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Posts Tagged ‘X-rays’

NASA’s WISE Spacecraft Discovers Most Luminous Galaxy In Universe

May 21, 2015 1 comment

Artist's concept. Image credit: N/A

Artist’s concept. Image credit: N/A

A remote galaxy shining with the light of more than 300 trillion suns has been discovered using data from NASA’s Wide-field Infrared Survey Explorer (WISE). The galaxy is the most luminous galaxy found to date and belongs to a new class of objects recently discovered by WISE — extremely luminous infrared galaxies, or ELIRGs.

“We are looking at a very intense phase of galaxy evolution,” said Chao-Wei Tsai of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, lead author of a new report appearing in the May 22 issue of The Astrophysical Journal. “This dazzling light may be from the main growth spurt of the galaxy’s black hole.

The brilliant galaxy, known as WISE J224607.57-052635.0, may have a behemoth black hole at its belly, gorging itself on gas. Supermassive black holes draw gas and matter into a disk around them, heating the disk to roaring temperatures of millions of degrees and blasting out high-energy, visible, ultraviolet, and X-ray light. The light is blocked by surrounding cocoons of dust. As the dust heats up, it radiates infrared light.

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SGR 1745-2900: Magnetar Near Supermassive Black Hole Delivers Surprises


Credit: NASA/CXC/INAF/F.Coti Zelati et al

Credit: NASA/CXC/INAF/F.Coti Zelati et al

In 2013, astronomers announced they had discovered a magnetar exceptionally close to the supermassive black hole at the center of the Milky Way using a suite of space-borne telescopes including NASA’s Chandra X-ray Observatory.

Magnetars are dense, collapsed stars (called “neutron stars”) that possess enormously powerful magnetic fields. At a distance that could be as small as 0.3 light years (or about 2 trillion miles) from the 4-million-solar mass black hole in the center of our Milky Way galaxy, the magnetar is by far the closest neutron star to a supermassive black hole ever discovered and is likely in its gravitational grip.

A new study uses long-term monitoring observations to reveal that the amount of X-rays from SGR 1745-2900 is dropping more slowly than other previously observed magnetars, and its surface is hotter than expected.

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NASA’s NuSTAR Captures Possible ‘Screams’ From Zombie Stars


Image credit: NASA/JPL-Caltech

Image credit: NASA/JPL-Caltech

Peering into the heart of the Milky Way galaxy, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) has spotted a mysterious glow of high-energy X-rays that, according to scientists, could be the “howls” of dead stars as they feed on stellar companions.

“We can see a completely new component of the center of our galaxy with NuSTAR’s images,” said Kerstin Perez of Columbia University in New York, lead author of a new report on the findings in the journal Nature. “We can’t definitively explain the X-ray signal yet — it’s a mystery. More work needs to be done.”

NuSTAR, launched into space in 2012, is the first telescope capable of capturing crisp images of this frenzied region in high-energy X-rays. The new images show a region around the supermassive black hole about 40 light-years across. Astronomers were surprised by the pictures, which reveal an unexpected haze of high-energy X-rays dominating the usual stellar activity.

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Widespread Winds And Feedback From Supermassive Black Holes

February 20, 2015 1 comment

Astronomers have discovered that the winds from supermassive black holes at the centre of galaxies blow outward in all directions, a suspected phenomenon that had been difficult to prove before now.

These new findings, by an international team of astrophysicists, were made possible by simultaneous observations of the luminous quasar PDS 456 with ESA’s XMM-Newton and NASA’s NuSTAR X-ray telescopes, and support the picture of black holes having a significant impact on star formation in their host galaxies.

At the core of every massive galaxy in the Universe, including our own Milky Way, sits a supermassive black hole, with a mass some millions or billions of times that of our Sun. Some of these black holes are active, meaning that their intense gravitational pull causes matter to spiral inward, and at the same time part of that matter is cast away through powerful winds.

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Unusual Light Signal Yields Clues About Elusive Black Hole Merger

January 8, 2015 Leave a comment

Credit: Santiago Lombeyda/Caltech Center for Data-Driven Discovery

Credit: Santiago Lombeyda/Caltech Center for Data-Driven Discovery

The central regions of many glittering galaxies, our own Milky Way included, harbor cores of impenetrable darkness—black holes with masses equivalent to millions, or even billions, of suns. What is more, these supermassive black holes and their host galaxies appear to develop together, or “co-evolve.” Theory predicts that as galaxies collide and merge, growing ever more massive, so too do their dark hearts.

Black holes by themselves are impossible to see, but their gravity can pull in surrounding gas to form a swirling band of material called an accretion disk. The spinning particles are accelerated to tremendous speeds and release vast amounts of energy in the form of heat and powerful X-rays and gamma rays. When this process happens to a supermassive black hole, the result is a quasar—an extremely luminous object that outshines all of the stars in its host galaxy and that is visible from across the universe. “Quasars are valuable probes of the evolution of galaxies and their central black holes,” says George Djorgovski, professor of astronomy and director of the Center for Data-Driven Discovery at Caltech.

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NASA Observatories Take An Unprecedented Look Into Superstar Eta Carinae

January 8, 2015 Leave a comment

Image Credit:  NASA, ESA, and the Hubble SM4 ERO Team

Image Credit:
NASA, ESA, and the Hubble SM4 ERO Team

Eta Carinae, the most luminous and massive stellar system within 10,000 light-years of Earth, is known for its surprising behavior, erupting twice in the 19th century for reasons scientists still don’t understand. A long-term study led by astronomers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, used NASA satellites, ground-based telescopes and theoretical modeling to produce the most comprehensive picture of Eta Carinae to date. New findings include Hubble Space Telescope images that show decade-old shells of ionized gas racing away from the largest star at a million miles an hour, and new 3-D models that reveal never-before-seen features of the stars’ interactions.

“We are coming to understand the present state and complex environment of this remarkable object, but we have a long way to go to explain Eta Carinae’s past eruptions or to predict its future behavior,” said Goddard astrophysicist Ted Gull, who coordinates a research group that has monitored the star for more than a decade.

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NASA’s NuSTAR Sees Rare Blurring Of Black Hole Light

August 12, 2014 Leave a comment

Credit: NASA-JPL / Caltech

Credit: NASA-JPL / Caltech

Scientists have used NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), an orbiting X-ray telescope, to capture an extreme and rare event in the regions immediately surrounding a supermassive black hole. A compact source of X-rays that sits near the black hole, called the corona, has moved closer to the black hole over a period of just days. The researchers publish their results in Monthly Notices of the Royal Astronomical Society.

“The corona recently collapsed in towards the black hole, with the result that the black hole’s intense gravity pulled all the light down onto its surrounding disk, where material is spiralling inward,” said Michael Parker of the Institute of Astronomy in Cambridge, lead author of the new paper.

As the corona shifted closer to the black hole, the black hole’s gravitational field exerted a stronger tug on the x-rays emitted by the corona. The result was an extreme blurring and stretching of the X-ray light. Such events had been observed previously, but never to this degree and in such detail.

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Astro Pro-Am: Professional And Amateur Astronomers Join Forces


Credit: X-ray: NASA/CXC/SAO; Optical: Detlef Hartmann; Infrared: NASA/JPL-Caltech

Credit: X-ray: NASA/CXC/SAO; Optical: Detlef Hartmann; Infrared: NASA/JPL-Caltech

Long before the term “citizen science” was coined, the field of astronomy has benefited from countless men and women who study the sky in their spare time. These amateur astronomers devote hours exploring the cosmos through a variety of telescopes that they acquire, maintain, and improve on their own. Some of these amateur astronomers specialize in capturing what is seen through their telescopes in images and are astrophotographers.

What happens when the work of amateur astronomers and astrophotographers is combined with the data from some of the world’s most sophisticated space telescopes? Collaborations between professional and amateur astronomers reveal the possibilities and are intended to raise interest and awareness among the community of the wealth of data publicly available in NASA’s various mission archives. This effort is particularly appropriate for this month because April marks Global Astronomy Month, the world’s largest global celebration of astronomy.

The images in this quartet of galaxies represent a sample of composites created with X-ray data from NASA’s Chandra X-ray Observatory, infrared data from the Spitzer Space Telescope, and optical data collected by an amateur astronomer.

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Supernova Cleans Up Its Surroundings


Credit: X-ray: NASA/CXC/Morehead State Univ / T.Pannuti et al.; Optical: DSS; Infrared: NASA/JPL-Caltech; Radio: NRAO/VLA / Argentinian Institute of Radioastronomy / G.Dubner

Credit: X-ray: NASA/CXC/Morehead State Univ / T.Pannuti et al.; Optical: DSS; Infrared: NASA/JPL-Caltech; Radio: NRAO/VLA / Argentinian Institute of Radioastronomy / G.Dubner

Supernovas are the spectacular ends to the lives of many massive stars. These explosions, which occur on average twice a century in the Milky Way, can produce enormous amounts of energy and be as bright as an entire galaxy. These events are also important because the remains of the shattered star are hurled into space. As this debris field – called a supernova remnant – expands, it carries the material it encounters along with it.

Astronomers have identified a supernova remnant that has several unusual properties. First, they found that this supernova remnant – known as G352.7-0.1 (or, G352 for short) – has swept up a remarkable amount of material, equivalent to about 45 times the mass of the Sun.

Another atypical trait of G352 is that it has a very different shape in radio data compared to that in X-rays. Most of the radio emission is shaped like an ellipse, contrasting with the X-ray emission that fills in the center of the radio ellipse.

A recent study suggests that, surprisingly, the X-ray emission in G352 is dominated by the hotter (about 30 million degrees Celsius) debris from the explosion, rather than cooler (about 2 million degrees) emission from surrounding material that has been swept up by the expanding shock wave. This is curious because astronomers estimate that G352 exploded about 2,200 years ago, and supernova remnants of this age usually produce X-rays that are dominated by swept-up material. Scientists are still trying to come up with an explanation for this behavior.

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Watching For A Black Hole To Gobble Up A Gas Cloud


Simulation. Image by ESO/MPE/Marc Schartmann

Simulation. Image by ESO/MPE/Marc Schartmann

Right now a doomed gas cloud is edging ever closer to the supermassive black hole at the center of our Milky Way galaxy. These black holes feed on gas and dust all the time, but astronomers rarely get to see mealtime in action.

Northwestern University’s Daryl Haggard has been closely watching the little cloud, called G2, and the black hole, called Sgr A*, as part of a study that should eventually help solve one of the outstanding questions surrounding black holes: How exactly do they achieve such supermassive proportions?

The closest approach between the black hole and gas cloud is predicted to occur any day now. Haggard has been using two world-class observatories, the Chandra X-ray Observatory and the Very Large Array, to gather data on this potentially spectacular encounter.

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