Metallicity distribution of the progenitor of the Giant Stellar Stream in the Andromeda Galaxy

Abstract

The Giant Stellar Stream (GSS) is a prominent tidal feature in the halo of the Andromeda Galaxy (M31), representing the ongoing destruction of a satellite galaxy. In this paper, we investigate the formation of the GSS through detailed numerical simulations of the tidal disruption of a progenitor system. Assuming that the stream was created in a single merger event between M31 and a dwarf spheroidal galaxy with stellar mass of $10^9{M}_{\odot }$, we successfully reproduce the dynamical properties of the GSS. As the metallicity distribution along the stream has been well determined from the observations (PAndAS and AMIGA data sets), we use Monte Carlo simulations to reconstruct the original metallicity distribution of the dwarf progenitor. We find that a progenitor dwarf galaxy with a negative radial metallicity gradient, $\Delta$FeH = -$0.3\pm 0.2$, reproduces the observed GSS properties at a time between 2.4 and 2.9 Gyrs into the merger. We also show that the observed double peak metallicity distribution along the stream is a transitory structure caused by unique merger circumstances where two groups of streaming stars are moving in opposite directions, intersecting to produce the peaks.

13 pages, 14 figures, MNRAS, accepted

References in corpus (12)

• The Haunted Halos of Andromeda and Triangulum: A panorama of galaxy formation in action
• The Metal-Poor Halo of the Andromeda Spiral Galaxy (M31)
• The Cosmic Evolution of Metallicity from the SDSS Fossil Record
• Investigating the Andromeda Stream: III. A Young Shell System in M31
• The mass-metallicity gradient relation of early-type galaxies
• Global Properties of M31's Stellar Halo from the SPLASH Survey: II. Metallicity Profile
• Was the Andromeda Stream Produced by a Disk Galaxy?
• The Once and Future Andromeda Stream
• Global Properties of M31's Stellar Halo from the SPLASH Survey: III. Measuring the Stellar Velocity Dispersion Profile
• Elemental Abundances in M31: Gradients in the Giant Stellar Stream
• Elemental Abundances in M31: Properties of the Inner Stellar Halo
• Metallicity Distribution Functions of Four Local Group dwarf galaxies

Cited by in corpus (7)

• DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of our Nearest Neighbor
• Implications of the Milky Way travel velocity for dynamical mass estimates of the Local Group
• The survey of planetary nebulae in Andromeda (M31). IV. Radial oxygen and argon abundance gradients of the thin and thicker disc
• The survey of planetary nebulae in Andromeda (M31) VI. Kinematics of M31 inner-halo substructures and comparison with major-merger simulation predictions
• Kinematics and Metallicity of Red Giant Branch Stars in the Northeast Shelf of M31
• The survey of planetary nebulae in Andromeda (M31) VII. Predictions of a major merger simulation model compared with chemodynamical data of the disc and inner halo substructures
• The origin of the metallicity distributions of the NE and W stellar shelves in the Andromeda Galaxy