This is the fourth in a series of posts introducing and providing essential facts about each of the Frontier Fields.
The gravitational lens created by the galaxy cluster MACS J1149 already has a record of stirring up excitement. In 2012, observations from NASA’s Hubble and Spitzer space telescopes found the cluster had magnified a distant background galaxy. The galaxy turned out to be extremely far away — in fact, the light we detected from the galaxy likely began its intergalactic journey approximately 500 million years after the Big Bang1. This galaxy appears to us as it looked when the universe was just 3.6 percent of its present age of 13.7 billion years — a baby picture of a (very) distant relative. Astronomers estimate that the gravitational lens of MACS J1149 magnified the brightness of this distant galaxy by 15 times; it would have remained undetected were it not for the help from one of nature’s powerful lenses. This discovery bodes well for the deeper images of galaxy clusters being undertaken in the Frontier Fields program.
The Massive Cluster Survey (MACS) contains a sample of more than 100 galaxy clusters, measured by the ROSAT telescope to be bright in high-energy X-ray light. The goal of the MACS survey is to understand distant, massive galaxy clusters.
Estimated Dates of Observations: April-June 2014, November 2014-February 2015, and April-July 2015
The planned dates for Hubble observations of the Frontier Fields include observations approximately six months apart. This is the time it takes for the cameras on Hubble to swap positions so that both visible-light data and infrared-light data can be captured from the galaxy cluster field and the adjacent parallel field, as described in this post.
Galaxy Cluster Redshift: 0.543
Redshift measures the lengthening of a light wave from an object that is moving away from an observer. For example, when a galaxy is traveling away from Earth, its observed wavelength shifts toward the red end of the electromagnetic spectrum. The galaxy cluster’s cosmological redshift refers to a lengthening of a light wave caused by the expansion of the universe. Light waves emitted by a galaxy cluster stretch as they travel through the expanding universe. The greater the redshift, the farther the light has traveled to reach us.
Galaxy Cluster Distance: approximately 5 billion light-years
Galaxy Cluster Field Coordinates (R.A., Dec.): 11:49:36.3, +22:23:58.1
Parallel Field Coordinates (R.A., Dec.): 11:49:40.5, +22:18:02.3
Related Hubble News:
- Frontier Fields: Hubble Goes Deep (science content reading for students & educators)
- NASA’s Great Observatories Begin Deepest Ever Probe of the Universe
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References to science journal articles: