High Energy Astrophysics at Southampton
Lead Research Organisation:
University of Southampton
Department Name: Sch of Physics and Astronomy
Abstract
On the smallest scales we are interested in why pulsars seem to favour the low neutral hydrogen environments in the SMC. We are also interested in the products of stellar collisions and near misses in the high density environment of globular clusters, and in studying the compact objects (ie black holes, neutron stars, or white dwarfs) in our Galaxy which are strong emitter of optical light from hydgrogen atoms. Some galactic X-ray binary sources, which consist of black hole of similar mass to our sun together with a more normal star have, as well as accretion discs, through which matter spirals onto the black hole, strong jets. We want to understand the relationship between the emission from jets and from the hot X-ray emitting coronae and to find out how the jet might emerge from the corona. In some cases the disappearance of the inner disc is followed by ejection of material along the jet and we shall determine whether such behaviour is typical in Active Galaxies, ie galaxies whose emission is powered material falling onto (ie being accreted) by a massive black hole. In the 20-100 keV band where absorption of photons by cold gas is unimportant, and so we obtain a very clear view, we are surveying the Galactic Plane with INTEGRAL to determine an unbiased census of compact objects. As time goes on, we will extend that survey to the extragalactic sky. We study the X-ray variability of Active Galaxies to determine how they relate to galactic X-ray binaries sources and whether characteristic timescales reflect only mass or another parameter such as accretion rate. We are interested in the binary populations of nearby galaxies and in the so-called `ultra luminous X-ray sources (ULXs)'. ULXs may be the long sought after black holes with masses intermediate between those of galactic binaries and Active Galaxies and so are very important for testing mass-based scaling relationships. We are interested in how the emission in different wavebands (Gamma-ray, X-ray, optical/IR, radio) in binaries and Active Galaxies is related and what is the dependence on mass. We are interested how the jet emission from Active Galaxies heats clusters of galaxies. On the largest scales, we are interested in whether the different faint source populations which we see in the radio, X-ray and IR bands are just different manifestations of the same underlying phenomenon and how massive black hole growth might be related to growth of the galaxy in which the black hole lives. We are also building detailed theoretical models, using computers, to explain the complicated variability which we see in the sky at high energies.
Organisations
Publications
Pratt G
(2009)
Galaxy cluster X-ray luminosity scaling relations from a representative local sample (REXCESS)
in Astronomy & Astrophysics
Del Santo M
(2009)
Broad-band X-ray spectral evolution of GX 339-4 during a state transition ?
in Monthly Notices of the Royal Astronomical Society
Coe M
(2009)
An X-ray and optical study of the new SMC X-ray binary pulsar system SXP7.92 and its probable optical counterpart, AzV285
in Monthly Notices of the Royal Astronomical Society
Breedt E
(2009)
Long-term optical and X-ray variability of the Seyfert galaxy Markarian 79
in Monthly Notices of the Royal Astronomical Society
Knigge C
(2009)
A binary origin for 'blue stragglers' in globular clusters.
in Nature
De Rosa A
(2009)
Hard X-ray observations of PSR J1833-1034 and its associated pulsar wind nebula
in Monthly Notices of the Royal Astronomical Society
Bird A
(2009)
Discovery of a 30-d period in the supergiant fast X-ray transient SAX J1818.6-1703
in Monthly Notices of the Royal Astronomical Society: Letters
Malizia A
(2009)
IGR J16351-5806: another close by Compton-thick AGN
in Monthly Notices of the Royal Astronomical Society: Letters
Casares J
(2009)
REFINED ORBITAL SOLUTION AND QUIESCENT VARIABILITY IN THE BLACK HOLE TRANSIENT GS 1354-64 (= BW Cir)
in The Astrophysical Journal Supplement Series
Capitanio F
(2009)
THE TWO INTEGRAL X-RAY TRANSIENTS IGR J17091-3624 AND IGR J17098-3628: A MULTIWAVELENGTH LONG-TERM CAMPAIGN
in The Astrophysical Journal