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
Arevalo P
(2006)
Spectral-timing evidence for a very high state in the narrow-line Seyfert 1 Ark 564
in Monthly Notices of the Royal Astronomical Society
McHardy I
(2007)
Simultaneous X-ray and infrared variability in the quasar 3C273 - II. Confirmation of the correlation and X-ray lag X-ray and IR variability in 3C273 - II
in Monthly Notices of the Royal Astronomical Society
Witham A
(2006)
The properties of cataclysmic variables in photometric Ha surveys Properties of CVs in Ha surveys
in Monthly Notices of the Royal Astronomical Society
Fender R
(2009)
An anticorrelation between X-ray luminosity and Ha equivalent width in X-ray binaries
in Monthly Notices of the Royal Astronomical Society
Coe M
(2007)
Now you see it, now you don't - the circumstellar disc in the GRO J1008-57 system
in Monthly Notices of the Royal Astronomical Society
Schurch M
(2009)
High-mass X-ray binary SXP18.3 undergoes the longest type II outburst ever seen in the Small Magellanic Cloud
in Monthly Notices of the Royal Astronomical Society
Sale S
(2009)
High spatial resolution Galactic 3D extinction mapping with IPHAS
in Monthly Notices of the Royal Astronomical Society
Niemela V
(2008)
The very massive X-ray bright binary system Wack 2134 (= WR 21a) ?
in Monthly Notices of the Royal Astronomical Society
Miller-Jones J
(2008)
Zooming in on a sleeping giant: milliarcsecond High Sensitivity Array imaging of the black hole binary V404 Cyg in quiescence
in Monthly Notices of the Royal Astronomical Society
Breedt E
(2010)
Twelve years of X-ray and optical variability in the Seyfert galaxy NGC 4051 X-ray/optical variability in NGC 4051
in Monthly Notices of the Royal Astronomical Society