Keck Cosmic Web Imager Archives

October 28, 2024October 28, 2024 by Evan Gough

This Ancient Supernova Remnant Looks Like a Stellar Dandelion

An artist’s concept of a supernova remnant called Pa 30—the leftover remains of a supernova explosion that was witnessed from Earth in the year 1181. Unusual filaments of sulfur protrude beyond a dusty shell of ejected material. The remains of the original star that exploded, now a hot inflated star which may cool to become a white dwarf, are seen at the center of the remnant. The Keck Cosmic Web Imager (KCWI) at the W.M. Keck Observatory in Hawai‘i has mapped the strange filaments in 3-D and shown that they are flying outward at approximately 1,000 kilometers per second. Image Credit: W.M. Keck Observatory/Adam Makarenko

In 1181, Japanese and Chinese astronomers saw a bright light appear in the constellation Cassiopeia. It shone for six months, and those ancient observers couldn’t have known it was an exploding star. To them, it looked like some type of temporary star that shone for 185 days.

In the modern astronomical age, we’ve learned a lot more about the object. It was a supernova called SN 1181 AD, and we know that it left behind a remnant “zombie” star. New research examines the supernova’s aftermath and the strange filaments of gas it left behind.

September 9, 2024September 9, 2024 by Evan Gough

The True Size of Galaxies is Much Larger Than We Thought

Visualisation of the gas shroud of starburst galaxy IRAS 08339+6517. Astronomers struggle to observe this gas clearly, but new research found a way. Image Credit: Cristy Roberts ANU/ASTRO 3D

Ask most people what a galaxy is made up of, and they’ll say it’s made of stars. Our own galaxy, the Milky Way, hosts between about 100 to 300 billion stars, and we can see thousands of them with our unaided eyes. But most of a galaxy’s mass is actually gas, and the extent of the gas has been difficult to measure.

Researchers have found a way to see how far that gas extends into the cosmos.

October 4, 2023October 4, 2023 by Evan Gough

Seeing the Web Connecting Galaxies Across the Universe

New research has imaged the Cosmic Web of cold dark gas that interconnects the Universe's galaxies. Image Credit: Martin et al. 2023.

One hundred years ago, we didn’t know there was anything outside of our own galaxy, the Milky Way. Now we know that our puny planet Earth, and everything else, is part of a vast structure called the Cosmic Web. Its scale is difficult to comprehend in any concrete way, and the system’s complexity and magnitude brings our most powerful supercomputers to their knees.

Astronomers have known about the Cosmic Web for some time, as they’ve caught glimpses of it. But a new instrument has given us our most complete view of it yet.