Scientists may have found a powerful new space object: ‘It doesn’t fit comfortably into any known category’
A powerful mystery object found in a nearby galaxy and only visible so far in millimeter radio wavelengths could be a brand new astrophysical object unlike all that astronomers have seen before.
The object was named “punctum”, derived from Latin pūnctum signifier “point” or
“DOT”, by a team of astronomers led by Elena Shablovinskaia of the Instituto d’Estudios Astrofísicos at the Ports de l’Universidad Diego in Chile. Shablovinskaia discovered it using Alma, the large network of ATACAMA millimeter / submillimitmet.
“Apart from the Supermassive black holes, Punctum is really powerful,” Shablovinskaia told Space.com.
Astronomers do not yet know what it is – only that it is compact, has an surprisingly structured magnetic field and, in its heart, is an object radiating of intense amounts of energy.
“When you put it in context, Punctum is surprisingly shiny – 10,000 to 100,000 times brighter than typical Aimtars, about 100 times brighter than microquasars, and 10 to 100 times brighter than almost all known supernova, with only the crab nebulae exceeding it among the sources linked to the stars in our galaxy,” said Shablovinskaia.
Punctum is located in the active Galaxy NGC 4945, which is an neighbor quite close to our Milky Way Galaxy, located 11 million light years old. It’s just beyond the limits of the local group. However, despite this proximity, it cannot be seen in the optical or X -ray light but rather only millimeter radio wavelengths. It only worsened the mystery, although the James Webb space telescope (JWST) has not yet taken a look at the object in almost infrared wavelengths.
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What could be punctuum?
Its brightness remained the same on several observations made in 2023, which means that it is not a rocket or another type of transitional phenomenon. The millimeter wave radiation generally comes from cold objects such as young protoplanetary discs and interstellar molecular clouds. However, very energetic phenomena such as quasars and pulsars can also produce radio waves through synchrotron radiation, where loaded particles moved near the speed of the light spiral around magnetic field lines and radiate radio waves.
What we know about Punctum is that on the basis of the strong polarization of its millimeter light, it must have a highly structured magnetic field. And so, Shablovinskaia thinks that what we see of Punctum is synchrotron radiation. Objects with strong polarization tend to be compact objects, because larger objects have disorderly magnetic fields that wash any polarization.
Perhaps this synchrotron radiation is powered by a magnetar, according to the team, which is a very magnetic pulsar. However, while the magnetic field ordered from a magnetar adapts to the bill, the magnetars (and the regular pulsars by the way) are much lower to the millimeter wavelengths than Punctum.
The remains of supernova such as the crab nebula, which are the disorderly bowl -in -law exploded in the space of a star which exploded in 1054 AD, are brilliant to millimeter wavelengths. The problem is that the remains of supernova are quite large – the crab nebula itself has approximately 11 light years in diameter – while Punctum is clearly a much smaller compact object.
“For the moment, Punctum is really distinguished – it does not fit comfortably in any known category,” said Shablovinskaia. “And honestly, nothing like it appeared in previous millimeters surveys, largely because, until recently, we had nothing as sensitive and high resolution as Alma.”
There is the warning that Punctum could be an aberrant value: an extreme version of an otherwise familiar object, like a magnetar in an unusual environment, or a supernova residing with a dense material. For the moment, however, these are only assumptions lacking in support. It is quite possible that Punctum is indeed the first of a new type of astrophysical object that we have not seen before simply because only Alma can detect them.
In the case of Punctum, it is 100 times lower than the active nucleus of NGC 4945 which is under tension by a supermassive black hole feeding on infallible material. Punctum would probably not have been noticed at all in the Alma data if it was not for its exceptionally strong polarization.
Other observations with Alma will certainly help shed light on the type of punctum object. The observations which discovered Punctum were in fact focused on the brilliant active nucleus of NGC 4945; It was just an event that Punctum was noticed in the field of vision. Future observations of Alma Punctum targeting could rather go to much lower noise levels without worrying about the brilliant nucleus of the overexposed galaxy, and it could also be observed at different frequencies.
The biggest aid could potentially come from the JWST. If he can see an infrared counterpart, his greatest resolution could help identify what Punctum is.
“The strong JWST resolution and the wide spectral range could help reveal whether Punctum’s emission is purely synchrotron or involves lines of dust or emission,” said Shablovinskaia.
For the moment, these are all sites and but, and all that we can say with certainty is that astronomers have a real mystery on their hands that has so far let them feel disconcerted.
“In any case,” concluded Shablovinskaia, “Punctum shows us that there is still a lot to discover in the sky millimeter.”
An article describing the discovery of Punctum was accepted by the magazine Astronomy & Astrophysics, and a pre-impression is available on Astro.ph.
