Mapping the galactic halo. V. Sagittarius dwarf spheroidal tidal debris 60° from the main body

Robbie C. Dohm-Palmer, Amina Helmi, Heather Morrison, Mario Mateo, Edward W. Olszewski, Paul Harding, Kenneth C. Freeman, John Norris, Stephen A. Shectman

Research output: Contribution to journalArticle

63 Scopus citations

Abstract

As part of the Spaghetti Project Survey, we have detected a concentration of giant stars well above expectations for a smooth halo model. The position (l ∼ 350°, b ∼ 50°) and distance (∼50 kpc) of this concentration match those of the northern overdensity detected by the Sloan Digital Sky Survey. We find additional evidence for structure at ∼80 kpc in the same direction. We present radial velocities for many of these stars, including the first published results from the 6.5 m Magellan telescope. The radial velocities for stars in these structures are in excellent agreement with models of the dynamical evolution of the Sagittarius dwarf tidal debris, whose center is 60° away. The metallicity of stars in these streams is lower than that of the main body of the Sgr dwarf, which may indicate a radial metallicity gradient prior to disruption.

Original languageEnglish (US)
Pages (from-to)L37-L40
JournalAstrophysical Journal
Volume555
Issue number1 PART 2
DOIs
StatePublished - Jul 1 2001

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Keywords

  • Galaxy: Evolution
  • Galaxy: Formation
  • Galaxy: Halo
  • Galaxy: Stellar content

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Dohm-Palmer, R. C., Helmi, A., Morrison, H., Mateo, M., Olszewski, E. W., Harding, P., Freeman, K. C., Norris, J., & Shectman, S. A. (2001). Mapping the galactic halo. V. Sagittarius dwarf spheroidal tidal debris 60° from the main body. Astrophysical Journal, 555(1 PART 2), L37-L40. https://doi.org/10.1086/321734