We present a catalog of point gamma-ray sources detected by the EGRET detector aboard the Compton Gamma Ray Observatory. We have used the whole gamma-ray dataset of reprocessed photons at energies above 100 MeV together with new Galactic interstellar emission models based on recent CO, HI, dark gas, and interstellar radiation field data. Two different assumptions have been used for the cosmic-ray distribution in the Galaxy to explore the resulting systematic uncertainties in source detection and characterization. We have used the same 2-dimensional maximum-likelihood detection method as for the 3rd EGRET catalogue. The revised catalogue lists 188 sources, 14 of which are marked as confused, compared to the 271 entries of the 3rd EGRET (3EG) catalogue. 107 former sources have not been confirmed because of the additional structure in the interstellar background. The vast majority of them were unidentified and marked as possibly extended or confused in the 3EG catalogue. In particular, we do not confirm most of the 3EG sources associated with the local clouds of the Gould Belt. Alternatively, we find 30 new sources with no 3EG counterpart. The new error circles for the confirmed 3EG sources largely overlap the previous ones, but several counterparts of particular interest that had been discussed in the litterature, such as Sgr A*, radiogalaxies and several microquasars are now found outside the error circles. We have cross-correlated the source positions with a large number of radio pulsars, pulsar wind nebulae, supernova remnants, OB associations, blazars and flat radiosources and we find a surprising large number of sources (87) at all latitudes with no counterpart among the potential gamma-ray emitters.
2MASS NIR photometry for 693 candidate globular clusters in M31 and the Revised Bologna Catalogue
我们已经在2 MASS数据库中识别出693个已知的和候选的M31球状星团。这些天体的2 MASS J、H、K星等被转换到与现有的M31球状星团近红外测光相同的均匀测光系统中，最终得到了279个已确认的M31星团、406个未确认的候选星团和8个分类有争议的天体的J、H、K积分测光。在这些天体中，有529个缺乏先前对其近红外星等的估计。新组装的近红外数据集已被实施到博洛尼亚M31球状天体目录的修订版本中，并在可能的情况下从文献中可用的最新CCD测光来源获取更新的光学（UBVRI）测光，并转换为常见的测光系统。最终修订的博洛尼亚星表（电子版）是目前已确认和候选的M31球状星团的最全面的列表，共有1164个条目。特别是，它包括337个已确认的GC，688个GC候选者，10个有争议的分类对象，70个已确认的星系，55个已确认的恒星，和4个位于~3度的HII区域。从M31星系的中心使用新组装的数据库，我们表明，V-K颜色提供了一个强大的工具来区分M31星系团和背景星系，我们确定了一个样本的83个球状星团的候选人，这是不太可能被错误分类的星系污染。
Exploring the Gamma Ray Horizon with the next generation of Gamma Ray Telescopes. Part 2: Extracting cosmological parameters from the observation of gamma-ray sources
即将发射的$γ$射线卫星将在银河系的子结构（或"团块"）中寻找暗物质湮灭。探测这些天体的前景在很大程度上取决于对暗物质在子结构中的分布以及银河系晕中子结构分布的假设。通过采用简化的，但相当极端的，这些量的处方，我们计算的源，可以检测到与即将到来的实验，如玻璃的数量，并表明，对于最乐观的粒子物理设置（$m_χ=40$ GeV和湮灭截面$σv = 3 \times 10^{-26}$ cm $^3$ s $^{-1}$），结果范围从零到$\sim$百源，所有的质量以上$10^{5}M\odot$。然而，对于具有质量$m_χ=100$ GeV和$σv = 10^{-26}$ cm $^3$ s $^{-1}$的基准DM候选物，通过类玻璃实验，在$5 σ$下，用1年的暴露时间，最多可以检测到少数大质量的亚结构。可以检测到微团块（即质量小至$10^{-6}M\odot$的团块）的情况受到EGRET检测到的弥漫$γ$射线背景的严重限制。
