Radio continuum and H I 21-cm line observations of the nearby luminous infrared galaxy IRAS 17526+3253

¹ College of Physics, Guizhou University, 550025 Guiyang, PR China
² Special Astrophysical Observatory of RAS, Nizhny Arkhyz 369167, Russia
³ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, PR China

^⋆ Corresponding author: zzwu08@gmail.com

Received: 27 January 2025
Accepted: 31 July 2025

Abstract

We present results from our European VLBI Network (EVN) and Giant Meterwave Radio Telescope (GMRT) observations of the radio continuum and spectral line emission in IRAS 17526+3253, along with an analysis of its arcsecond-scale radio properties using archival Very Large Array (VLA) data. The EVN observations detected radio continuum emission from both the northwest (NW) and southeast (SE) nuclei. The NW nucleus shows two components with high brightness temperatures and radio luminosities, likely indicating the presence of an active galactic nucleus (AGN) core and jet. Meanwhile, our EVN observation failed to detect the OH line emission, possibly due to radio frequency interference (RFI) and/or the emission being partly resolved out and below our detection limit. The multiband radio spectral energy distribution deviates from a single power law at low frequencies, suggesting low-frequency absorption. The GMRT spectral line data reveal both H I absorption and emission. The H I emission is diffuse and shows a velocity gradient from about 7500 km s⁻¹ in the NW to 7800 km s⁻¹ in the SE nucleus. On larger scales, the H I emission extends about 4′ along the NW–SE direction, with the SE extension matching the optical tidal tail. In addition, the weak H I absorption features show broad line profiles, possibly due to overlapping H I gas from the two nuclei. The aforementioned results are consistent with properties of intermediate-stage mergers reported in the literature.