Difficult to see, these enormously dense objects are buried at the hearts of galaxies.
Our Milky Way's giant black hole
NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, has captured these first, focused views of the supermassive black hole at the heart of our galaxy in high-energy X-ray light. The background image, taken in infrared light, shows the location of our Milky Way's humongous black hole, called Sagittarius A*, or Sgr A* for short. NuSTAR is the first telescope to be able to focus high-energy X-rays, giving astronomers a new tool for probing extreme objects such as black holes.
In the main image, the brightest white dot is the hottest material located closest to the black hole, and the surrounding pinkish blob is hot gas, likely belonging to a nearby supernova remnant. The time series at right shows a flare caught by NuSTAR over an observing period of two days in July; the middle panel shows the peak of the flare, when the black hole was consuming and heating matter to temperatures up to 180 million degrees Fahrenheit (100 million degrees Celsius).
The main image is composed of light seen at four different X-ray energies. Blue light represents energies of 10 to 30 kiloelectron volts (keV); green is 7 to 10 keV; and red is 3 to 7 keV. The time series shows light with energies of 3 to 30 keV.
The background image of the central region of our Milky Way was taken at shorter infrared wavelengths by NASA's Spitzer Space Telescope.
Merging X-ray data (blue) from NASA's Chandra X-ray Observatory with microwave (orange) and visible images reveals the jets and radio-emitting lobes emanating from Centaurus A's central black hole.
Photo by: ESO/WFI (visible); MPIfR/ESO/APEX/A.Weiss et al. (microwave); NASA/CXC/CfA/R.Kraft et al. (X-ray) / Caption by:
CNET Reviews staff
Actively growing supermassive black hole
This image shows optical data from the Hubble Space Telescope in red, green, and blue; X-ray data from NASA's Chandra X-ray Observatory in purple; and radio data from the National Radio Astronomy Observatory's Very Large Array in yellow. A compact X-ray source at the center of the galaxy coincides with a radio source, giving evidence of an actively growing supermassive black hole with a mass of about 1 million times that of the sun.
The combined observations from multiple telescopes of Henize 2-10, a dwarf starburst galaxy located about 30 million light-years from Earth, have provided astronomers with a detailed look at how galaxy and black hole formation may have occurred in the early universe.
Photo by: X-ray (NASA/CXC/Virginia/A.Reines et al); Radio (NRAO/AUI/NSF); Optical (NASA/STScI) / Caption by:
CNET Reviews staff
Galaxy cluster PKS 0745-19
The black hole at the center of this galaxy is part of a survey of 18 of the biggest black holes in the universe. This large elliptical galaxy is in the center of galaxy cluster PKS 0745-19, which is located about 1.3 billion light-years from Earth.
X-ray data from NASA's Chandra X-ray Observatory are shown in purple, and optical data from the Hubble Space Telescope are in yellow.
Photo by: NSF's Karl G. Jansky Very Large Array (JVLA) and the Australia Telescope Compact Array (ATCA) and infrared data from the 2 Micron All-Sky Survey (2MASS) / Caption by:
CNET Reviews staff
By studying the inner regions of nine elliptical galaxies with Chandra, scientists can now estimate the rate at which gas is falling toward the galaxies' supermassive black holes. These images also allowed them to estimate the power required to produce radio-emitting bubbles in the hot X-ray gas.
The composite image of NGC 4696 shows a vast cloud of hot gas (red), surrounding high-energy bubbles 10,000 light-years across (blue) on either side of the bright white area around the supermassive black hole. Images of the other galaxies in the study show a similar structure. (The green dots in the image show infrared radiation from star clusters on the outer edges of the galaxy.)
W49B, seen here in a composite image captured by the Chandra telescope, is thought to be a forming black hole just 26,000 light-years away from Earth.
Photo by: (X-ray: NASA/CXC/MIT/L.Lopez et al; Infrared: Palomar; Radio: NSF/NRAO/VLA) - See more at: http://theweek.com/article/index/240197/photo-this-beautiful-black-hole-is-the-youngest-ever-discovered#sthash.2nulX4iA.dpuf / Caption by:
CNET Reviews staff
The Eye of Sauron
NGC 4151, sometimes called the Eye of Sauron, is an active Seyfert 1 galaxy in Canes Venatici and, at 39 million light-years away, is one of the closest galaxies to house a supermassive black hole, which shines brightly in X-rays.
At left and center, respectively, are Swift UVOT images in the optical (v, b, and u filters) and ultraviolet (uvw1, uvm2, and uvw2 filters). Note how the outlying spiral arms are more easily visible in the ultraviolet image. The panel at right shows X-ray observations (0.2-10 keV) from Swift's X-ray Telescope.
NGC 3516 is an active Seyfert 1 galaxy located 127 million light-years away in the constellation Draco. At left and center, respectively, are Swift UVOT images in the optical (v, b, and u filters) and ultraviolet (uvw1, uvm2, and uvw2 filters). The image at the right shows X-ray observations (0.2-10 keV) from Swift's X-ray Telescope, which highlights high-energy emissions from the galaxy's central black hole.
NGC 1313, also known as the Topsy Turvy Galaxy, is a barred spiral located 13 million light-years away in the constellation Reticulum. Its uneven shape and off-center rotation make it unique, and it is currently undergoing a strong episode of star formation, which astronomers call a "starburst."
At left and center, respectively, are Swift UVOT images in the optical (v, b, and u filters) and ultraviolet (uvw1, uvm2, and uvw2 filters). The panel at right shows X-ray observations (0.2-10 keV) from Swift's X-ray Telescope. It reveals ultraluminous X-ray sources thought to be massive black holes rapidly accreting gas.
NGC 1097 -- also known as Arp 77 -- is a barred spiral galaxy whose nucleus harbors a massive and active black hole.
Situated 61 million light-years away in the constellation Fornax, NGC 1097 has long, arcing spiral arms partially affected by the presence of a faint companion at the two o'clock position. The companion is roughly 40,000 light-years from the big galaxy's brilliant eye-like center and is faintly visible in this composite of images from Swift's UV filters (uvw1, uvm2, and uvw2).
NASA's Chandra X-ray Observatory has discovered an extraordinary outburst by a black hole in spiral galaxy M83, located about 15 million light-years from Earth. Using Chandra, astronomers found a new ultraluminous X-ray source (ULX), or objects that give off more X-rays than most "normal" binary systems in which a companion star is in orbit around a neutron star or black hole.
On the left is an optical image of M83 from the Very Large Telescope in Chile, operated by the European Southern Observatory. On the right is a composite image showing X-ray data from Chandra in pink and optical data from the Hubble Space Telescope in blue and yellow. The ULX is located near the bottom of the composite image. (Mouse over for the exact position.)
In Chandra observations that spanned several years, the ULX in M83 increased in X-ray brightness by at least 3,000 times. This sudden brightening is one of the largest changes in X-rays ever seen for this type of object, which do not usually show dormant periods.
A Chandra X-ray Observatory image of Messier 82, or M82, shows the result of star formation on overdrive. M82 is located about 12 million light-years from Earth and is the nearest place to us where the conditions are similar to those when the universe was much younger with lots of stars forming.
M82 is a starburst galaxy, where stars are forming at rates that are tens or even hundreds of times higher than in a normal galaxy. The burst of star birth may be caused by a close encounter or collision with another galaxy, which sends shock waves rushing through the galaxy. In the case of M82, astronomers think that a brush with its neighbor galaxy, M81, millions of years ago set off this torrent of star formation.
This Chandra image is colorized to highlight a population of point-like "ultraluminous" X-ray sources in M82, a starburst galaxy 11 million light-years from Earth.
Red represents the low-energy band, green intermediate, and blue the highest observed energies. The white and yellow sources are those that emit significant amounts of both low- and high-energy X-rays.
The ultraluminous sources, which emit 10 to several hundred times more X-ray power than similar sources in our Galaxy, are believed to be either massive black holes, or black holes that are beaming energy toward Earth. The brightest point-like source, located near the center of the image, is the most powerful ultraluminous source detected in any galaxy to date.
M82, at a distance of 11 million light-years from Earth, is the nearest starburst galaxy. Massive stars are forming and expiring in M82 at a rate 10 times higher than in our galaxy. The bright spots in the center are supernova remnants and X-ray binaries.
These are some of the brightest such objects known. The luminosity of the X-ray binaries suggests that most contain a black hole. The diffuse X-ray light in the image extends over several thousand light-years, and is caused by multimillion-degree gas flowing out of M82. A close encounter with a large galaxy, M81, in the last 100 million years is thought to be the cause of the starburst activity.