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arXiv 1504.02087astro-ph.HEastro-ph.COastro-ph.GAhep-ph
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检查费米-LAT第三源星表寻找暗物质暗晕

Examining The Fermi-LAT Third Source Catalog In Search Of Dark Matter Subhalos

Bridget Bertoni, Dan Hooper, Tim Linden

摘要:

发生在附近的暗晕中的暗物质湮灭可能表现为伽马射线源,而在其他波长处没有可检测到的对应物。在这项研究中,我们认为收集的非关联伽马射线源的费米合作报告,努力确定最有前途的暗物质subhalo的候选人。虽然我们确定了24个明亮的、高纬度的、不可变的源,其光谱与~20-70 GeV暗物质粒子的湮灭(假设湮灭为$b\bar{b}$)一致,但目前还不可能将这些源与无线电微弱的伽马射线源区分开来。更深入的多波长观测对于澄清这些来源的性质至关重要。值得注意的是,我们没有发现任何这样的来源,是很好地适合暗物质粒子重约100 GeV。我们还研究了来自这组次晕候选者的伽马射线的角分布,发现源3FGL J2212.5+0703比点源更倾向于空间扩展的轮廓(宽度约为0.15 $^{\circ}$),显著性为4.2 $σ$(3.6 $σ$,经过试验因子)。虽然尚未确定,但这个明亮的高纬度伽马射线源非常适合作为附近的$m_χ \simeq$ 20-50 GeV暗物质粒子的次晕(湮灭为$b\bar{b}$),值得进一步多波长研究。基于数值模拟预测的次晕分布,我们推导出暗物质湮灭截面的约束条件,这些约束条件与矮球状星系、银河系中心和河外伽马射线背景的伽马射线观测结果具有竞争力。

英文摘要:

Dark matter annihilations taking place in nearby subhalos could appear as gamma-ray sources without detectable counterparts at other wavelengths. In this study, we consider the collection of unassociated gamma-ray sources reported by the Fermi Collaboration in an effort to identify the most promising dark matter subhalo candidates. While we identify 24 bright, high-latitude, non-variable sources with spectra that are consistent with being generated by the annihilations of ~20-70 GeV dark matter particles (assuming annihilations to $b\bar{b}$), it is not possible at this time to distinguish these sources from radio-faint gamma-ray pulsars. Deeper multi-wavelength observations will be essential to clarify the nature of these sources. It is notable that we do not find any such sources that are well fit by dark matter particles heavier than ~100 GeV. We also study the angular distribution of the gamma-rays from this set of subhalo candidates, and find that the source 3FGL J2212.5+0703 prefers a spatially extended profile (of width ~0.15$^{\circ}$) over that of a point source, with a significance of 4.2$σ$ (3.6$σ$ after trials factor). Although not yet definitive, this bright and high-latitude gamma-ray source is well fit as a nearby subhalo of $m_χ \simeq$ 20-50 GeV dark matter particles (annihilating to $b\bar{b}$) and merits further multi-wavelength investigation. Based on the subhalo distribution predicted by numerical simulations, we derive constraints on the dark matter annihilation cross section that are competitive to those resulting from gamma-ray observations of dwarf spheroidal galaxies, the Galactic Center, and the extragalactic gamma-ray background.

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