This is very likely, and just last year a new very large galaxy in our Local Group was discovered. The Milky Way is a very thick band of light on the sky measuring 20 degrees wide. This translates into a significant amount of volume in the Local Group, and in the last 20 years no fewer than 3 galaxies have been found hidden among the murk and stars of our galaxy. These are mostly dwarf galaxies, or low surface brightness spirals.
Deemed the "Sagittarius Dwarf", this small galaxy went unnoticed until its discovery in 1994 by R. Ibata, G. Gilmore and M. Irwin (RGO). The reason the Sagittarius Dwarf hadn't been discovered earlier is because it is so dim, it is so spread out over the sky, and there are so many Milky Way stars in front of it. The distance to the Sagittarius Dwarf was recently measured to be about one third of the distance to the LMC. Astronomers now believe that this galaxy is slowly being torn apart by the vast gravitational forces of our Galaxy. Here is the abstract of their discovery paper. The above photo is by A. Oksanen, who used the 2.6 meter Nordic Optical Telescope
We have discovered a new Galactic satellite galaxy in the constellation of Sagittarius. The Sagittarius dwarf galaxy subtends an angle of ~10 deg on the sky, lies at a distance of 24 kpc and is comparable in size and luminosity to the largest dwarf spheroidal, Fornax. The new galaxy has many features in common with the other eight Galactic dwarf spheroidal systems, including an extended low-density spatial structure, a well-populated red horizontal branch with a blue extension, and a substantial carbon star population. In terms of stellar populations it most closely resembles the Fornax dwarf, having a strong intermediate-age stellar component and evidence of a metallicity spread. Sagittarius is the nearest galaxy known and currently lies only ~16 kpc from the centre of the Milky Way. Isodensity maps show it to be markedly elongated along a direction pointing towards the Galactic Centre, and suggest that it has been tidally distorted. The close proximity to the Galactic Centre, the morphological appearance and the radial velocity of 140 km s^-1 indicate that this system must have undergone at most very few close orbital encounters with the Milky Way. It is currently undergoing strong tidal disruption prior to being integrated into the Galaxy. We find that at least some of the four globular clusters, M54, Arp 2, Ter 7 and Ter 8, are associated with the Sagittarius dwarf galaxy, and will probably share the fate of their progenitor. The Sagittarius dwarf galaxy was found serendipitously using a combination of UK Schmidt Telescope sky survey plates, the APM automatic plate measuring facility and the Anglo-Australian Telescope multifibre spectrograph, AUTOFIB.
Copyright 1997 Dr. Sten Odenwald
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