Reddening and metallicity maps of the Milky Way bulge from VVV and 2MASS: II. the complete high resolution extinction map and implications for Galactic bulge studies

O. A. Gonzalez, M. Rejkuba, M. Zoccali, E. Valenti, D. Minniti, M. Schultheis, R. Tobar, B. Chen

Resultado de la investigación: Article

154 Citas (Scopus)

Resumen

Context. The Milky Way bulge is the nearest galactic bulge and the most readily accessible laboratory for studies of stellar populations in spheroids based on individual stellar abundances and kinematics. These studies are challenged by the strongly variable and often large extinction on a small spatial scale. Aims. We use the Vista Variables in the Via Lactea (VVV) ESO public survey data to measure extinction values in the complete area of the Galactic bulge covered by the survey at high resolution. Methods. We derive reddening values using the method described in Paper I. This is based on measuring the mean (J-K s) color of red clump giants in small subfields of 2′ × 2′ to 6′ × 6′ in the following bulge area:-10.3° ≤ b ≤ +5.1° and-10.0° ≤ l ≤ +10.4°. To determine the reddening values E(J-K s) for each region, we measure the RC color and compare it to the (J-K s) color of RC stars measured in Baade's Window, for which we adopt E(B-V) = 0.55. This allows us to construct a reddening map sensitive to small-scale variations minimizing the problems arising from differential extinction. Results.The significant reddening variations are clearly observed on spatial scales as small as 2′. We find good agreement between our extinction measurements and Schlegel maps in the outer bulge, but, as already stated in the literature the Schlegel maps are unreliable for regions within |b| ≈ 6. In the inner regions, we compare our results with maps derived from DENIS and Spitzer surveys. While we find good agreement with other studies in the corresponding overlapping regions, our extinction map is of higher quality owing to both its higher resolution and a more complete spatial coverage of the bulge. We investigate the importance of differential reddening and demonstrate the need for high spatial resolution extinction maps for detailed studies of bulge stellar populations and structure. Conclusions. We present the first extinction map covering uniformly ∼315 sq. deg. of the Milky Way bulge at high spatial resolution. We consider a 30 arcmin window at a latitude of b =-4°, which corresponds to a frequently studied low extinction window, the so-called Baade's Window, and find that its AK s values can vary by up to 0.1 mag. Larger extinction variations are observed at lower Galactic latitudes. The extinction variations on scales of up to 2′-6′ must be taken into account when analyzing the stellar populations of the Galactic bulge.

Idioma originalEnglish
Número de artículoA13
PublicaciónAstronomy and Astrophysics
Volumen543
DOI
EstadoPublished - 28 jun 2012

Huella dactilar

galactic bulge
metallicity
extinction
high resolution
color
spatial resolution
spheroids
clumps
European Southern Observatory
coverings
kinematics
stars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

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title = "Reddening and metallicity maps of the Milky Way bulge from VVV and 2MASS: II. the complete high resolution extinction map and implications for Galactic bulge studies",
abstract = "Context. The Milky Way bulge is the nearest galactic bulge and the most readily accessible laboratory for studies of stellar populations in spheroids based on individual stellar abundances and kinematics. These studies are challenged by the strongly variable and often large extinction on a small spatial scale. Aims. We use the Vista Variables in the Via Lactea (VVV) ESO public survey data to measure extinction values in the complete area of the Galactic bulge covered by the survey at high resolution. Methods. We derive reddening values using the method described in Paper I. This is based on measuring the mean (J-K s) color of red clump giants in small subfields of 2′ × 2′ to 6′ × 6′ in the following bulge area:-10.3° ≤ b ≤ +5.1° and-10.0° ≤ l ≤ +10.4°. To determine the reddening values E(J-K s) for each region, we measure the RC color and compare it to the (J-K s) color of RC stars measured in Baade's Window, for which we adopt E(B-V) = 0.55. This allows us to construct a reddening map sensitive to small-scale variations minimizing the problems arising from differential extinction. Results.The significant reddening variations are clearly observed on spatial scales as small as 2′. We find good agreement between our extinction measurements and Schlegel maps in the outer bulge, but, as already stated in the literature the Schlegel maps are unreliable for regions within |b| ≈ 6. In the inner regions, we compare our results with maps derived from DENIS and Spitzer surveys. While we find good agreement with other studies in the corresponding overlapping regions, our extinction map is of higher quality owing to both its higher resolution and a more complete spatial coverage of the bulge. We investigate the importance of differential reddening and demonstrate the need for high spatial resolution extinction maps for detailed studies of bulge stellar populations and structure. Conclusions. We present the first extinction map covering uniformly ∼315 sq. deg. of the Milky Way bulge at high spatial resolution. We consider a 30 arcmin window at a latitude of b =-4°, which corresponds to a frequently studied low extinction window, the so-called Baade's Window, and find that its AK s values can vary by up to 0.1 mag. Larger extinction variations are observed at lower Galactic latitudes. The extinction variations on scales of up to 2′-6′ must be taken into account when analyzing the stellar populations of the Galactic bulge.",
keywords = "Dust, extinction, Galaxy: bulge, Stars: abundances",
author = "Gonzalez, {O. A.} and M. Rejkuba and M. Zoccali and E. Valenti and D. Minniti and M. Schultheis and R. Tobar and B. Chen",
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Reddening and metallicity maps of the Milky Way bulge from VVV and 2MASS : II. the complete high resolution extinction map and implications for Galactic bulge studies. / Gonzalez, O. A.; Rejkuba, M.; Zoccali, M.; Valenti, E.; Minniti, D.; Schultheis, M.; Tobar, R.; Chen, B.

En: Astronomy and Astrophysics, Vol. 543, A13, 28.06.2012.

Resultado de la investigación: Article

TY - JOUR

T1 - Reddening and metallicity maps of the Milky Way bulge from VVV and 2MASS

T2 - II. the complete high resolution extinction map and implications for Galactic bulge studies

AU - Gonzalez, O. A.

AU - Rejkuba, M.

AU - Zoccali, M.

AU - Valenti, E.

AU - Minniti, D.

AU - Schultheis, M.

AU - Tobar, R.

AU - Chen, B.

PY - 2012/6/28

Y1 - 2012/6/28

N2 - Context. The Milky Way bulge is the nearest galactic bulge and the most readily accessible laboratory for studies of stellar populations in spheroids based on individual stellar abundances and kinematics. These studies are challenged by the strongly variable and often large extinction on a small spatial scale. Aims. We use the Vista Variables in the Via Lactea (VVV) ESO public survey data to measure extinction values in the complete area of the Galactic bulge covered by the survey at high resolution. Methods. We derive reddening values using the method described in Paper I. This is based on measuring the mean (J-K s) color of red clump giants in small subfields of 2′ × 2′ to 6′ × 6′ in the following bulge area:-10.3° ≤ b ≤ +5.1° and-10.0° ≤ l ≤ +10.4°. To determine the reddening values E(J-K s) for each region, we measure the RC color and compare it to the (J-K s) color of RC stars measured in Baade's Window, for which we adopt E(B-V) = 0.55. This allows us to construct a reddening map sensitive to small-scale variations minimizing the problems arising from differential extinction. Results.The significant reddening variations are clearly observed on spatial scales as small as 2′. We find good agreement between our extinction measurements and Schlegel maps in the outer bulge, but, as already stated in the literature the Schlegel maps are unreliable for regions within |b| ≈ 6. In the inner regions, we compare our results with maps derived from DENIS and Spitzer surveys. While we find good agreement with other studies in the corresponding overlapping regions, our extinction map is of higher quality owing to both its higher resolution and a more complete spatial coverage of the bulge. We investigate the importance of differential reddening and demonstrate the need for high spatial resolution extinction maps for detailed studies of bulge stellar populations and structure. Conclusions. We present the first extinction map covering uniformly ∼315 sq. deg. of the Milky Way bulge at high spatial resolution. We consider a 30 arcmin window at a latitude of b =-4°, which corresponds to a frequently studied low extinction window, the so-called Baade's Window, and find that its AK s values can vary by up to 0.1 mag. Larger extinction variations are observed at lower Galactic latitudes. The extinction variations on scales of up to 2′-6′ must be taken into account when analyzing the stellar populations of the Galactic bulge.

AB - Context. The Milky Way bulge is the nearest galactic bulge and the most readily accessible laboratory for studies of stellar populations in spheroids based on individual stellar abundances and kinematics. These studies are challenged by the strongly variable and often large extinction on a small spatial scale. Aims. We use the Vista Variables in the Via Lactea (VVV) ESO public survey data to measure extinction values in the complete area of the Galactic bulge covered by the survey at high resolution. Methods. We derive reddening values using the method described in Paper I. This is based on measuring the mean (J-K s) color of red clump giants in small subfields of 2′ × 2′ to 6′ × 6′ in the following bulge area:-10.3° ≤ b ≤ +5.1° and-10.0° ≤ l ≤ +10.4°. To determine the reddening values E(J-K s) for each region, we measure the RC color and compare it to the (J-K s) color of RC stars measured in Baade's Window, for which we adopt E(B-V) = 0.55. This allows us to construct a reddening map sensitive to small-scale variations minimizing the problems arising from differential extinction. Results.The significant reddening variations are clearly observed on spatial scales as small as 2′. We find good agreement between our extinction measurements and Schlegel maps in the outer bulge, but, as already stated in the literature the Schlegel maps are unreliable for regions within |b| ≈ 6. In the inner regions, we compare our results with maps derived from DENIS and Spitzer surveys. While we find good agreement with other studies in the corresponding overlapping regions, our extinction map is of higher quality owing to both its higher resolution and a more complete spatial coverage of the bulge. We investigate the importance of differential reddening and demonstrate the need for high spatial resolution extinction maps for detailed studies of bulge stellar populations and structure. Conclusions. We present the first extinction map covering uniformly ∼315 sq. deg. of the Milky Way bulge at high spatial resolution. We consider a 30 arcmin window at a latitude of b =-4°, which corresponds to a frequently studied low extinction window, the so-called Baade's Window, and find that its AK s values can vary by up to 0.1 mag. Larger extinction variations are observed at lower Galactic latitudes. The extinction variations on scales of up to 2′-6′ must be taken into account when analyzing the stellar populations of the Galactic bulge.

KW - Dust, extinction

KW - Galaxy: bulge

KW - Stars: abundances

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U2 - 10.1051/0004-6361/201219222

DO - 10.1051/0004-6361/201219222

M3 - Article

AN - SCOPUS:84862670193

VL - 543

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A13

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