VVV Survey of Blue Horizontal Branch Stars in the Bulge-Halo Transition Region of the Milky Way

Katherine Montenegro, Dante Minniti, Javier Alonso-García, Maren Hempel, Roberto K. Saito, Timothy C. Beers, David Brown

Resultado de la investigación: Article

Resumen

We characterize the population of blue horizontal branch (BHB) stars in the bulge-halo transition region of the Milky Way using the VISTA Variables in the Vía Láctea (VVV) ESO Public Survey data. The selection of BHB stars is made using the globular cluster M22 as a reference standard and constructing color-magnitude and color-color diagrams with specific cuts in the ZYJHK s near-infrared (IR) passbands. A total of 12,554 BHB stars were detected, in a region within -10.°0 ≤ ℓ ≤ 10.°2 and -10.°2 ≤ b ≤ -8.°0. We provide accurate coordinates and near-IR photometry for this sample of BHB stars. We searched for overdensities of stars with sizes similar to those of known globular clusters and stellar streams. By comparing real data with Monte Carlo simulations, we conclude that the few overdensities detected are of low significance. We also constructed K s -band light curves for the BHB stars to study their variability. Taking an average of 52 epochs to calculate periods and amplitudes, we identify hundreds of candidate eclipsing binaries and a dozen pulsating stars. Finally, we made some comparisons with results obtained in a previous study for RR Lyrae variable stars in this same region.

Idioma originalEnglish
Número de artículo206
PublicaciónAstrophysical Journal
Volumen872
N.º2
DOI
EstadoPublished - 1 ene 2019

Huella dactilar

horizontal branch stars
blue stars
halos
near infrared
globular clusters
color-color diagram
stars
infrared photometry
diagram
variable stars
European Southern Observatory
light curve
simulation
time measurement
color

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Montenegro, K., Minniti, D., Alonso-García, J., Hempel, M., Saito, R. K., Beers, T. C., & Brown, D. (2019). VVV Survey of Blue Horizontal Branch Stars in the Bulge-Halo Transition Region of the Milky Way. Astrophysical Journal, 872(2), [206]. https://doi.org/10.3847/1538-4357/aae379
Montenegro, Katherine ; Minniti, Dante ; Alonso-García, Javier ; Hempel, Maren ; Saito, Roberto K. ; Beers, Timothy C. ; Brown, David. / VVV Survey of Blue Horizontal Branch Stars in the Bulge-Halo Transition Region of the Milky Way. En: Astrophysical Journal. 2019 ; Vol. 872, N.º 2.
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abstract = "We characterize the population of blue horizontal branch (BHB) stars in the bulge-halo transition region of the Milky Way using the VISTA Variables in the V{\'i}a L{\'a}ctea (VVV) ESO Public Survey data. The selection of BHB stars is made using the globular cluster M22 as a reference standard and constructing color-magnitude and color-color diagrams with specific cuts in the ZYJHK s near-infrared (IR) passbands. A total of 12,554 BHB stars were detected, in a region within -10.°0 ≤ ℓ ≤ 10.°2 and -10.°2 ≤ b ≤ -8.°0. We provide accurate coordinates and near-IR photometry for this sample of BHB stars. We searched for overdensities of stars with sizes similar to those of known globular clusters and stellar streams. By comparing real data with Monte Carlo simulations, we conclude that the few overdensities detected are of low significance. We also constructed K s -band light curves for the BHB stars to study their variability. Taking an average of 52 epochs to calculate periods and amplitudes, we identify hundreds of candidate eclipsing binaries and a dozen pulsating stars. Finally, we made some comparisons with results obtained in a previous study for RR Lyrae variable stars in this same region.",
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Montenegro, K, Minniti, D, Alonso-García, J, Hempel, M, Saito, RK, Beers, TC & Brown, D 2019, 'VVV Survey of Blue Horizontal Branch Stars in the Bulge-Halo Transition Region of the Milky Way', Astrophysical Journal, vol. 872, n.º 2, 206. https://doi.org/10.3847/1538-4357/aae379

VVV Survey of Blue Horizontal Branch Stars in the Bulge-Halo Transition Region of the Milky Way. / Montenegro, Katherine; Minniti, Dante; Alonso-García, Javier; Hempel, Maren; Saito, Roberto K.; Beers, Timothy C.; Brown, David.

En: Astrophysical Journal, Vol. 872, N.º 2, 206, 01.01.2019.

Resultado de la investigación: Article

TY - JOUR

T1 - VVV Survey of Blue Horizontal Branch Stars in the Bulge-Halo Transition Region of the Milky Way

AU - Montenegro, Katherine

AU - Minniti, Dante

AU - Alonso-García, Javier

AU - Hempel, Maren

AU - Saito, Roberto K.

AU - Beers, Timothy C.

AU - Brown, David

PY - 2019/1/1

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KW - binaries: eclipsing

KW - Galaxy: bulge

KW - stars: horizontal-branch

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