Science with the Daksha High Energy Transients Mission

Abstract

We present the science case for the proposed Daksha high energy transients mission. Daksha will comprise of two satellites covering the entire sky from 1 keV to >1 MeV. The primary objectives of the mission are to discover and characterize electromagnetic counterparts to gravitational wave sources; and to study Gamma Ray Bursts (GRBs). Daksha is a versatile all-sky monitor that can address a wide variety of science cases. With its broadband spectral response, high sensitivity, and continuous all-sky coverage, it will discover fainter and rarer sources than any other existing or proposed mission. Daksha can make key strides in GRB research with polarization studies, prompt soft spectroscopy, and fine time-resolved spectral studies. Daksha will provide continuous monitoring of X-ray pulsars. It will detect magnetar outbursts and high energy counterparts to Fast Radio Bursts. Using Earth occultation to measure source fluxes, the two satellites together will obtain daily flux measurements of bright hard X-ray sources including active galactic nuclei, X-ray binaries, and slow transients like Novae. Correlation studies between the two satellites can be used to probe primordial black holes through lensing. Daksha will have a set of detectors continuously pointing towards the Sun, providing excellent hard X-ray monitoring data. Closer to home, the high sensitivity and time resolution of Daksha can be leveraged for the characterization of Terrestrial Gamma-ray Flashes.

Prospects of measuring gamma-ray burst polarization with the Daksha mission

“…One such addition to this era would be the proposed high-energy transient mission Daksha. 35,36 When launched, it will be one of the most sensitive high-energy telescopes in the world that can also perform hard x-ray polarization measurements. Here, we present the expected hard x-ray polarization sensitivity of Daksha.…”

“…In the upcoming years, dedicated GRB polarimeters, such as POLAR-2, 32 COSI, 33 and LEAP, 34 have been proposed to obtain more sensitive polarization measurements. One such addition to this era would be the proposed high-energy transient mission Daksha 35 , 36 . When launched, it will be one of the most sensitive high-energy telescopes in the world that can also perform hard x-ray polarization measurements.…”