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From the Milky Way to Andromeda: A PAndAS View of Galactic Halos

From the Milky Way to Andromeda: A PAndAS View of Galactic Halos. Brendan McMonigal Supervisor - Geraint F. Lewis Sydney Institute for Astronomy School of Physics, The University of Sydney. Original image: Stephen Rahn (Flikr). Outline. A PAndAS Introduction Mapping the contamination

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From the Milky Way to Andromeda: A PAndAS View of Galactic Halos

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  1. From the Milky Way to Andromeda: A PAndAS View of Galactic Halos Brendan McMonigal Supervisor - Geraint F. Lewis Sydney Institute for Astronomy School of Physics, The University of Sydney Original image: Stephen Rahn (Flikr)

  2. Outline • A PAndAS Introduction • Mapping the contamination • The Smooth Halo of M31 • A new MW Stream

  3. PAndAS(Pan-Andromeda Archaeological Survey) MegaCam (~1 degree FOV) Canada-France-Hawaii Telescope CFHT – 3.6m on Hawaii

  4. Andromeda & Triangulum (M31 & M33) M31 is a grand design spiral very similar to the MW, located at 780kpc. M33 has a mass ~1/10th that of the MW, located at a distance of 860kpc. Separated on the sky by ~15 degrees on the sky (physical separation of 230kpc) and M33 may be a bound satellite of M31, although it appears to be very undisturbed.

  5. Ibata et al (2014)

  6. Martin et al (2013)

  7. Martin et al (2013)

  8. Original image: Stephen Rahn (Flikr)

  9. Original image: Stephen Rahn (Flikr)

  10. PAndAS Collaborators Alan McConnachie Lead PI Scott Chapman Mike Irwin Geraint Lewis Rodrigo Ibata Nicolas Martin Annette Ferguson PAndAS: The Pan-Andromeda Archaeological Survey

  11. PAndAS Collaborators

  12. Expectations from Simulations 300kpc Bullock & Johnston (2005)

  13. Full PAndAS CMD [Fe/H] = -1.91 [Fe/H] = -1.29 [Fe/H] = -0.71 [Fe/H] = -0.20 Ibata et al (2014)

  14. PAndAS Contamination α β γ Martin et al (2013)

  15. Before and... Martin et al (2013)

  16. ...After Martin et al (2013)

  17. Source Identification Smoothed Density Significance η M31 Halo [Fe/H] Dwarf [Fe/H] Log(N) Half light radius Detections Martin et al (2013)

  18. Significance Map Known Dwarf Known GC Martin et al (2013)

  19. Detections Known Dwarf Known GC Algorithm Detection Martin et al (2013)

  20. A New Extended Cluster Martin et al (2013)

  21. The search for the smooth halo Metal Rich Metal Rich-ish Metal Poor-ish Metal Poor Ibata et al (2014)

  22. The search for the smooth halo Metal Rich Metal Rich-ish Metal Poor-ish Metal Poor Ibata et al (2014)

  23. Combined Map Ibata et al (2014)

  24. Residuals Metal Rich Metal Rich-ish Metal Poor-ish Metal Poor Ibata et al (2014)

  25. Profiling: Metal Poor Ibata et al (2014)

  26. Profiling: Metal Poor-ish Ibata et al (2014)

  27. Profiling: Metal Rich (and Rich-ish) Ibata et al (2014)

  28. Substructure in the Milky Way

  29. Substructure in the Milky Way Koposov et al (2012) SDSS-III

  30. Substructure in the Milky Way Martin et al. (2014)

  31. Take home points… • PAndAS: We now have the most comprehensive view of a galaxy halo out to 150kpc (as well as to 50kpc in M33) • Substructure: We see extensive substructure, consisting of streams and clumps, both in Andromeda and the MW. • Dwarf Population: We’ve uncovered a large populations of dwarf galaxies, but still not as many as expected from cosmological predictions (modulo gas physics). • Still to come: Globular Clusters (Nick), 3D structure (Anthony)

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