作为宇宙信使的X射线

60年前，里卡多·贾科尼团队用探空火箭首次探测到了来自太阳系以外的X射线辐射，从此打开了人类探索宇宙的一个全新的窗口。与我们所熟悉的可见光天空不同，在“看不见”的X射线宇宙，明亮的发光天体涵盖了黑洞、中子星、白矮星等致密天体，星系团和星系中弥漫的大量不可见的高温气体，以及各种剧烈的灾变事件。它们代表着宇宙中最为奇特的天体和极端的物理条件，如极强引力场、极强磁场和极高温。文章重点介绍最有代表性的X射线源，包括中子星和黑洞X射线双星、超大质量黑洞和活动星系核、星系团，以及伽马暴、超新星和潮汐瓦解恒星事件等爆发天体。

X-rays as a cosmic messenger

Sixty years ago, a team led by Riccardo Giacconi discovered the first cosmic Xray source outside our solar system, opening a new window to explore the universe. Unlike the visual sky that our eyes are accustomed to, the“invisible”X-ray universe is alien and glows with compact objects such as black holes, neutron stars, white dwarfs, and hot diffuse gases within clusters of galaxies and galaxies, as well as assorted violent catastrophic events. They manifest the most exotic objects in the universe, as well as extreme physical environments such as the strongest gravity and magnetic fields, and the hottest regions. This article focuses on representative X-ray sources, mainly neutron star and black hole X-ray binaries, supermassive black holes and active galactic nuclei, clusters of galaxies, as well as eruptive events such as gamma-ray bursts, supernovae, and tidal disruption events.