"40 years of research in Radioastronomy, 25 at IAG/USP"

A workshop in honor of Zulema Abraham


HIGHLIGHTS


ETA CARINAE AS SEEN BY ALMA






Eta Carine was mapped with 23 antennas of the ALMA array in November 2012, in the continuum of 3 mm, 1.3 mm, 1 mm
and 454 μm, the lowest submillimeter wavelength ever achieved, with resolution of 0.4 arc sec. Hydrogen  recombination lines
H42α H40α, H30α, H28α and H21α were also detected at these wavelengths. The radio maps showed a  very strong compact
structure coincident with the position of the binary system and spectrum of bremsstrahlung  emission, with the turn over between optically thick and thin spectrum between 3 and 1.3 mm. The radio
recombination lines are even stronger than the continuum, even at 454 μm, indicating departure of LTE and that the  emitting
region has electron densities of the order of (10⁶ – 10⁷) cm^-3 . The central velocity of the  recombination lines coincides with
 the velocity of the Weigelt blobs. Besides the very strong unresolved source,
the radio maps  show weak emission that extends for a few arc sec, with a structure similar to what was observed at higher  wavelengths (Abraham et al. 2014, in press).