Dedicated amateur discovers supernova in remote galaxy

Astronomy is increasingly becoming an online affair. Recent discoveries of interstellar Comet 3I/ATLAS and R2 SWAN have highlighted this fact, when both were first discussed on message boards and verified via remote telescopes before confirmation. Another recent find also shows what’s possible, as devoted amateur astronomer Filipp Romanov has accomplished an amazing feat, and discovered a supernova in a remote galaxy.

“I managed to discover a supernova using the remote telescope T59 of iTelescope.net and it was confirmed by spectrum,” Romanov told Universe Today.

The discovery is designated AT 2025umq (PSN J00481888+0759006) in the galaxy SDSS J004819.14+075856.8. The phone number-esque names denote the galaxy’s position in the constellation Pisces the Fishes.

The discovery was made thanks to a keen process of deduction and perseverance on Romanov’s part.

“I made calculations of the sky coordinates and requested shooting on remote telescopes to search for astronomical objects,” Romanov said. “When I received and viewed one of the series of images, I found a star in them, which—upon checking in various information sources—turned out to be an already known supernova. Such a find is unusual for me, because in several years of searching in images, I did not come across even a single known supernova.”

Emboldened by the personal best, Romanov decided to press on with his research. He soon struck pay dirt.

“When checking five photographs with exposures of 300 seconds taken on this date with another remote telescope (the 0.51-meter iTelescope T59 instrument, located at Siding Spring, Australia), at the very edge of the images (only 12 arcseconds from the edges of the frames), I saw a relatively faint star (shining at only +20th magnitude) that was absent from archival photographs,” he explained.

Indeed, the only object at this position was the remote galaxy SDSS J004819.14+075856.8.

Assuming the new star was actually a supernova embedded in the distant galaxy, Romanov double-checked its position, measured its brightness, and sent the information off to the official International Astronomical Union’s (IAU) source for reporting new astronomical transients, the Transient Name Server (TNS). The candidate supernova was then published, and given the provisional designations AT 2025umq (PSN J00481888+0759006). The IAU also issued a provisional CBAT message for the discovery.

Romanov then made backup observations from another site. “On August 19, I made remote observations of this star with a two-meter aperture robotic Liverpool Telescope (located on the Canary Island of La Palma). According to my calculations and request, the spectrum of this star was obtained, (and) as a result of its analysis, this star was classified as a fading Type IA supernova at a redshift of 0.159.”

The supernova later turned up in pre-discovery images from the Zwicky Transient Facility (ZTF) survey from August 10th. Romanov is listed as first author on the Astronomer’s Telegram (Atel No. 17361) on the discovery.

Extra-galactic Type IA supernovae are important as “cosmic yardsticks” used to measure vast distances. The redshift value indicates that the supernova and the galaxy it’s in is located a stupendous distance away, about 2 billion light-years distant. When light was leaving this supernova, the Great Oxidation Event was just coming to a close on Earth.

You can see how, for a brief span of a few days, the supernova exceeds the brightness of the host galaxy itself. We’re witnessing the process of heavy elements forged inside the dying star getting seeded back into the cosmos.

“It is important that this is the first supernova discovered by me personally,” says Romanov. “Earlier, I discovered two supernovae (SN 2022bsi and SN 2022jhn) in the images of the Catalina Real-time Transient Survey (CRTS), so I am the first co-author on these discoveries.”

These were also lower redshift value objects, at z=0.0369 and 0.013 respectively.

“I consider it luck that supernova SN 2025umq was not outside the boundaries of the images, because it was very close to the edges of the frames. It was big luck that I, an amateur astronomer, was able to discover such a low-brightness supernova.”

We’ve featured Romanov’s amazing work before, including his asteroid discoveries: 623826 Alekseyvarkin and 623827 Nikandrilyich named after Romanov’s grandfathers, and 679999 Mariyavarkina and 679996 Mariyafilippovna, named after his grandmothers.

To date, Romanov’s tally of discoveries is impressive, also including 82 variable stars, 10 planetary nebula candidates, 8 asteroids, 3 novae in the nearby Andromeda galaxy Messier 31, and 4 probable physical binary star pairs.

Romanov’s work is all the more amazing, considering that he’s self-educated in astronomy and lives in far eastern Russia. He’s also managed to capture very early images of Comet R2 SWAN (now prominently featured on the comet’s wiki page) and one of my favorites: an occultation of the planet Uranus by the moon during a total lunar eclipse.

This discovery serves as a tour de force of what’s possible, with a little bit of vigilance and patience. Romanov’s hard work and do-it-yourself dedication is an inspiration to the rest of us, showing us that amateur astronomy discoveries aren’t dead; they’ve just moved online.