevin, Treu, Tommaso, Ellis, Richard S.

We examine the properties of a morphologically selected sample of 0.4 < z < 1.0 spheroidal galaxies in the GOODS fields in order to ascertain whether or not their increase in abundance with time...

A Wide-field Survey of Two Z~0.5 Galaxy Clusters: Identifying the Physical Processes Responsible for the Observed Transformation of Spirals into S0s (2007)

Moran, Sean M., Ellis, Richard S., Treu, Tommaso, Smith, Graham P., Rich, R. Michael, Smail, Ian

We present new results from our comprehensive comparative survey of two massive, intermediate redshift galaxy clusters, Cl0024+17 (z=0.39) and MS0451-03 (z=0.54). We identify and study several key...

Cosmic Evolution of Black Holes and Spheroids. II: Scaling Relations at z=0.36 (2007)

Treu, Tommaso, Woo, Jong-Hak, Malkan, Matthew A., Blandford, Roger D.

We combine Hubble Space Telescope images of a sample of 20 Seyfert galaxies at z=0.36 with spectroscopic information from the Keck Telescope to determine the black hole mass - spheroid luminosity...

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, Koopmans, Leon, Bolton, Adam, 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...

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...

Reflections of Cluster Assembly in the Stellar Populations and Dynamics of Member Galaxies (2007)

Moran, Sean M., Ellis, Richard S., Treu, Tommaso, Smith, Graham P.

We combine optical (HST) and UV (GALEX) imaging of two intermediate redshift galaxy clusters with spectroscopy of member galaxies, to study the relation between the formation history of cluster...

Dynamical Evidence for Environmental Evolution of Intermediate Redshift Spiral Galaxies (2007)

Moran, Sean M., Miller, Neil, Treu, Tommaso, Ellis, Richard S., Smith, Graham P.

Combining resolved optical spectroscopy with panoramic HST imaging, we study the dynamical properties of spiral galaxies as a function of position across two intermediate redshift clusters, and we...

The Dynamical Distinction between Elliptical and Lenticular Galaxies in Distant Clusters: Further Evidence for the Recent Origin of S0 Galaxies (2007)

Moran, Sean M., Loh, Boon Liang, Ellis, Richard S., Treu, Tommaso, Bundy, Kevin, MacArthur, Lauren A.

We examine resolved spectroscopic data obtained with the Keck II telescope for 44 spheroidal galaxies in the fields of two rich clusters, Cl0024+16 (z=0.40) and MS0451-03 (z=0.54), and contrast this...

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, Koopmans, Leon, Bolton, Adam, 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...

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, Koopmans, Leon, Bolton, Adam, 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...

Preprint typeset using LATEX style emulateapj v. 6/22/04 DYNAMICAL EVIDENCE FOR ENVIRONMENTAL EVOLUTION OF INTERMEDIATE REDSHIFT SPIRAL GALAXIES (2007)

Sean M. Moran, Neil Miller, Tommaso Treu, Richard S. Ellis, Graham P. Smith

Combining resolved optical spectroscopy with panoramic HST imaging, we study the dynamical properties of spiral galaxies as a function of position across two intermediate redshift clusters, and we...

Spheroids scaling relations over cosmic time (2006)

Treu, Tommaso

I report on recent measurements of two scaling relations of spheroids in the distant universe: the Fundamental Plane, and the relation between lensing velocity dispersion and stellar velocity...

GALEX Observations of "Passive Spirals" in the Cluster Cl 0024+17: Clues to the Formation of S0 Galaxies (2006)

Moran, Sean M., Ellis, Richard S., Treu, Tommaso, Salim, Samir, Rich, R. Michael, Smith, Graham P., ...

We present new results from deep GALEX UV imaging of the cluster Cl 0024+17 at z~0.4. Rest-frame far UV emission is detected from a large fraction of so-called ``passive spiral galaxies'' -a...

Cosmic Evolution of Black Holes and Spheroids. I: The M_BH-sigma Relation at z=0.36 (2006)

Woo, Jong-Hak, Treu, Tommaso, Malkan, Matthew A., Blandford, Roger D.

We test the evolution of the correlation between black hole mass and bulge velocity dispersion (M$_{\rm BH}-\sigma$), using a carefully selected sample of 14 Seyfert 1 galaxies at $z=0.36\pm0.01$. We...

GALEX Observations of "Passive Spirals" in the Cluster Cl 0024+17: Clues to the Formation of S0 Galaxies (2006)

Moran, Sean M., Ellis, Richard S., Treu, Tommaso, Salim, Samir, Rich, R. Michael, Smith, Graham P., ...

We present new results from deep GALEX UV imaging of the cluster Cl 0024+17 at z~0.4. Rest-frame far UV emission is detected from a large fraction of so-called ``passive spiral galaxies'' -a...

GALEX Observations of "Passive Spirals" in the Cluster Cl 0024+17: Clues to the Formation of S0 Galaxies (2006)

Moran, Sean M., Ellis, Richard S., Treu, Tommaso, Salim, Samir, Rich, R. Michael, Smith, Graham P., ...

We present new results from deep GALEX UV imaging of the cluster Cl 0024+17 at z~0.4. Rest-frame far UV emission is detected from a large fraction of so-called ``passive spiral galaxies'' -a...

GALEX Observations of "Passive Spirals" in the Cluster Cl 0024+17: Clues to the Formation of S0 Galaxies (2006)

Moran, Sean M., Ellis, Richard S., Treu, Tommaso, Salim, Samir, Rich, R. Michael, Smith, Graham P., ...

We present new results from deep GALEX UV imaging of the cluster Cl 0024+17 at z~0.4. Rest-frame far UV emission is detected from a large fraction of so-called ``passive spiral galaxies'' -a...

The Sloan-Lens ACS Survey II: stellar populations and internal structure of early-type lens galaxies (2005)

Treu, Tommaso, Koopmans, Leon, Bolton, Adam, Burles, Scott, Moustakas, Leonidas

We derive Fundamental Plane parameters of 15 early-type lens galaxies identified by the Sloan Lens ACS (SLACS) Survey. The size of the sample allows us to investigate for the first time the...

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...

A Wide-field Hubble Space Telescope Survey of the Cluster Cl 0024+16 at z=0.4. III: Spectroscopic Signatures of Environmental Evolution in Early Type Galaxies (2005)

Moran, Sean M., Ellis, Richard S., Treu, Tommaso, Smail, Ian, Dressler, Alan, Coil, Alison L., ...

We report results from a panoramic spectroscopic survey of 955 objects in the field of the rich cluster Cl 0024+1654 (z~0.4), complementing the HST imaging presented in the first paper in this...

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,...

The relation between black hole mass and velocity dispersion at z~0.37 (2004)

Treu, Tommaso, Malkan, Matthew, Blandford, Roger

The velocity dispersion of 7 Seyfert 1 galaxies at z~0.37 is measured using high signal-to-noise Keck spectra. Black hole (BH) mass estimates are obtained via an empirically calibrated...

Galaxy Groups Associated with Gravitational Lenses and H_0 from B1608+656 (2004)

Fassnacht, Chris, Lubin, Lori, McKean, John, Gal, Roy, Squires, Gordon, Koopmans, Leon, ...

Compact groups of galaxies recently have been discovered in association with several strong gravitational lens systems. These groups provide additional convergence to the lensing potential and thus...

Discovery of a Transient U-band Dropout in a Lyman-Break Survey: A Tidally-Disrupted Star at z = 3.3? (2004)

Stern, Daniel, Van Dokkum, P. G., Nugent, Peter, Sand, D. J., Ellis, R. S., Sullivan, Mark, ...

We report the discovery of a transient source in the central regions of galaxy cluster Abell 267. The object, which we call "PALS1", was found in a survey aimed at identifying highly-magnified...

Galactic cannibalism and CDM density profiles (2004)

Nipoti, Carlo, Treu, Tommaso, Ciotti, Luca, Stiavelli, Massimo

Using N-body simulations we show that the process of formation of the brightest cluster galaxy through dissipationless galactic cannibalism can affect the inner cluster dark matter density profile....

Evolution Since z=1 of the Morphology-density Relation of Galaxies (2004)

Smith, Graham P., Treu, Tommaso, Ellis, Richard S., Moran, Sean M., Dressler, Alan

We measure the morphology-density relation of galaxies at z=1 across the full three orders of magnitude in projected galaxy density available in low-redshift studies. Our study adopts techniques that...

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....

A unique small-scale gravitational arc in Abell 1201 (2003)

Edge, Alastair C., Smith, Graham P., Sand, David J., Treu, Tommaso, Ebeling, Harald, Allen, Steven W., ...

We present a snapshot Hubble Space Telescope (HST) image of the galaxy cluster A1201 (z=0.169), revealing a tangential arc 2arcsec from the brightest cluster galaxy (BCG). Keck-ESI spectroscopy...

The Dark Matter Distribution in the Central Regions of Galaxy Clusters: Implications for CDM (2003)

Sand, David J., Treu, Tommaso, Smith, Graham P., Ellis, Richard S.

We have undertaken a spectroscopic survey of gravitational arcs in a carefully chosen sample of six clusters each containing a dominant brightest cluster galaxy. We use these systems to study the...

HST imaging and Keck Spectroscopy of z~6 I-band Drop-Out Galaxies in the ACS GOODS Fields (2003)

Stanway, Elizabeth, Bunker, Andrew, McMahon, Richard, Ellis, Richard, Treu, Tommaso, McCarthy, Patrick

We measure the surface density of i'-band dropout galaxies at z~6 through wide field HST/ACS imaging and ultra-deep Keck/DEIMOS spectroscopy. Using deep HST/ACS SDSS-i' (F775W) and SDSS-z' (F850LP)...

A Wide Field Hubble Space Telescope Study of the Cluster Cl0024+1654 at z=0.4 II: The Cluster Mass Distribution (2003)

Kneib, Jean-Paul, Hudelot, Patrick, Ellis, Richard S., Treu, Tommaso, Smith, Graham P., Marshall, Phil, ...

(abridged) We present a comprehensive lensing analysis of the rich cluster Cl0024+1654 based on panoramic sparse-sampled imaging conducted with HST. We demonstrate an ability to detect reliably weak...

Constraints on the equation of state of dark energy and the Hubble constant from stellar ages and the CMB (2003)

Jimenez, Raul, Verde, Licia, Treu, Tommaso, Stern, Daniel

We place tight constraints on the redshift-averaged, effective value of the equation of state of dark energy, w, using only the absolute ages of Galactic stars and the observed position of the first...

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...

The dark matter density profile of the lensing cluster MS2137-23: a test of the cold dark matter paradigm (2002)

Sand, David J., Treu, Tommaso, Ellis, Richard S.

We present new spectroscopic observations of the gravitational arcs and the brightest cluster galaxy (BCG) in the cluster MS2137-23 (z=0.313) obtained with the Echelle Spectrograph and Imager on the...

The internal structure and formation of early-type galaxies: the gravitational--lens system MG2016+112 at z=1.004 (2002)

Treu, Tommaso, Koopmans, Leon

[Abridged] We combine our measurements of the velocity dispersion and the surface brightness profile of the lens galaxy D in the system MG2016+112 (z=1.004) with constraints from gravitational...

Near-infrared Spectroscopy and HST Imaging of a Dusty Starburst ERO (2001)

Smith, Graham P., Treu, Tommaso, Ellis, Richard, Smail, Ian, Kneib, Jean-Paul, Frye, Brenda

We present near-IR spectroscopy and HST imaging of EROJ164023, an Extremely Red Object (ERO) with R-K=5.9 at z=1.05. EROJ164023 is a disk galaxy, with an optical/IR spectral energy distribution which...