NASA - Messier 61 Looks Straight Into Hubble's Camera: "The NASA/ESA Hubble Space Telescope has captured this image of nearby spiral galaxy Messier 61, also known as NGC 4303. The galaxy, located only 55 million light-years away from Earth, is roughly the size of the Milky Way, with a diameter of around 100 000 light-years. The galaxy is notable for one particular reason — six supernovae have been observed within Messier 61, a total that places it in the top handful of galaxies alongside Messier 83, also with six, and NGC 6946, with a grand total of nine observed supernovae. In this Hubble image the galaxy is seen face-on as if posing for a photograph, allowing us to study its structure closely. The spiral arms can be seen in stunning detail, swirling inwards to the very center of the galaxy, where they form a smaller, intensely bright spiral. In the outer regions, these vast arms are sprinkled with bright blue regions where new stars are being formed from hot, dense clouds of gas. Messier 61 is part of the Virgo Galaxy Cluster, a massive group of galaxies in the constellation of Virgo (the Virgin). Galaxy clusters, or groups of galaxies, are among the biggest structures in the Universe to be held together by gravity alone. The Virgo Cluster contains more than 1300 galaxies and forms the central region of the Local Supercluster, an even bigger gathering of galaxies. The image was taken using data from Hubble’s Wide Field Camera 2."
NASA | A Swift Tour of the Nearest Galaxies in UV Light: Astronomers at NASA's Goddard Space Flight Center in Greenbelt, Md., and the Pennsylvania State University in University Park, Pa., have used NASA's Swift satellite to create the most detailed surveys of the Large and Small Magellanic Clouds, the two closest major galaxies, in ultraviolet light. Thousands of images were assembled into seamless portraits of the main body of each galaxy to produce the highest-resolution surveys of the Magellanic Clouds at ultraviolet wavelengths. The project was proposed by Stefan Immler, an astronomer at Goddard. The Large and Small Magellanic Clouds, or LMC and SMC for short, lie about 163,000 and 200,000 light-years away, respectively, and orbit each other as well as our own Milky Way galaxy. Compared to the Milky Way, the LMC has about one-tenth its physical size and only 1 percent of its mass. The SMC is only half the size of the LMC and contains about two-thirds of its mass. The new images reveal about a million ultraviolet sources within the LMC and about 250,000 in the SMC. Viewing in the ultraviolet allows astronomers to suppress the light of normal stars like the sun, which are not very bright at these higher energies, and provide a clearer picture of the hottest stars and star-formation regions. Only Swift's Ultraviolet/Optical Telescope, or UVOT, is capable of producing such high-resolution wide-field multi-color surveys in the ultraviolet. The LMC and SMC images range from 1,600 to 3,300 angstroms, UV wavelengths largely blocked by Earth's atmosphere. The Large and Small Magellanic Clouds are readily visible from the Southern Hemisphere as faint, glowing patches in the night sky. The galaxies are named after Ferdinand Magellan, the Portuguese explorer who in 1519 led an expedition to sail around the world. He and his crew were among the first Europeans to sight the objects. All visible light imagery provided by Axel Mellinger, Central Michigan University. This video is public domain.
