By Andy Tomaswick
April 8, 2025
Until recently, the astronomy was completely dependent on electromagnetic waves. While this changed with the confirmation of gravitational waves in 2016, astronomers had developed fundamental framework conditions in the electromagnetic spectrum at that time. A critical framework broke the spectrum in three categories based on its wavelength – infrared, optically and ultraviolet. For astronomers, each of these categories was created by another physical phenomenon, and monitoring gave every insight into what this phenomenon did, regardless of what the other spectra said. This was particularly common in researching galaxies, since infrared and optical wavelengths were used to analyze various aspects of galaxy formation and behavior. Christian Kragh Jespersen of Princeton's Department of Astrophysics and his colleagues believe that they have found a secret that breaks all the electromagnetic scaffolding – the optical and the infrared are connected.
This is the simple title of a new paper that the researchers published and describe their remarkable performance. They predicted the infrared levels of galaxies examined by the Peitfeld Infrared Explorer (Wise) by using optical data recorded by the Sloan Digital Sky Survey (SDSS).
Most galaxy astronomy is based on the assumption that various “components” of a galaxy (ie their super massive black hole or the stars on the edge of its spiral arms are “separable” because they emit over different wavelengths. This separation is simplified to a value that is referred to as spectral energy distribution or SED adjustment code. They are usually used to characterize the physical properties of the galaxies that you describe.
Video that describes the Sloan Digital Sky Survey – one of the data sources for paper.
Credit – American Museum of Natural History YouTube Channel
Unfortunately, after analyzing the paper, the assumption that is based on the SED codes is based – that of the “separation” of galaxy components – is fundamentally wrong. As the paper says: “We conclude from it [IR emitting and optical emitting] Processes must be very coupled. This can surprise the reader or not, but it violates the assumptions of the current SED models. “
In order to prove their point of view, the researchers examined the data collected by SDSS and Wise. They collected data on over 500,000 different galaxies and then used the optical data collected by SDSS after some training and validation of an algorithm to predict the infrared data collected by Wise for every single galaxy. This process has been made easier because indices were already together the wise and SDSS data per galaxy.
The results were striking – the algorithm was able to predict the infrared value exclusively at the optical input with very little noise. In order to prove their point of view, the authors used two SED coding tools, Cigale and Prospector. Both have widespread the brand when they tried to calculate the right value and enabled the authors to mark a number of graphs that show how bad their estimates were “monitoring and biased”.
This video evaluates some of the infrared images that come from Weise – the other data source for paper.
Credit – Sciencemagazine YouTube channel
On the other hand, your own data matched the observed data from the Weisen database. At the author's honor, they indicate some vulnerabilities in their argument, such as the fact that wise and SDS were recorded with different aperture sizes that could influence the adaptation of their algorithm. However, the overwhelming overwhelming overweight of the evidence indicates a simple conclusion – that the assumption of “separation”, which is based on a large part of our understanding of the physical properties of galaxies.
The paper is only in Arxiv and has not yet been accepted in a journal examined by experts. But if it is so, it seems to be ready to influence our understanding of our universe fundamentally and, above all, which frameworks we use to understand it.
Learn more:
Ck Jespersen et al. – The optical and the infrared are connected
UT – the ESO publishes the most detailed infrared card of our galaxy, which has ever been made
UT – The Sloan Digital Sky Survey: “A great and brave thing”
Ut – end of the line by wise
