Constraints on Cold HI in the Halo of NGC 3079 from Absorption Measurements of Q0957+561

Judith A. Irwin , Lawrence M. Widrow , Jayanne English, PASA, 16 (1), in press.

Next Section: Constraints on Fractal HI
Title/Abstract Page: Constraints on Cold HI
Previous Section: Observations
Contents Page: Volume 16, Number 1

Results

The continuum map is shown in Fig. 1 (Right), with components labelled according to Greenfield et al.(1985) and Avruch et al.(1997). The lensing galaxy is associated with radio source, G, seen as a northern extension to component B. There are 28 beams across this background emission at levels > 10 x the rms noise, i.e. we have 28 independent probes of HI absorption per channel.

The HI continuum-subtracted cube was inspected for signs of emission or absorption features. No HI features were detected above $\sim$ 3 x the rms noise per channel. The same conclusion is reached if a continuum map is subtracted from a more restricted range of velocity channels, if the naturally weighted maps are instead examined, or if the continuum-subtracted cube is smoothed over systematically varying velocity or spatial ranges.


Next Section: Constraints on Fractal HI
Title/Abstract Page: Constraints on Cold HI
Previous Section: Observations
Contents Page: Volume 16, Number 1

Welcome... About Electronic PASA... Instructions to Authors
ASA Home Page... CSIRO Publishing PASA
Browse Articles HOME Search Articles
ASKAP
Public