Surveying the Extreme Sky with EXIST

TL;DR

The paper reviews the evolution of the EXIST mission concept, highlighting its enhanced multiwavelength capabilities for studying high-energy astrophysical phenomena like GRBs and SMBHs, aiming to understand the universe's early history.

Contribution

It introduces an advanced, multi-instrument design of the EXIST mission, significantly improving sensitivity and capability for transient and high-energy source studies.

Findings

Enhanced detection of GRBs and SMBHs across multiple wavebands.

Improved ability to study the birth and evolution of early stars and galaxies.

Autonomous redshift determination for many GRBs.

Abstract

The recent hard X-ray surveys performed by INTEGRAL and Swift have started to reveal the demographics of compact sources including Super-Massive Black Holes hosted in AGNs and have proven invaluable in tracking explosive events as the death of massive stars revealed by Gamma-Ray Bursts up to cosmological distances. Whereas the observations have contributed significantly to our understanding of the sources populations in the Local Universe, it has also become evident that revealing the processes that drive the birth and evolution of the first massive stars and galaxies would have required a further big step in both sensitivity and capability to study transient phenomena since their very beginning and covering different wavebands simultaneously. Therefore, after its decennial history as a proposed hard X-ray survey mission, EXIST has now turned into a new, more advanced concept with three instruments on board covering the IR/optical and X-ray/soft gamma-ray bands. The EXIST new design (Grindlay 2009a) is therefore much improved in its capability for prompt study of GRBs (with autonomous determination of the redshift for many of them) and broadband spectral studies of SMBHs and transients in the high energy band from 0.1 to several hundred keV, with sensitive optical/NIR and soft X-ray identifications and followup studies.