Abstract
X-RAY heating of matter accreting on to a compact object can create unstable flows leading to irregular X-ray emission1–4. Previous discussions of this instability have concentrated on the case of spherically symmetrical infall onto a stationary object. The rise-time of X-ray variations is then related to the free-fall time-scale from the choking or accretion radius, whichever is relevant. Phenomena due to the presence of a magnetosphere4 may, however, reduce this estimate. It is not clear that bursts with duty cycles as short as 10−3 can arise from the heatine instability. Such bursts are observed, and here I investigate the effect of the motion of a compact object through a relatively dense medium. The passage of the compact object through a denser shell, which builds up outside the X ray-heated gas, produces a short burst of X rays. This creates yet another hot region leading to the repetition of bursts on a crossing time. Such behaviour may be relevant to the weak bursts possibly associated with the Cómetary Globule NGC 5367 (ref. 5), and the much shorter timescale luminous X-ray bursts6, some of which are associated with globular clusters.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Shvartsman, V. F. Soviet Astro. -AJ 14, 662–668 (1971).
Buff, J. & McCray, R. Astrophys. J. 189, 147–155 (1974).
Ostriker, J. P., McCray, R., Weaver, R. & Yahil, A. Astrophys. J. Lett. 208, L61–L65 (1976).
Lamb, F. K., Fabian, A. C., Pringle, J. E. & Lamb, D. Q. Astrophys. J. (in the press).
Cooke, B. A. Nature 261, 564–566 (1976).
Lewin, W. H. G. 8th Texas Symp., N. Y. Acad. Sci. (in the press).
Van Till, H., Loren, R. & Davis, J. Astrophys. J. 198, 235–239 (1975).
Cruddace, R., Paresce, F., Bowyer, S. & Lampton, M. Astrophys. J. 187, 497–504 (1974).
Slutz, S. Astrophys. J. 210, 750–756 (1976).
Schwarz, J. Astrophys. J. 182, 449–475 (1973).
Kaluzienski, L. J., Holt, S. S., Boldt, E. A. & Serlemitsos, P. J. Nature 265, 606–607 (1977).
Jones, C., Forman, W., Tananbaum, H. & Turner, M. J. L. Astrophys. J. Lett. 210, L9 (1976).
Fabian, A. C., Pringle, J. E. & Rees, M. J. Mon. Not. R. astr. Soc. 1975, 43–60 (1976).
Clark, G. I. et al. Mon. Not. R. astr. Soc. 179, 651–658 (1977).
Bahcall, N. A., Lasker, B. M. & Wamsteker, W. Astrophys. J. Lett. 213, L105–L107 (1977).
Leroy, J. L., Aurière, M. & Laques, P. Astr. Astrophys. 53, 227–230 (1976).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
FABIAN, A. X-ray bursts from dense clouds. Nature 268, 607–608 (1977). https://doi.org/10.1038/268607a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/268607a0
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.