GAMMA-RAY EMISSION FROM THE SNR HB3

Image: At a distance of about 20,000 light years, G292.0+1.8 is one of only three supernova remnants in the Milky Way known to contain large amounts of oxygen. These oxygen-rich supernovas are of great interest to astronomers because they are one of the primary sources of the heavy elements (that is, everything other than hydrogen and helium) necessary to form planets and people. The X-ray image from Chandra shows a rapidly expanding, intricately structured, debris field that contains, along with oxygen (yellow and orange), other elements such as magnesium (green) and silicon and sulfur (blue) that were forged in the star before it exploded. Credit: NASA/CXC/SAO

The processes of particles acceleration to very high energies from the supernova shock region and diffusion in the interstellar medium of such particles has not been well understood so far. Gamma-ray observations in the GeV regime are a powerful probe of these mechanisms

In a recent paper (Katagiri et al. 2016, ApJ) the authors report the discovery of extended gamma-ray emission spatially correlated with the region of the supernova remnant (SNR) HB 3 (G132.7+1.3) and the W3 H II complex adjacent to the southeast of the remnant. W3 is a region rich of CO clouds.

Supernova remnant HB 3 (www.cfa.harvard.edu)

The authors find that the decay of neutral pions produced in nucleon-nucleon interactions between accelerated hadrons and interstellar gas provides a reasonable explanation for the gamma-ray emission from HB3. The cosmic rays accelerated in HB 3 irradiate the CO clouds and generate the emission from W3 region.

▪ Katagiri et al. 2016, ApJ - Fermi LAT Discovery of Extended Gamma-Ray Emissions in the Vicinity of the HB3 Supernova Remnant (arXiv)

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ABOUT THE FORMATION OF THE COLD CLASSICAL KUIPER BELT

Image: The Kuiper Belt. Credit: NASA . The Kuiper belt is a circumstellar disc in the Solar System beyond the planets, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt (the circumstellar disc located roughly between the orbits of the planets Mars and Jupiter), but it is far larger-20 times as wide and 20 to 200 times as massive.

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Hubble Spots Expanding Light Echo around Supernova

Light Echo around SN 2014J in M82 . Credits NASA , ESA , and Y. Yang (Texas A&M University and Weizmann Institute of Science, Israel). Acknowledgment: M. Mountain (AURA) and The Hubble Heritage Team ( STScI /AURA) Light from a supernova explosion in the nearby starburst galaxy M82 is reverberating off a huge dust cloud in interstellar space. The supernova, called SN 2014J, occurred at the upper right of M82, and is marked by an “X.” The supernova was discovered on Jan. 21, 2014. The inset images at top reveal an expanding shell of light from the stellar explosion sweeping through interstellar space, called a “light echo.” The images were taken 10 months to nearly two years after the violent event (Nov. 6, 2014 to Oct. 12, 2016). The light is bouncing off a giant dust cloud that extends 300 to 1,600 light-years from the supernova and is being reflected toward Earth. SN 2014J is classified as a Type Ia supernova and is the closest such blast in at least four ...

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