Bibcode
Falcón-Barroso, J.; van de Ven, G.; Peletier, R. F.; Bureau, M.; Jeong, H.; Bacon, R.; Cappellari, M.; Davies, R. L.; de Zeeuw, P. T.; Emsellem, E.; Krajnović, D.; Kuntschner, H.; McDermid, R. M.; Sarzi, M.; Shapiro, K. L.; van den Bosch, R. C. E.; van der Wolk, G.; Weijmans, A.; Yi, S.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 417, Issue 3, pp. 1787-1816.
Advertised on:
11
2011
Citations
71
Refereed citations
66
Description
We present ground-based MDM Observatory V-band and Spitzer/InfraRed
Array Camera 3.6-?m-band photometric observations of the 72
representative galaxies of the SAURON survey. Galaxies in our sample
probe the elliptical E, lenticular S0 and spiral Sa populations in the
nearby Universe, both in field and cluster environments. We perform
aperture photometry to derive homogeneous structural quantities. In
combination with the SAURON stellar velocity dispersion measured within
an effective radius (σe), this allows us to explore the
location of our galaxies in the colour-magnitude,
colour-σe, Kormendy, Faber-Jackson and Fundamental
Plane scaling relations. We investigate the dependence of these
relations on our recent kinematical classification of early-type
galaxies (i.e. slow/fast rotators) and the stellar populations. Slow
rotator and fast rotator E/S0 galaxies do not populate distinct
locations in the scaling relations, although slow rotators display a
smaller intrinsic scatter. We find that Sa galaxies deviate from the
colour-magnitude and colour-σe relations due to the
presence of dust, while the E/S0 galaxies define tight relations.
Surprisingly, extremely young objects do not display the bluest
(V-[3.6]) colours in our sample, as is usually the case in optical
colours. This can be understood in the context of the large contribution
of thermally pulsing asymptotic giant branch stars to the infrared, even
for young populations, resulting in a very tight
(V-[3.6])-σe relation that in turn allows us to define
a strong correlation between metallicity and σe. Many
Sa galaxies appear to follow the Fundamental Plane defined by E/S0
galaxies. Galaxies that appear offset from the relations correspond
mostly to objects with extremely young populations, with signs of
ongoing, extended star formation. We correct for this effect in the
Fundamental Plane, by replacing luminosity with stellar mass using an
estimate of the stellar mass-to-light ratio, so that all galaxies are
part of a tight, single relation. The new estimated coefficients are
consistent in both photometric bands and suggest that differences in
stellar populations account for about half of the observed tilt with
respect to the virial prediction. After these corrections, the slow
rotator family shows almost no intrinsic scatter around the best-fitting
Fundamental Plane. The use of a velocity dispersion within a small
aperture (e.g. Re/8) in the Fundamental Plane results in an
increase of around 15 per cent in the intrinsic scatter and an average
10 per cent decrease in the tilt away from the virial relation.
Related projects
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
Ignacio
Martín Navarro