ESO 148-2

Characteristics

ESO 148-2 is the product of two disk galaxies caught in a late-stage collision, its main body heavily warped and reminiscent of the Antennae galaxies. The system’s overall shape suggests an owl in mid-flight, with long, curved tidal tails—composed of stars and gas—serving as wings. At its heart lies a black hole with a mass of 4.4 × 10^7 solar masses. The galaxy shines brightly, forming stars at a rate of 149 solar masses per year and glowing in the infrared with a luminosity of 10^11.71 L☉, a sign of dust heated by intense star formation. Type N Wolf-Rayet stars are present, emitting N III λ4641 and He II λ4686 lines, the brightest of their kind. The H II regions, dominated by star formation, show a metallicity of 9.09 ± 0.03. A point-like source contributes two spectral components: a thermal one with a luminosity of about 1.5 × 10^41 erg s⁻¹ and a de-absorbed power-law component at roughly 2.7 × 10^42 erg s⁻¹.

Two nuclei sit close together, separated by about 4.5 arcseconds. The northern nucleus has a velocity dispersion consistent with star formation and emission-line ratios that match both LINERs and H II regions. The southern nucleus is three times brighter at 24 micrometers and hosts an active galactic nucleus, detected in infrared and X-rays, with an absorption-corrected luminosity of logL₂₋₁₀ = 42.38⁺⁰·²⁴₋₀·₂₈. Powerful outflows from its supermassive black hole trigger the birth of new stars. In the central region, firm emission lines appear with a full width at half maximum of 600 km/s and are blueshifted by 320 km/s relative to the absorption spectrum.