白小姐论坛

The discovery was a fluke 鈥� a 10 minute telescope workshop for undergraduate students听that led to a global scramble to acquire confirming images and spectra of a supernova in one of the most unusual and interesting of our near-neighbour galaxies.

鈥淭he weather was closing in, with increasing cloud,鈥� Fossey says, 鈥渟o instead of the planned practical astronomy class, I gave听the students an introductory demonstration of how to use the CCD听camera on one of the observatory鈥檚 automated 0.35鈥搈etre telescopes.鈥�

The students chose M 82, a bright and photogenic galaxy as their target, as it was in one of the shrinking patches of clear sky. While adjusting the telescope鈥檚 position, Fossey noticed a 鈥榮tar鈥� overlaid on the galaxy which he did not recognise from previous observations.

They inspected online archive images of the galaxy, and it became听apparent that there was indeed a new star-like object in M 82. With clouds closing in, there was hardly time to check:听so they switched to taking a rapid series of 1 and 2 minute exposures through听different coloured filters to check that the object persisted, and to be able to measure its brightness and colour.听

Meanwhile, they started up a听second telescope to obtain a second source of data, to ensure the object was not听an instrumental artefact. By about 19:40 GMT, the cloud cover was almost听complete, but it was just possible to make out the new object in the second data set: this was a real astronomical source.

There were no online reports of any prior discoveries of this object, so听it seemed clear that this was a new transient source, such as a听supernova. It was important to move quickly to alert astronomers worldwide听to confirm the discovery, and most importantly, to obtain a听spectrum 鈥� which would confirm whether or not it was a supernova, rather than some other phenomenon, such as an asteroid that happened to lie in front of the galaxy.

Fossey prepared a report for the International Astronomical Union鈥檚 Central Bureau for Astronomical Telegrams, the organisation that catalogues supernovae. He also alerted a US-based supernova search, team who have access to spectroscopic facilities.

Spectra collected by astronomers at other observatories around the world suggest that it is a Type Ia supernova, caused by a white dwarf star pulling matter off a larger neighbouring star until it becomes unstable and explodes.

The IAU鈥檚 official report last night (UK time; daytime 22 January in the US), confirms that Fossey was the first to report the new supernova, and gives the supernova the designation SN 2014J.

The two images here show the Cigar Galaxy before and during the event. Above, an image taken on 10 December 2013, and below the image taken by the students on 21 January 2014. A bright spot of light (labelled) is clearly visible, even though the exposure is shorter and the rest of the galaxy appears darker.

The supernova is one of the nearest to be observed in recent decades. The closest by far since the invention of the telescope was Supernova 1987A (the remnant of which was recently ) in February 1987, located at a distance of 168 000 light years. This discovery is more distant at around 12 million light years, about the same as the 1993 discovery of a supernova in nearby Messier 81.

The students said:

Ben Cooke: 鈥淭he chances of finding anything new in the sky is astronomical but this was particularly astounding as it was one of the first images we had taken on this telescope. My career plan had been to continue my studies in astrophysics. It's going to be hard to ever top this though!鈥�

Guy Pollack: 鈥淚t was a surreal and exciting experience taking images of the unidentified object as Steve ran around the observatory verifying the result. I鈥檓 very chuffed to have helped in the discovery of the M 82 Supernova.鈥�

Tom Wright: 鈥淥ne minute we鈥檙e eating pizza then five minutes later we鈥檝e helped to discover a supernova. I couldn鈥檛 believe it. It reminds me why I got interested in astronomy in the first place.鈥�

Matt Wilde: 鈥淭o be honest it was just a really odd experience. We were expecting a standard quick look through the telescope and a chance to use the camera for the first time before the clouds moved in, that's all. When we started looking and Steve began getting a bit more excited none of us could really believe what was going on. I can't wait to get back on a telescope next week now.鈥�

Notes

• Magnitudes of the supernova were measured from discovery images in R and V听filters, obtained in poor sky conditions, with reference to the nearby听star BD +70 587. The object's magnitude is estimated to be: V=11.7 (2014听Jan 21.818), R=10.5 (2014 Jan 21.805). This is bright enough to see with a good quality amateur telescope.

Related links

High鈥搑esolution image

Supernova in Messier 82

Credit: 白小姐论坛/University of London Observatory/Steve Fossey/Ben Cooke/Guy Pollack/Matthew Wilde/Thomas Wright

听

Celestron C14 telescope at the University of London Observatory

One of ULO鈥檚 two 0.35-metre Celestron C14 telescopes. These were used to find the supernova in M 82

Photo: 白小姐论坛 MAPS/O. Usher

These images can be reproduced freely providing the source is credited

Science contact

Dr Steve Fossey
白小姐论坛 Physics & Astronomy 鈥� University of London Observatory
020 8238 8876
s.fossey@ucl.ac.uk

Media contacts

Oli Usher
白小姐论坛 Faculty of Mathematical and Physical Sciences
020 7679 7964
o.usher@ucl.ac.uk

David Weston (out of hours)
白小姐论坛 Media Relations
07917 271 364
d.weston@ucl.ac.uk