The meaning of WISE colours - I. The Galaxy and its satellites
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Archivos
Fecha
2014-08
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
ISSN de la revista
Título del volumen
Editor
Oxford University Press
Nombre de Curso
Licencia CC
Licencia CC
Resumen
Through matches with the Sloan Digital Sky Survey (SDSS) catalogue we identify the location
of various families of astronomical objects in WISEcolour space.We identify reliable indicators
that separate Galactic/local from extragalactic sources and concentrate here on the objects in
our Galaxy and its closest satellites. We develop colour and magnitude criteria that are based
only on WISE data to select asymptotic giant branch (AGB) stars with circumstellar dust
shells, and separate them into O-rich and C-rich classes. With these criteria we produce an
all-sky map for the count ratio of the two populations. The map reveals differences between
the Galactic disc, the Magellanic Clouds and the Sgr Dwarf Spheroidal galaxy, as well as
a radial gradient in the Large Magellanic Cloud (LMC) disc. We find that the C:O number
ratio for dusty AGB stars increases with distance from the LMC centre about twice as fast as
measured for near-IR selected samples of early AGB stars. Detailed radiative transfer models
show that WISE colours are well explained by the emission of centrally heated dusty shells
where the dust has standard properties of interstellar medium (ISM) grains. The segregation
of different classes of objects in WISE colour space arises from differences in properties of
the dust shells: those around young stellar objects have uniform density distributions while in
evolved stars they have steep radial profiles.
Notas
Indexación: Scopus.
Palabras clave
Radiative Transfer, Stars: AGB and post-AGB, Galaxy: Structure, Magellanic Clouds, Infrared: General, Infrared: Stars
Citación
Monthly Notices of the Royal Astronomical Society. Volume 442, Issue 4, Pages 3361 - 3379. August 2014
DOI
10.1093/mnras/stu1087