The Compton Spectrometer and Imager

In this Astro2020 APC White Paper, we describe a Small Explorer (SMEX) mission concept called the Compton Spectrometer and Imager. COSI is a Compton telescope that covers the bandpass often referred to as the "MeV Gap" because it is the least explored region of the whole electromagnetic spectrum. COSI provides a significant improvement in sensitivity along with high-resolution spectroscopy, enabling studies of 511 keV electron-positron annihilation emission and measurements of several radioactive elements that trace the Galactic history of supernovae. COSI also measures polarization of gamma-ray bursts (GRBs), accreting black holes, and pulsars as well as detecting and localizing multimessenger sources. In the following, we describe the COSI science, the instrument, and its capabilities. We highlight many Astro2020 science WPs that describe the COSI science in depth.

[1]  C. Tseng,et al.  Polarimetric Analysis of the Long Duration Gamma-Ray Burst GRB 160530A With the Balloon Borne Compton Spectrometer and Imager , 2017, 1709.05349.

[2]  M.-H. A. Huang,et al.  DETECTION AND IMAGING OF THE CRAB NEBULA WITH THE NUCLEAR COMPTON TELESCOPE , 2011, 1106.0323.

[3]  C. A. Wilson-Hodge,et al.  An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A , 2017, 1710.05446.

[4]  G. Skinner,et al.  The Galactic distribution of the 511 keV e+/e- annihilation radiation , 2015 .

[5]  Astro 2020 Science White Paper Core Collapse Supernovae and Multi-Messenger Astronomy , 2022 .

[6]  Martin C. Weisskopf,et al.  The Imaging X-ray Polarimetry Explorer (IXPE) , 2016, Astronomical Telescopes + Instrumentation.

[7]  J. Stephen,et al.  Polarized Gamma-Ray Emission from the Crab , 2008, Science.

[8]  C. Tseng,et al.  Maximum Likelihood Compton Polarimetry with the Compton Spectrometer and Imager , 2017, 1709.05352.

[9]  The Ligo Scientific Collaboration,et al.  GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral , 2017, 1710.05832.

[10]  Roland Diehl,et al.  Positron Annihilation in the Galaxy , 2019 .

[11]  A. Lien,et al.  Energetic Particles of Cosmic Accelerators II: Active Galactic Nuclei and Gamma-ray Bursts , 2019, 1903.04639.

[12]  I. Grenier,et al.  Polarization of the Crab Pulsar and Nebula as Observed by the INTEGRAL/IBIS Telescope , 2008, 0809.1292.

[13]  F. R. Harnden,et al.  The Spectrum of Low-Energy Gamma Radiation from the Galactic-Center Region. , 1972 .

[14]  C.-Y. Chu,et al.  The polarimetric performance of the Compton Spectrometer and Imager (COSI) , 2018, Astronomical Telescopes + Instrumentation.

[15]  P. Shawhan,et al.  Multi-Messenger Astrophysics Opportunities with Stellar-Mass Binary Black Hole Mergers , 2019, 1903.11116.

[16]  K. Long,et al.  A precision measurement of the X-ray polarization of the Crab Nebula without pulsar contamination. , 1978 .

[17]  J. Roques,et al.  ON THE MORPHOLOGY OF THE ELECTRON–POSITRON ANNIHILATION EMISSION AS SEEN BY SPI/INTEGRAL , 2010, 1007.4753.

[18]  D. Thompson,et al.  High-Energy Polarimetry - a new window to probe extreme physics in AGN jets , 2019, 1903.04607.

[19]  Robert Andritschke,et al.  MEGAlib – The Medium Energy Gamma-ray Astronomy Library , 2006 .

[20]  Martin C. Weisskopf,et al.  Detection of X-Ray Polarization of the Crab Nebula , 1972 .

[21]  J. Rodriguez,et al.  Polarized Gamma-Ray Emission from the Galactic Black Hole Cygnus X-1 , 2011, Science.

[22]  M. Leventhal,et al.  Detection of 511 keV positron annihilation radiation from the galactic center direction. [gamma ray astronomy , 1978 .

[23]  D. J. Clark,et al.  SEPARATION OF TWO CONTRIBUTIONS TO THE HIGH ENERGY EMISSION OF CYGNUS X-1: POLARIZATION MEASUREMENTS WITH INTEGRAL SPI , 2012, 1210.4783.

[24]  S. E. Boggs,et al.  Event reconstruction in high resolution Compton telescopes , 2000 .

[25]  Chao-Hsiung Tseng,et al.  The 2016 Super Pressure Balloon flight of the Compton Spectrometer and Imager , 2017, 1701.05558.

[26]  Catching Element Formation In The Act - The Case for a New MeV Gamma-Ray Mission: Radionuclide Astronomy in the 2020s , 2019 .

[27]  Tanmoy Chattopadhyay,et al.  Prompt Emission Polarimetry of Gamma-Ray Bursts with the AstroSat CZT Imager , 2017, The Astrophysical Journal.

[28]  J. Greiner,et al.  Gamma-ray spectroscopy of Positron Annihilation in the Milky Way , 2015, 1512.00325.