Lecturer: Dr. Or Graur Affiliation: New York University Abstract: Based on a sample of nearby supernovae discovered in the Lick Observatory Supernova Search (LOSS), Li et al. (2011b) found that galaxies with higher stellar masses hosted lower supernova rates per unit mass ("specific rates") for all types of supernovae. Using a code that detects and classifies supernovae in galaxy spectra, we have discovered a sample of ~135 Type Ia and II supernovae, which we use to measure specific supernova rates as a function of galaxy stellar mass, as well as star-formation rate (SFR) and specific SFR. We show that the so- called "rate-mass relation" for Type Ia supernovae can be explained as a combination of the delay-time distribution (DTD) for each type of supernova and galaxy downsizing (i.e., massive galaxies tend to be older than less massive ones). This model accounts for the correlations between the specific supernova rates and galaxy SFR and specific SFR, as well. Additional details of the upcoming Astrophysics' seminars can be found on the following link. ‏האירוע הזה כולל שיחת וידאו ב-Google Hangouts. הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/astrophysics?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.los0mfvutshf851cv3824mt21g&hs=121