Tag Archives: Black Holes

NGC 3185

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potw1326Spiral galaxy NGC 3185 is about 80 million light-years away from us in the constellation of Leo (the Lion). The galaxy’s spiral arms swirl outward from the center of the galaxy toward the rim where they join a blue disk of young stars. At the galactic center of is a small but very bright nucleus containing a supermassive black hole. Supermassive black holes have masses many thousands of times that of our Sun, and they become active as matter falls towards them. When this happens the black hole lights up, sending away streams of particles and radiation at almost the speed of light.

ML_GalaxyNGC 3185 is a member of a four-galaxy group known as Hickson 44. NGC 3190 is a somewhat more famous member of the group. Apple used a blue-tinted image of it as the default wallpaper for its Mountain Lion operating system.

Image Credits: NASA, Apple

A Stellar Death Spiral

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Roughly 290 million years ago, a star more or less like the Sun got too close to the central black hole of its galaxy. Intense tides tore the star apart and the resulting outburst of visible, ultraviolet and X-ray light first reached Earth in 2014. Observations from the Swift satellite have mapped out how and where these different wavelengths were produced as the shattered star’s debris circled the black hole. This animation illustrates how debris from a tidally disrupted star collided with itself, creating shock waves that emit ultraviolet and visible light. According to the Swift observations, that debris then took about a month to fall back to the black hole, where they produced changes in its X-ray emission that correlated with the earlier UV and visible light bursts.

Video Credit: NASA

A Deep View in X-Rays

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chandra-deep-field-southMade with over 7 million seconds (about 11-1/2 weeks) of Chandra X-Ray Observatory observing time, this image is part of the Chandra Deep Field-South and is the deepest X-ray image ever obtained. This look at the early Universe in X-rays gives astronomers the best look yet at the growth of black holes over billions of years starting soon after the Big Bang. In this image, low, medium, and high-energy X-rays that Chandra detects are shown as red, green, and blue respectively.

Image Credit: NASA

Mergers and Acquisitions

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This simulation of a pair of black holes merging plays in slow motion, but the real merger would take about one third of a second in real time. The black holes extreme gravity lenses the light from the stars, galaxies, gas, and dust behind them into Einstein rings as they spiral closer and finally merge into one. The otherwise invisible gravitational waves generated as the massive objects rapidly coalesce cause the visible image to ripple and slosh both inside and outside the Einstein rings even after the black holes have merged.

The gravitational waves recently detected by LIGO are consistent with the merger of 36 and 29 solar mass black holes at a distance of 1.3 billion light-years. The final, single black hole has 62 times the mass of the Sun—the remaining 3 solar masses were converted into energy as gravitational waves.

Video Credit: SXS

Shredding a Star

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This animation illustrates how astronomers think a star is shredded by a black hole. When a star wanders too close to a black hole, the intense tidal forces tear the star apart. During such a tidal disruption, some of the star’s debris is thrown outward while the most falls toward the black hole. The result is a distinctive X-ray flare that can last for a several years.

[youtube https://www.youtube.com/watch?v=hu6hIhW00Fk]

Video Credit: NASA

Rings Around a Black Hole

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V404 Cygni Black HoleV404 Cygni is a binary system that contains an erupting black hole. These rings of x-ray light centered on that system were imaged by the x-ray telescope aboard the Swift satellite. Color indicates the energy of the X-rays, with red representing the lowest (800 to 1,500 electron volts, eV), green for medium (1,500 to 2,500 eV), and blue for the most energetic (2,500 to 5,000 eV). Visible light has energies ranging from about 2 to 3 eV. The dark lines running diagonally through the image are artifacts of the imaging system.

Image Credits: Andrew Beardmore (Univ. of Leicester) and NASA

Black Hole Feedback

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The evolution of a galaxy is related to the growth of the supermassive black hole at its center. During the galaxy’s quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. This animation illustrates how black-hole feedback works during that phase. Dense gas and dust in the center simultaneously powers the black hole and hides it from view. The black hole’s radiation wind drives huge outflows of cold gas causing a shock wave that clears gas and dust from the central galaxy.

[youtube https://www.youtube.com/watch?v=OOm_RI_JcyE]

Video Credit: NASA