Bibcode
Martig, Marie; Crocker, Alison F.; Bournaud, Frédéric; Emsellem, Eric; Gabor, Jared M.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bureau, Martin; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; Dekel, Avishai; de Zeeuw, P. T.; Duc, Pierre-Alain; Falcón-Barroso, J.; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; McDermid, Richard M.; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Griffin, Kristen Shapiro; Teyssier, Romain; Weijmans, Anne-Marie; Young, Lisa M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 432, Issue 3, p.1914-1927
Advertised on:
7
2013
Citations
106
Refereed citations
100
Description
We study the global efficiency of star formation in high-resolution
hydrodynamical simulations of gas discs embedded in isolated early-type
and spiral galaxies. Despite using a universal local law to form stars
in the simulations, we find that the early-type galaxies are offset from
the spirals on the large-scale Kennicutt relation, and form stars two to
five times less efficiently. This offset is in agreement with previous
results on morphological quenching: gas discs are more stable against
star formation when embedded in early-type galaxies due to the lower
disc self-gravity and increased shear. As a result, these gas discs do
not fragment into dense clumps and do not reach as high densities as in
the spiral galaxies. Even if some molecular gas is present, the fraction
of very dense gas (typically above 104 cm-3) is
significantly reduced, which explains the overall lower star formation
efficiency. We also analyse a sample of local early-type and spiral
galaxies, measuring their CO and H I surface densities and their star
formation rates as determined by their non-stellar 8 μm emission. As
predicted by the simulations, we find that the early-type galaxies are
offset from the Kennicutt relation compared to the spirals, with a twice
lower efficiency. Finally, we validate our approach by performing a
direct comparison between models and observations. We run a simulation
designed to mimic the stellar and gaseous properties of NGC 524, a local
lenticular galaxy, and find a gas disc structure and global star
formation rate in good agreement with the observations. Morphological
quenching thus seems to be a robust mechanism, and is also consistent
with other observations of a reduced star formation efficiency in
early-type galaxies in the COLD GASS survey. This lower efficiency of
star formation is not enough to explain the formation of the whole red
sequence, but can contribute to the reddening of some galaxies.
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