Shaping Our Galaxy Now: The Low-Latitude Stellar Stream around the Milky Way

• Applicant: Professor Dr. Hans-Walter Rix
• Subject Area: Astrophysics and Astronomy
• Term: from 2005 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5448769

• Final Report Year: 2012

Final Report Abstract

The project set out to develop and implement approaches to find, map and interpret stellar substructure in the outskirts of our Milky Way, which serve as a signpost and a diagnostic of hierarchical galaxy formation in our immediate cosmic neighborhood. In particular, the project has focussed on a comprehensive empirical picture of the Low Latitude stellar stream around the MW and its possible progenitor, the Canis Major stellar overdensity (CMa). For its data, the project has drawn on SDSS/SEGUE imaging data, increasingly supplemented by follow-up imaging in the second part of the SPP. On that basis we were able to develop optimal techniques to find stellar streams in the Milky Way, to characterize and model them; and the project has produced the state of the art map of the ‘Monoceros stream’, showing that it actually encircles much of the Galaxy, that it cannot be modeled as a simple warp or flare, and that it exhibits a distinct stellar metallicity structure. Overall, these results established a picture of a complex outer MW disk, which is indeed undergoing significant tidal interaction.

Publications

• (2007): A Canis Major Overdensity Imaging Survey. I. Stellar Content and Star-Count Maps: A Distinctly Elongated Body of Main-Sequence Stars. In: AJ 133 (5), S. 2274–2290
  Butler, D. J., Martínez-Delgado, D., Rix, H.-W., Peñarrubia, J., & de Jong, J. T. A.
  
• (2007): Cats and Dogs, Hair and a Hero: A Quintet of New Milky Way Companions. In: ApJ 654 (2), S. 897–906
  Belokurov, V., Zucker, D. B., Evans, N. W., et al.
  
• (2007): Discovery of an Unusual Dwarf Galaxy in the Outskirts of the Milky Way. In: ApJ 656 (1), L13-L16
  Irwin, M. J., Belokurov, V., Evans, N. W., et al.
  
• (2007): Modeling the Stellar Populations in the Canis Major Overdensity: The Relation between the Old and Young Populations. In: ApJ 662 (1), S. 259–271
  de Jong, J. T. A., Butler, D. J., Rix, H. W., Dolphin, A. E., & Martínez-Delgado, D.
  
• (2007): The Discovery of Two Extremely Low Luminosity Milky Way Globular Clusters. In: ApJ 669 (1), S. 337–342
  Koposov, S., de Jong, J. T. A., Belokurov, V., et al.
  
• (2007): The Elongated Structure of the Hercules Dwarf Spheroidal Galaxy from Deep Large Binocular Telescope Imaging. In: ApJ 668 (1), L43-L46
  Coleman, M. G., de Jong, J. T. A., Martin, N. F., et al.
  
• (2008). Numerical color-magnitude diagram analysis of sloan digital sky survey data and application to the new milky way satellites. The Astronomical Journal, 135(4), 1361
  de Jong, J. T. A., Rix, H.-W., Martin, N. F., et al.
  
• (2008): A Comprehensive Maximum Likelihood Analysis of the Structural Properties of Faint Milky Way Satellites. In: ApJ 684 (2), S. 1075–1092
  Martin, N. F., de Jong, J. T. A., & Rix, H.-W.
  
• (2008): A Deep Large Binocular Telescope View of the Canes Venatici I Dwarf Galaxy. In: ApJ 672 (1), L13-L16
  Martin, N. F., Coleman, M. G., De Jong, J. T. A., et al.
  
• (2008): The Accretion Origin of the Milky Way’s Stellar Halo. In: ApJ 680 (1), S. 295–311
  Bell, E. F., Zucker, D. B., Belokurov, V., et al.
  
• (2008): The Structural Properties and Star Formation History of Leo T from Deep LBT Photometry. In: ApJ 680 (2), S. 1112–1119
  de Jong, J. T. A., Harris, J., Coleman, M. G., et al.
  
• (2010). Mapping the stellar structure of the Milky Way thick disk and halo using SEGUE photometry. The Astrophysical Journal, 714(1), 663
  de Jong, J. T. A., Yanny, B., Rix, H.-W., et al.
  
• (2010). The enigmatic pair of dwarf galaxies Leo IV and Leo V: coincidence or common origin?. The Astrophysical Journal, 710(2), 1664
  de Jong, J. T. A., Martin, N. F., Rix, H.-W., et al.
  
• (2011). A Deep Photometric Look at Two of Andromeda's Dwarf Spheroidals: X and XVII. The Astrophysical Journal, 729(1), 23
  Brasseur, C. M., Martin, N. F., Rix, H.-W., et al.