A rotating disk of gas, dust, and other matter that spirals into a central massive object like a black hole. The material heats up due to friction and gravitational forces, emitting radiation across various wavelengths.
Source: nasa.gov

18/04/2011

05/09/2010

26/04/2010

17/11/2009

08/06/2009

19/04/2009

11/08/2008

27/06/2008

30/04/2007

26/07/2006

22/07/2006

01/07/2006

28/05/2006

21/05/2006

24/02/2006

05/05/2005

12/03/2005

26/12/2004

28/11/2003

10/11/2003

01/06/2003

08/10/2002

27/09/2002

29/10/2001

08/05/2001

19/01/2001

19/12/1999

31/08/1999

22/08/1997

13/04/1997