When taking snapshots, a good telephoto lens can be handy, but when your subject is 2.5 million light years away, it’s invaluable. To show off the capabilities of the new Hyper-Suprime Cam (HSC) located on Mauna Kea, Hawaii, an international team of astrophysicists has released high resolution images of the Andromeda galaxy that not only show off incredible detail, but may help shed light on the evolution of the Universe and the distribution of dark matter.
Dubbed the world's most powerful astronomical camera, the HSC can capture objects one billion times fainter than what can be seen by the naked eye. The images of the Andromeda galaxy were taken at Mauna Kea in Hawaii, where the HSC is installed on the Subaru Telescope, which is an 8.2-m (26.9-ft) optical and infrared telescope that was built in 1998.
The HSC is a 900-megapixel, ultra-wide-field camera that sits 15 m (49 ft) above the Subaru Telescope’s mirror and uses CCD light sensors cooled by a cryogenic vacuum dewar. Its field of vision is wide enough to take in the entire Andromeda Galaxy, which stretches some 60,000 light years across, in one go in very high resolution and is clear over the entire field of view.
These two capabilities are very important because most telescopes have to choose either field of vision or resolution. This means that images of, for example, the Andromeda galaxy are either large, but relatively blurry, or made up of a mosaic of higher resolution images. The HSC's ability to carry this off in one go makes it suitable for large-area sky surveys.
The Andromeda galaxy, also known as Messier 31, M31, or NGC 224, is one of our nearest galaxies and the largest in our cosmic neighborhood. Situated 2.5 million light-years away in the constellation of Andromeda, it contains some one trillion stars, which is more than twice as many as the Milky Way, and is visible to the naked eye on a dark, clear night.
The Andromeda images are intended to demonstrate the capabilities of the HSC, which is currently being used for a large-scale survey to study the evolution of the Universe. The research team says the camera is sensitive enough to measure the distortions in the shapes of hundreds of millions of galaxies caused by dark matter, so will be used to attempt to map the distribution of this mysterious matter, which physicists theorize may make up a quarter of the Universe’s mass and energy.
"In essence, this means an expansion of applications that derive from the [Subaru Telescope's] capacity to make nearly invisible and distant faint objects visible, and for bringing dark energy and dark matter into the arena of scientific identification and investigation," says Satoshi Miyazaki, director of the HSC project. "The design of HSC facilitates this task with faster survey speed and tenfold expansion of file size."
The HSC was built by the National Astronomical Observatory of Japan (NAOJ), with Princeton researchers working with a team from Tokyo University's Kavli Institute for the Physics and Mathematics of the Universe on developing the software for analyzing the data coming from the instrument.
"From my first involvement in this project, I have been amazed at its boldness," says Paul Price, an astronomical software scientist at Princeton. "We can take what has long been one of the best astronomical cameras in the world, and make it 10 times better again."
The video below gives a tour of the Andromeda galaxy images.