In recent years a major focus of our group is to detect and study supernovae shortly (a day or less) after explosion. Observations during these first hours illuminate fundamental topics about the physics of supernova explosions and the nature of the progenitor stars,
The advent of massive wide-field variability surveys continues to lead to disocveries of rare and often unexpected new classes of transients. Perhaps the best known group of such object is the class of superluminous supernovae (SNe). Our group pioneered the studies of SLSNe (for example these papers by Ofek et al., Gal-Yam et al. and Quimby et al.) and continues to work on this subject, most recently mainly on studies of samples of events, e.g., the large sample of SLSNe from PTF. Two recent sample papers deal with spectroscopy (Quimby et al. 2018) and photometry (De Cia et al. 2018) of SLSNe-I from PTF. A semi-popular acrticle on SLSNe and their discovery can be found here.
Our group develops astrophysical instrumentation mainly using technologies that are invented here at Weizmann.
The (i)PTF wide-field variability sky survey is conducted by a consortium led by Prof. Shri Kulkarni from Caltech, of which The Weizmann Institute of Science is a founding member. The survey instrument is the recommissioned CFHT 12k camera, mounted on the 48'' Oschin Schmidt Telescope at Palomar Observatory, delivering a 7.8 square degrees field-of view per image. This dedicated wide-field survey instrument saw first light on Dec. 2008 and is in routine operations since March 2009. The survey will conclude at the end of February 2017, to allow the ZTF survey to commence later this year. PTF will provided a dedicated ``discovery machine'', probing unexplored regions in observational parameter space, in terms of a combination of field of view, survey depth and temporal search cadence. The study of core-collapse supernovae discovered by the PTF is a key project led by me at the Weizmann Institute.
Ultra-violet (UV) spectroscopy is needed to properly understand observations of supernovae at high-redshift that are obtained, e.g., by HST and will be obtained in large numbers by JWST, Euclid and WFIRST, observing the restframe UV in visible or IR light. However, UV spectroscopy of core-collapse SNe is very scarce. We are using several different spacecraft to collect such UV data, working toward a complete characterization of the UV spectral evolution of SNe of all types.
Direct observations of massive stars - before they explode - provide a model free identification of SN progenitors. A high-resolution image of the location of a SN, serendipitously obtained before it exploded, is combined with a precise localization of the SN (after it exploded) to enable us to select the correct progenitor from among the stars in the pre-explosion SN images. After decades of effort, less than a dozen SN progenitors have so far been detected.
This web page describes "Transients in the Dark" - a proposal for an Early Release Science (ERS) observing campaign with JWST that will push the investigation of cosmic supernova explosions to redshift 6 and beyond, search for the first black holes and the explosions of the first stars in the Universe, and set the foundations for time domain astrophysics using JWST.
The proposal will combine a JWST two-epoch wide-field study of an area of ~400 square arcminutes (covering several million cubic mega-parsec and high redshifts) in the K (2.2micron) and 4.4micron bands, with supporting ground-based wide field z- and Y-band studies, as well as spectroscopic observations of the most promising high-redshift sources with NIRSPEC on board JWST.
