The Mass and Size of the Hot Galactic Halo

Absorption in the OVII (21.60 A) line at zero redshift shows the presence of hotgas. Our recent study, using 26 absorption sightlines, shows that thisabsorption is probably from a halo around the Milky Way rather than a LocalGroup medium. However, the size of the hot halo is poorly known (15110 kpc)because there are no useful existing absorption sightlines across the Galacticbulge, which provide the strongest constraints. We propose a lengthy observationof the brightest known AGN in the direction of the Galactic bulge, whereexisting data indicate an absorption line of above average strength. Theresulting equivalent width measurement will strongly constrain the size and massof the hot halo. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]