Τμήμα Φυσικής
ΣΧΟΛΗ ΘΕΤΙΚΩΝ ΕΠΙΣΤΗΜΩΝ ΕΚΠΑ
ΤΜΗΜΑ ΦΥΣΙΚΗΣ
ΤΟΜΕΑΣ ΑΣΤΡΟΦΥΣΙΚΗΣ ΑΣΤΡΟΝΟΜΙΑΣ ΚΑΙ ΜΗΧΑΝΙΚΗΣ
Σ Ε Μ Ι Ν Α Ρ Ι Ο
Τετάρτη 20 Μαρτίου 2019, 13:00-14:00
Αίθουσα Διαλέξεων Τομέα Αστροφυσικής, Αστρονομίας και Μηχανικής
Dust and star formation properties of ~800 local galaxies
Dr Sophia Lianou
Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing/National Observatory of Athens
& Institut d'Astrophysique de Paris, France
The local Universe is the best laboratory in which to understand the evolution of galaxies, making it the focus of current and upcoming surveys. Using a sample of ~800 local galaxies, treated statistically as an ensemble, we study their star formation versus the interstellar medium properties. We use mid-IR observations to derive star formation rates (SFR) and stellar masses and to examine how these relate to the derived dust emission properties, which we derive via modeling their dust spectral energy distributions (dust-SEDs). The derived dust emission properties are the dust masses, the average interstellar radiation field intensities, and the mass fraction of very small dust grains. We use the extended Kennicutt-Schmidt (KS) law to estimate the gas mass and the gas-to-dust mass ratio (GDR). An average GDR estimated for the late-type galaxies and irregular galaxies is 390, while including the early-type galaxies gives an average of 570. The gas mass derived from the extended KS law is on average 10% higher than that derived from the KS law. The specific-SFR increases with galaxy type, while this is not the case for the dust-specific SFR (= SFR/Mdust), showing an almost constant star formation efficiency per galaxy type. The galaxy sample is characterised by a tight relation between the dust mass and the stellar mass for the late-type galaxies and irregulars, while early-type galaxies scatter around this relation and tend towards smaller dust masses. Preliminary results on the dust-SED analyses applied to galaxies on local scales are also discussed.