Résumé / Abstract Journal-club_Galaxies

Journal-club Galaxies

« On the interdependence of galaxy morphology, star formation, and environment in massive galaxies in the nearby Universe »

Omkar Bait
The National Centre for Radio Astrophysics, Tata Institute of Fundamental Research (Pune, Inde)

Using multi-wavelength data we study the dependence of star formation on the morphology and environment of massive galaxies in the local Universe. We find that, early-type spirals and S0s predominate in the green valley, which is a transition zone between the star forming and quenched regions. The fraction of early-type spirals decreases as we enter the green valley from the blue cloud, which coincides with the increase in the fraction of S0s. This points towards the morphological transformation of early-type spiral galaxies into S0s which can happen due to environmental effects such as ram-pressure stripping, galaxy harassment, or tidal interactions. We also find a second population of S0s which are actively star-forming and are present in all environments. Since morphological T-type, specific star formation rate (sSFR), and environmental density are all correlated with each other, we compute the partial correlation coefficient for each pair of parameters while keeping the third parameter as a control variable. We find that morphology most strongly correlates with sSFR, independent of the environment, while the other two correlations are weaker. Thus, we conclude that the physical processes that shape the galaxies are also the ones that determine their star-forming state.
jeudi 13 septembre 2018 - 11:30
Salle 281, Institut d'Astrophysique
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