A Pair of Black Holes


CircinusThe magenta spots in this image show a couple of black holes in the Circinus galaxy—the supermassive black hole at its heart and a smaller one closer to the edge. The smaller one belongs to a class of objects called ultraluminous X-ray sources, or ULXs. ULXs are black holes actively feeding off material drawn in from a partner star.

The ULX was spotted by NuSTAR which sees high-energy X-ray light. The magenta X-ray data in the image above come from the NuSTAR and are overlaid on a visible/infrared image from the Digitized Sky Survey.

The Circinus galaxy is located 13 million light-years away in the southern sky constellation Circinus.

Image Credit: NASA

Unusual X-Rays


The blobs of blue and green in this image of the Fireworks Galaxy (NGC 6946) show the locations of extremely bright sources of X-ray light captured by the NuSTAR space observatory. They were generated by some of the most energetic processes in the universe, and the surprise appearance and rapid disappearance of the green source near the center of the galaxy is puzzling.

The primary objective of the NuSTAR observations was to study the supernova that appears as a bright blue-green spot at upper right. The green blob near the bottom of the galaxy wasn’t visible during the first NuSTAR observation, but it was burning bright at the start of a second observation 10 days later. When the Chandra X-ray Observatory later observed that the ultraluminous X-ray source, it had disappeared. The object has since been named ULX-4 because it is the fourth ULX identified in this galaxy. No visible light was detected with the X-ray source, so it’s unlikely that it is also a supernova.

A new study explores the possibility that the light came from a black hole consuming another object, such as a star. If an object gets too close to a black hole, gravity will pull the object apart, and the debris will enter a close orbit around the black hole. Material at the inner edge of the newly formed disk will move so fast that it heats up to millions of degrees and radiates X-rays. Most ULXs are typically long-lived because they’re created by a black hole, that will feed on the victim star for an extended period of time. Short-lived, or “transient,” X-ray sources like ULX-4 are rare, but a single dramatic event such as a black hole swallowing a star in one gulp might explain ULX-4.

Image Credit: NASA

Sloshing Supernova


This animation was generated the first mapping data of radioactivity in a supernova remnant, the blown-out bits and pieces of a massive star that exploded. The data was take by a NASA satellite called NuSTAR. The results, from a remnant named Cassiopeia A (Cas A), reveal how shock waves probably rip apart massive dying stars.

While small stars like our Sun die less violent deaths, larger stars (at least eight times as massive as the Sun) end up as supernovae. The high temperatures and particles created in explosions fuse lighter elements together to create heavier elements. The explosions of supernovae seeding the universe with many elements, including the gold in jewelry, the calcium in bones, and the iron in blood.

NuSTAR is the first telescope capable of producing maps of radioactive elements in supernova remnants—in this case, titanium-44. The NuSTAR map of Cas A shows the titanium concentrated in clumps at the remnant’s center and suggests a possible solution to the mystery of how the star met its demise. When researchers simulate supernova blasts with computers, as a massive star dies and collapses, the main shock wave often stalls out and the star fails to shatter. The latest findings strongly suggest that Cas A sloshed around, re-energizing the stalled shock wave and allowing the star to finally blow off its outer layers.

Video Credit: NASA

Andromeda’s Bright X-Ray Source


The Andromeda galaxy is our nearest neighboring large galaxy. It has a mysterious dominant source of high-energy X-ray emission called Swift J0042.6+4112. Recent observations by the NuSTAR (Nuclear Spectroscopic Telescope Array) mission have pinpointed a pulsar that is for this high-energy radiation. A pulsar is the dense remnant of a dead star that is highly magnetized and spinning. The strong pulsar in Andromeda is likely in a binary system in which material from a stellar companion gets pulled onto the pulsar. X-rays are radiated by the material as it heats up.

The highest energy x-rays are color code blue in the NuSTAR image above, and the pulsar is shown as a blue dot. It appears brighter in high-energy X-rays than anything else in the galaxy.

Image Credit: NASA

X-ray Sources in Andromeda


Andromeda NUSTARThe Nuclear Spectroscopic Telescope Array (or NuSTAR) has captured the best high-energy X-ray view yet of a band across Andromeda, our nearest large, neighboring galaxy. The satellite has observed 40 “X-ray binaries,” intense sources of X-rays comprised of a black hole or neutron star that feeds off a stellar companion.

Image Credit: NASA

A Pulsar in M82


M82 PulsarAstronomers have found a pulsating, dead star beaming with the energy of about 10 million greater than the Sun. A pulsar is a dense stellar remnant left over from a supernova explosion, and this one is the brightest pulsar ever recorded. The discovery was made using the Nuclear Spectroscopic Telescope Array, or NuSTAR. The pulsar is shown in pink at the center of the Messier 82 galaxy in this multi-wavelength image. NASA’s NuSTAR mission discovered the “pulse” of the pulsar using its high-energy X-ray vision.

Image Credit: NASA

The Black Holes of the Circinus Galaxy


CircinusThe magenta spots in this image show a couple of black holes in the Circinus galaxy—the supermassive black hole at its heart and a smaller one closer to the edge. The smaller one belongs to a class of objects called ultraluminous X-ray sources, or ULXs. ULXs are black holes actively feeding off material drawn in from a partner star.

The ULX was spotted by NuSTAR which sees high-energy X-ray light. The magenta X-ray data in the image above come from the NuSTAR and are overlaid on a visible/infrared image from the Digitized Sky Survey.

The Circinus galaxy is located 13 million light-years away in the southern sky constellation Circinus.

Image Credit: NASA

Sloshing Supernova


This animation was generated the first mapping data of radioactivity in a supernova remnant, the blown-out bits and pieces of a massive star that exploded. The data was take by a NASA satellite called NuSTAR. The results, from a remnant named Cassiopeia A (Cas A), reveal how shock waves probably rip apart massive dying stars.

While small stars like our Sun die less violent deaths, larger stars (at least eight times as massive as the Sun) end up as supernovae. The high temperatures and particles created in explosions fuse lighter elements together to create heavier elements. The explosions of supernovae seeding the universe with many elements, including the gold in jewelry, the calcium in bones, and the iron in blood.

NuSTAR is the first telescope capable of producing maps of radioactive elements in supernova remnants—in this case, titanium-44. The NuSTAR map of Cas A shows the titanium concentrated in clumps at the remnant’s center and suggests a possible solution to the mystery of how the star met its demise. When researchers simulate supernova blasts with computers, as a massive star dies and collapses, the main shock wave often stalls out and the star fails to shatter. The latest findings strongly suggest that Cas A sloshed around, re-energizing the stalled shock wave and allowing the star to finally blow off its outer layers.

Video Credit: NASA

X-ray Vision


Sculptor_xraySuperman doesn’t have a monopoly on X-ray vision. There’s a fleet of satellites on orbit doing x-ray astronomy, and X-ray astronomy shows object such as the Sculptor galaxy in a new light. This composite picture was assembled using images from the Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Southern Observatory in Chile. The visible light image from the ground observatory shows the usual view of the galaxy made up of stars, while NuSTAR data (the colored blobs) show high-energy X-ray sources. The NuSTAR observations are the sharpest X-ray images ever taken of this galaxy.

This galaxy, like most, has black holes, and this X-ray data and other from the Chandra X-ray Observatory seem to indicate that the supermassive black hole at the center of the Sculptor galaxy has mysteriously dozed off, or gone inactive, sometime in the past decade.

Sculptor_nustarThe NuSTAR data (at left without the visible light background) also shows a flaring source of high-energy X-rays, called an ultraluminous X-ray source, or ULX. This object, which appears as a blue spot near the hotter, central region of the galaxy, is either a black hole or a dense, dead star, called a neutron star, feeding off a partner star. The orange and reddish blobs are probably other X-ray-generating pairs of stars scatted throughout the galaxy. Red shows low-energy X-ray radiation (3 to 7 keV), green is medium energy (7 to 10 keV), and blue is high energy (10 to 20 keV).

Image Credit: NASA

“Seeing” Black Holes


NuSTAR_IC342This picture of spiral galaxy IC 342 (aka Caldwell 5) has X-ray data from NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR superimposed over a visible light image. The NuSTAR data are shown in magenta. The sources of the X-rays are black holes. These black holes appear much brighter than typical stellar-mass black holes, such as those found around our own galaxy, but they cannot be supermassive black holes, or they would have moved to the galaxy’s center. They appear to be intermediate in mass—or there may be some unknown process going on causing their extremely energetic state.

IC 342 lies 7 million light-years away in the consellation Camelopardalis.

Image Credit: NASA

The Remains of a Dead Star


CasA_NuSTARA few weeks ago I posted an X-ray image of Cassiopeia A. recorded by the Chandra X-ray Observatory. Here’s a newer picture taken by NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR. In this false color image, blue indicates the highest energy of X-rays, while red and green show the lower end of NuSTAR‘s energy range, which overlaps with NASA’s high-resolution Chandra. X-ray light with energies between 10 and 20 keV (kiloelectron-volt) are blue; X-rays of 8 to 10 keV are green; and X-rays of 4.5 to 5.5 keV are red.

Astronomer’s believe that the first light from the stellar explosion that created Cassiopeia A reached Earth about 300 years ago, after traveling 11,000 years to get here. While the star is dead, its remains are bursting with action. The x-ray represented by the outer blue ring are caused by the shock wave from the supernova blast slamming into surrounding material, accelerating particles up to nearly the speed of light.

Image Credit: NASA

 

The Black Hole at the Center of the Galaxy


A black hole called Sagittarius A* (pronounced A-star) lies at the center of our Milky Way Galaxy, only 27,000 light-years away. Its mass is roughly 4 million times the mass of the Sun. Our galaxy’s black hole is mild-mannered compared to the central black holes in some other galaxies, much more calmly consuming material around it. However, it does sometimes flare-up. An flareup lasting several hours is documented in this series of X-ray images from the orbiting Nuclear Spectroscopic Telescope Array (NuSTAR). NuSTAR is the first instrument to provide focused views of the area surrounding Sgr A* at X-ray energies higher than those accessible to the Chandra and XMM observatories. The flare sequence is shown in the panels on the right. The images cover a two-day span. X-rays are generated in material heated to over 100 °C and travelling at nearly the speed of light as it falls into the black hole. The center X-ray image spans about 100 light-years. Its bright white region is the hottest material closest to the black hole; the pinkish cloud probably belongs to the remnant of a nearby supernova. Click the picture to embiggen it.

Image Credit: NASA