Bibcode
DOI
Garzon, F.; Lopez-Corredoira, M.; Hammersley, P.; Mahoney, T. J.; Calbet, X.; Beckman, J. E.
Referencia bibliográfica
Astrophysical Journal Letters v.491, p.L31
Fecha de publicación:
12
1997
Número de citas
35
Número de citas referidas
31
Descripción
We present an analysis of the optical spectroscopy of 58 stars in the
Galactic plane at l=27^° , where a prominent excess in the flux
distribution and star counts have been observed in several spectral
regions, in particular in the Two-Micron Galactic Survey (TMGS) catalog.
The sources were selected from the TMGS to have a K magnitude brighter
than +5 mag and to be within 2 deg of the Galactic plane. More than 60%
of the spectra correspond to stars of luminosity class I, and a
significant proportion of the remainder are very late and fast-evolving
giants. This very high concentration of young sources points to the
existence of a major star formation region in the Galactic plane,
located just inside the assumed origin of the Scutum spiral arm. Such
regions can form because of the concentrations of shocked gas where a
galactic bar meets a spiral arm, as is observed at the ends of the bars
of face-on external galaxies. Thus, the presence of a massive star
formation region is very strong supporting evidence for the presence of
a bar in our Galaxy.