Speaker
Dr
Meng Su
(MIT, USA)
Description
We propose a high angular resolution telescope dedicated to the sub-GeV
gamma-ray astronomy as a candidate for the CAS-ESA joint small mission.
This mission, called PANGU (PAir-productioN Gamma-ray Unit), will open up a
unique window of electromagnetic spectrum that has never been explored with
great precision. A wide range of topics of both astronomy and fundamental
physics can be attacked with a telescope that has an angular resolution
about one order of magnitude better than the currently operating Fermi
Gamma-ray Space Telescope (Fermi) in the sub-GeV range, covering galactic
and extragalactic cosmic-ray physics, extreme physics of a variety of
extended (e.g. supernova remnants, galaxies, galaxy clusters) and compact
(e.g. black holes, pulsars, gamma-ray bursts) objects, solar and
terrestrial gamma-ray phenomena, and searching for Dark Matter (DM) decay
and/or annihilation signature etc. The unprecedented resolution can be
achieved with a pair-production telescope that, instead of the high-Z
converter commonly used, relies on a large number of thin active tracking
layers to increase the photon conversion probability, and to precisely
reconstruct the pair-produced electron and positron tracks. Scintillating
fibers or thin silicon micro-strip detectors are suitable technology for
such a tracker. The energy measurement is achieved by measuring the
momentum of the electrons and positrons through a magnetic field. The
innovated spectrometer approach provides superior photon conversion
identification and photon pointing resolution, and is particular suitable
in the sub-GeV range, where the opening angle between the electron and
positron is relatively large. The level of tracking precision makes it
possible to measure the polarization of gamma rays, which would open up a
new frontier in gamma-ray astronomy. The sub-GeV full sky survey by PANGU
would provides crucial link with GeV to TeV maps from current/future
missions including Fermi, DAMPE, HERD, and CTA.
Author
Dr
Meng Su
(MIT, USA)
