The X-ray source GRS 1915+105, one of the several galactic objects producing observable superluminal jets (Mirabel & Rodriguez 1994), was discovered by GRANAT observatory as a transient in 1992 (Castro-Tirado, Brandt & Lund 1992). Long-term monitoring of GRS 1915+105 with RXTE revealed repetitive character of the source variability patterns. Basing on the results of spectral and timing analysis, bursting behavior of the source can be roughly reduced to the sequence of varying `hard' and `soft' states qualitatively distinguished by their spectral and temporal properties (Belloni et al. 1997a, b ; Markwardt et al. 1999; Muno et al. 1999).
© European Southern Observatory (ESO) 1999
Online publication: November 3, 1999