gjdonatiello
Milky Way and Sagittarius DEG (SagDEG) density map
Milky Way and Sagittarius DEG (SagDEG)
Credit: ESA/Gaia DR3, Giuseppe Donatiello
The Sagittarius Dwarf Elliptical Galaxy (Sag DEG or Sgr dSph) is a loop-shaped satellite galaxy of our Milky Way that lies about 70,000 light-years in Sagittarius.
Sag DEG is currently in process of being disrupted by tidal gravitational forces in this encounter. It has orbited the Milky Way, with a period of about 600 million years, at a distance of about 50,000 light-years from the galactic core, strucking our galaxy some 1.9 billion years ago and producing streams of stars out in loops, the Sagittarius Stream.
It contains four globular clusters, with the brightest of them – NGC 6715 (M54) – being known well before the discovery of the galaxy itself in 1994. At a distance from Earth of about 26.8 kpc (50,000 light-years), M54 most likely is the ancient nucleus of Sagittarius Dwarf Elliptical Galaxy.
Obtaining an image of this extremely diffuse galaxy, which is also immersed in the very rich star field of the Galactic Center, was prohibitive in the past, but now, using data from the GAIA satellite, the position and shape of Sag DEG can be revealed, creating density maps like in this image.
This one obtained by me is one of the few available of this nearby satellite that should not be confused with the almost homonymous Sag DIG at about 3.5 million light years.
Milky Way and Sagittarius DEG (SagDEG) density map
Milky Way and Sagittarius DEG (SagDEG)
Credit: ESA/Gaia DR3, Giuseppe Donatiello
The Sagittarius Dwarf Elliptical Galaxy (Sag DEG or Sgr dSph) is a loop-shaped satellite galaxy of our Milky Way that lies about 70,000 light-years in Sagittarius.
Sag DEG is currently in process of being disrupted by tidal gravitational forces in this encounter. It has orbited the Milky Way, with a period of about 600 million years, at a distance of about 50,000 light-years from the galactic core, strucking our galaxy some 1.9 billion years ago and producing streams of stars out in loops, the Sagittarius Stream.
It contains four globular clusters, with the brightest of them – NGC 6715 (M54) – being known well before the discovery of the galaxy itself in 1994. At a distance from Earth of about 26.8 kpc (50,000 light-years), M54 most likely is the ancient nucleus of Sagittarius Dwarf Elliptical Galaxy.
Obtaining an image of this extremely diffuse galaxy, which is also immersed in the very rich star field of the Galactic Center, was prohibitive in the past, but now, using data from the GAIA satellite, the position and shape of Sag DEG can be revealed, creating density maps like in this image.
This one obtained by me is one of the few available of this nearby satellite that should not be confused with the almost homonymous Sag DIG at about 3.5 million light years.