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Post Info TOPIC: M31 ULX-2
Blobrana


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Posts: 131433
Date:
XMMU J004243.6+412519
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Title: Bright radio emission from an ultraluminous stellar-mass microquasar in M31
Authors: Matthew J. Middleton, James C. A. Miller-Jones, Sera Markoff, Rob Fender, Martin Henze, Natasha Hurley-Walker, Anna M. M. Scaife, Timothy P. Roberts, Dominic Walton, John Carpenter, Jean-Pierre Macquart, Geoffrey C. Bower, Mark Gurwell, Wolfgang Pietsch, Frank Haberl, Jonathan Harris, Michael Daniel, Junayd Miah, Chris Done, John Morgan, Hugh Dickinson, Phil Charles, Vadim Burwitz, Massimo Della Valle, Michael Freyberg, Jochen Greiner, Margarita Hernanz, Dieter H. Hartmann, Despina Hatzidimitriou, Arno Riffeser, Gloria Sala, Stella Seitz, Pablo Reig, Arne Rau, Marina Orio, David Titterington, Keith Grainge

A subset of ultraluminous X-ray sources (those with luminosities < 10^40 erg/s) are thought to be powered by the accretion of gas onto black holes with masses of ~5-20 M_solar, probably via an accretion disc. The X-ray and radio emission are coupled in such Galactic sources, with the radio emission originating in a relativistic jet thought to be launched from the innermost regions near the black hole, with the most powerful emission occurring when the rate of infalling matter approaches a theoretical maximum (the Eddington limit). Only four such maximal sources are known in the Milky Way, and the absorption of soft X-rays in the interstellar medium precludes determining the causal sequence of events that leads to the ejection of the jet. Here we report radio and X-ray observations of a bright new X-ray source whose peak luminosity can exceed 10^39 erg/s in the nearby galaxy, M31. The radio luminosity is extremely high and shows variability on a timescale of tens of minutes, arguing that the source is highly compact and powered by accretion close to the Eddington limit onto a stellar mass black hole. Continued radio and X-ray monitoring of such sources should reveal the causal relationship between the accretion flow and the powerful jet emission.

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Blobrana


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Greedy black hole discovered in Andromeda

Studying the Andromeda galaxy with ESA's XMM-Newton X-ray space observatory, astronomers have discovered a new bright X-ray source that hosts a stellar-mass black hole accreting mass at a very high rate. The source's location in an external galaxy allowed the astronomers to probe the emission both from the black hole's accretion disc, at X-ray wavelengths, and from its jets, in radio waves. These observations revealed, for the first time in an extragalactic stellar-mass black hole, the link between the source's X-ray brightening and the ejection of radio-bright material from the vicinity of the black hole into the jets, indicating an accretion rate close to the black hole's Eddington limit, or even above it.
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Blobrana


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Posts: 131433
Date:
M31 ULX-2
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Astronomers discover "missing link" of black holes

The discovery of a bingeing black hole in our nearest neighbouring galaxy, Andromeda, has shed new light on some of the brightest X-ray sources seen in other galaxies, according to new work co-authored by astronomers from the International Centre for Radio Astronomy Research's Curtin University node.
Using a suite of Earth-orbiting X-ray telescopes, including NASA's Swift and the European Space Agency's XMM-Newton satellites, a large international team of astronomers watched as the X-ray emission from the black hole - found over 2million light years away - brightened and faded over the course of six months.
The study, published in the prestigious scientific journal Nature, also shows what happens when black holes feast rapidly on the material stripped from a companion star.
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