Black Holes in Astrophysics
- Review article by Ramesh Narayan (Harvard-Smithsonian Center for Astrophysics) about the astrophysical evidence for black holes.
- http://arxiv.org/abs/gr-qc/0506078

Field Guide to X-ray Sources
- Pages on the website of the Chandra X-Ray Observatory; includes information about stellar, mid-mass and supermassive black holes, Chandra images, and a podcast.
- http://chandra.harvard.edu/xray_sources/blackholes.html

Black Holes
- Black hole page from NASA's "Imagine the universe!" site; includes a section on observational aspects - "If We Can't See Them, How Do We Know They're There?"
- http://imagine.gsfc.nasa.gov/docs/science/know_l2/black_holes.html

Closest Star Seen Orbiting the Supermassive Black Hole at the Centre of the Milky Way
- Article by R. Schodel and colleagues (Max Planck Institute for Extraterrestrial Physics) about the best evidence to date for the existence of a supermassive black hole in the center of our own galaxy - the way it influences the orbits of nearby stars.
- http://arxiv.org/abs/astro-ph/0210426

The Afterglow of Massive Black Hole Coalescence
- Article by Milos Milosavljevic and Stearl Phinney; describes the kind of afterglow that should be visible for X-ray telescopes when two massive black holes merge.
- http://arxiv.org/abs/astro-ph/0410343

Detection of Hard X-ray Emission from the Galactic Nuclear Region with INTEGRAL
- Article by Guillaume Belanger and colleagues; recounts X-ray observations of the neighborhood of our galaxy's central black hole.
- http://arxiv.org/abs/astro-ph/0311147

Radio Astronomers Lift 'Fog' on Milky Way's Dark Heart
- Press release by the National Radio Astronomy Observatory about observations of the immediate neighborhood of our galaxy's central supermassive black hole.
- http://www.nrao.edu/pr/2004/sagastar/

Evidence for the Black Hole Event Horizon
- Review article by Ramesh Narayan about possible observational evidence for the defining feature of black holes.
- http://arxiv.org/abs/astro-ph/0310692

Study of Accretion Processes on Black Holes: Fifty Years of Developments
- Review article by Sandip K. Chakrabarti of the research done on one of the main mechanisms by which black holes cause highly luminous phenomena in their immediate neighborhood.
- http://arxiv.org/abs/astro-ph/0402562

Hubble Space Telescope Discovers Disk Fueling Possible Black Hole
- News item published on the website of the Space Telescope Science Institute.
- http://hubblesite.org/newscenter/archive/releases/1992/27/text/

XMM: Black Holes and Quasars
- Educational pages on the website of the space-borne X-ray telescope XMM, hosted by the University of Birmingham. Information about black holes and other astronomical sources of X-rays.
- http://www.sr.bham.ac.uk/xmm/blackholes.html

Astrophysical Evidence for the Existence of Black Holes
- Review article by Annalisa Celotti, John C. Miller, and Dennis W. Sciama (SISSA, Trieste) about the current state of the search for observational evidence for the existence of both stellar-mass and supermassive black holes.
- http://arxiv.org/abs/astro-ph/9912186

Do Black Holes Exist?
- Brief text by Pablo G. Ostrov about the evidence for the existence of black holes, aimed at a general audience.
- http://pgostrov.googlepages.com/e3.html