JWST detects an unknown emission line twice in the HUDF field — ScienceAlert
The James Webb Space Telescope twice detected an unusual signal in the Hubble Ultra Deep Field region of the sky in the constellation Fornax. A bright emission line in the near-infrared range appeared where previous observations by the Hubble and James Webb telescopes had found no visible object, ScienceAlert reports.
The signal recurred after 88 days
A research team led by University of Minnesota astrophysicist Mason Huberty analyzed data from the NIRSpec spectrograph. Unlike typical observations of previously known objects, the scientists opened nearly all of the instrument's microshutters, closing only those corresponding to known foreground objects. They then searched for emission lines in the collected spectra.
The observations were conducted in August and November 2023, 88 days apart and at different telescope orientation angles. The signal, with a wavelength of about 1.6 micrometers, was detected in all four sets of combined exposures. The measurements were consistent, making it difficult to explain the finding as a technical malfunction or artifact.
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None of the explanations has been confirmed
Within this study, six other detected signals were matched with distant galaxies already known in the HUDF field. The seventh signal remained without such a counterpart: no other emission lines were detected nearby that could help determine the distance to the source and its nature.
The researchers considered several possible explanations: a galaxy from the early Universe, a closer galaxy, a supernova, or the tidal disruption of a star by a black hole. However, none of these versions fully agrees with the available data. As the authors of the study note, deeper and more sensitive spectroscopic observations may reveal additional emission lines, establish the redshift, and clarify the physical nature of the source. The study was published in The Astrophysical Journal.
