Detection of a 60°-long Dwarf Galaxy Debris Stream

We report on a 60 degree-long stream of stars, extending from Ursa Major toSextans, in the Sloan Digital Sky Survey. The stream is approximately 2 degreeswide and is clearly distinct from the northern tidal arm of the Sagittariusdwarf galaxy. The apparent width of the stream suggests a progenitor with asize and mass similar to that of a dwarf galaxy. The stream is about 21 kpcdistant and appears to be oriented almost perpendicular to our line of sight.The visible portion of the stream does not pass near any known dwarf galaxies,though we cannot rule out that the stream may form the inner part of a knowndwarf galaxy's orbit. The most likely explanation is that the streamconstitutes the remains a dwarf galaxy that has been completely disrupted atsome point in the past. We also briefly report on the discovery of a diminutiveGalactic satellite which lies near the projected path of the new stream, but isunlikely to be related to it.Comment: Modified to conform to published versio