Two Red Clumps and the X-Shaped Milky Way Bulge
Andrew McWilliam (1), Manuela Zoccali (2) ((1) Carnegie, Observatories, (2) Departamento Astronomia y Astrofisica, Pontifica, Universidad Catolica de Chile)

TL;DR
This study uses infrared photometry to reveal two co-existing red clump populations in the Milky Way bulge, indicating an X-shaped structure formed by the Galactic bar, challenging previous tilted bar models.
Contribution
It provides evidence for an X-shaped bulge structure through analysis of red clump populations, offering new insights into the Milky Way's morphology.
Findings
Two red clump populations are separated by ~2.3 kpc.
The bulge exhibits an X-shaped structure consistent with N-body simulations.
The double red clump is incompatible with a simple tilted bar model.
Abstract
From 2MASS infra-red photometry we find two red clump (RC) populations co-existing in the same fields toward the Galactic bulge at latitudes |b|>5.5 deg., ranging over ~13 degrees in longitude and 20 degrees in latitude. We can only understand the data if these RC peaks simply reflect two stellar populations separated by ~2.3 kpc; at (l,b)=(+1,-8) the two RCs are located at 6.5 and 8.8+/-0.2 kpc. The double-peaked RC is inconsistent with a tilted bar morphology. Most of our fields show the two RCs at roughly constant distance with longitude, which is also inconsistent with a tilted bar, although an underlying bar may be present. The stellar densities in the two RCs changes dramatically with longitude: on the positive longitude side the foreground RC is dominant, while the background RC dominates negative longitudes. A line connecting the maxima of the foreground and background…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
