|Raymond Oonk, Dyas Utomo, Raffaela Morganti (ASTRON)
| Dyas Utomo (Institut Teknologi Bandung) has been working with Raymond Oonk and Raffaella Morganti at ASTRON during the last two months as a summer student. For his summer project he used the Westerbork Radio Synthesis Telescope to search for HI in absorption against the central radio-loud galaxy in clusters of galaxies at redshifts of about 0.1.
Observing HI at these redshifts is difficult due to strong radio interference. None the less his search was very successful as HI was detected in absorption in four out of six targets. In the two other targets we obtained stringent limits on the HI. Getting a good limit on the HI mass in these systems is very important in our ongoing multi-wavelength study of the gas content in these systems.
One of the non-detections is NGC 4104. This is the central galaxy of the most nearby galaxy cluster in our sample (MKW 4s, z=0.03). Interestingly, HI was detected in emission just north of this source (see Figure). This location is coincident with a disturbed spiral galaxy in the cluster.