Credit: ESO/T. Contini (IRAP, Toulouse), B. Epinat (LAM, Marseille)
Measuring more than 300 000 light-years across, three times the diameter of the Milky Way, this colourful bubble of ionised
gas is the biggest to ever have been discovered. The enormous bubble
contains 10 individual galaxies and is situated in a particularly dense
region of a galaxy group called COSMOS-Gr30, 6.5 billion light-years
away from Earth. Targeted due to its high density of galaxies, this
group is extremely varied — some galaxies are actively forming stars
while others are passive; some are bright while others are dim; some are
massive and others are tiny.
This record-breaking bubble was discovered and studied in detail thanks to the incredible sensitivity of the MUSE instrument, mounted on ESO’s Very Large Telescope.
Operating in visible wavelengths, MUSE combines the capabilities of an
imaging device with the measuring capacity of a spectrograph, creating a
unique and powerful tool that can shed light on cosmological objects
that would otherwise remain in the dark.
MUSE’s powerful eye on
the sky has allowed astronomers to understand that this large pocket of
gas is not pristine, but was expelled from galaxies either during
violent interactions or by superwinds driven by active black holes and
supernovae. They also studied how this magnificent bubble became
ionised. It is believed that the gas in the upper area (shown in blue)
was ionised by intense electromagnetic radiation from newborn stars and
shock waves stemming from galactic activity.
Astronomers suspect that
the violent red active galactic nucleus towards the lower left of the image could have ripped the electrons from their atoms.
Links
- Slider comparison of the galaxy group COSMOS-Gr30 seen with Hubble and MUSE
- COSMOS-Gr30 seen with the NASA/ESA Hubble Space Telescope
- Research paper
Source: ESO/Potw
