Special Talk

• Special Talks

  Speaker: Dave Coulter (STScI)
  Title: Discovery of a likely Type II SN at z=3.6 with JWST  
  Abstract: This high-z SN is best fit by a SN II model at a redshift of ~3.6, which is considered the highest SN redshift to date. The host galaxy photo-z and subsequent follow-up spectroscopy confirm this redshift, and the host spectrum reveals a low extinction, metal poor, star forming galaxy, that suggests that TR10 came from a low-metallicity progenitor. This SN is a key anchor for the metallicity-luminosity relationship of SN II at high-z, and demonstrates the need for facilities like JWST to understand the poorly constrained relationship between progenitor metallicity and massive star evolution.

  Speaker: Matthew Siebert (STScI)
  Title: Discovery of a Stripped Envelope Supernova at z=2.8 with JWST​​​​​​​
  Abstract: The combined depth and wavelength coverage of JWST is beginning to enable a new era of transient discovery at redshifts z>2. During Cycles 1 and 2, the JADES program obtained multiple epochs of the same field, allowing for one of the first searches for transients in deep images (~30 AB mag) over a relatively wide area (27 arcmin^2). One of the transient candidates discovered, has a light-curve and host galaxy spectroscopic redshift consistent with a Type Ic-BL supernova (SN Ic-BL) at z = 2.83, making it the most distant stripped-envelope SN (SESN) discovered to date. Its light curve matches well with other SESNe and the broad absorption features in its spectrum are consistent with other SNe Ic-BL 1-3 weeks after peak brightness. We measure a Ca II NIR triplet expansion velocity of 28,000 km s^-1. The host galaxy of this SN is irregular, and modeling of its SED indicate a metallicity of Z = 0.35 Zsol. The presence of a stripped envelope supernova at this distance challenges explosion models, and has important implications for the formation of dust in the early universe.

  Speaker: Armin Rest and Ori Fox (STScI)​​​​​​​
  Title: Exploring the high-z Transient Universe with JWST​​​​​​​
  Abstract: Time-domain astronomy in the early, high-redshift (z>3) Universe is an unexplored regime that offers the possibility of probing the first stars and Epoch of Reionization (EoR). JWST's unique depth and wavelength access allow us, for the first time, to detect the supernovae (SNe) from these early times. These transients are red, faint, and slowly evolving with implications for an evolving initial mass function (IMF), luminosity evolution for Type Ia supernova (SN Ia) cosmology, and stellar evolution in the early universe. We present the first sample of high-redshift transients from the JADES and COSMOS-Web projects, including SN Ia and massive star SNe between 2<z<4.