High Energy Astrophysics at Southampton
Lead Research Organisation:
University of Southampton
Department Name: Sch of Physics and Astronomy
Abstract
Our research concerns compact objects, ie white dwarfs, neutron stars and black holes (BHs), both stellar sized and supermassive (SMBHs). We aim to understand how they evolve and how they produce radiation.
X-ray binaries (XRBs), which contain bright accretion discs around BHs and neutron stars, allow detailed examination of how these discs vary. As they vary quickly, many measurements of variability can be made, allowing us to see how variability at different frequencies is tied together. Using these measurements, we can test fundamental ideas about how and why matter falls in through discs. Using variations in the infrared emission, we can look at variations in the jet, and learn how the discs feed the relativistic jets we see in XRBs.
Strong radio emission from the jet often accompanies accretion, particularly in the `hard' state of XRBs. We will investigate how radio emission, as seen in new observatories such as LOFAR and eMERLIN, is related to X-ray emission, as a means of studying the accretion/outflow connection. We will study why, in hard state sources, the potential accretion energy is sometimes converted efficiently into radiation, and sometimes not. We will measure black hole spin, which is important in determining how much of the accretion energy can be liberated as radiation.
Studying massive stars in binary systems and their evolution gives important insight into recent star formation in the Milky Way and nearby galaxies. The evolved stellar population of the SMC points to recent turbulent interactions with its companion galaxy, producing a very active period of star formation. Many of these massive stars have evolved through a supernova phase, producing a large population of neutron stars. Studies of this population are revealing crucial insight into the nature of stellar evolution.
Accreting white dwarfs (AWD) are astrophysically important. They include Type Ia Supernova progenitors, and the processes that drive their evolution are relevant in many other settings. Here we will extend our leading work on the evolution of AWDs and related systems. We will implement a new evolution track for AWDs, directly detect the first sub-stellar secondary, determine the space density of AWD, carry out a search for "dead" AWDs and confirm the first double-degenerate SN Ia progenitor.
We will study the relationship between stellar-mass BHs and SMBHs (ie AGN), asking whether properties such as variability timescales, or time lags between energy bands, scale only with mass, or also with accretion rate. We will see whether AGN which have jets vary differently to those which don't, and if X-rays and Gamma-rays vary differently. We will observe how optical and radio variations are related to X-ray variations in AGN with and without jets. Thus, in different AGN types, we will determine how and where the emissions in different wavebands are produced and why they vary.
The large-scale jets from SMBHs can extend for distances of millions of light years, transporting energy not only to their host galaxy but also to the surrounding group or cluster of galaxies. This energy input plays an important role in how galaxies and clusters form and evolve. We will use new radio facilities, e.g. LOFAR and e-MERLIN, to measure the energetic impact of, and investigate the life cycles of, different populations of radio-loud AGN, to understand their role in
galaxy evolution.
SMBHs exist in the nuclei of possibly all galaxies but are often undetectable due to very low accretion rates. To study these low luminosity AGN, which dominate the local universe, we are making a sensitive radio and X-ray survey of the best-selected sample of nearby galaxies, the Palomar sample, to find faint AGN and determine which host galaxy properties (eg mass, starformation rate) most strongly control AGN luminosity. We will also perform the cleanest measurement yet of how radio emission, X-ray emission and BH mass are related.
X-ray binaries (XRBs), which contain bright accretion discs around BHs and neutron stars, allow detailed examination of how these discs vary. As they vary quickly, many measurements of variability can be made, allowing us to see how variability at different frequencies is tied together. Using these measurements, we can test fundamental ideas about how and why matter falls in through discs. Using variations in the infrared emission, we can look at variations in the jet, and learn how the discs feed the relativistic jets we see in XRBs.
Strong radio emission from the jet often accompanies accretion, particularly in the `hard' state of XRBs. We will investigate how radio emission, as seen in new observatories such as LOFAR and eMERLIN, is related to X-ray emission, as a means of studying the accretion/outflow connection. We will study why, in hard state sources, the potential accretion energy is sometimes converted efficiently into radiation, and sometimes not. We will measure black hole spin, which is important in determining how much of the accretion energy can be liberated as radiation.
Studying massive stars in binary systems and their evolution gives important insight into recent star formation in the Milky Way and nearby galaxies. The evolved stellar population of the SMC points to recent turbulent interactions with its companion galaxy, producing a very active period of star formation. Many of these massive stars have evolved through a supernova phase, producing a large population of neutron stars. Studies of this population are revealing crucial insight into the nature of stellar evolution.
Accreting white dwarfs (AWD) are astrophysically important. They include Type Ia Supernova progenitors, and the processes that drive their evolution are relevant in many other settings. Here we will extend our leading work on the evolution of AWDs and related systems. We will implement a new evolution track for AWDs, directly detect the first sub-stellar secondary, determine the space density of AWD, carry out a search for "dead" AWDs and confirm the first double-degenerate SN Ia progenitor.
We will study the relationship between stellar-mass BHs and SMBHs (ie AGN), asking whether properties such as variability timescales, or time lags between energy bands, scale only with mass, or also with accretion rate. We will see whether AGN which have jets vary differently to those which don't, and if X-rays and Gamma-rays vary differently. We will observe how optical and radio variations are related to X-ray variations in AGN with and without jets. Thus, in different AGN types, we will determine how and where the emissions in different wavebands are produced and why they vary.
The large-scale jets from SMBHs can extend for distances of millions of light years, transporting energy not only to their host galaxy but also to the surrounding group or cluster of galaxies. This energy input plays an important role in how galaxies and clusters form and evolve. We will use new radio facilities, e.g. LOFAR and e-MERLIN, to measure the energetic impact of, and investigate the life cycles of, different populations of radio-loud AGN, to understand their role in
galaxy evolution.
SMBHs exist in the nuclei of possibly all galaxies but are often undetectable due to very low accretion rates. To study these low luminosity AGN, which dominate the local universe, we are making a sensitive radio and X-ray survey of the best-selected sample of nearby galaxies, the Palomar sample, to find faint AGN and determine which host galaxy properties (eg mass, starformation rate) most strongly control AGN luminosity. We will also perform the cleanest measurement yet of how radio emission, X-ray emission and BH mass are related.
Planned Impact
The Astronomy Group has achieved significant impact in both its outreach activities and in knowledge exchange. The School's outreach work reaches a large number of people (typically 9000 per year), in which astronomy plays a central role. While these activities have traditionally focussed on the general public and students, more recently there have been targetted opportunities to give support to teachers, such as the School's partnership with the local Science Learning Centre. Thus we have been able to provide input and support to the teachers which can have much longer-term value for their future teaching of basic scientific principles. Our outreach activities, including teacher support, is enhanced through the new Winchester Science Centre and Planetarium, in which the Astronomy Group plays a significant role. There have also been many opportunities for Astronomy Group members to participate in science open days, fairs and cafes, interest in which has exploded following the highly successful International Year of Astronomy in 2009.
Exploiting astronomy research in completely different environments and communities has always been important in the Astronomy Group whenever
appropriate circumstances arise, and our work has recently provided two examples of such knowledge exchange. Both were related to the
mathematical techniques that had to be developed in order to model the rapid variability observed in X-ray binaries and AGN. The techniques
themselves were of interest to the University's own Complexity Group, whilst the students involved in developing the techniques for their
theses obtained positions in the financial world where these techniques have the potential to be applied to the variability of stocks and shares. Furthermore, the Astronomy Group's years of developing satellite hardware led to the creation of Symetrica, a now highly successful spin-off company in the international security market, who have in turn funded PhD studentships and participate in supporting our undergraduate projects.
Exploiting astronomy research in completely different environments and communities has always been important in the Astronomy Group whenever
appropriate circumstances arise, and our work has recently provided two examples of such knowledge exchange. Both were related to the
mathematical techniques that had to be developed in order to model the rapid variability observed in X-ray binaries and AGN. The techniques
themselves were of interest to the University's own Complexity Group, whilst the students involved in developing the techniques for their
theses obtained positions in the financial world where these techniques have the potential to be applied to the variability of stocks and shares. Furthermore, the Astronomy Group's years of developing satellite hardware led to the creation of Symetrica, a now highly successful spin-off company in the international security market, who have in turn funded PhD studentships and participate in supporting our undergraduate projects.
Organisations
Publications
Brinkworth C
(2013)
MEASURING THE ROTATIONAL PERIODS OF ISOLATED MAGNETIC WHITE DWARFS
in The Astrophysical Journal
Pretorius M
(2013)
The space density of magnetic cataclysmic variables
in Monthly Notices of the Royal Astronomical Society
Scaringi S
(2013)
Broad-band timing properties of the accreting white dwarf MV Lyrae
in Monthly Notices of the Royal Astronomical Society
Emmanoulopoulos D
(2013)
X-ray spectral analysis of the low-luminosity active galactic nucleus NGC 7213 using long XMM-Newton observations?
in Monthly Notices of the Royal Astronomical Society
Fiocchi M
(2013)
THE INTEGRAL SOURCE IGR J16328-4726: A HIGH-MASS X-RAY BINARY FROM THE BEPPOSAX ERA
in The Astrophysical Journal
Rajoelimanana A
(2013)
Optical and X-ray properties of CAL 83 - I. Quasi-periodic optical and supersoft variability
in Monthly Notices of the Royal Astronomical Society
Van Haarlem M
(2013)
LOFAR: The LOw-Frequency ARray
in Astronomy & Astrophysics
Cornelisse R
(2013)
The origin of the tilted disc in the low-mass X-ray binary GR Mus (XB 1254-690)
in Monthly Notices of the Royal Astronomical Society
Huppenkothen D
(2013)
QUASI-PERIODIC OSCILLATIONS AND BROADBAND VARIABILITY IN SHORT MAGNETAR BURSTS
in The Astrophysical Journal
Fender R
(2013)
The closest black holes
in Monthly Notices of the Royal Astronomical Society
Muñoz-Darias T
(2013)
Inclination and relativistic effects in the outburst evolution of black hole transients
in Monthly Notices of the Royal Astronomical Society
Skipper C
(2013)
Very fast X-ray spectral variability in Cygnus X-1: origin of the hard- and soft-state emission components
in Monthly Notices of the Royal Astronomical Society
Jonker P
(2013)
DISCOVERY OF A NEW KIND OF EXPLOSIVE X-RAY TRANSIENT NEAR M86
in The Astrophysical Journal
Heinz S
(2013)
THE YOUNGEST KNOWN X-RAY BINARY: CIRCINUS X-1 AND ITS NATAL SUPERNOVA REMNANT
in The Astrophysical Journal
Kalamkar M
(2013)
SWIFT X-RAY TELESCOPE TIMING OBSERVATIONS OF THE BLACK HOLE BINARY SWIFT J1753.5-0127: DISK-DILUTED FLUCTUATIONS IN THE OUTBURST PEAK
in The Astrophysical Journal
Alston W
(2013)
The flux-dependent X-ray time lags in NGC 4051
in Monthly Notices of the Royal Astronomical Society
Cassatella P
(2013)
Accretion flow diagnostics with X-ray spectral timing: the hard state of SWIFT J1753.5-0127
in Monthly Notices of the Royal Astronomical Society
Staley T
(2013)
Automated rapid follow-up of Swift gamma-ray burst alerts at 15 GHz with the AMI Large Array
in Monthly Notices of the Royal Astronomical Society
Soleri P
(2013)
A complex state transition from the black hole candidate Swift J1753.5-0127
in Monthly Notices of the Royal Astronomical Society
Bartlett E
(2013)
Timing and spectral analysis of the unusual X-ray transient XTE J0421+560/CI Camelopardalis
in Monthly Notices of the Royal Astronomical Society
Norris R
(2013)
Radio Continuum Surveys with Square Kilometre Array Pathfinders
in Publications of the Astronomical Society of Australia
Curran P
(2013)
The evolving polarized jet of black hole candidate Swift J1745-26
in Monthly Notices of the Royal Astronomical Society
Wykes S
(2013)
Mass entrainment and turbulence-driven acceleration of ultra-high energy cosmic rays in Centaurus A
in Astronomy & Astrophysics
Acharya B
(2013)
Introducing the CTA concept
in Astroparticle Physics
Drave S
(2013)
INTEGRAL and XMM-Newton observations of IGR J16418-4532: evidence of accretion regime transitions in a supergiant fast X-ray transient
in Monthly Notices of the Royal Astronomical Society
De Marco B
(2013)
Discovery of a relation between black hole mass and soft X-ray time lags in active galactic nuclei
in Monthly Notices of the Royal Astronomical Society
Brocksopp C
(2013)
XTE J1752-223 in outburst: a persistent radio jet, dramatic flaring, multiple ejections and linear polarization
in Monthly Notices of the Royal Astronomical Society
Armas Padilla M
(2014)
Swift J1357.2-0933: the faintest black hole?
in Monthly Notices of the Royal Astronomical Society
Uttley P
(2014)
Multi-Wavelength Variability Accretion and Ejection at the Fastest Timescales
in Space Science Reviews
Parisi P
(2014)
Accurate classification of 75 counterparts of objects detected in the 54-month Palermo Swift /BAT hard X-ray catalogue
in Astronomy & Astrophysics
Kara E
(2014)
The curious time lags of PG 1244+026: discovery of the iron K reverberation lag
in Monthly Notices of the Royal Astronomical Society: Letters
Higginbottom N
(2014)
LINE-DRIVEN DISK WINDS IN ACTIVE GALACTIC NUCLEI: THE CRITICAL IMPORTANCE OF IONIZATION AND RADIATIVE TRANSFER
in The Astrophysical Journal
Connolly S.D.
(2014)
The largest Swift AGN monitoring campaign: UV/optical variability in NGC 5548
in Proceedings of Science
Kelly B
(2014)
FLEXIBLE AND SCALABLE METHODS FOR QUANTIFYING STOCHASTIC VARIABILITY IN THE ERA OF MASSIVE TIME-DOMAIN ASTRONOMICAL DATA SETS
in The Astrophysical Journal
Plant D
(2014)
Revealing accretion on to black holes: X-ray reflection throughout three outbursts of GX 339-4
in Monthly Notices of the Royal Astronomical Society
Fender R
(2014)
An Overview of Jets and Outflows in Stellar Mass Black Holes
in Space Science Reviews
McHardy I
(2014)
Swift monitoring of NGC 5548: X-ray reprocessing and short-term UV/optical variability
in Monthly Notices of the Royal Astronomical Society
Malizia A
(2014)
THE INTEGRAL HIGH-ENERGY CUT-OFF DISTRIBUTION OF TYPE 1 ACTIVE GALACTIC NUCLEI
in The Astrophysical Journal
Bassani L
(2014)
The counterpart/s of IGR J20159+3713/SWIFT J2015.9+3715: dissecting a complex region with emission from keV to TeV
in Astronomy & Astrophysics
Deane RP
(2014)
A close-pair binary in a distant triple supermassive black hole system.
in Nature
Caccianiga A
(2014)
SDSS J143244.91+301435.3: a link between radio-loud narrow-line Seyfert 1 galaxies and compact steep-spectrum radio sources?
in Monthly Notices of the Royal Astronomical Society
Coenen T
(2014)
The LOFAR pilot surveys for pulsars and fast radio transients
in Astronomy & Astrophysics
Uttley P
(2014)
X-ray reverberation around accreting black holes
in The Astronomy and Astrophysics Review
Emmanoulopoulos D
(2014)
General relativistic modelling of the negative reverberation X-ray time delays in AGN?
in Monthly Notices of the Royal Astronomical Society
Neilsen J
(2014)
A LINK BETWEEN X-RAY EMISSION LINES AND RADIO JETS IN 4U 1630-47?
in The Astrophysical Journal
Barentsen G
(2014)
The second data release of the INT Photometric Ha Survey of the Northern Galactic Plane (IPHAS DR2)
in Monthly Notices of the Royal Astronomical Society
Milone A
(2014)
The M 4 Core Project with HST - II. Multiple stellar populations at the bottom of the main sequence
in Monthly Notices of the Royal Astronomical Society
Ramakrishnan V
(2014)
The connection between the parsec-scale radio jet and ?-ray flares in the blazar 1156+295
in Monthly Notices of the Royal Astronomical Society
Jelic V
(2014)
Initial LOFAR observations of epoch of reionization windows II. Diffuse polarized emission in the ELAIS-N1 field
in Astronomy & Astrophysics
Schady P
(2014)
Herschel observations of gamma-ray burst host galaxies: implications for the topology of the dusty interstellar medium
in Astronomy & Astrophysics
| Description | This grant comprised of allocations to 3 separate research areas: Disc-jet coupling (Fender), AGN feedback in groups and clusters (Croston) and AGN variability (McHardy). In Disc-Jet coupling a major discovery of the ubiquity of winds from the accretion discs in soft state X-ray binary systems was made. Also a new track was found in the relationship between X-ray and radio luminosities of X-ray binaries, casting doubt on the assumption that only one mode of emission (inefficient) occurred in hard state X-ray binary systems. In AGN feedback, questions have been posed regarding the validity of our understanding of radio relics by the observation (in X-rays) of shocks with very different velocities to those expected on the basis of the radio observations. In AGN variability we published the first major General Relativistic modelling survey of Fourier-resolved X-ray lags in AGN. We were able to measure black hole masses, black hole spin and the size of the X-ray source. Also, we made the first detailed study of the size of AGN accretion discs by careful measurement of the lags between the X-ray, UV and optical wavebands. We found the discs to be three times larger than expected based on the standard theoretical model for accretion discs which all astronomers have relied on for over 40 years. |
| Exploitation Route | Others will wish to investigate further the results mentioned above. Eg large observational programmes are now being carried out using the NASA Swift X-ray observatory to measure X-ray/UV/optical lags in more AGN. |
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| URL | http://adsabs.harvard.edu/abstract_service.html |