Hostname: page-component-77c89778f8-7drxs Total loading time: 0 Render date: 2024-07-18T13:49:55.592Z Has data issue: false hasContentIssue false

106-107 K Gas in the Magellanic Clouds

Published online by Cambridge University Press:  25 May 2016

S. L. Snowden*
Affiliation:
Universities Space Research Association, NASA/GSFC, Greenbelt, MD 20771, USA

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.

The Large Magellanic Cloud contains an extensive distribution of hot plasma and is one of the brightest extragalactic regions in the diffuse 0.5–2.0 keV X-ray sky. The plasma is not isothermal but increases in color temperature from west to east from ~106.6 K to ~106.9 K. The total flux from this plasma is ~ 1038 ergs s−1. The average emission measure is ~ 0.014 cm−6 pc, which if the emitting plasma is distributed uniformly throughout the LMC, implies a space density of ne ~ 0.002 cm−3. There is an apparent ¼ keV enhancement in the southwest of the LMC, which if associated with the LMC implies a considerable emission measure of ~ 106 K plasma. (The foreground column density of Galactic neutral hydrogen is ~ 6 × 1020 cm−2, or several optical depths for ¼ keV emission.)

The Small Magellanic Cloud exhibits less diffuse X-ray emission in the 0.5–2.0 keV band than the LMC with a total flux of ~ 4 × 1036 ergs s−1. The average emission measure of ~ 0.006 cm−6 pc also implies a space density of ne ~ 0.002 cm−3. The optical depth of Galactic HI for ¼ keV X-rays from the SMC is considerably lower than that for the LMC. However, while there is a significant variation in the ¼ keV band intensity over the SMC field, it is in general not particularly well correlated with anything associated with the SMC, although there is an enhancement which may be related to the leading edge of the SMC. Considerably more work is needed to unravel the origin of the structure, which may be associated instead with either emission or absorption variations in either the disk or halo of the Milky Way.

Type
Part 2. Interstellar Medium
Copyright
Copyright © Astronomical Society of the Pacific 1999 

References

Kuntz, K., & Snowden, S. L. 1998, NASA/GSFC, ROSAT GOF Google Scholar
Morrison, R., & McCammon, D. 1983, ApJ, 270, 119 CrossRefGoogle Scholar
Raymond, J. C., & Smith, B. W. 1977, ApJS, 35, 419 Google Scholar
Snowden, S. L., & Kuntz, K. 1998, NASA/GSFC, ROSAT GOF Google Scholar
Snowden, S. L., et al. 1994, ApJ, 424, 714 Google Scholar
Snowden, S. L., et al. 1995, ApJ, 454, 643 CrossRefGoogle Scholar
Trümper, J. 1992, QJRAS, 33, 165 Google Scholar
Wang, Q. D. 1991, ApJ, 377, L85 Google Scholar
Wang, Q. D., et al. 1991, ApJ, 374, 475 CrossRefGoogle Scholar