ASTROPHYSICS: Magnified Megacluster

Astrophysics. Multiple images of a highly magnified supernova formed by an early-type cluster galaxy lens.

In 1964, Refsdal hypothesized that a supernova whose light traversed multiple paths around a strong gravitational lens could be used to measure the rate of cosmic expansion. We report the discovery of such a system. In Hubble Space Telescope imaging, we have found four images of a single supernova forming an Einstein cross configuration around a redshift z = 0.54 elliptical galaxy in the MACS J...

Magnified Real-Time Tomographic Reflection

Real Time Tomographic Reflection (RTTR) permits in situ visualization of ultrasound images so that direct hand-eye coordination can be employed during invasive procedures. The method merges the visual outer surface of a patient with a simultaneous ultrasound scan of the patient’s interior. It combines a flat-panel monitor with a half-silvered mirror such that the image on the monitor is reflect...

Magnified time-domain ghost imaging

Perceived contrast of electronically magnified video

It has been observed that electronic magnification of imagery results in a decrease in the apparent contrast of the magnified image relative to the original. The decrease in perceived contrast might be due to a combination of image blur and of sub-sampling the larger range of contrasts in the original image. In a series of experiments, we measured the effect on apparent contrast of magnificatio...

Astrophysics.

Using the oscillation frequencies of α Cen A recently discovered by Bouchy & Carrier (2001, 2002), the available astrometric, photometric and spectroscopic data, we tried to improve the calibration of the visual binary system α Cen. With the revisited masses of Pour-baix et al. (2002) we do not succeed to obtain a solution satisfying all the seismic observational constraints. Relaxing the const...