The Massive Compact Halo Object (MACHO) Project Data Archive

The MACHO Project was a collaboration between scientists at the Mt. Stromlo and Siding Spring Observatories, the Center for Particle Astrophysics at the Santa Barbara, San Diego, and Berkeley campuses of the University of California, and the Lawrence Livermore National Laboratory. Our primary aim was to test the hypothesis that a significant fraction of the dark matter in the halo of the Milky Way is made up of objects like brown dwarfs or planets: these objects have come to be known as MACHOs, for MAssive Compact Halo Objects. The signature of these objects is the occasional amplification of the light from extragalactic stars by the gravitational lens effect. The amplification can be large, but events are extremely rare: it was necessary to monitor photometrically several million stars for a period of 10 years in order to obtain a useful detection rate. For this purpose we built a two channel system that employed eight 2048*2048 CCDs, mounted on the 50 inch telescope at Mt. Stromlo. The MACHO project data archive consists of approximately 127,000 two-colour images of fields collected between 1992 and 2003 covering the large and small Magellanic clouds and the galactic bulge and two-colour light-curves for approximately 18 million stars in the LMC and galactic bulge.

MACHO项目是由斯特罗姆洛山天文台（Mt. Stromlo Observatory）与赛丁泉天文台（Siding Spring Observatory）、加州大学圣巴巴拉分校、圣地亚哥分校及伯克利分校的粒子天体物理中心，以及劳伦斯利弗莫尔国家实验室（Lawrence Livermore National Laboratory）的科学家联合发起的合作项目。本项目的核心目标是验证一项假说：银河系银晕中相当比例的暗物质由褐矮星、行星这类天体构成；这类天体如今被称为MACHO（MAssive Compact Halo Objects，大质量致密晕天体）。这类天体的观测特征是通过引力透镜效应，偶尔放大河外恒星的光线。该放大效应可能十分显著，但相关事件极为罕见：为获得有效的探测率，团队需要对数百万颗恒星进行长达10年的测光监测。为此，团队搭建了一套双通道观测系统，在斯特罗姆洛山的50英寸望远镜上搭载了8块2048×2048像素的电荷耦合器件（Charge-Coupled Device，CCD）。MACHO项目的数据档案包含1992年至2003年间采集的、覆盖大麦哲伦云（Large Magellanic Cloud, LMC）、小麦哲伦云和银河核球的约12.7万张天区双色图像，以及大麦哲伦云与银河核球中约1800万颗恒星的双色光变曲线。

搜集汇总

背景与挑战

背景概述

该数据集是MACHO项目的数据档案，旨在通过引力透镜效应探测银河系晕中的暗物质候选体（MASSive Compact Halo Objects）。它包含1992年至2003年间收集的约127,000张双色图像和约1,800万颗恒星的光变曲线，覆盖大、小麦哲伦云和银河系核球区域，数据可公开访问。