Judith A. Irwin , Lawrence M. Widrow , Jayanne English, PASA, 16 (1), 89
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Constraints on Cold HI in the Halo of NGC 3079 from Absorption Measurements of Q0957+561
Judith A. Irwin 1,2
Lawrence M. Widrow 1
Jayanne English 3
1 Queen's University, Kingston, Ontario, Canada, K7L 3N6
irwin@astro.queensu.ca, widrow@astro.queensu.ca
2 National Centre for Radio Astrophysics, Pune University Campus, Post Bag 3, Pune, 411 007, India
3 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, USA, 21218
jenglish@stsci.edu
Abstract:
. We have considered models for HI + H2 clouds characterized by the cloud radius and fractal dimension. Using the upper limit on absorption, we have ruled out a limited but interesting region of this parameter space. The observations do not rule out the possibility that all the dark matter could be hidden in the form of cold fractal clouds. By contrast, if the gas is diffuse with unity filling factors, then HI cannot constitute more than 10-5, by mass, of the galaxy's dark matter.
Keywords: dark matter -- galaxies: halos -- galaxies: individual (NGC 3079) -- ISM: structure
- Introduction
- Observations
- Results
- Constraints on Fractal HI in a Dark Matter Halo
- Conclusions
- Acknowledgements
- References
© Copyright Astronomical Society of Australia 1997