X-ray absorber models for the doubly lensed flat-spectrum radio source PKS 1830-211

X-ray Absorption and AGN Structure

X-ray Absorption by Cold Gas in Cluster Cooling Flows

X-ray Absorption by the Intergalactic Medium

X-Ray Absorption in Active Galactic Nuclei

X-ray absorption in Circinus X-1 in the low state

X-ray absorption in radio-quiet QSOS

X-Ray Absorption in the BL Lacertae Object PKS 0548-322

X-ray Absorption in the Interstellar Medium

X-ray Absorption Lines in the Galactic Black Hole Candidate XTE J1650-500

X-ray Absorption Study of the Missing Baryons

X-ray activities in a Young Open Cluster: Chandra Observations of NGC2516

X-ray Activity and Close-in Giant Planets

X-Ray Activity and Rotation on Bright Late-Type Giants and Supergiants

X-Ray Activity in Cygnus and Aquila

X-ray activity in GX 339-4

X-Ray Activity in Near-Contact Binary Stars

X-ray activity in pre-main sequence stars

X-Ray Activity in the Open Cluster IC 4665

X-ray activity of IGR J17379-3747 confirmed with INTEGRAL