The largest near-infrared image of galaxies ever taken by the Hubble Space Telescope has provided a playground for astronomers looking for potential targets for the James Webb Space Telescope.
The image is the result of a project called 3D-DASH and was captured by the The Hubble Space TelescopeHubble’s Wide Field Camera 3 (WFC3), with additional archival data from Hubble’s Advanced Camera for Surveys. It spans 1.35 square degrees of sky, equivalent to about six full moons, and contains thousands of galaxies. The goal is to identify galaxies worthy of further study by the James Webb Space Telescope and other telescopes in the future.
“I am curious to know the giant galaxieswhich are the most massive in the universe formed by the merger of other galaxies,” said Lamiya Mowla, an astronomer at the University of Toronto’s Dunlap Institute for Astronomy and Astrophysics and leader of the new research, said in a statement. “How did their structures develop and what caused the changes in their shape? It was difficult to study these extremely rare events using existing images, which motivated the design of this extensive investigation.
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Normally, it would have taken 2,000 hours of Hubble observations to create such a large image, but Mowla’s team used a new technique called Drift and Shift (DASH), which takes multiple photos and stitches them together, stitching together images individuals eight times larger. than the typical WFC3 field of view (0.04 x 0.04 degrees). Also, rather than taking an image each time it orbits Earth, Hubble could take eight images using the DASH technique. With a total of 1,256 individual WFC3 shots, it took only 250 observation hours to complete the entire mosaic.
Most of the galaxies in the image are visible as patches of infrared light. The outermost are seen as they existed about 10 billion years ago, and light from bright star-forming regions within them has been red shifted speak expansion of the universe in the near infrared wavelengths. You can see these galaxies in more detail in an interactive online version of the image of the 3D-Dash Image Explorer.
Unlike Hubble, Webb will be able to peer into these galaxies in greater detail, thanks to the increased light-gathering power of the new telescope’s 6.5-meter (21.3-foot) mirror. Featuring Webb’s first science-grade images release scheduled for July 12the release of 3D-DASH data is timely.
For larger survey images, astronomers will have to wait for the European Space Agency Euclid mission and NASA Nancy Grace Roman Space Telescopewhich will have larger fields of view (0.79 x 1.16 degrees and 0.8 x 0.4 degrees, respectively) than Hubble and Webb and are expected to launch in 2023 and 2027, respectively.
The research has been accepted for publication in The Astrophysical Journal, and a preprint version is available through the arXiv database.
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