1 research outputs found
Crowded field 3D spectroscopy of LBV candidates in M33
We present integral field spectroscopy of the LBV candidate stars B416 and
v532 in the local group galaxy M33. B416 is surrounded by an elongated
ring-like nebula, which has a projected radius of 20x30 pc. From the datacube
we create ionization and radial velocity maps of the nebula. The excitation of
the gas decreases towards the outer part of the ring, while the inner part of
the nebula is filled with a more excited gas. In the EW direction the ring is
seen to expand with a maximum projected velocity amplitude of about 40 km/s.
The eastern part approaches the observer. We estimate the nebula dynamical
lifetime 8*10E5 years. It could be a residual MS bubble, which indicates a
main-sequence or pre-LBV status of the star. We classify B416 as an "iron star"
or B[e]-supergiant. In v532 an elongated nebula has been marginally detected.
The total projected size of the nebula along the main axis is 30 pc, and the
total radial velocity gradient is 44+/-11 km/s. v532 exhibits both strong
photometric and spectral variability. At the time of our observations it was in
an intermediate brightness state with a rich nitrogen spectrum. We classify
v532 as an LBV, showing LBV Ofpe/WN transitions. We stress the importance
of integral field spectroscopy as the optimal technique for studying nebulae
and the evolution of LBV-like stars in nearby galaxies.Comment: 12 pages, 10 Postscript figures, A&A accepte