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2 years ago in Astronomy , Extragalactic Astronomy By Trisha
Does the galactic equator in the coordinate system match the actual Milky Way equator?
 I'm mapping the vertical distribution of a specific stellar population and using galactic latitude 'b=0' as my reference plane. My preliminary data shows an asymmetric warp. I need to know if I'm detecting a real astrophysical warp or if some of this signal is an artifact of the coordinate system itself being a simplified model of a more complex structure.
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By Suresh Answered 1 year ago
This is a critical detail for precise work. The IAU 1958 galactic coordinate system was defined based on the best radio data of the time, approximating the Sun's orbital plane. However, we now know the Milky Way's H I disk is significantly warped, especially in the outer regions, and has a flare. Consequently, 'b=0' is an idealized great circle that can be off by several degrees from the local stellar or gas midplane. For your study, I would recommend deriving your own local midplane from your stellar population, using a technique like median filtering in latitude bins, and then analyzing deviations from that empirically determined plane.
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