THE CHANDRA M101 MEGASECOND: DIFFUSE EMISSION

Journal Article · Sat May 15 00:00:00 EDT 2010 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/188/1/46· OSTI ID:21454865

Kuntz, K D ^[1]

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1. Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

Because M101 is nearly face-on, it provides an excellent laboratory in which to study the distribution of X-ray-emitting gas in a typical late-type spiral galaxy. We obtained a Chandra observation with a cumulative exposure of roughly 1 Ms to study the diffuse X-ray emission in M101. The bulk of the X-ray emission is correlated with the star formation traced by the far-UV (FUV) emission. The global FUV/X-ray correlation is nonlinear (the X-ray surface brightness is roughly proportional to the square root of the FUV surface brightness) and the small-scale correlation is poor, probably due to the delay between the FUV emission and the X-ray production in star-forming regions. The X-ray emission contains only minor contributions from unresolved stars ({approx}<3%), unresolved X-ray point sources ({approx}<4%), and individual supernova remnants ({approx}3%). The global spectrum of the diffuse emission can be reasonably well fitted with a three-component thermal model, but the fitted temperatures are not unique; many distributions of emission measure can produce the same temperatures when observed with the current CCD energy resolution. The spectrum of the diffuse emission depends on the environment; regions with higher X-ray surface brightnesses have relatively stronger hard components, but there is no significant evidence that the temperatures of the emitting components increase with surface brightness.

• OSTI ID: 21454865
• Journal Information: Astrophysical Journal, Supplement Series, Vol. 188, Issue 1; Other Information: DOI: 10.1088/0067-0049/188/1/46; ISSN 0067-0049
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BRIGHTNESS
CHARGE-COUPLED DEVICES
ENERGY RESOLUTION
HARD COMPONENT
NONLINEAR PROBLEMS
PHOTON EMISSION
POINT SOURCES
STARS
SUPERNOVA REMNANTS
X-RAY GALAXIES
COSMIC RADIATION
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
EMISSION
GALAXIES
IONIZING RADIATIONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATION SOURCES
RADIATIONS
RESOLUTION
SEMICONDUCTOR DEVICES