Bibcode
Beckman, John E.; Gutiérrez, Leonel; Erwin, Peter; Azzollini, Ruyman; Martínez-Valpuesta, Inma
Referencia bibliográfica
Galaxies and their Masks, by Block, David L.; Freeman, Kenneth C.; Puerari, Ivânio, ISBN 978-1-4419-7316-0. Springer Science+Business Media, LLC, 2010, p. 169
Fecha de publicación:
0
2010
Número de citas
0
Número de citas referidas
0
Descripción
Deriving the azimuthally averaged radial surface brightness profile of a
galaxy is a schematic way of presenting the light and then the mass
structure of disc galaxies. In this overview we will dwell on the outer
discs, as it has become possible, with modern data to explore the light
profile out to ever increasing galactocentric radii. We find that these
profiles can be well classified into three main types: truncated
profiles, untruncated profiles, and antitruncated profiles, denoted as
Types II, I, and III, respectively, amplifying an original
classification into Types I and II by Freeman. We present statistics of
these types over the range of the Hubble galaxy classification for 187
nearby galaxies. We then analyse a sample of disc profiles for a sample
of nearly 500 galaxies in three redshift bins, out to z = 1.1, from HST
data. For the Type II discs we show that the “break” radii
where the inner disc slope changes to a more abrupt outer slope have
increased with epoch, but that at all epochs this radius has the bluest,
i.e. the youngest stellar population. This can be explained via models
which combine stellar migration due to non-axisymmetry with continuous
star formation due to gas infall, one version of inside-out disc growth.
We note that the observed features of Type I and Type III profiles are
not explained in this scenario and show the need for even deeper
profiles, especially in the IR, the UV, and Hα.