Science & Technology

Astronomers See “Space Jellyfish” – Stunning Space Phenomena

A composite image of the Abel 2877 USS jellyfish showing an optical digitized sky survey (background) using XMM X-ray data (magenta overlay) and MWA 118 MHz radio data (red-yellow overlay). Credits: Torrance Hodgson, ICRAR / Curtin University

A radio telescope in the hinterland of Western Australia observed a cosmic phenomenon very similar to a jellyfish.

Today, the Australian and Italian teams, published in the Astrophysical Journal, used the Murchison Widefield Array (MWA) telescope to observe a cluster of galaxies known as the Abel 2877.

Torrance Hodgson, Principal Writer and PhD Candidate from Curtin University Node, International Center for Radio Astronomy Studies (ICRARIn Perth, the team said they observed 12-hour clusters on five radio frequencies from 87.5 to 215.5 MHz.

“When I looked at the data, less often, ghostly jellyfish-like structures began to appear,” he said.

“This radio jellyfish holds some kind of world record. It’s bright at normal FM radio frequencies, but at 200MHz the radiation is almost gone.

MWA tile 107 outliers

Tile 107, or as it is known, the “outlier” is one of MWA’s 256 tiles located 1.5 km from the telescope core. MWA is the predecessor of SKA. Credits: Pete Wheeler, ICRAR

“It has never been observed that such extragalactic releases disappear so quickly.”

This unique steep spectrum is difficult to explain. “To understand the story of the ancient background of jellyfish, we had to undertake some space archeology,” Hodison said.

“Our theory is that about 2 billion years ago, a small number of supermassive black holes from multiple galaxies ejected powerful jets. plasma.. This plasma has declined, has become quiet, and has become dormant.

“Then two things happened very recently. The plasma began to mix as soon as a very gentle shock wave passed through the system.

“This temporarily reignited the plasma and illuminated the jellyfish and its tentacles so that we could see them.”
Jellyfish are more than one-third the diameter of the Moon when viewed from Earth, but can only be seen with a low-frequency radio telescope.
“Most radio telescopes cannot achieve such low observations because of their design and location,” Hodison said.

The predecessor of the Square Kilometer Array (SKA), MWA, is located at CSIRO’s Murchison Radio Observatory in a remote location in western Australia.

The site has been selected to host SKA’s low frequency antennas and construction is expected to begin within a year.

SKA-Western Australia Low Telescope

Composite image of the SKA-Low telescope in Western Australia. This image blends the actual photo (left) of the SKA-Low prototype station AAVS 2.0 already on site with the artist’s impression of the future SKA-Low station as seen during construction. Hundreds of thousands of these dipole antennas investigate the sky of electric waves at a low frequency of 50 MHz. Credits: ICRAR and SKAO

Professor Johnston Hollit, Hodison’s supervisor and co-author, said SKA will give us an unparalleled view of the low-frequency universe.

“SKA is thousands of times more sensitive and has much better resolution than MWA, so it may be waiting for many other mysterious radio jellyfish to be discovered once it goes live. there is.

“We’re building equipment for making high-resolution, high-frame-rate movies in the evolving radio universe. It will show us from the first stars and galaxies to the present.” She said.

“Discovery like jellyfish only suggests what’s going to happen. It’s an exciting time for anyone looking for answers to basic questions about the universe.”

See also: Torrance Hodgson, Iacopo Bartalucci, Melanie Johnston-Hollitt, Benjamin McKinley, Franco Vazza, Denis Wittor, “Ultra-Steep Spectral Radio Jellyfish Discovered in Abell 2877”, March 17, 2021 Astrophysical Journal..
DOI: 10.3847 / 1538-4357 / abe384

Astronomers See “Space Jellyfish” – Stunning Space Phenomena Astronomers See “Space Jellyfish” – Stunning Space Phenomena

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