gjdonatiello
Andromeda 450 kpc Survey - Deep survey of the halo of M31
Andromeda 450 kpc Survey - Deep survey of the halo of M31
Credit: Giuseppe Donatiello (Oria Amateur Astrophysical Observatory - OAAO)
doi.org/10.5281/zenodo.17622941
Deep survey of the halo of M31
The outskirts of galaxies contain vital clues to their formation history. It is in these regions that new material continues to arrive as part of their ongoing assembly, and it is also in these regions that material was deposited during violent interactions in the galaxy's past. Furthermore, the long dynamical timescales ensure that debris from accreted material takes a long time to be washed away by the merger process. This means that many formation legacies can be detected as coherent structures in space.
Andromeda is the nearest large spiral galaxy and the only other significant one in the Local Group. In many ways, Andromeda is the Milky Way, having very similar total masses, they share a common origin and, probably, the same ultimate fate when they merge. However, there are significant differences between them. M31 is slightly brighter than the Milky Way and has a higher rotation rate and a bulge with a higher velocity dispersion. M31 has a globular cluster system with ~500 members, about 3 times more than the Milky Way.
Andromeda's disk is also much more extended, but is now forming stars at a slower rate than the Galaxy. There are indications that the Milky Way has undergone an exceptionally low amount of mergers and has an unusually low specific angular momentum, while M31 appears to be a much more normal galaxy in these respects.
Andromeda has one compact elliptical galaxy (M32), three dwarf elliptical galaxies (NGC 205, NGC 147, NGC 185) among its entourage of 41 satellites, as well as no dwarf irregular (dIrr) star-forming galaxies within 200 kpc. The Milky Way has no ellipticals but two dIrr (Magellanic Clouds). However, it is perhaps in their supposed halo populations that the differences between the two galaxies are most curious and interesting.
This study of mine, based on ultra-deep imaging, highlights faint structures in the extended halo of M31, NGC 147 3 NGC 185. Some structures appear here for the first time.
Andromeda 450 kpc Survey - Deep survey of the halo of M31
Andromeda 450 kpc Survey - Deep survey of the halo of M31
Credit: Giuseppe Donatiello (Oria Amateur Astrophysical Observatory - OAAO)
doi.org/10.5281/zenodo.17622941
Deep survey of the halo of M31
The outskirts of galaxies contain vital clues to their formation history. It is in these regions that new material continues to arrive as part of their ongoing assembly, and it is also in these regions that material was deposited during violent interactions in the galaxy's past. Furthermore, the long dynamical timescales ensure that debris from accreted material takes a long time to be washed away by the merger process. This means that many formation legacies can be detected as coherent structures in space.
Andromeda is the nearest large spiral galaxy and the only other significant one in the Local Group. In many ways, Andromeda is the Milky Way, having very similar total masses, they share a common origin and, probably, the same ultimate fate when they merge. However, there are significant differences between them. M31 is slightly brighter than the Milky Way and has a higher rotation rate and a bulge with a higher velocity dispersion. M31 has a globular cluster system with ~500 members, about 3 times more than the Milky Way.
Andromeda's disk is also much more extended, but is now forming stars at a slower rate than the Galaxy. There are indications that the Milky Way has undergone an exceptionally low amount of mergers and has an unusually low specific angular momentum, while M31 appears to be a much more normal galaxy in these respects.
Andromeda has one compact elliptical galaxy (M32), three dwarf elliptical galaxies (NGC 205, NGC 147, NGC 185) among its entourage of 41 satellites, as well as no dwarf irregular (dIrr) star-forming galaxies within 200 kpc. The Milky Way has no ellipticals but two dIrr (Magellanic Clouds). However, it is perhaps in their supposed halo populations that the differences between the two galaxies are most curious and interesting.
This study of mine, based on ultra-deep imaging, highlights faint structures in the extended halo of M31, NGC 147 3 NGC 185. Some structures appear here for the first time.