A gravitational lens is a distribution of matter between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein's general theory of relativity. Treating light as corpuscles travelling at the speed of light, Newtonian physics also predicts the bending of light, but only half of that predicted by general relativity.
A galaxy cluster, or cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity with typical masses ranging from 1014–1015 solar masses. They are the second largest known gravitationally bound structures in the universe after galaxy filaments and were believed to be the largest known structures in the universe until the 1980s, when superclusters were discovered. One of the key features of clusters is the intracluster medium (ICM). The ICM consists of heated gas between the galaxies and has a peak temperature between 2–15 keV that is dependent on the total mass of the cluster. Galaxy clusters should not be confused with star clusters, such as galactic clusters—also known as open clusters—which are structures of stars within galaxies, or with globular clusters, which typically orbit galaxies. Small aggregates of galaxies are referred to as galaxy groups rather than clusters of galaxies. The galaxy groups and clusters can themselves cluster together to form superclusters.
Rychard J. Bouwens is an associate professor at Leiden University. He is also a former member of the Advanced Camera for Surveys Guaranteed Time Observation team and postdoctoral research astronomer at the University of California, Santa Cruz. He obtained his bachelor's degree in physics, chemistry, and mathematics from Hope College. He then went on to earn his Ph.D. in physics at the University of California, Berkeley under the supervision of Joseph Silk and also worked with Tom Broadhurst.
Abell 1689 is a galaxy cluster in the constellation Virgo over 2.3 billion light-years away.
SDSSJ0946+1006 is an unusual gravitational lens system consisting of three galaxies at distances of respectively three, six, and eleven billion light years from Earth. In a report presented at the 211th meeting of the American Astronomical Society, researchers Raphael Gavazzi and Tommaso Treu of the University of California, Santa Barbara described the discovery of a double Einstein ring produced by the gravitational lensing of light from two distant galaxies. The observations were made using the Hubble Space Telescope.
Marc Postman is an American astronomer at the Space Telescope Science Institute in Baltimore, Maryland, United States. His research interests include observational studies of the formation and evolution of galaxies and large scale structure in the universe. His work focuses on determining, observationally, the relationships between galaxy-scale phenomena and the surrounding large-scale environment and matter distribution.
MACS J0717.5+3745 is a large galaxy cluster located 5.4 billion light years away in the constellation Auriga, appearing in the Massive Cluster Survey (MACS).
UDFj-39546284 is the designation given to a stellar structure reported on January 27, 2011, as light from the oldest object detected through infrared observation within the Hubble Space Telescope. The object, located in the Fornax constellation, was identified by G. Illingworth, R. Bouwens and the HUDF09 Team during 2009 and 2010. It was initially thought to be at redshift z~10 using Hubble and Spitzer telescope photometric data, including Hubble Extreme Deep Field (XDF). Subsequently, it was reported to possibly be at a record-breaking redshift z = 11.9 using Hubble and Spitzer telescope data, including Hubble Ultra-Deep Field (HUDF). Recent analyses have suggested this source is more likely to be a low redshift interloper, with extreme emission lines in its spectrum producing the appearance of a very high redshift source.
Abell 383 is a galaxy cluster in the Abell catalogue.
MACS0647-JD is a galaxy with a redshift of about z = 10.7, equivalent to a light travel distance of 13.26 billion light-years. If the distance estimate is correct, it formed about 427 million years after the Big Bang.
The MAssive Cluster Survey (MACS) compiled and characterized a sample of very X-ray luminous, distant clusters of galaxies. The sample comprises 124 spectroscopically confirmed clusters at 0.3 < z < 0.7. Candidates were selected from the ROSAT All-Sky Survey data.
Abell 2261 is one of 25 galaxy clusters being studied as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, a major project to build a library of scientific data on lensing clusters.
RX J1347.5–1145 is one of the most massive galaxy clusters known discovered in X-rays with ROSAT. As a result, it is also one of the most X-ray-luminous because of its hot gas content. The object resides roughly 5 billion light-years away from the Solar System in the constellation of Virgo. Redshift was noted as z=0.451 with an X-ray luminosity of 1045 ergs s−1 in a paper from 2002. In 2013, one study found eight cases of the same object resulting from the intense gravitational bending of light, which makes it possible to identify a series of remote galaxies located inside the galaxy cluster with calculations from the photometric method between 5.5 and 7.5. That study made use of data from Cluster Lensing and Supernova survey with Hubble (CLASH) as well as other sources. The colors in the galaxy cluster are known to correspond with the level of brightness, or the number of electrons trapped in the examined wavelength range of the cluster, with the colors red, orange, and yellow as high intensity, blue-green and green as medium intensity, and blue and violet as low intensity. It is considered one of the brightest objects that is known by X-ray.
MACS J0416.1-2403 is a cluster of galaxies at a redshift of z=0.397 with a mass 160 trillion times the mass of the Sun inside 200 kpc (650 kly). Its mass extends out to a radius of 950 kpc (3,100 kly) and was measured as 1.15 × 1015 solar masses. The system was discovered in images taken by the Hubble Space Telescope during the Massive Cluster Survey, MACS. This cluster causes gravitational lensing of distant galaxies producing multiple images. Based on the distribution of the multiple image copies, scientists have been able to deduce and map the distribution of dark matter. The images, released in 2014, were used in the Cluster Lensing And Supernova survey with Hubble (CLASH) to help scientists peer back in time at the early Universe and to discover the distribution of dark matter.
SN Refsdal is the first detected multiply-lensed supernova, visible within the field of the galaxy cluster MACS J1149+2223. It was given its nickname in honor of the Norwegian astrophysicist Sjur Refsdal, who, in 1964, first proposed using time-delayed images from a lensed supernova to study the expansion of the universe. The observations were made using the Hubble Space Telescope.
MACS J1149 Lensed Star 1, also known as Icarus, is a blue supergiant star observed through a gravitational lens. It is the second most distant individual star to have been detected so far, at approximately 14 billion light-years from Earth. Light from the star was emitted 4.4 billion years after the Big Bang. According to co-discoverer Patrick Kelly, the star is at least a hundred times more distant than the next-farthest non-supernova star observed, SDSS J1229+1122, and is the first magnified individual star seen.
SPT0615-JD is a dwarf galaxy situated within the constellation Pictor, and is the farthest galaxy ever imaged by means of gravitational lensing, as of 2018. Brett Salmon of the Space Telescope Science Institute in Baltimore was the lead scientist of the study of the galaxy.
WHL0137-LS, also known as Earendel, is a star in the constellation of Cetus. Discovered in 2022 by the Hubble Space Telescope, it is the earliest and most distant known star, at a comoving distance of 28 billion light-years. The previous farthest known star, MACS J1149 Lensed Star 1, a.k.a. Icarus, at a comoving distance of 14.4 billion light-years, was discovered by Hubble in 2018.
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