| Issue |
A&A
Volume 709, May 2026
|
|
|---|---|---|
| Article Number | A149 | |
| Number of page(s) | 18 | |
| Section | Extragalactic astronomy | |
| DOI | https://doi.org/10.1051/0004-6361/202558393 | |
| Published online | 12 May 2026 | |
H I 21-cm line properties of the nearby luminous infrared galaxy IRAS 04296+2923
1
College of Physics, Guizhou University, 550025 Guiyang, PR China
2
National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China
3
Guizhou Radio Astronomical Observatory, Guizhou University, Guiyang 550000, China
★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.
Received:
4
December
2025
Accepted:
9
March
2026
Abstract
We present an analysis of archival Very Large Array (VLA) and Five-hundred-meter Aperture Spherical radio Telescope (FAST) H 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 H 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 Δv = 26 km s−1, and comparable total H I masses on the order of 109 M⊙. Both galaxies exhibit regular H I velocity fields and characteristic double-horn profiles in the VLA and FAST data, accompanied by only subtle asymmetries and extended H 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 (q8.4 ≃ 3.2), implying a young, dust-obscured nuclear starburst. Taken together, the regular H 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.
Key words: galaxies: interactions / galaxies: starburst / radio continuum: galaxies / radio lines: galaxies
© The Authors 2026
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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