Browsing by Author "Sokmen, E."

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    Mapping the stellar age of the Milky Way bulge with the VVV I. The method
    (2019) Surot, F.; Valenti, E.; Hidalgo, S.L.; Zoccali, Manuela; Sokmen, E.; Rejkuba, M.; Minniti, D.; Gonzalez, O.A.; Cassisi, S.; Renzini, O.; Weiss, A.
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    Mapping the stellar age of the Milky Way bulge with the VVV II. Deep JKs catalog release based on PSF photometry
    (2019) Surot, F.; Valenti, E.; Hidalgo, S. L.; Zoccali, M.; Gonzalez, O. A.; Sokmen, E.; Minniti, D.; Rejkuba, M.; Lucas, P. W.
    Context. The bulge represents the best compromise between old and massive Galactic components, and as such its study is a valuable opportunity to understand how the bulk of the Milky Way formed and evolved. In addition, being the only bulge in which we can individually resolve stars in all evolutionary sequences, the properties of its stellar content provide crucial insights into the formation of bulges.
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    Mapping the stellar age of the Milky Way bulge with the VVV III. High-resolution reddening map
    (2020) Surot, F.; Valenti, E.; Gonzalez, O. A.; Zoccali, M.; Sokmen, E.; Hidalgo, S. L.; Minniti, D.
    Context. A detailed study of the Galactic bulge stellar population necessarily requires an accurate representation of the interstellar extinction, particularly toward the Galactic plane and center, where severe and differential reddening is expected to vary on sub-arcmin scales. Although recent infrared surveys have addressed this problem by providing extinction maps across the whole Galactic bulge area, dereddened color-magnitude diagrams near the plane and center appear systematically undercorrected, prompting the need for higher resolution. These undercorrections affect any stellar study sensitive to color (e.g., star formation history analyses via color-magnitude diagram fitting), either making them inaccurate or limiting them to small and relatively stable extinction windows where this value is low and better constrained.Aims. This study is aimed at providing a high-resolution (2 arcmin to similar to 10 arcsec) color excess map for the VVV bulge area in J-K-s color.Methods. We used the MW-BULGE-PSFPHOT catalogs, sampling similar to 300 deg(2) across the Galactic bulge (|l| < 10 degrees and -10 degrees< b< 5 degrees) to isolate a sample of red clump and red giant branch stars, for which we calculated the average J-K-s color in a fine spatial grid in (l, b) space.Results. We obtained an E(J-K-s) map spanning the VVV bulge area of roughly 300 deg(2), with the equivalent of a resolution between similar to 1 arcmin for bulge outskirts (l< 6 degrees) to below 20 arcsec within the central |l| < 1 degrees, and below 10 arcsec for the innermost area (|l| < 1 degrees and |b| < 3 degrees).