Each of these Hubble Space Telescope snapshots reveals four distorted images of a background quasar surrounding the central core of a foreground massive galaxy.
The multiple quasar images were produced by the gravity of the foreground galaxy, which is acting like a magnifying glass by warping the quasar’s light in an effect called gravitational lensing. Quasars are extremely distant cosmic streetlights produced by active black holes.
The light rays from each lensed quasar image take a slightly different path through space to reach Earth. The pathway’s length depends on the amount of matter that is distorting space along the line of sight to the quasar. To trace each pathway, the astronomers monitor the flickering of the quasar’s light as its black hole gobbles up material. When the light flickers, each lensed image brightens at a different time. This flickering sequence allows researchers to measure the time delays between each image as the lensed light travels along its path to Earth.
These time-delay measurements helped astronomers calculate how fast the universe is growing, a value called the Hubble constant.
The Hubble images were taken between 2003 and 2004 with the Advanced Camera for Surveys.
Credits
NASA, ESA, S.H. Suyu (Max Planck Institute for Astrophysics, Technical University of Munich, and Academia Sinica Institute of Astronomy and Astrophysics), and K.C. Wong (University of Tokyo’s Kavli Institute for the Physics and Mathematics of the Universe)| About The Object | |
|---|---|
| Object Name | RXJ1131-1231, B1608+656, HE0435-1223, WFI2033-4723 |
| Object Description | Background quasars lensed by foreground galaxies |
| About The Data | |
| Data Description | The HST observations include those from programs (C. Kochanek) and (C. Fassnacht). |
| Instrument | ACS/ WFC |
| Exposure Dates | 22 June 2004, 24 Aug 2004, 18 Aug 2003, 23 July 2004 |
| Filters | F555W, F606W, F814W |
| About The Image | |
| Color Info | These images are a composite of separate exposures acquired by the ACS/WFC instrument on the Hubble Space Telescope. Several filters were used to sample particular wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are Cyan: F555W/F606W Orange: F814W. |
| Compass Image |  |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
