J. Anthony Tyson

Detection of weak gravitational lensing distortions of distant galaxies by cosmic dark matter at large scales

Most of the matter in the Universe is not luminous, and can be observed only through its gravitational influence on the appearance of luminous matter. Weak gravitational lensing is a technique that uses the distortions of the images of distant galaxies as a tracer of dark matter: such distortions are induced as the light passes through large-scale distributions of dark matter in the foreground. The patterns of the induced distortions reflect the density of mass along the line of sight and its distribution, and the resulting ‘cosmic shear’ can be used to distinguish between alternative cosmologies. But previous attempts to measure this effect have been inconclusive. Here we report the detection of cosmic shear on angular scales of up to half a degree using 145,000 galaxies and along three separate lines of sight. We find that the dark matter is distributed in a manner consistent with either an open universe, or a flat universe that is dominated by a cosmological constant. Our results are inconsistent with the standard cold-dark-matter model.

Detailed Mass Map of CL 0024+1654 from Strong Lensing

We construct a high-resolution mass map of the cluster 00241654, based on a parametric inversion z 0.39 of the associated gravitational lens. The lens creates eight well-resolved subimages of a background galaxy, seen in deep imaging with the Hubble Space Telescope. 1 Excluding mass concentrations centered on visible galaxies, more than 98% of the remaining mass is represented by a smooth concentration of dark matter centered near the brightest cluster galaxies, with a 35 kpc soft core. The asymmetry in the mass distribution is less than 3% 1 h inside 107 h 1 kpc radius. The dark matter distribution we observe in CL 0024 is far more smooth, symmetric, and nonsingular than in typical simulated clusters in either or cold dark matter cosmologies. Q 1 Q 0.3 Integrated to a 107 h 1 kpc radius, the rest-frame mass-to-light ratio is M /. L 276 40 h (M/L ) VV

Microscopic fluorescent imaging of surface temperature profiles with 0.01 °C resolution

We have exploited the temperature‐dependent fluorescence quantum efficiency in europium thenoyltrifluoroacetonate (EuTTA) to make high‐resolution, noncontact temperature measurements on the surface of an integrated circuit chip. The EuTTA is spun onto the chip in a polymer film. The chip is illuminated with long‐wave UV light, and the orange fluorescence is imaged onto a charge‐coupled‐device (CCD) camera. Digital image processing completely removes the optical features in the image, leaving a purely thermal map of the surface temperature profile with a measured temperature resolution of better than 0.01 °C and a spatial resolution of 15 μm. With a different camera and optics, 1‐μm resolution should be possible, allowing thermal imaging of the smallest high‐speed integrated circuits.

The Mass Distribution of the Most Luminous X-Ray Cluster RXJ 1347.5-1145 From Gravitational Lensing

Galaxy cluster mass distribution are potentially useful probes of

Distance-redshift and growth-redshift relations as two windows on acceleration and gravitation : Dark energy or new gravity?

\Omega_0

Remote thermal imaging with 0.7‐μm spatial resolution using temperature‐dependent fluorescent thin flims

and the nature of the dark matter. Large clusters will distort the observed shapes of background galaxies through gravitational lensing allowing the measurement of the cluster mass distributions. In this paper we describe weak statistical lensing measurements of the most luminous X-ray cluster known, RXJ1347.5-1145 at z=0.45. We detect a shear signal in the background galaxies at a signal-to-noise ratio of 7.5 in the radial range

DISCOVERY OF A DISSOCIATIVE GALAXY CLUSTER MERGER WITH LARGE PHYSICAL SEPARATION

120 \le r \le 1360 h^{-1}

Cosmology at the millennium

kpc. A mass map of the cluster reveals an 11

Light at deep-sea hydrothermal vents

\sigma

Unlensing Multiple Arcs in 0024+1654: Reconstruction of the Source Image

peak in the cluster mass distribution consistent with the position of the central dominant galaxy and 3