These illustrations show how the powerful gravity of a massive galaxy cluster bends and focuses the light from a supernova behind it, resulting in multiple images of the exploding star. This phenomenon is called gravitational lensing, and astronomers use it to search for distant objects that might otherwise be too faint to see, even with today's powerful telescopes.
The upper graphic shows that when the star explodes, its light travels through space and encounters the foreground galaxy cluster. If the cluster were not present, astronomers would detect only the supernova light that is directed straight at Earth and would see only a single image of the supernova. In the case of the multiply imaged supernova, however, the light paths are bent by the cluster's gravity and redirected onto new paths, several of which are pointed at Earth. Astronomers, therefore, see multiple images of the exploding star, each one corresponding to one of those altered light paths. Each image takes a different route through the cluster and arrives at a different time, due, in part, to differences in the length of the pathways the light follows to reach Earth.
In the lower graphic, the redirected light passes through a giant elliptical galaxy within the cluster. This galaxy adds another layer of lensing, once again redirecting several light paths that would otherwise have missed us, and focusing them so that they do reach Earth. This phenomenon produces four images of the supernova that form a cross-shaped pattern called an Einstein Cross.
Credits
Illustration: NASA, ESA, and A. Feild (STScI);Science: NASA, ESA, and S. Rodney (JHU) and the FrontierSN team; T. Treu (UCLA), P. Kelly (UC Berkeley), and the GLASS team; J. Lotz (STScI) and the Frontier Fields team; M. Postman (STScI) and the CLASH team; and Z. Levay (STScI)
| About The Data | |
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| Data Description | This image is created from data from the following HST proposals: T. Treu (UCLA) et al. and the GLASS team, J. Lotz (STScI) et al. and the Frontier Fields team, S. Rodney (JHU) et al. and the FrontierSN team, and P. Kelly (UCLA) et al. and the Refsdal team. The science team includes: P. Kelly (UC Berkeley), S. Rodney (JHU), T. Treu (UCLA), R. Foley (University of Illinois at Urbana-Champaign), G. Brammer (STScI), K. Schmidt (UC Santa Barbara), A. Zitrin (Caltech), A. Sonnenfeld (UCLA), L.-G. Strolger (Western Kentucky University/STScI), O. Graur (New York University/American Museum of Natural History), A. Filippenko (UC Berkeley), S. Jha (Rutgers University), A. Riess (JHU/STScI), M. Bradac (UC Davis), B. Weiner (Steward Observatory/UA), D. Scolnic (University of Chicago), M. Malkan (UCLA), A. von der Linden (Dark Cosmology Centre, Copenhagen/KIPAC, Stanford), M. Trenti (University of Melbourne), J. Hjorth (Dark Cosmology Centre, Copenhagen), R. Gavazzi (Institut d'Astrophysique de Paris), A. Fontana (INAF-OAR), J. Merten (Caltech), C. McCully and T. Jones (UC Santa Barbara), M. Postman (STScI), A. Dressler (Carnegie Observatories), B. Patel (Rutgers University), S. B. Cenko (NASA/GSFC), M. Graham (UC Berkeley), and B. Tucker (UC Berkeley/Australia National University). |
| About The Object | |
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| 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 |
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| 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. |
