The Chemodynamical Nature of the Triangulum-Andromeda Overdensity

Author(s)

Abuchaim, Yuri ; Perottoni, Helio D. ; Rossi, Silvia ; Limberg, Guilherme ; Perez-Villegas, Angeles ; Santucci, Rafael M. ; Placco, Vinicius M. ; Sales-Silva, Joao V. ; Anders, Friedrich ; Rocha-Pinto, Helio J.

• Document type: Journal article
• Source: ASTROPHYSICAL JOURNAL; v. 949, n. 2, p. 13-pg., 2023-06-01.

Abstract

We present a chemodynamical study of the Triangulum-Andromeda overdensity (TriAnd) employing a sample of 31 candidate stars observed with the GRACES high-resolution (R = 40,000) spectrograph at the Gemini North (8.1 m) telescope. TriAnd is a stellar substructure found toward the outer disk of the Milky Way, located at R (GC) similar to 18 kpc from the Sun, toward Galactic latitude b similar to 25 degrees. Most stars in our sample have dynamical properties compatible with a disk stellar population. In addition, by applying an eccentricity cut, we are able to detect a stellar contamination that seems to be consistent with an accreted population. In chemical abundance space, the majority of our TriAnd candidates are similar to the outer thin-disk population, suggesting that the overdensity has an in situ origin. Finally, the found accreted halo interlopers spatially overlapping with TriAnd should explain the historical discussion of the overdensity's nature due to its complex chemical patterns. (AU)

• FAPESP's process: 22/04079-0 - Characterizing ultra-faint dwarf galaxies with S-PLUS survey
• Grantee: Hélio Dotto Perottoni
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 18/21250-9 - Identification of bright ultra-metal-poor stars from Multi-Band photometry and spectroscopic follow-up
• Grantee: Hélio Dotto Perottoni
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/50374-0 - Mosaic: the multi-object spectrograph for the ESO Extremely Large Telescope
• Grantee: Silvia Cristina Fernandes Rossi
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/18100-4 - Stellar populations in the Milky Way: bulge, halo, disk and star forming regions; instrumentation for high resolution spectroscopy
• Grantee: Beatriz Leonor Silveira Barbuy
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 21/10429-0 - The chemodynamical structure of the ancient galactic halo
• Grantee: Guilherme Limberg
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 22/07301-5 - Chemical-abundance patterns of disrupted dwarf galaxies
• Grantee: Guilherme Limberg
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)