A bonfire that no one sees, but everyone feels the warmth: that's how astronomers found a flare in a distant galaxy. Not by its light, but by the infrared radiation of heated dust. The galaxy SDSS J010320.39+140152.5 caught attention when its center suddenly blazed in the infrared, as if someone had thrown logs onto an invisible fire.
The flare lasted about a year. At its peak, it emitted 5.4×10⁴³ ergs per second, like a billion suns gathered in one spot and covered with a thick blanket. Telescopes showed the source sits exactly at the galaxy's core, with an offset of no more than a hundred parsecs (about 300 light-years — a tiny distance by galactic standards). The surrounding dust heated to 900 kelvins, and its thermal glow revealed the hidden catastrophe.
So what happened? An ordinary supernova doesn't fit: there was no optical flash. Astronomers lean toward a tidal disruption scenario: a star wandered too close to a supermassive black hole and was torn apart by tidal forces. Usually such events are visible in optical light, but here a dense veil of dust absorbed the visible light and re-emitted it in the infrared. It's like watching a fire through frosted glass: you can't see the flames, but the glass heats up.
Such dusty tidal disruption events are an important missing piece of the puzzle. Optical surveys miss them, creating a false impression that stars die less often in certain galaxies. In reality, they're just hiding behind dust. Now we have the tools to peer behind that veil, and see the warmth of an invisible bonfire.
as written by the authors arXiv:2605.29616
We present a comprehensive study of an infrared (IR) flare in the star-forming galaxy SDSS J010320.39+140152.5, which is selected from the sample of mid-IR (MIR) outbursts in nearby galaxies (MIRONG). Its MIR luminosity rose rapidly to a peak of $$\sim5.4\times10^{43}$$ \lum, maintained in the high state for about a year, and decreased continuously afterward. No optical variability was detected throughout the IR flare. Near-IR follow-up observations around the peak pinpointed the flare's location to spatially coincide with the galactic nucleus, with a $$3\sigma$$ upper limit of the offset of $$\lesssim100$$ pc. The IR spectral energy distribution (SED) of the flare is consistent with thermal emission of dust with temperatures of $$\sim900$$ K. Using a dust radiative transfer model, we inferred a peak UV luminosity of $$\sim(4-10)\times10^{44}$$ erg s$$^{-1}$$ and a total energy of $$\sim(0.9-2)\times10^{52}$$ ergs released. We ruled out the possibility of a supernova, and prefer that the IR flare originated from an obscured tidal disruption event (TDE) rather than a changing-look active galactic nucleus (AGN). This flare stands as one of the most compelling cases to date for the emerging class of dust-obscured TDEs in recent years. They are missed by optical surveys, partly accounting for the observed bias in TDE host galaxies, and represent a crucial, yet often overlooked, component for a complete understanding of the TDE population.
The dust temperature in this flare (900 kelvins) is close to that of lava from a freshly erupted volcano, about 600–1200 kelvins, but on cosmic scales, this is considered 'warm' dust.
In Stanislaw Lem's novel 'Solaris', the planet's ocean hides its motives behind an impenetrable surface, just as dust in galactic cores hides titanic events from us, forcing us to search for invisible clues.