First Observation of the MeV Gamma-Ray Universe with Bijective Imaging Spectroscopy Using the Electron-tracking Compton Telescope on Board SMILE-2+

  title={First Observation of the MeV Gamma-Ray Universe with Bijective Imaging Spectroscopy Using the Electron-tracking Compton Telescope on Board SMILE-2+},
  author={Atsushi Takada and Taito Takemura and Kei Yoshikawa and Yoshitaka Mizumura and Tomonori Ikeda and Yuta Nakamura and Ken Onozaka and Mitsuru Abe and Kenji Hamaguchi and Hidetoshi Kubo and Shunsuke Kurosawa and Kentaro Miuchi and K. Saito and Tatsuya Sawano and Toru Tanimori},
  journal={The Astrophysical Journal},
MeV gamma-rays provide a unique window for the direct measurement of line emissions from radioisotopes, but observations have made little significant progress since COMPTEL on board the Compton Gamma-ray Observatory (CGRO). To observe celestial objects in this band, we are developing an electron-tracking Compton camera (ETCC) that realizes both bijective imaging spectroscopy and efficient background reduction gleaned from the recoil-electron track information. The energy spectrum of the… 

MeV Gamma-Ray Source Contribution to the Inner Galactic Diffuse Emission

The origin of the inner Galactic emission, measured by COMPTEL with a flux of ∼10−2 MeV cm−2 s−1 sr−1 in the 1–30 MeV energy range from the inner Galactic region, has remained unsettled since its

Dark matter prospects with COSI: ALPs, PBHs and sub-GeV dark matter

We study the prospects in the search of dark matter offered by the newly selected NASA MeV mission COSI (Compton Spectrometer and Imager). This instrument is designed and optimized to detect spectral

A global analysis of resonance-enhanced light scalar dark matter

We study a minimal model for a light scalar dark matter, requiring a light scalar mediator to address the core-cusp problem and interact with the standard model particles. We analyze the model

Gamma Ray Source Localization for Time Projection Chamber Telescopes Using Convolutional Neural Networks

Diverse phenomena such as positron annihilation in the Milky Way, merging binary neutron stars, and dark matter can be better understood by studying their gamma ray emission. Despite their

Development and Applications of Compton Camera—A Review

The history of Compton cameras began with the detection of radiation sources originally for applications in astronomy. A Compton camera is a promising γ-ray detector that operates in the wide energy

Development of the ComPair gamma-ray telescope prototype

There is a growing interest in the science uniquely enabled by observations in the MeV range, particularly in light of multi-messenger astrophysics. The Compton Pair (ComPair) telescope, a prototype

Compton Telescopes for Gamma-ray Astrophysics

Compton telescopes rely on the dominant interaction mechanism in the MeV gamma-ray energy range: Compton scattering. By precisely recording the position and energy of multiple Compton scatter

Telescope Concepts in Gamma-Ray Astronomy

This chapter outlines the general principles for the detection and characterisation of high-energy $\gamma$-ray photons in the energy range from MeV to GeV. Applications of these fundamental

Time projection chambers for gamma-ray astronomy

The detection of photons with energies greater than a few tenths of an MeV, interacting via Compton scattering and/or pair production, faces a number of difficulties. The reconstruction of

Gamma-Ray Diagnostics of r-process Nucleosynthesis in the Remnants of Galactic Binary Neutron-star Mergers

We perform a full nuclear-network numerical calculation of the r-process nuclei in binary neutron-star mergers (NSMs), with the aim of estimating gamma-ray emissions from the remnants of Galactic

Hard X-ray emission of the Earth's atmosphere: Monte Carlo simulations

We perform Monte Carlo simulations of cosmic ray-induced hard X-ray radiation from the Earth's atmosphere. We find that the shape of the spectrum emergent from the atmosphere in the energy range

The first COMPTEL source catalogue

The imaging Compton telescope COMPTEL aboard NASA's Compton Gamma-Ray Observatory has opened the MeV gamma-ray band as a new window to astronomy. COMPTEL provided the first complete all-sky survey in

INTEGRAL SPI All-Sky View in Soft Gamma Rays: A Study of Point-Source and Galactic Diffuse Emission

We have processed the data accumulated with the INTEGRAL SPI instrument over 4 years (~51 Ms) to study the morphology of the Galactic “diffuse” emission in the 20 keV to 8 MeV energy range. To

Development of convolutional neural networks for an electron-tracking Compton camera

The Electron-Tracking Compton Camera (ETCC), which is a complete Compton camera that tracks Compton scattering electrons with a gas micro time projection chamber, is expected to open up MeV

Imaging the 511 keV Positron Annihilation Sky with COSI

The balloon-borne Compton Spectrometer and Imager (COSI) had a successful 46-day flight in 2016. The instrument is sensitive to photons in the energy range 0.2–5 MeV. Compton telescopes have the

Detection of the 511 keV Galactic Positron Annihilation Line with COSI

The signature of positron annihilation, namely the 511 keV γ-ray line, was first detected coming from the direction of the Galactic center in the 1970s, but the source of Galactic positrons still

INTEGRAL/SPI γ -ray line spectroscopy : Response and background characteristics

© 2018 ESO. Reproduced with permission from Astronomy & Astrophysics. Content in the UH Research Archive is made available for personal research, educational, and non-commercial purposes only. Unless

Measurements of low-energy gamma radiation from the Crab Nebula and from pulsar NP 0532

A balloon-altitude measurement of the energy spectra from the Crab Nebula and pulsar NP0532 was conducted on 1973 May 15. The measurements were conducted in the 0.056--12.110 MeV energy interval with