Colloquium on Jan. 8, 2020

High-velocity feature as the indicator of stellar population of Type Ia supernovae

Speaker: Xiangchun Meng (YNU)

Venue: Room 2111, SWIFAR Building

Time: 3:00 PM, Wednesday, Jan. 8, 2020

Abstract: 

Although Type Ia supernovae (SNe Ia) are very useful in many astrophysical fields, their exact nature is still unclear, e.g., the progenitor and explosion models. The high-velocity features (HVFs) in optical spectra of SNe Ia could provide some meaningful information to constrain the nature of SNe Ia. Here, I show strong evidence that the SNe Ia with a strong Ca II infrared triple (Ca II IR3) HVF around maximum brightness are associated with a relatively younger population than those with a weak Ca II IR3 HVF. I also find that the strength of the Ca II IR3 HVF is  linearly dependent on the difference of the absorption-weighted velocities between the Ca II IR3 and Si II 635.5 nm absorption lines. I will discuss the origin of the HVFs and the constraints from our discoveries on the progenitor model of SNe Ia.