Building blocks of the Milky Way halo

C. Chung, Y. W. Lee, M. Pasquato

Research output: Contribution to journalConference article

Abstract

Recently, Deason et al. suggested that the number ratio between blue stragglers (BSs) and blue horizontal branch stars (BHBs) can be used as a population indicator of various stellar systems. Using this number ratio, they suggested that the Milky Way outer halo formed mostly from dwarf spheroidals rather than globular clusters (GCs). However, we demonstrate that this result is biased because they neglect the effect of BHB stars from helium-enhanced second-generation population on the number ratio. We also perform dynamical evolution models and found that the high BS-to-BHB ratio observed in the outer halo fields is most likely due to the preferential removal of the first-generation stars in GCs. Therefore, the BS-to-BHB number ratio is not a good population indicator for claiming that more massive dwarf galaxies are the main building blocks of the Milky Way outer halo.

Original languageEnglish
Pages (from-to)681-682
Number of pages2
JournalMemorie della Societa Astronomica Italiana - Journal of the Italian Astronomical Society
Volume87
Issue number4
Publication statusPublished - 2016 Jan 1

Fingerprint

Stars
halos
globular clusters
Galaxies
Population
horizontal branch stars
blue stars
stars
Helium
stellar systems
dwarf galaxies
helium

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering
  • Radiology Nuclear Medicine and imaging
  • Astronomy and Astrophysics
  • Instrumentation
  • Atomic and Molecular Physics, and Optics

Cite this

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abstract = "Recently, Deason et al. suggested that the number ratio between blue stragglers (BSs) and blue horizontal branch stars (BHBs) can be used as a population indicator of various stellar systems. Using this number ratio, they suggested that the Milky Way outer halo formed mostly from dwarf spheroidals rather than globular clusters (GCs). However, we demonstrate that this result is biased because they neglect the effect of BHB stars from helium-enhanced second-generation population on the number ratio. We also perform dynamical evolution models and found that the high BS-to-BHB ratio observed in the outer halo fields is most likely due to the preferential removal of the first-generation stars in GCs. Therefore, the BS-to-BHB number ratio is not a good population indicator for claiming that more massive dwarf galaxies are the main building blocks of the Milky Way outer halo.",
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Building blocks of the Milky Way halo. / Chung, C.; Lee, Y. W.; Pasquato, M.

In: Memorie della Societa Astronomica Italiana - Journal of the Italian Astronomical Society, Vol. 87, No. 4, 01.01.2016, p. 681-682.

Research output: Contribution to journalConference article

TY - JOUR

T1 - Building blocks of the Milky Way halo

AU - Chung, C.

AU - Lee, Y. W.

AU - Pasquato, M.

PY - 2016/1/1

Y1 - 2016/1/1

N2 - Recently, Deason et al. suggested that the number ratio between blue stragglers (BSs) and blue horizontal branch stars (BHBs) can be used as a population indicator of various stellar systems. Using this number ratio, they suggested that the Milky Way outer halo formed mostly from dwarf spheroidals rather than globular clusters (GCs). However, we demonstrate that this result is biased because they neglect the effect of BHB stars from helium-enhanced second-generation population on the number ratio. We also perform dynamical evolution models and found that the high BS-to-BHB ratio observed in the outer halo fields is most likely due to the preferential removal of the first-generation stars in GCs. Therefore, the BS-to-BHB number ratio is not a good population indicator for claiming that more massive dwarf galaxies are the main building blocks of the Milky Way outer halo.

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