NASA's Swift Reveals a Black Hole Bull's-eye

Posted by pt91 at Jul 10, 2015 10:09 AM |
University of Leicester astronomers capture images of erupting X-rays

Issued by NASA on 8 July 2015

What looks like a shooting target is actually an image of nested rings of X-ray light centred on an erupting black hole. On June 15, NASA's Swift satellite detected the start of a new outburst from V404 Cygni, where a black hole and a sun-like star orbit each other. Since then, astronomers around the world have been monitoring the on-going light show.

On June 30, a team led by Andrew Beardmore at the University of Leicester, U.K., imaged the system using the X-ray Telescope aboard Swift, revealing a series concentric rings extending about one-third the apparent size of a full moon. A movie made by combining additional observations acquired on July 2 and 4, released today, shows the expansion and gradual fading of the rings.

Astronomers say the rings result from an "echo" of X-ray light. The black hole's flares emit X-rays in all directions. Dust layers that lie between the Earth and the black hole reflect some of these X-rays back to us, but the light emitted at small angles to our line of sight travels a longer distance and reaches us slightly later than light traveling a more direct path. The time delay creates the light echo, forming rings that expand with time.

Detailed analysis of the expanding rings shows that they are the result of a single brief outburst from the black hole system on June 26 at 17:40 UT. This coincided with one of the largest flares seen by the instruments on the European Space Agency’s INTEGRAL satellite. There are multiple rings because there are multiple reflecting dust layers between 4,000 and 7,000 light-years away from us. Regular monitoring of the rings and how they change with time will allow astronomers to better understand their nature.

"The flexible planning of Swift observations has given us the best X-ray ring images from dust-scattering ever seen," Dr. Beardmore said. "With these observations we can make a detailed study of the normally invisible interstellar dust in the direction of this black hole."

“We were very happy to find the estimated start time of the rings align with a large flare in the public observations by INTEGRAL”, commented Erik Kuulkers, INTEGRAL project scientist at ESA. “It has given us a `once in a professional lifetime’ opportunity’ to study such effects in unprecedented detail.”

V404 Cygni is located about 8,000 light-years away. Every couple of decades the black hole fires up in an outburst of high-energy light. Its previous eruption occurred in 1989.

The investigating team includes scientists from the Universities of Leicester, Southampton, and Oxford in the U.K., the University of Alberta in Canada, and the European Space Agency in Spain.

Further Information

Swift was launched in November 2004 and is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. Goddard operates the spacecraft in collaboration with Penn State University in University Park, Pennsylvania, the Los Alamos National Laboratory in New Mexico and Orbital Sciences Corp. in Dulles, Va. International collaborators are located in the United Kingdom and Italy.

The X-ray camera on Swift was designed and built at the University of Leicester. The University continues to provide calibration support for the X-ray telescope and runs the UK Swift Science Data Centre (http://www.swift.ac.uk) that makes Swift data and products available within hours of it being collected.  The UK involvement in Swift is funded by the UK Space Agency.

The INTEGRAL data are available from the INTEGRAL Science Data Centre for Astrophysics at the University of Geneva, Switzerland (http://www.isdc.unige.ch/integral/).

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Contact Details

Dr Andrew Beardmore

ab271@le.ac.uk

Captions

1) Video:

Rings of X-ray light centred on V404 Cygni, a binary system containing an erupting black hole (dot at centre), were imaged by the X-ray Telescope aboard NASA's Swift satellite from June 30 to July 4. A narrow gap splits the middle ring in two. Colour 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 the most energetic (2,500 to 5,000 eV) shown in blue. For comparison, visible light has energies ranging from about 2 to 3 eV. The dark diagonal lines through the image are artefacts of the imaging system.

Video credit: Andrew Beardmore (Univ. of Leicester) and NASA/Swift

2) Images:

a) Rings of X-ray light centred on V404 Cygni, a binary system containing an erupting black hole (dot at centre), were imaged by the X-ray Telescope aboard NASA's Swift satellite on June 30. A narrow gap splits the middle ring in two. Colour 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 the most energetic (2,500 to 5,000 eV) shown in blue. For comparison, visible light has energies ranging from about 2 to 3 eV. The dark diagonal lines through the image are artefacts of the imaging system.

Image credit: Andrew Beardmore (Univ. of Leicester) and NASA/Swift

b) The Swift X-ray image of V404 Cyg (on the right) shows a patch of the sky equal to about half the apparent diameter of the full moon, which is shown for comparison.

Image credit: NASA's Scientific Visualization Studio, Andrew Beardmore (Univ. of Leicester) and NASA/Swift

Download this video and images in HD formats from NASA Goddard's Scientific Visualization Studio http://svs.gsfc.nasa.gov/goto?11948 or from the UK Swift Science Date centre at http://www.swift.ac.uk/about/V404Cyg.php

Related Links

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http://www.nasa.gov/feature/goddard/nasa-missions-monitor-a-waking-black-hole

MONSTER BLACK HOLE WAKES UP AFTER 26 YEARS

http://sci.esa.int/integral/56094-monster-black-hole-wakes-up-after-26-years/

NASA’s Chandra Captures X-Ray Echoes Pinpointing Distant Neutron Star

https://www.nasa.gov/press-release/nasa-s-chandra-captures-x-ray-echoes-pinpointing-distant-neutron-star

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