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
Jonker P
(2013)
DISCOVERY OF A NEW KIND OF EXPLOSIVE X-RAY TRANSIENT NEAR M86
in The Astrophysical Journal
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
Oonk J
(2014)
Discovery of carbon radio recombination lines in absorption towards Cygnus A
in Monthly Notices of the Royal Astronomical Society
Scaringi S
(2013)
Discovery of Fourier-dependent time lags in cataclysmic variables
in Monthly Notices of the Royal Astronomical Society
Kara E
(2013)
Discovery of high-frequency iron K lags in Ark 564 and Mrk 335
in Monthly Notices of the Royal Astronomical Society
Schady P
(2012)
Dust and metal column densities in GRB host galaxies
in Proceedings of the International Astronomical Union
Guidetti D
(2013)
e-MERLIN observations at 5 GHz of the GOODS-N region: pinpointing AGN cores in high-redshift galaxies
in Monthly Notices of the Royal Astronomical Society
Coti Zelati F
(2014)
Engulfing a radio pulsar: the case of PSR J1023+0038
in Monthly Notices of the Royal Astronomical Society
Konar C
(2013)
Episodic radio galaxies J0116-4722 and J1158+2621: can we constrain the quiescent phase of nuclear activity?
in Monthly Notices of the Royal Astronomical Society
McHardy I
(2023)
First detection of the outer edge of an AGN accretion disc: very fast multiband optical variability of NGC 4395 with GTC/HiPERCAM and LT/IO:O
in Monthly Notices of the Royal Astronomical Society
Van Weeren R
(2012)
First LOFAR observations at very low frequencies of cluster-scale non-thermal emission: the case of Abell 2256
in Astronomy & Astrophysics
Molina M
(2012)
Flat-spectrum radio sources as likely counterparts of unidentified INTEGRAL sources
in Astronomy & Astrophysics
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
Corbel S
(2013)
Formation of the compact jets in the black hole GX 339-4
in Monthly Notices of the Royal Astronomical Society: Letters
Kapinska A
(2013)
Fundamental parameters of FR II radio galaxies and their impact on groups and clusters' environments
in Astronomische Nachrichten
Kapinska A
(2012)
Fundamental properties of Fanaroff-Riley type II radio galaxies investigated via Monte Carlo simulations Fundamental properties of FR II radio galaxies
in Monthly Notices of the Royal Astronomical Society
Lal D
(2013)
GAS SLOSHING AND RADIO GALAXY DYNAMICS IN THE CORE OF THE 3C 449 GROUP
in The Astrophysical Journal
Emmanoulopoulos D
(2014)
General relativistic modelling of the negative reverberation X-ray time delays in AGN?
in Monthly Notices of the Royal Astronomical Society
Emmanoulopoulos D
(2013)
Generating artificial light curves: revisited and updated
in Monthly Notices of the Royal Astronomical Society
Walton D
(2013)
HARD X-RAY LAGS IN ACTIVE GALACTIC NUCLEI: TESTING THE DISTANT REVERBERATION HYPOTHESIS WITH NGC 6814
in The Astrophysical Journal
Molina M
(2013)
Hard-X-ray spectra of active galactic nuclei in the INTEGRAL complete sample
in Monthly Notices of the Royal Astronomical Society
Schady P
(2014)
Herschel observations of gamma-ray burst host galaxies: implications for the topology of the dusty interstellar medium
in Astronomy & Astrophysics
Cigan P
(2016)
HERSCHEL SPECTROSCOPIC OBSERVATIONS OF LITTLE THINGS DWARF GALAXIES
in The Astronomical Journal
Britt C
(2013)
IDENTIFICATION OF FIVE INTERACTING BINARIES IN THE GALACTIC BULGE SURVEY
in The Astrophysical Journal
Bassani L
(2012)
IGR J12319-0749: evidence for another extreme blazar found with INTEGRAL
in Astronomy & Astrophysics
Molina M
(2014)
IGR J17488-2338: a newly discovered giant radio galaxy
in Astronomy & Astrophysics
Muñoz-Darias T
(2013)
Inclination and relativistic effects in the outburst evolution of black hole transients
in Monthly Notices of the Royal Astronomical Society
Greiss S
(2012)
INITIAL DATA RELEASE OF THE KEPLER -INT SURVEY
in The Astronomical Journal
Jelic V
(2014)
Initial LOFAR observations of epoch of reionization windows II. Diffuse polarized emission in the ELAIS-N1 field
in Astronomy & Astrophysics
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
Acharya B
(2013)
Introducing the CTA concept
in Astroparticle Physics
Russell D
(2013)
Jet spectral breaks in black hole X-ray binaries
in Monthly Notices of the Royal Astronomical Society
Cassatella P
(2012)
Joint spectral-timing modelling of the hard lags in GX 339-4: constraints on reflection models Modelling of the hard lags in GX 339-4
in Monthly Notices of the Royal Astronomical Society
Higginbottom N
(2014)
LINE-DRIVEN DISK WINDS IN ACTIVE GALACTIC NUCLEI: THE CRITICAL IMPORTANCE OF IONIZATION AND RADIATIVE TRANSFER
in The Astrophysical Journal
Van Haarlem M
(2013)
LOFAR: The LOw-Frequency ARray
in Astronomy & Astrophysics
Grinberg V
(2014)
Long term variability of Cygnus X-1 VI. Energy-resolved X-ray variability 1999-2011
in Astronomy & Astrophysics
Fabian A
(2013)
Long XMM observation of the narrow-line Seyfert 1 galaxy IRAS 13224-3809: rapid variability, high spin and a soft lag
in Monthly Notices of the Royal Astronomical Society
Connolly S
(2014)
Long-term wind-driven X-ray spectral variability of NGC 1365 with Swift
in Monthly Notices of the Royal Astronomical Society
De Gasperin F
(2012)
M 87 at metre wavelengths: the LOFAR picture
in Astronomy & Astrophysics
Wykes S
(2013)
Mass entrainment and turbulence-driven acceleration of ultra-high energy cosmic rays in Centaurus A
in Astronomy & Astrophysics
Brinkworth C
(2013)
MEASURING THE ROTATIONAL PERIODS OF ISOLATED MAGNETIC WHITE DWARFS
in The Astrophysical Journal
Cackett E
(2014)
Modelling the broad Fe Ka reverberation in the AGN NGC 4151
in Monthly Notices of the Royal Astronomical Society
Foster D
(2013)
Monitoring the very-long-term variability of X-ray sources in the giant elliptical galaxy M87
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
Ogrean G
(2014)
Multiple density discontinuities in the merging galaxy cluster CIZA J2242.8+5301
in Monthly Notices of the Royal Astronomical Society
Ponti G
(2012)
Multiwavelength campaign on Mrk 509 XI. Reverberation of the Fe K a line
in Astronomy & Astrophysics
Drave S
(2014)
New insights on accretion in supergiant fast X-ray transients from XMM-Newton and INTEGRAL observations of IGR J17544-2619
in Monthly Notices of the Royal Astronomical Society
Hoard D
(2014)
NOVA-LIKE CATACLYSMIC VARIABLES IN THE INFRARED
in The Astrophysical Journal
Leigh N
(2012)
Nuclear star clusters and the stellar spheroids of their host galaxies Nuclear clusters and their host spheroids
in Monthly Notices of the Royal Astronomical Society
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. |
Sectors | Education Leisure Activities including Sports Recreation and Tourism Culture Heritage Museums and Collections |
URL | http://adsabs.harvard.edu/abstract_service.html |