Radio properties of the OH megamaser galaxy IRAS 02524+2046

¹ College of Physics, Guizhou University, 550025 Guiyang, PR China
e-mail: zzwu08@gmail.com
² Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, PR China
³ School of Astronomy and Space Science, Nanjing University, 22 Hankou Road, Nanjing 210093, PR China
⁴ Center for Astrophysics, GuangZhou University, Guangzhou 510006, PR China
⁵ Special Astrophysical Observatory, Russian Academy of Sciences, 369167 Nizhnii Arkhyz, Russia

Received: 23 January 2020
Accepted: 21 April 2020

Abstract

We present results from VLBI observations of continuum and OH line emission in IRAS 02524+2046 as well as arcsecond-scale radio properties of this galaxy using VLA archive data. We found that there is no significant detection of radio continuum emission from VLBI observations. The arcsecond-scale radio images of this source show no clear extended emission. The total radio flux density at L and C bands are approximately 2.9 mJy and 1.0 mJy, respectively, which indicates a steep radio spectral index between the two bands. A steep spectral index, low brightness temperature, and high q-ratio (i.e., the far-infrared to the radio flux density), which are three critical indicators in the classification of radio activity in the nuclei of galaxies, are all consistent with the classification of this source as a starburst galaxy from its optical spectrum. The high-resolution line profile reveals that we detected both the 1665 MHz and 1667 MHz OH maser lines, which show two and three clear components, respectively. The channel maps show that the maser emission are distributed in a region of ∼210 pc × 90 pc. The detected maser components in different regions indicate similar double spectral features, which might be evidence that this galaxy is at a stage of major merger as seen from the optical morphology.