J0011+3443: A GPS compact symmetric object, gravitational lens, or dual active galactic nucleus
Year: 2026
Type: article
Abstract: We present new multifrequency VLBA observations of J0011+3443 (TXS 0008+344, z = 0.89) at 2.3, 4.9, 8.5, and, for the first time, 23.6 GHz. The source consists of two compact components, A and B, at a projected separation of 314 ± 2 pc, plus a third feature, C, detected at 23.6 GHz at 0.6 mas from A. Archival low-resolution radio measurements confirm an integrated gigahertz-peaked spectrum, with an observed-frame peak frequency of ν peak = 0.73 ± 0.08 GHz and a peak flux density of S peak = 879 ± 125 mJy. A comparison with nearly frequency-matched low-resolution measurements shows that the VLBA recovers 0.85 ± 0.11 of the 4.85 GHz flux density and 0.50 ± 0.06 of the 8.46 GHz flux density. The lower recovered fraction at 8.5 GHz suggests that the low-surface-brightness emission is resolved out or falls below the VLBA surface-brightness sensitivity. We therefore interpreted the VLBA component spectra as spectra of the compact recovered emission only. The 23.6 GHz morphology, absence of a detected flat-spectrum core, similar compact spectra of A and B, and steep integrated GHz spectrum favor an interpretation of J0011+3443 as a GPS-class compact symmetric object, possibly in a short-lived or relic phase; however, we note that a dual active galactic nucleus (AGN) origin cannot be excluded without multi-epoch astrometry.
Source: Astronomy and Astrophysics
Authors: E. Traianou, T. Liu, R. Gold, R. Mushotzky
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W7214404912