Super-Eddington accretion and ultraluminous X-ray sources
Lead Research Organisation:
Durham University
Department Name: Physics
Abstract
Black holes are amazing concepts, sounding more like science fiction than physics, where they get linked to time travel, faster-than-light space travel via wormholes, and portals to other universes. In reality, they are the ultimate triumph of gravity, with spacetime so warped that not even light can escape. There is lots of evidence that such extreme objects really do exist in our Universe, and they are most spectacularly seen where gas is captured - accreted - onto the black hole. The spiralling, infalling matter can convert some of its immense gravitational potential energy into high-energy X and gamma-ray emission before disappearing forever below the event horizon. It is this copious X-ray emission from accretion which led to the discovery of 'real' black holes, transforming them from a speculative theoretical concept of Einstein's gravity to mainstream science. Despite their exotic nature, black holes are actually very simple systems. The general rule is that the higher the rate at which material accretes onto the black hole, and the bigger the mass of the black hole, the brighter it shines. The mass of black holes formed from collapse of the most massive stars is limited to around 20x the mass of our Sun, so the brightness of these systems is determined by the rate at which a binary companion star supplies the accreting matter. However, when the accretion rate becomes sufficiently extreme, the energy radiated from close to the black hole is so intense that it is able to disrupt the flow of material inwards, blowing it out in a wind and halting further accretion. This combination of a limit on the mass and mass accretion rate means a limit on the brightness of black hole binary systems. Yet we see sources which are more luminous than this limit! These 'ultraluminous X-ray sources' (ULXs for short) either then require a new and exotic formation mechanism to produce bigger black holes or a new and exotic way to circumvent the luminosity limit. Recent studies show a clear preference for the latter explanation. While these objects are relatively rare, with no more than 1 on average per Milky Way-sized galaxy, they are seen in much larger numbers in galaxies undergoing a period of very rapid star formation ('starburst' galaxies). This makes it most likely that ULXs are black holes that accrete from short-lived but very massive young stars (20 - 40 times bigger than our own Sun), with these giant stars providing the perfect reservior of material to rapidly supply the black hole. If this is true then somehow accretion flows can be brighter than the limit at which they should blow themselves apart! We will critically test the idea that ULX are 'normal' black holes accreting at extreme rates. Firstly, we will compile the largest ever catalogue of binaries in other galaxies to see if this shows the expected transition between ULX behaviour and 'normal' accretion flows seen in standard black hole binary systems. Secondly, we will develop the best computer models of extreme accretion flows. Current simulations of the wind from these extreme accretion flows show that this is dense enough to scatter the intrinsic emission many times before it can escape from the flow. We will calculate how this distorts the observed emission and variability, and compare this to the real X-ray data - from the world's foremost X-ray observatories like XMM-Newton, Chandra, Swift and RXTE - to assess whether our physical understanding is correct. This work focuses on the ULXs, but understanding extreme accretion rates is also important in understanding the growth of the first black holes which power the first quasars in the early Universe, and their impact on the formation of galaxies.
Publications
Chiang C
(2010)
An additional soft X-ray component in the dim low/hard state of black hole binaries
in Monthly Notices of the Royal Astronomical Society
Done C
(2012)
Intrinsic disc emission and the soft X-ray excess in active galactic nuclei The soft X-ray excess in AGN
in Monthly Notices of the Royal Astronomical Society
DONE C
(2012)
OBSERVATIONAL CONSTRAINTS ON STRONG GRAVITY
in International Journal of Modern Physics D
Done C
(2010)
A re-analysis of the iron line in the XMM-Newton data from the low/hard state in GX339-4 The low/hard state iron line in GX339-4
in Monthly Notices of the Royal Astronomical Society
Fanidakis N
(2012)
The evolution of active galactic nuclei across cosmic time: what is downsizing? The evolution of AGNs across cosmic time
in Monthly Notices of the Royal Astronomical Society
Fanidakis N
(2011)
Grand unification of AGN activity in the ?CDM cosmology Grand unification of AGN activity
in Monthly Notices of the Royal Astronomical Society
Feroci M
(2011)
The Large Observatory for X-ray Timing (LOFT)
in Experimental Astronomy
Gladstone J
(2011)
Unlocking the nature of ultraluminous X-ray sources using their X-ray spectra
in Astronomische Nachrichten
Gruyters P
(2012)
A VLT VIMOS IFU study of the ionisation nebula surrounding the supersoft X-ray source CAL 83
in Astronomy & Astrophysics
Hiemstra B
(2011)
A strong and broad Fe line in the XMM-Newton spectrum of the new X-ray transient and black hole candidate XTE J1652-453 XTE J1652-453 in the hard-intermediate state
in Monthly Notices of the Royal Astronomical Society
Ingram A
(2012)
Modelling variability in black hole binaries: linking simulations to observations Physical PSD model
in Monthly Notices of the Royal Astronomical Society
Ingram A
(2012)
The effect of frame dragging on the iron Ka line in X-ray binaries Frame dragging and the iron line
in Monthly Notices of the Royal Astronomical Society
Ingram A
(2010)
A physical interpretation of the variability power spectral components in accreting neutron stars Power spectra of atolls
in Monthly Notices of the Royal Astronomical Society
Ingram A
(2011)
A physical model for the continuum variability and quasi-periodic oscillation in accreting black holes Physical PSD model
in Monthly Notices of the Royal Astronomical Society
Irwin J
(2010)
EVIDENCE FOR A STELLAR DISRUPTION BY AN INTERMEDIATE-MASS BLACK HOLE IN AN EXTRAGALACTIC GLOBULAR CLUSTER
in The Astrophysical Journal
Jackson F
(2012)
On the nature of high X-ray luminosities in Sloan Digital Sky Survey galaxies High X-ray luminosities in SDSS galaxies
in Monthly Notices of the Royal Astronomical Society
Jenkins L
(2011)
INVESTIGATING THE NUCLEAR ACTIVITY OF BARRED SPIRAL GALAXIES: THE CASE OF NGC 1672
in The Astrophysical Journal
Jin C
(2012)
A combined optical and X-ray study of unobscured type 1 active galactic nuclei - II. Relation between X-ray emission and optical spectra A spectral study of type 1 AGNs - II
in Monthly Notices of the Royal Astronomical Society
Jin C
(2012)
A combined optical and X-ray study of unobscured type 1 active galactic nuclei - III. Broad-band SED properties A spectral study of type 1 AGNs - III
in Monthly Notices of the Royal Astronomical Society
Jin C
(2012)
A combined optical and X-ray study of unobscured type 1 active galactic nuclei - I. Optical spectra and spectral energy distribution modelling A spectral study of unobscured type 1 AGNs - I
in Monthly Notices of the Royal Astronomical Society
Jonker P
(2012)
THE NATURE OF THE BRIGHT ULX X-2 IN NGC 3921: A CHANDRA POSITION AND HST CANDIDATE COUNTERPART
in The Astrophysical Journal
Kolehmainen M
(2011)
Modelling the high-mass accretion rate spectra of GX 339-4: black hole spin from reflection? High-mass accretion in GX 339-4
in Monthly Notices of the Royal Astronomical Society
Kolehmainen M
(2010)
Limits on spin determination from disc spectral fitting in GX 339-4 Black hole spin from disc spectra in GX 339-4
in Monthly Notices of the Royal Astronomical Society
Kubota A
(2010)
TESTING ACCRETION DISK STRUCTURE WITH SUZAKU DATA OF LMC X-3
in The Astrophysical Journal
Lachowicz P
(2010)
Quasi-periodic oscillations under wavelet microscope: the application of Matching Pursuit algorithm
in Astronomy and Astrophysics
Lehmer B
(2010)
A CHANDRA PERSPECTIVE ON GALAXY-WIDE X-RAY BINARY EMISSION AND ITS CORRELATION WITH STAR FORMATION RATE AND STELLAR MASS: NEW RESULTS FROM LUMINOUS INFRARED GALAXIES
in The Astrophysical Journal
Liu B
(2011)
THE EFFECT OF CORONAL RADIATION ON A RESIDUAL INNER DISK IN THE LOW/HARD SPECTRAL STATE OF BLACK HOLE X-RAY BINARY SYSTEMS
in The Astrophysical Journal
Luangtip W
(2015)
A deficit of ultraluminous X-ray sources in luminous infrared galaxies
in Monthly Notices of the Royal Astronomical Society
Mezcua M
(2013)
Radio observations of extreme ULXs: revealing the most powerful ULX radio nebula ever or the jet of an intermediate-mass black hole?
in Monthly Notices of the Royal Astronomical Society
Middleton M
(2012)
The missing link: a low-mass X-ray binary in M31 seen as an ultraluminous X-ray source The missing link: a LMXB in M31 seen as a ULX
in Monthly Notices of the Royal Astronomical Society
Middleton M
(2012)
Identifying a new intermediate polar using XMM-Newton and INTEGRAL Identifying a new IP using XMM and INTEGRAL
in Monthly Notices of the Royal Astronomical Society
Middleton M
(2011)
Does NGC 5408 X-1 really contain an intermediate-mass black hole?
in Astronomische Nachrichten
Middleton M
(2010)
The X-ray binary analogy to the first AGN quasi-periodic oscillation
in Monthly Notices of the Royal Astronomical Society
Middleton M
(2011)
Searching for the trigger of the active galactic nucleus quasi-periodic oscillation: 8 years of RE J1034+396 8 years of RE J1034+396
in Monthly Notices of the Royal Astronomical Society
Middleton M
(2011)
Challenging times: a re-analysis of NGC 5408 X-1 A re-analysis of NGC 5408 X-1
in Monthly Notices of the Royal Astronomical Society
Middleton M
(2011)
X-ray spectral evolution in the ultraluminous X-ray source M33 X-8 X-ray spectral evolution in M33 X-8
in Monthly Notices of the Royal Astronomical Society
Middleton MJ
(2013)
Bright radio emission from an ultraluminous stellar-mass microquasar in M 31.
in Nature
Prestwich A
(2012)
CHANDRA OBSERVATIONS OF THE COLLISIONAL RING GALAXY NGC 922
in The Astrophysical Journal
Rasmussen J
(2012)
HOT AND COLD GALACTIC GAS IN THE NGC 2563 GALAXY GROUP
in The Astrophysical Journal
Richings A
(2010)
THE HOT INTERSTELLAR MEDIUM OF THE INTERACTING GALAXY NGC 4490
in The Astrophysical Journal
Roberts T
(2012)
A VARIABLE ULTRALUMINOUS X-RAY SOURCE IN A GLOBULAR CLUSTER IN NGC 4649
in The Astrophysical Journal
Roberts T
(2011)
(No) dynamical constraints on the mass of the black hole in two ULXs
in Astronomische Nachrichten
Russell D
(2011)
New observations of ULX supershells, and their implications
in Astronomische Nachrichten
Sobolewska M
(2011)
Evidence for a change in the X-ray radiation mechanism in the hard state of Galactic black holes GBH hard-state X-ray radiation mechanism change
in Monthly Notices of the Royal Astronomical Society
Straub O
(2013)
The effect of advection at luminosities close to Eddington: The ULX in M 31
in Astronomy & Astrophysics
Sutton A
(2012)
The most extreme ultraluminous X-ray sources: evidence for intermediate-mass black holes? The most extreme ULXs: evidence for IMBHs?
in Monthly Notices of the Royal Astronomical Society
Sutton A
(2011)
Key results from an XMM-Newton and Chandra study of a new sample of extreme ULXs from the 2XMM catalogue
in Astronomische Nachrichten
Tamura M
(2012)
THE TRUNCATED DISK FROM SUZAKU DATA OF GX 339-4 IN THE EXTREME VERY HIGH STATE
in The Astrophysical Journal
Torii S
(2011)
Spectral and Timing Studies of Cyg X-1 in the Low/Hard State with Suzaku
in Publications of the Astronomical Society of Japan
Description | We discovered that the brightest X-ray sources in nearby galaxies, excluding those located at the galaxy centres, are likely to be powered by a new, extreme process of material accretion on to relatively small black holes (about 10 times the mass of our Sun). |
Exploitation Route | The results will form the basis for developing a better understanding of these new, extreme accretion modes. |
Sectors | Education,Culture, Heritage, Museums and Collections |
Description | International Exchanges Scheme |
Amount | £3,000 (GBP) |
Funding ID | IE110366 |
Organisation | The Royal Society |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 02/2012 |
End | 05/2012 |
Description | JAXA ASTRO-H Science Team |
Organisation | Japanese Aerospace Exploration Agency |
Department | Institute of Space and Astronautical Science |
Country | Japan |
Sector | Academic/University |
PI Contribution | Potential science goals for the ASTRO-H satellite |
Collaborator Contribution | Potential science goals for the ASTRO-H satellite |
Impact | publications |
Start Year | 2009 |
Description | JAXA Suzaku Science Team |
Organisation | Japanese Aerospace Exploration Agency |
Department | Institute of Space and Astronautical Science |
Country | Japan |
Sector | Academic/University |
PI Contribution | Science exploitation of Suzaku results |
Collaborator Contribution | Science exploitation of Suzaku results |
Impact | publications |
Start Year | 2006 |
Description | Press release 1 |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Press release to media, publicising a result picked up by several international outlets (MSNBC, Voice of America, French Tribune |
Year(s) Of Engagement Activity | 2012 |
Description | Press release 2 |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | press release picked up by many media outlets, interviews with several online outlets. Press coverage including TV news in Australia, local & international press stories, interview on Naked Scientist podcast. |
Year(s) Of Engagement Activity | 2012 |