X-ray Emission of SDSS Quasars from ROSAT PSPC Pointed Observations: The Catalog and Initial Analysis

X-ray emitters in the bulge of M31

X-ray evidence of an AGN in M82

X-Ray Fingerprinting Techniques for Recognizing A Hydrological Role in the Formation of Minerals on the Surface of Mars

X-ray flare and short-wave fade duration model. Outage time is directly related to solar peak of X-ray event by use of event rise characteristics

X-ray Flashes from Off-axis Gamma-Ray Bursts

X-ray fluorescence observations of the moon by SMART-1/D-CIXS and the first detection of Ti Kα from the lunar surface

X-ray Fluorescence Spectrometry with the SELENE Orbiter

X-ray Galaxy Clusters & Cosmology

X-ray galaxy clusters in the large-scale structure

X-Ray Heated Disks in Compact Binary Systems

X-Ray Ionization Effects on the Stellar Wind of Cygnus X-1

X-ray light curves of active galactic nuclei are phase incoherent

X-ray Line Emission from Accretion Disk Atmospheres

X-ray line emission from the TYCHO supernova remnant

X-ray lines and absorption edges in GRBS and their afterglows

X-ray Lines in Gamma-ray Bursts and Cerenkov Line Emissions

X-Ray Luminosity--Mass Relation and AGN Feedback in Galaxy Groups

X-ray Luminous Groups in the Process of Formation

X-ray Mass Proxies From Hydrodynamic Simulations Of Galaxy Clusters