Best ultraviolet maps of 2 nearest galaxies created
Washington: Astronomers at NASA and Pennsylvania State University have used the Swift satellite to create the most detailed ultraviolet light surveys ever of the Large and Small Magellanic Clouds, the two closest major galaxies.
"We took thousands of images and assembled them into seamless portraits of the main body of each galaxy, resulting in the highest-resolution surveys of the Magellanic Clouds at ultraviolet wavelengths," Stefan Immler, who proposed the program and led NASA's contribution from the agency's Goddard Space Flight Center in Greenbelt, Md said.
Immler presented a 160-megapixel mosaic image of the Large Magellanic Cloud (LMC) and a 57-megapixel mosaic image of the Small Magellanic Cloud (SMC) at the 222nd American Astronomical Society meeting in Indianapolis on Monday.
The new images reveal about 1 million ultraviolet sources in the LMC and about 250,000 in the SMC.
The images include light ranging from 1,600 to 3,300 angstroms, which is a range of UV wavelengths largely blocked by Earth's atmosphere.
The LMC and SMC lie about 163,000 light-years and 200,000 light-years away, respectively, and orbit each other as well as our own Milky Way galaxy.
The LMC is about one-tenth the size of the Milky Way and contains only 1 percent of the Milky Way's mass.
The SMC is half the size of the LMC and contains about two-thirds of its mass.
To produce the 160-megapixel LMC mosaic, Swift's UVOT acquired 2,200 snapshots for a cumulative exposure of 5.4 days. The 57-megapixel SMC image comprises 656 individual images with a total exposure of 1.8 days.