Rosemary Wyse

    Research Interests: 

    Galaxy formation and evolution 

     
    Publications:
    Images:  The following images show 
    an optical image of the central regions of the 
    Milky Way Galaxy, adapted (by Richard Sword, 
    IoA, Cambridge) from that of 
    Madsen & Laustsen (1986).  The field covered 
    is 70 deg by 50 deg.  The Galactic Plane is 
    illustrated by the horizontal line, and the Galactic 
    Center by the cross in the center of the image. 
    The smooth solid curves on either side of the 
    Plane indicate the outline of the COBE/DIRBE 
    image of the central Galaxy.  The   approximate 
    known outline of the Sagittarius dwarf 
    spheroidal galaxy is the extended irregular 
    shape below the Galactic Center (taken 
    from Ibata, Wyse et al 1997).  This companion 
    galaxy to the Milky Way is actually on the far 
    side of the Galactic Center.  This little 
    galaxy cannot be noticed on  images of 
    the central regions of the Milky Way, 
    due to its extremely low surface brightness; 
    there are too few stars that are members of 
    this galaxy, compared to the many stars along 
    the line-of sight that are in the Milky Way 
    Galaxy.  This little galaxy was discovered 
    in 1994 by Ibata , Gilmore and Irwin, 
    during a study of stars in the central regions 
    of our own Galaxy, the Milky Way.  These 
    astronomers studied stars in the little boxes 
    that run parallel and perpendicular to the 
    Galactic PLane in this image.  They found that 
    some of the stars in the lines-of-sight that 
    run through the outline of the Sagittarius 
    dwarf on the image were not moving as 
    they should if they were in the central 
    regions of the Milky Way.  They realised 
    they had found a little galaxy, hiding. 
     
     
     
      
     
    • Rosemary Wyse Department of Physics & Astronomy, The Johns Hopkins University
    Last Modified: January 26, 1998.