Hostname: page-component-78c5997874-dh8gc Total loading time: 0 Render date: 2024-11-13T09:54:20.928Z Has data issue: false hasContentIssue false
  • English
  • Français

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

Published online by Cambridge University Press:  05 March 2013

Judith A. Irwin ,
Lawrence M. Widrow  and
Jayanne English
Judith A. Irwin
Affiliation:
Queen's University, Kingston, Ontario K7L 3N6, Canada; irwin@astro.queensu.ca National Centre for Radio Astrophysics, Pune University Campus, Post Bag 3, Pune 411 007, India
Lawrence M. Widrow
Affiliation:
Queen's University, Kingston, Ontario K7L 3N6, Canada; widrow@astro.queensu.ca
Jayanne English
Affiliation:
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA; jenglish@stsci.edu
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We perform the first observational test of dark matter in the form of cold (3 K) fractal clouds, as described by Pfenniger et al. (1994) and Pfenniger & Combes (1994). This is accomplished by probing for HI absorption in the halo of NGC 3079 against the background quasar, Q 0957+561, which is separated from the centre of NGC 3079 by 64 kpc, in projection. No absorption is detected to a limit of 3ΔTb/(–Tc) = 0·01. We have considered models for HI + H2 clouds characterised 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 mattergalaxies: halosgalaxies: individual (NGC 3079)ISM: structure
Type
Research Article
Information
Publications of the Astronomical Society of Australia , Volume 16 , Issue 1 , 1999 , pp. 89 - 94
Copyright
Copyright © Astronomical Society of Australia 1999

References

Ashman, K. 1992, PASP, 104, 1109 CrossRefGoogle Scholar
Avruch, I. M., Cohen, A. S., Lehár, J., Conner, S. R., Haarsma, D. B., & Burke, B. F. 1997, ApJ, 488, L121 CrossRefGoogle Scholar
Carr, B. 1994, ARAA, 32, 531 CrossRefGoogle Scholar
Diamond, P. J., et al. 1989, ApJ, 347, 302 CrossRefGoogle Scholar
Elmegreen, B. G., & Falgarone, E. 1996, ApJ, 471, 816 Google Scholar
Greenfield, P. E., Roberts, D. H., & Burke, B. F. 1985, ApJ, 293, 370 Google Scholar
Henriksen, R. N. 1991, ApJ, 377, 500 CrossRefGoogle Scholar
Henriksen, R. N., & Widrow, L. M. 1995, ApJ, 441, 70 CrossRefGoogle Scholar
Irwin, J. A., & Seaquist, E. R. 1991, ApJ, 371, 111 Google Scholar
Palla, F., Salpeter, E. E., & Stahler, S. W. 1983, ApJ, 271, 632 CrossRefGoogle Scholar
Pfenniger, D., & Combes, F. 1994, A&A, 285, 94 (PC)Google Scholar
Pfenniger, D., Combes, F., & Martinet, L. 1994, A&A, 285, 79 (PCM)Google Scholar
Rawlings, J. M. C. 1988, MNRAS, 232, 507 Google Scholar
Schmidt, R., & Wambsganss, J. 1998, A&A, 335, 379 Google Scholar
Vogelaar, M. G. R., & Wakker, B. P. 1994, A&A, 291, 557 Google Scholar
Walsh, D., Carswell, R. F., & Weymann, R. J. 1979, Nature, 179, 381 Google Scholar