An image of a huge plasma arc next to the Andromeda Galaxy (M31) has won the Royal Observatory Greenwich's Astronomy of the Photographer of the Year award this year.
Marcel Drechsler, Xavier Strottner and Yann Sainty took the photograph entitled Andromeda, Unexpected.
Scientists are now investigating the giant object in a transnational collaboration as it could be the largest such structure nearest to us in the universe.
The Andromeda Galaxy is the closest spiral galaxy to the Milky Way and is thought to be one of the most photographed deep sky objects ever.
The discovery of such a large structure in the immediate vicinity of the galaxy was all the more surprising as it is just 1.2 degrees away from the centre of M31 and south-east of the main body of the galaxy.
"It's an enormous honour for our team to receive this important award and we are grateful for all the support, friendship and encouragement we have received along our journey," the three winners said in a statement.
"It encourages us to continue to pursue our passion for astrophotography and, of course, research with dedication."
Laszlo Francsics, awards judge and astrophotographer, said: "This astrophoto is as spectacular as [it is] valuable.
"It not only presents Andromeda in a new way, but also raises the quality of astrophotography to a higher level."
The Young Astronomy Photographer of the Year award was won by two fourteen-year-old boys from China.
Runwei Xu and Binyu Wang collaborated to capture The Running Chicken Nebula.
Yuri Beletsky, judge and professional astronomer, described it as a "strikingly beautiful picture".
The other winning images include Circle of Light by Andreas Ettl, which shows the Northern Lights reflected on Skagsanden beach, Norway, and The Dark Wolf – Fenrir by James Baguley, which shows a molecular cloud in the form of a wolf.
A Sun Question by Eduardo Schaberger Poupeau also won an award. It captured a huge filament in the shape of a question mark.
Grand Cosmic Fireworks by Angel An, a photograph of the extremely rare phenomenon of atmospheric luminescence, was also awarded.
In the Annie Maunder Prize for Image Innovation, judges were impressed by John White’s Black Echo, which used audio source material from Nasa’s Chandra Sonification Project to visually capture the sound of the black hole at the centre of the Perseus Galaxy.
Another of the judges’ favourite images was New Class of Galactic Nebulae around the Star YY Hya by Marcel Drechsler, which won the Stars and Nebulae category.
The photograph captures a previously unknown galactic nebula containing a pair of stars surrounded by a common envelope, adding another exciting discovery to the winning images.
"Once again, entrants to the Astronomy Photographer of the Year competition have conspired to make things difficult for the judges, with a flood of high-quality images covering an amazing range of targets," said Dr Ed Bloomer, astronomer at the Royal Observatory Greenwich.
"The highlight of this year is perhaps a number of genuine discoveries being imaged, but we've had wonderful efforts in every category and I'm particularly pleased to see the continued strength of our young entrants and those eligible for The Sir Patrick Moore Prize for Best Newcomer.
"It has led to some intense debate amongst the judges as we try to choose the very best of the best, but we don’t mind."
The Astronomy Photographer of the Year competition is run by the Royal Observatory Greenwich, supported by Liberty Specialty Markets and in association with BBC Sky at Night Magazine.
There were more than 4,000 entries from 64 countries.