Diffuse Galactic antimatter from faint thermonuclear supernovae in old stellar populations
Diffuse Galactic antimatter from faint thermonuclear supernovae in old stellar populations
复制标题
DOI：
10.1038/s41550-017-0135
复制
发表时间：
2016-07
期刊：
影响因子：
14.1
通讯作者：
R. Crocker;A. Ruiter;I. Seitenzahl;I. Seitenzahl;F. Panther;S. Sim;H. Baumgardt;A. Moller;D. N
中科院分区：
文献类型：
--
作者：
R. Crocker;A. Ruiter;I. Seitenzahl;I. Seitenzahl;F. Panther;S. Sim;H. Baumgardt;A. Moller;D. N
我们的银河系每秒钟都会发生1043个低能正电子的湮灭。能够提供这种正电子的放射性同位素在恒星、恒星残骸和超新星中合成。然而，几十年来，一直没有确定一个主要的恒星正电子源，这导致了许多正电子来自外来源的建议，如银河系中心的超大质量黑洞或暗物质湮灭。在这里，我们表明，一个单一类型的瞬态源，来自年龄为3-6 Gyr的恒星群体和产生的正电子发射体44 Ti的10.03 M <$A，可以同时解释银河系正电子湮没信号的强度和形态和太阳系的丰度的44 Ti衰变产物44 Ca。这种瞬变可能是两个低质量白色矮星的合并，在外部星系中观察到的亚发光热核超新星被称为SN 1991 bg。
Our Galaxy hosts the annihilation of a few 1043low-energy positrons every second. Radioactive isotopes capable of supplying such positrons are synthesized in stars, stellar remnants and supernovae. For decades, however, there has been no positive identification of a main stellar positron source, leading to suggestions that many positrons originate from exotic sources like the Galaxy’s central supermassive black hole or dark matter annihilation. Here we show that a single type of transient source, deriving from stellar populations of age 3–6 Gyr and yielding ∼0.03M⊙of the positron emitter44Ti, can simultaneously explain the strength and morphology of the Galactic positron annihilation signal and the Solar System abundance of the44Ti decay product44Ca. This transient is likely the merger of two low-mass white dwarfs, observed in external galaxies as the sub-luminous, thermonuclear supernova known as SN 1991bg-like.