A Wide Spectrum Look at M101


It’s one of the last entries in Charles Messier’s famous catalog, but M101 is definitely not one of the least. The galaxy is big—roughly 170,000 light-years across, almost twice the size of our own Milky Way Galaxy. This multiwavelength view is a composite of images recorded by space-based telescopes. Color coded from X-rays to infrared wavelengths (high to low energies), the image data was taken from the Chandra X-ray Observatory (x-rays, purple), the Galaxy Evolution Explorer (ultraviolet, blue), the Hubble Space Telescope (visible light, yellow), and the Spitzer Space Telescope (infrared, red). While the X-ray data shows the multimillion degree gas around M101’s exploded stars and neutron star and black hole binary star systems, the lower energy data shows the stars and dust that define M101’s grand spiral arms. Known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major. It’s about 25 million light-years away.

Image Credit: NASA

Happy Anniversary, Swift


Ten years ago yesterday, a Delta rocket from Cape Canaveral launched the Swift satellite into orbit. From time to time, I’ve published pictures and videos based on data taken by Swift. Most of it has been related to X-ray astronomy because the instrument that I worked on is an X-ray instrument.

M101_Swift_UVSwift has also been doing excellent UV astronomy as well. The picture on the left is the first light UV image from ten years ago. It’s M101, the Pinwheel Galaxy.

Swift‘s UV Optical Telescope has been used to create the most detailed ultraviolet light surveys ever of the Large and Small Magellanic Clouds, the two closest major galaxies. Nearly a million ultraviolet sources appear in the mosaic of the Large Magellanic Cloud below. It was assembled from 2,200 images taken by the UVOT. The 160-megapixel image (drastically reduced resolution here!) required a cumulative exposure of 5.4 days. The image includes light from 160 to 330 nm. Those UV wavelengths are largely blocked by Earth’s atmosphere. The Large Magellanic Cloud is about 14,000 light-years across.lmc_swift

Image Credits: NASA

Dwarves


dwarf galaxyHappy, Sneezy, Dopey, … No, no … Balin, Bifur, Bofur, … No, not them either. This post is about one of the dwarf galaxies that is part of the M101 group. Ursa Major (The Great Bear) is home to Messier 101, the Pinwheel Galaxy. Messier 101 is one of the biggest and brightest spiral galaxies in the night sky. Like the Milky Way, Messier 101 is not alone with smaller dwarf galaxies in its neighborhood. NGC 5477, which is the main subject of the Hubble Space Telescope image above, is one of those companion galaxies. It’s a typical irregular dwarf galaxy with no obvious structure but plenty of signs of new star creation. The bright nebulae that extend across the galaxy are clouds of glowing hydrogen gas in which those new stars are forming. These glow pinkish red in real life, but appear white in this false color image which was taken through green and infrared filters using Hubble‘s Advanced Camera for Surveys. The field of view is about 3.3 arcminutes wide.

The picture includes numerous galaxies in the background; some are visible right through NGC 5477. This demonstrates that galaxies, far from being solid, opaque objects, are actually largely made up of the empty space between their stars.

Image Credit: NASA

The Pinwheel Galaxy


It’s one of the last entries in Charles Messier’s famous catalog, but M101 is definitely not one of the least. The galaxy is big—roughly 170,000 light-years across, almost twice the size of our own Milky Way Galaxy. This multiwavelength view is a composite of images recorded by space-based telescopes. Color coded from X-rays to infrared wavelengths (high to low energies), the image data was taken from the Chandra X-ray Observatory (x-rays, purple), the Galaxy Evolution Explorer (ultraviolet, blue), the Hubble Space Telescope (visible light, yellow), and the Spitzer Space Telescope (infrared, red). While the X-ray data shows the multimillion degree gas around M101’s exploded stars and neutron star and black hole binary star systems, the lower energy data shows the stars and dust that define M101’s grand spiral arms. Known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major. It’s about 25 million light-years away.

Image Credit: NASA

IR to UV


When I worked in the audio business, we used to jokingly describe a wide band system as working from dc to daylight. This picture of the M101 (aka, the Pinwheel Galaxy) uses images take in the infrared, visible, ultraviolet and X-rays from four of NASA’s space-based telescopes. The wide-spectrum view shows that both young and old stars are evenly distributed along the galaxy’s spiral arms. Composite images allow astronomers to see how features in one part of the spectrum match up with those seen in other parts. It is like seeing with IR night-vision goggles, a regular camera, an ultraviolet camera, and X-ray vision, all at the same time.

The Pinwheel Galaxy is in the constellation of the Big Dipper. It is about 70 percent larger than our own Milky Way Galaxy about 21 million light years from Earth.

Image Credit: NASA

Supernova in M101


These images from the Ultraviolet/Optical Telescope (UVOT) on board NASA’s SWIFT satellite show the nearby spiral galaxy M101 before and after the appearance of SN 2011fe (circled, right). The supernova was discovered on 24 August, 2011. Only about 21 million light-years away, it was the nearest Type Ia supernova since 1986. Left: This view was constructed from images taken in March and April, 2007. Right: The supernova was so bright that most UVOT exposures were short, so this view includes imagery from August through November, 2011 to better show the galaxy.

Image Credit: NASA