Surface Photometry and Metallicity of the Polar Ring Galaxy A0136-0801

TL;DR

This study combines photometric and spectroscopic data to analyze the structure, stellar populations, and metallicity of the polar ring galaxy A0136-0801, providing insights into its formation history.

Contribution

It offers a detailed multi-wavelength analysis of A0136-0801, constraining its stellar ages, metallicity, and possible formation scenarios, which is novel for this galaxy type.

Findings

Host galaxy dominates light emission across bands.

Polar structure is more luminous in optical and three times more extended.

Stellar populations are 3-5 Gyrs old in the spheroid and 1-3 Gyrs in the polar structure.

Abstract

We present a photometric and spectroscopic study of the polar ring galaxy A0136-0801 in order to constrain its formation history. Near-Infrared (NIR) and optical imaging data are used to extract surface brightness and color profiles of the host galaxy and the wide polar structure in A0136-0801. The host galaxy dominates the light emission in all bands; the polar structure is more luminous in the optical bands and is three times more extended than the main spheroid. The average stellar population in the spheroid is redder than in the polar structure and we use their (B-K) vs. (J-K) colors to constraint the ages of these populations using stellar population synthesis models. The inferred ages are 3-5 Gyrs for the spheroid and 1-3 Gyrs for the polar structure. We then use long slit spectra along the major axis of the polar structure to derive the emission line ratios and constrain the oxygen abundance, metallicity and star formation rate in this component. We find 12+log(O/H) = 8.33 +- 0.43 and Z ~ 0.32 Zsun, using emission line ratios. These values are used, together with the ratio of the baryonic masses of the host galaxy and polar structure, to constraint the possible models for the formation scenario. We conclude that the tidal accretion of gas from a gas rich donor or the disruption of a gas-rich satellite are formation mechanisms that may lead to systems with physical parameters in agreement with those measured for A0136-0801.