Located in the southern hemisphere constellation Fornax, the small patch of sky that the Hubble Space Telescope focused on for more than 270 hours for its famous Ultra Deep Field image stands out as one of the most thoroughly cataloged regions of the universe. The James Webb Space Telescope focused on this area, which hosts approximately 10 thousand galaxies stretching billions of light years, with its advanced infrared capabilities.
In the analysis, a strange signal was detected in a corner of this small area twice, three months apart. However, the fact that no object was found at this point in both Hubble’s and Webb’s past observations makes the situation mysterious. Although it is thought that an object too faint to be detected may have caused a short-term strong flash, the nature of the source cannot yet be explained.
A NEW DISCOVERY METHOD WAS TRIED WITH THE HELP OF SPECTROSCOPY
The team, led by astrophysicist Mason Huberty from the University of Minnesota, used Webb’s Near Infrared Spectrograph in an innovative approach to discover previously unknown objects. By opening areas other than the covers covering known foreground objects, the researchers separated the light they collected into spectra and looked for emission lines. Six distant galaxies were successfully detected as a result of repeated scans 88 days apart in August and November 2023.
The seventh detection revealed during the scans turned the entire process into a riddle. The single, bright line visible at approximately 1.6 micrometers had no other emission lines accompanying it. This signal, which appeared consistently in four different exposure sets, eliminating the possibility of technical error, was not included in the images in October 2022. This strengthens the possibility that the signal was not there at that time.
FOUR SCENARIOS BEHIND THE MYSTERIOUS SOURCE
Since the exact distance of the signaling object is not known, it is not yet clear whether the infrared light is an energetic glow coming from very far away or a weak emission coming from closer. Researchers consider four different possibilities that could explain this situation. While the possibility of a galaxy in the early universe remains slim due to the neutral hydrogen barrier, scenarios for a younger galaxy or supernova do not fit well due to missing emission lines. Although the model of a black hole tearing apart a star can produce a strong emission line, there is not yet enough data to prove this.
The authors of the study published in The Astrophysical Journal emphasize that more precise follow-up observations are essential to pinpoint the origin of this extraordinary object and the physical source of the emission, which tests extreme physical conditions.
