Hierarchical structure formation leads to a clumpy distribution of dark matter in the Milky Way. These clumps are possible targets to search for dark matter annihilation with present and future $γ$-ray instruments. Many uncertainties exist on the clump distribution, leading to disputed conclusions about the expected number of detectable clumps and the ensuing limits that can be obtained from non-detection. In this paper, we use the CLUMPY code to simulate thousands of skymaps for several clump distributions. This allows us to statistically assess the typical properties (mass, distance, angular size, luminosity) of the detectable clumps. Varying parameters of the clump distributions allows us to identify the key quantities to which the number of detectable clumps is the most sensitive. Focusing our analysis on two extreme clump configurations, yet consistent with results from numerical simulations, we revisit and compare various calculations made for the Fermi-LAT instrument, in terms of number of dark clumps expected and the angular power spectrum for the Galactic signal. We then focus on the prospects of detecting dark clumps with the future CTA instrument, for which we make a detailed sensitivity analysis using open-source CTA software. Based on a realistic scenario for the foreseen CTA extragalactic survey, and accounting for a post-trial sensitivity in the survey, we show that we obtain competitive and complementary limits to those based on long observation of a single bright dwarf spheroidal galaxy.
Searches for dark matter subhaloes with wide-field Cherenkov telescope surveys
在暗物质晕中存在子结构是冷暗物质范例的不可避免的结果。这些天体的间接信号已经用宇宙射线和伽马射线进行了广泛的研究。乍看起来，切伦科夫望远镜似乎不太适合这样的搜索，因为它们的视场很小，天空中可能的暗物质子结构位置也很随机。然而，只要有足够长的曝光时间和足够的观测策略，这种实验技术非常好的灵敏度使我们能够约束粒子暗物质模型。我们在这里面对HESS实验的灵敏度图，该实验是从他们的银河扫描调查到最先进的宇宙学N体模拟Via Lactea II建立的。我们在10^-24 - 10 ^-23 cm ^3 s ^-1水平上得到了湮灭截面的竞争约束。结果外推到未来的切伦科夫望远镜阵列，在银河平面调查和更广泛的河外调查的情况下。在后一种情况下，它表明，切伦科夫望远镜阵列的灵敏度将足以达到最自然的粒子暗物质模型。
Impact of Observational and Modelling Assumptions on Intergalactic Magnetic Field Constraints from TeV Gamma-Ray Bursts with the Cherenkov Telescope Array Observatory
Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM（巴黎萨克雷大学，巴黎西岱大学，法国原子能委员会，法国国家科学研究中心，天体物理学与宇宙微波背景研究组）
Broadband Modelling of GRB 230812B Afterglow: Implications for VHE $γ$-ray Detection with IACTs
Indian Institute of Technology Indore（印度印多尔理工学院）；Gran Sasso Science Institute（格兰萨索科学研究所）；INFN - Laboratori Nazionali del Gran Sasso（意大利国家核物理研究所-格兰萨索国家实验室）；INFN - Sezione di Padova（意大利国家核物理研究所帕多瓦分部）；INAF - Osservatorio Astronomica di Brera（意大利国家天体物理研究所布雷拉天文台）；INFN, Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）
GRB 230812B后glow的宽带建模揭示了VHE γ射线探测的重要性，展示了通过ICATs在不同波段识别光谱成分的潜力。
Discovery prospects of dwarf spheroidal galaxies for indirect dark matter searches
我们研究了大型巡天望远镜（LSST）在银河系中发现新矮球状星系的前景。采用Milky-Way晕子结构模型和连接暗晕和卫星星系的唯象公式，我们得到了$V$波段的表面亮度分布，预测LSST将发现几十到几百个高于其灵敏度的矮球状星系。即将被发现的矮星将是间接寻找暗物质湮灭产率的有趣目标。我们预测了这些天体中暗物质湮灭产生的γ射线辐射的分布函数，并讨论了这些信号在费米大天区望远镜（LAT）和切伦科夫望远镜阵列（CTA）上的可探测性。通过结合预测的矮星系的信息，我们得到了预期的灵敏度$10^{-26}$ cm $^3$ s $^{-1}$（对于质量为10 GeV的暗物质粒子与费米LAT）和$5\times 10^{-24}$ cm $^3$ s $^{-1}$（对于质量为500 GeV的暗物质粒子与CTA）的湮灭截面$\langle σv \rangle$。我们发现，目前的不确定性的银河晕的质量测量是相对较小的泊松误差相比，绘制最有前途的矮星从底层的通量分布。
