Multiwavelength study of the radio emission from a tight galaxy pair Arp 143

TL;DR

This study uses multiwavelength radio observations to analyze the magnetic fields, spectral ages, and emission structures in the galaxy pair Arp 143, revealing insights into their starburst activity and magnetic properties.

Contribution

It provides a detailed multi-frequency radio analysis of Arp 143, highlighting magnetic field strengths and spectral ages of different regions, which was not previously characterized.

Findings

Strong magnetic fields in the collisional ring (up to 12 μG).

Spectral age of the ring exceeds that of star-forming regions, indicating different origins.

Young spectral age of the galactic core suggests ongoing starburst activity.

Abstract

We present results of the recent low-frequency radio observations of a tight galaxy pair Arp 143 at 234 and 612 MHz. These data are analysed together with the archive data at 1490, 4860, 8440, and 14940 MHz. From the analysis of the radio emission we derive constraints on the age of the radio emitting structures as well as on the properties of their magnetic field. We show that the collisional ring of NGC 2445 hosts strong magnetic fields (reaching 12 $\mu$G in its northwestern part) manifesting as a steep--spectrum, nonthermal radiation at radio frequencies. The spectral age of this structure is higher than estimates derived for the star-forming regions from the H$\alpha$ distribution, suggesting that the radio emission might have a different origin. The galactic core is of a very young spectral age, suggesting an ongoing starburst activity. Additionally we identify a possible ridge of emission between the ring galaxy and its elliptical companion NGC 2444.