正电子和511keV辐射作为近期双中子星合并的示踪剂。
Positrons and 511 keV Radiation as Tracers of Recent Binary Neutron Star Mergers.
作者信息
Fuller George M, Kusenko Alexander, Radice David, Takhistov Volodymyr
机构信息
Department of Physics, University of California, San Diego La Jolla, California 92093-0354, USA.
Department of Physics and Astronomy, University of California, Los Angeles Los Angeles, California 90095-1547, USA.
出版信息
Phys Rev Lett. 2019 Mar 29;122(12):121101. doi: 10.1103/PhysRevLett.122.121101.
Neutron-rich material ejected from neutron star-neutron star (NS-NS) and neutron star-black-hole (NS-BH) binary mergers is heated by nuclear processes to temperatures of a few hundred keV, resulting in a population of electron-positron pairs. Some of the positrons escape from the outer layers of the ejecta. We show that the population of low-energy positrons produced by NS-NS and NS-BH mergers in the Milky Way can account for the observed 511-keV line from the Galactic center (GC). Moreover, we suggest how positrons and the associated 511-keV emission can be used as tracers of recent mergers. Recent discovery of 511-keV emission from the ultrafaint dwarf galaxy Reticulum II, consistent with a rare NS-NS merger event, provides a smoking-gun signature of our proposal.
从中子星-中子星（NS-NS）和中子星-黑洞（NS-BH）双星合并中喷射出的富含中子的物质通过核过程被加热到几百千电子伏特的温度，从而产生了大量电子-正电子对。一些正电子从喷射物的外层逃逸。我们表明，银河系中NS-NS和NS-BH合并产生的低能正电子群体可以解释从银河系中心（GC）观测到的511千电子伏特谱线。此外，我们还提出了正电子和相关的511千电子伏特辐射如何可以用作近期合并的示踪剂。最近在超微弱矮星系网罟座II中发现的511千电子伏特辐射，与罕见NS-NS合并事件一致，为我们的提议提供了确凿的证据。
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