סמינר באסטרונומיה ובאסטרופיזיקה: Clues to SN Ia progenitors from the delay time distribution and the alpha/Fe patterns of MW stars

Abstract:  

I will show how several recent observational developments have led to convergence toward two slightly different delay-time distributions (DTDs) for Type Ia supernovae (SNe Ia), one DTD for field environments and another in galaxy-cluster environments. I use the field DTD to derive the cosmic history of iron enrichment, [Fe/H] and, for the first time, the cosmic history of the ratio of alpha-elements to iron, [alpha/Fe].  The cosmic track in the [alpha/Fe] vs. [Fe/H] plane is similar to the main chemical abundance locus in this plane for Milky Way stars, and it is easy to find a simple Galactic star-formation history that, combined with the observed SN DTD and observed SN iron yields, produces an excellent match to the stellar locus. An early burst-like MW SF history, combined with a cluster-like DTD, reproduces the "high-alpha" locus of MW halo stars, suggesting the MW halo has had a galaxy-cluster-like SF history and DTD. This is additional evidence that galaxies in cluster-like environments, for some reason, are a few times more efficient than field galaxies at producing SNe Ia, per formed stellar mass

מארגת הסמינר: פרופ' שרה בק