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NGC 1929 in N44:
A Surprisingly Bright Superbubble
LHA 120-N 44, NGC 1929
Description: Normal Stars & Star Clusters
Position (J2000): RA 5h 21m 37.98s Dec -67° 54' 42.75"
Scale: Image is 25 arcmin across (1200 light years)
Observation Date: Sept 22, 2002
Observation Time: 5 hours 33 min.
Field of view: 25.28 x 20.18 arcminutes
Orientation: North is 0.1° right of vertical
Color Code: X-ray (Blue); Infrared (Red); Optical (Yellow)
Image Credit: X-ray: NASA/CXC/U.Mich./S.Oey, IR: NASA/JPL, Optical: ESO/WFI/2.2-m
Release Date: August 30, 2012
Closeup: N1125 N44: N0332a
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ABOUT THIS IMAGE:
This composite image shows a superbubble in the Large Magellanic Cloud (LMC), a small satellite galaxy of the Milky Way, located about 160,000 light years from Earth. Many new stars, some of them very massive, are forming in the star cluster NGC 1929, which is embedded in the nebula N44. The massive stars produce intense radiation, expel matter at high speeds, and race through their evolution to explode as supernovas. The winds and supernova shock waves carve out huge cavities called superbubbles in the surrounding gas. X-rays from NASA's Chandra X-ray Observatory (blue) show hot regions created by these winds and shocks, while infrared data from NASA's Spitzer Space Telescope (red) outline where the dust and cooler gas are found. The optical light from the 2.2m Max-Planck-ESO telescope (yellow) in Chile shows where ultraviolet radiation from hot, young stars is causing gas in the nebula to glow.
A long-running problem in high-energy astrophysics has been that some superbubbles in the LMC, including N44, give off a lot more X-rays than expected from models of their structure. A Chandra study published in 2011 showed that there are two extra sources of the bright X-ray emission: supernova shock waves striking the walls of the cavities, and hot material evaporating from the cavity walls. The observations show no evidence for an enhancement of elements heavier than hydrogen and helium in the cavities, thus ruling out this possibility as an explanation for the bright X-ray emission. This is the first time that the data have been good enough to distinguish between different sources of the X-rays produced by superbubbles.
The Chandra study of N44 and another superbubble in the LMC was led by Anne Jaskot from the University of Michigan in Ann Arbor. The co-authors were Dave Strickland from Johns Hopkins University in Baltimore, MD, Sally Oey from University of Michigan, You-Hua Chu from University of Illinois and Guillermo Garcia-Segura from Instituto de Astronomia-UNAM in Ensenada, Mexico.
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass
the ESO release:
At the center of this very rich region of gas, dust and young stars lies the star cluster NGC 1929. Its massive stars produce intense radiation, expel matter at high speeds as stellar winds, and race through their short but brilliant lives to explode as supernovae. The winds and supernova shock waves have carved out a huge cavity, called a superbubble, in the surrounding gas.
Observations with NASA's Chandra X-ray Observatory (shown here in blue) reveal hot regions created by these winds and shocks, while infrared data from NASA's Spitzer Space Telescope (shown in red) outline where the dust and cooler gas are found. The visible-light view from the MPG/ESO 2.2-meter telescope (in yellow) completes the picture and shows the hot young stars themselves as well as the glowing clouds of gas and dust that surround them.
Combining these different views of this dramatic region has allowed astronomers to solve a mystery: why are N44, and similar superbubbles, giving off such strong X-rays? The answer seems to be that there are two extra sources of bright X-ray emission: supernova shock waves striking the walls of the cavities, and hot material evaporating from the cavity walls. This X-ray emission from the edge of the superbubble shows up clearly in the picture.
The designation of this object indicates that it was included in the Catalogue
of H-alpha emission stars and nebulae in the Magellanic Clouds, compiled
and published in 1956 by American astronomer-astronaut Karl Henize (1926-1993).
The letter "N" indicates that it is a nebula. The object is
often called simply N44.