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On the claimed X-shaped structure in the Milky Way bulge

Published online by Cambridge University Press:  02 August 2018

Daniel Han
Affiliation:
Center for Galaxy Evolution Research & Department of Astronomy, Yonsei University, Seoul 03722, Republic of Korea email: daniel.han@yonsei.ac.kr, ywlee2@yonsei.ac.kr
Young-Wook Lee
Affiliation:
Center for Galaxy Evolution Research & Department of Astronomy, Yonsei University, Seoul 03722, Republic of Korea email: daniel.han@yonsei.ac.kr, ywlee2@yonsei.ac.kr
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Abstract

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A number of recent studies have claimed that the double red clump observed in the Milky Way bulge is a consequence of an X-shaped structure. In particular, Ness & Lang (2016) report a direct detection of a faint X-shaped structure in the bulge from the residual map of the Wide-Field Infrared Survey Explorer (WISE) image. Here we show, however, that their result is seriously affected by a bulge model subtracted from the original image. When a boxy bulge model is subtracted, instead of a simple exponential bulge model as has been done by Ness & Lang, we find that most of the X-shaped structure in the residuals disappears. Furthermore, even if real, the stellar density in the claimed X-shaped structure is way too low to be observed as a strong double red clump (dRC) at l = 0°.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2018 

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