标题： 用DESI的宇宙大尺度结构交叉关联未分辨伽马射线背景：对天体物理学和暗物质的意义 显示英文标题

标题： Cross Correlating the Unresolved Gamma-Ray Background with Cosmic Large-Scale Structure from DESI: Implications for Astrophysics and Dark Matter

摘要： 未解决的伽马射线背景（UGRB）是一种来自大量低于探测阈值的河外源的弥散伽马射线辐射，是伽马射线天空的重要组成部分。 研究UGRB对于理解宇宙中的高能天体物理过程以及探索基础物理至关重要，例如暗物质的本质。 在这项工作中，我们预测了UGRB与暗能量光谱仪（DESI）巡天的星系目录之间的交叉关联。 首先，我们研究了UGRB预期的天体物理贡献及其与DESI光谱星系的交叉关联。 我们的计算表明，交叉关联的信噪比预计会显著，由于红移分布与UGRB的重叠度较高，预计DESI亮红星系的最高值将达到20.6。 我们考虑了两个可以应用UGRB-光谱星系交叉关联的科学案例：1）测量红移依赖的UGRB流量，在某些红移区间内达到10%的精度；2）搜索湮灭暗物质，其质量可能高达约300 GeV，比目前最强限制高出三倍。 这项工作强调了将UGRB与宇宙大尺度结构示踪物进行交叉关联的重要性，并突出了多波段方法在推进我们对高能天体现象和基础物理的理解方面的潜力。 显示英文摘要

摘要： The unresolved gamma-ray background (UGRB) is a diffuse gamma-ray emission arising from numerous extragalactic sources below the detection threshold and is an important component of the gamma-ray sky. Studying the UGRB is crucial for understanding high-energy astrophysical processes in the universe and for probing fundamental physics, such as the nature of dark matter. In this work, we forecast the cross-correlation between the UGRB and galaxy catalogs from the Dark Energy Spectroscopic Instrument (DESI) survey. First, we study the expected astrophysical contributions to the UGRB and their cross-correlation with DESI spectroscopic galaxies. Our calculations show that the cross-correlation signal-to-noise ratio is expected to be significant, with the highest value predicted to be 20.6 for DESI luminous red galaxies due to a higher predicted overlap in the redshift distribution with the UGRB. We consider two science cases that the UGRB-spectroscopic galaxies cross-correlation can be applied to: 1) measuring the UGRB flux as a function of redshift, achieving a precision of 10\% in some redshift bins, and 2) searching for annihilating dark matter potentially up to a mass of about 300~GeV, three times higher than the currently strongest constraints. This work underscores the importance of cross correlating the UGRB with cosmic large-scale structure tracers and highlights the multiwavelength approaches to advancing our understanding of high-energy astrophysical phenomena and fundamental physics.