Analysis reveals gravitational dynamics and internal processes in infrared galaxy IRAS 04296+2923, suggesting unique interactions.
We present an analysis of archival Very Large Array (VLA) and Five-hundred-meter Aperture Spherical radio Telescope (FAST) ̋I 21 cm data, together with archival multiband radio continuum observations, of the nearby luminous infrared galaxy (LIRG) IRAS 04296+2923. The system, located behind the Taurus dark cloud at a distance of ∼29 Mpc, forms a small galaxy group consisting of five members as revealed by the ̋I imaging. IRAS 04296+2923 has a close companion, HI 0432+2926, with a projected separation of ∼40 kpc, a small line-of-sight velocity difference of Δ v = 26 km -1 $, and comparable total ̋I masses on the order of 10^9 M_⊙. Both galaxies exhibit regular ̋I velocity fields and characteristic double-horn profiles in the VLA and FAST data, accompanied by only subtle asymmetries and extended ̋I structures, indicating rotation-dominated kinematics with early signs of weak tidal interaction. Radio continuum emission is detected only from IRAS 04296+2923 and is confined to its nuclear region, consistent with previous studies. Modeling its multiband radio spectrum reveals a significant contribution from free--free emission at high frequencies ($>30 GHz) and a high FIR-to-radio flux ratio (q_ 8.4 implying a young, dust-obscured nuclear starburst. Taken together, the regular ̋I kinematics, the small velocity offset, and the group-scale environment favor an interpretation in which IRAS 04296+2923 and HI 0432+2926 form a gravitationally bound, orbiting galaxy pair embedded in a small group, rather than an advanced merger. In this context, the LIRG nature of IRAS 04296+2923 is more plausibly driven by internal processes, such as bar-induced gas inflow, possibly modulated by long-timescale, low-level tidal interactions with nearby group companions.
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Feng et al. (2026) studied this question.