| |
| |
Deep observations of neutral Hydrogen in galaxies in and around the
galaxy cluster Abell 2192 at z=0.1887 were obtained with the VLA and
the GMRT radio synthesis telescopes. These observations resulted in the
highest redshift HI emission to date.
|
| |
|
|
| |
The figure above shows the combined VLA and GMRT neutral Hydrogen data as
coloured contours. Each contour shows the distribution of HI at a
particular recession velocity. The contours are overlayed on a R-band
image obtained with the NOAO Mosaic camera on the 0.9m telescope at Kitt
Peak. One can clearly see the presence of a barred spiral galaxy at the
position of the HI contours. Furthermore, the HI contours seem to change
their location along the major axis of the galaxy as a function of
velocity. This is the typical signature of a rotating gas disk.
|
|
| |
To confirm this detection of neutral Hydrogen emission, the identified
galaxy was observed with PMAS to obtain an independent measurement of its
redshift by means of the H-alpha emission line. PMAS detected the H-alpha
emission line at exactly the same redshift as the HI emission.
Furthermore, the imaging capabilities of the PMAS lenslet array allowed
the construction of an H-alpha velocity field as shown in the figure
below. The kinematic major axis of the velocity field is aligned with the
optical major axis and is identical to the direction in which the HI
emission changes its position with velocity. The PMAS data confirms the
redshift of the galaxy and the reality of the highest redshift HI emission
detected to date.
|
|
| |
|
