TUNA Lunch Talk:

Gerrit Verschuur

Physics Department, University of Memphis

On the Morphological Similarities between Galactic Neutral Hydrogen Structure and WMAP Data and What They Reveal About Interstellar Physics

June 24

12:10PM, Room 230, NRAO, Edgemont Road

Abstract:

Examination of over 1,000 detailed HI maps at hundreds of velocities has led to the discovery that the morphologies of galactic HI and WMAP ILC structure in areas of sky bounded by latitudes |b| = 30 & 70 are closely related. To date, over 200 closely associated pairs of features have been ident ified and some of the most informative cases will be discussed in the context of what they reveal about interstellar phenomena. In the case of HI features MI & MII, HI, WMAP and soft X-ray structure are all associated and most of the close associations published to date are found to lie on the IV A rch while the average separation between associated HI & WMAP peaks is 0.8 0.2. This study causes us to ask just how much we really know about the structure and dynamics of interstellar HI. The pattern emerging in the data suggests that in directions where HI features (segments of filaments) are interacting either with one another or with the ambient interstellar plasma, physical processes at the interface give rise to the weak continuum radiation structure observed by WMAP (and, by implication, COBE as well). If, on the other hand, all the apparent associations are to be attributed to chance one must ask whether we are so sure about interstellar physics that we can safely ignore the phenomenon in order to draw far-reaching cosmological conclusions from the WMAP data.