Evidence of a forming nucleus in the Fourcade–Figueroa galaxy

Abstract

We analyze data from the IRAS, Wide-field Infrared Survey Explorer, and Planck satellites, revealing an unresolved dust condensation at the center of the Fourcade–Figueroa galaxy (ESO270-G017), which may correspond to a forming nucleus. We model the condensation's continuum spectrum in the spectral range from 3 to 1300 μm using the DUSTY code. The best-fit model, based on the chi-square test, indicates that the condensation is a shell with an outer temperature of Tout ≈ 12 K and an inner boundary temperature of Ti ≈ 500 K. The shell's outer radius is ro = 86.2 pc, and the inner cavity radius is ri = 0.082 pc. The condensation produces an extinction AV = 50 mag, and its luminosity is Lc = 1.08 × 1034 W, which would correspond to a burst of massive star formation approximately similar to the central 5 pc of R 136 in the LMC and NGC 3603, the ionizing cluster of a giant Carina arm H ii region. The comparison with normal, luminous, and ultraluminous IR galaxies leads us to consider this obscured nucleus as the nearest and weakest object of this category.