Observations of Extragalactic Neutral Hydrogen. Spencer Wolfe Kristina Nyland Laura Trouille Blakesley Burkhart Robert Minchin. Why observe the 21 cm line in other galaxies?. Center of line provides recessional velocity of galaxy provides distance to galaxy (if unknown) Width of line
Above: The Circinus spiral galaxy mapped in HI by the ATCA. The left and right sides represent (respectively) the moment 0 (integrated flux) and the moment 1 (velocity).
Spiral (SBc, starburst)
First 21-cm detection of NGC 6021 !
M(HI) = 3.8e8
Mdyn = 2.3e10
M(HI) = 1.4e9
Mdyn = 7.5e9
Unknown classification in NED,
found in 2MASS survey
M(HI) = 9.7e8
Mdyn = 4.5e9
Mdyn = 4.7e10
M(HI) = 3.6e8
Mdyn = 8.5e10
1) HI in looser spirals tends to account for a greater portion of their total mass.
2) Tighter spiral and elliptical have a lower fraction of HI compared to their total mass.
3) This supports the general view of spiral vs elliptical galaxy characteristics.
We would like to thank Robert Minchin for his help with observing and reducing our data. Thanks Robert!