Stephan's Quintet, a group of five galaxies, has intrigued astronomers since its 1877 discovery. This galactic ensemble includes NGC 7317, NGC 7318a, NGC 7318b, NGC 7319, and NGC 7320c. It represents a hub of cosmic activity where galactic collisions leave behind intricate debris fields.

The latest observations focus on NGC 7318b, a galaxy moving at over 3.2 million kilometers per hour. Its collision with the group has created an immense shockwave, akin to a jet's sonic boom. Dr. Arnaudova explained, "This system presents an ideal laboratory to understand the chaotic and often violent relationship between galaxies, and as such was the focus of the first-light observations by the WEAVE Large Integral Field Unit (LIFU)."

Published in the 'Monthly Notices of the Royal Astronomical Society (MNRAS)', the study combined WEAVE's LIFU data with insights from other advanced tools like LOFAR, the Very Large Array (VLA), and the James Webb Space Telescope (JWST). This approach revealed the dual nature of the shockwave. "As the shock moves through pockets of cold gas, it travels at hypersonic speeds - several times the speed of sound - powerful enough to rip apart electrons from atoms, leaving behind a glowing trail of charged gas, as seen with WEAVE," said Dr. Arnaudova.

Meanwhile, PhD student Soumyadeep Das noted, "When the shock passes through the surrounding hot gas, it becomes much weaker. Instead of causing significant disruption, the weak shock compresses the hot gas, resulting in radio waves that are picked up by radio telescopes like LOFAR."

Dr. Marc Balcells, Director of the Isaac Newton Group of Telescopes, remarked, "I'm excited to see that the data gathered at the WEAVE first light already provide a high-impact result, and I'm sure this is just an early example of the types of discoveries that will be made possible with WEAVE on the William Herschel Telescope in the coming years."

Professor Gavin Dalton, WEAVE Principal Investigator at RAL Space and the University of Oxford, added, "The level of detail uncovered here by WEAVE is remarkable. These observations offer profound insights into the shock front and the evolving collision in Stephan's Quintet while also shedding light on the formation and evolution of faint galaxies at the edge of detectability."

Building the WEAVE Spectrograph

The Isaac Newton Group of Telescopes (ING) spearheaded WEAVE's development, a euro 20-million collaboration with contributions from institutions in the UK, Spain, the Netherlands, France, and Italy. This wide-field spectrograph is tailored to complement large-scale surveys like ESA's Gaia, addressing key astrophysical questions of the next decade.

Key WEAVE components include:

- Fibre Positioner: Designed by the University of Oxford (UK), supported by the Instituto de Astrofisica de Canarias (IAC).

- Prime-Focus System: A joint effort of ING, IAC, and SENER, with lenses polished by KiwiStar (NZ).

- Spectrograph: Constructed by NOVA (NL) with optical design from RAL Space (UK).

- Field Rotator: Provided by IAC and manufactured by IDOM (ES).

- LIFU and CCD Systems: Built by NOVA (NL) and Liverpool John Moores University (UK), respectively.

- Data and Observatory Systems: Managed by institutions in the UK, Spain, and Italy.

The WEAVE consortium, led by Gavin Dalton (UK), Scott Trager (NL), Don Carlos Abrams (ING), and Chris Benn (ING), exemplifies international collaboration at the forefront of astrophysics.

Research Report:WEAVE First Light Observations: Origin and Dynamics of the Shock Front in Stephan's Quintet

Related Links

William Herschel Telescope Enhanced Area Velocity Explorer (WEAVE)

Stellar Chemistry, The Universe And All Within It