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This page written by Graziella Branduardi-Raymont (gbr@mssl.ucl.ac.uk).
Last modified 10th July 2006
Posters abstracts
| Session 1: Clusters, galaxies and AGN | |||||||
1-1 Rowan Temple (Birmingham)
Background subtraction for XMM-Newton observations of extended sources
The XMM-Newton Legacy Large Project is an unbiased sample of 34 galaxy clusters selected from the REFLEX survey. These have all been observed with XMM-Newton recently. In order for detailed cluster modelling to be done, accurate measuring of the observables properties, such as temperature and density profiles, needs to be carried out. To ensure reliable results, accurate treatment of the background is essential. We look at some of the properties of the background, and compare different methods of background subtraction in the form of temperature profiles for a few of the clusters in the sample.
1-2 Yueheng Xu (Leicester)
Normal galaxies in the XMM-2dF survey
The XMM-2dF project aims to optically identify a significant sample of X-ray sources drawn from XMM-Newton observations covering over 10 square degrees using the Two Degree Field system (2dF) on the Anglo-Australian Telescope (AAT). The 2dF observations carried out provide optical spectra for ~3000 potential counterparts to XMM-Newton X-ray sources down to R ~ 21 mag. Of these ~1000 X-ray sources have been positively identified. Here we discuss a sample of 72 galaxies which are the 2dF X-ray counterparts and which show normal or narrow emission line spectra, The sample is selected to exclude canonical broad-line AGN and is thus expected to be dominated by non-active (i.e. "normal") galaxies and low luminosity AGN. We discuss the classification of these galaxies in terms of the underlying emission mechanisms using the X-ray colours and morphology from XMM-Newton and optical spectra from 2dF, combined with the optical morphology. For 10 galaxies in the sample for which the XMM-Newton observations provide sufficient photon counts, we have also carried out a detailed X-ray spectral analysis which allows further refinement of the correct classification.
1-3 Richard Owen (Leicester)
XMM-Newton observations of NGC 3184
Abstract not available
1-4 Lindsey Shaw Greening (Open University)
Cumulative X-ray Luminosity Function for M31
Cumulative luminosity functions and colour-colour diagrams for selected M31 regions are presented. For the first time cumulative luminosity functions have been created for M31 using individual fits for each source rather than an assumed emission model. The 6 selected overlapping XMM-Newton fields along the semi major axis of M31 cover the bulge and part of the disc. A total of 554 point sources were detected and for each source an energy spectrum, power density spectrum and light curve were generated and analysed to determine the source properties and classify each source wherever possible.
1-5 Poshak Gandhi (Cambridge)
Angular clustering of hard X-ray AGN in a large contiguous survey
X-ray point sources detected over 4.2 pseudo-contiguous sq. deg. in the 0.5-2 keV and 2-10 keV bands down to fluxes of 2x10^{-15} and 8x10^{-15} erg/s/cm^2 are analyzed as part of the XMM-Newton Large Scale Structure Survey. We study the two-point angular clustering of point sources using nearest neighbours and correlation function statistics and find a weak, positive signal for ~1130 sources in the 0.5-2 keV band, but no correlation for ~400 sources in the 2-10 keV band below scales of 100 arcsec. A sub-sample of ~200 faint sources with hard X-ray count ratios, that is likely to be dominated by obscured AGN, does show a positive signal with the data allowing for a large scaling of the angular correlation length, but only at the ~2 (3) sigma level, based on re-sampling (Poisson) statistics. Possible implications of the clustering of obscured AGN are discussed and the importance of wider, complete surveys is emphasized in order to fully understand the large scale structure of the X-ray sky.
| Session 2: AGN, galaxies, gamma-ray and un-identified objects | |||||||
2-1 Alex Blustin (UCL/MSSL)
Exceptionally high signal-to-noise XMM-Newton RGS spectroscopy of the ionised outflow from NGC 7469
We present a very high signal-to-noise soft X-ray spectrum of NGC 7469 from a 150 ks observation with the XMM-Newton RGS. This enables us to do detailed spectroscopy on the absorption lines from its ionised outflow (warm absorber). This outflow contains one main ionisation phase with an ionisation parameter of log xi = 2.5, a total absorbing column of 2.9 x 10^21 cm^-2 and a line-of-sight outflow speed of 690 km/s. There is also a broad absorption feature consistent with the presence of an Unresolved Transition Array of M-shell iron (at log xi of ~1), although, interestingly, there is little evidence of the lowly ionised states of oxygen that we would expect to observe accompanying it. We compare our results with previous X-ray spectroscopic observations of this source.
2-2 Rebecca Smith (UCL/MSSL)
The high resolution X-ray spectrum of Mrk 509
We present a detailed analysis of the soft X-ray spectrum of Markarian 509 taken with the Reflection Grating Spectrometer onboard XMM-Newton. The warm absorber is shown to consist of three phases each with a different ionization and column density with outflow velocities ranging from 140 to 492 km/s. Also anlysed is the emission profile, including two broad emission lines due to O VII and C VI, with FWMH = 10300 km/s, and two narrow emission lines due to oxygen.
2-3 Patricia Schady (UCL/MSSL)
The dust and gas content in the local environment of gamma-ray bursts (GRBs)
Swift's capabilities to obtain simultaneous X-ray and optical/UV data make it ideal to probe Gamma-Ray Burst (GRB) local environments and constrain the levels of rest-frame dust extinction and photoelectric absorption from their spectral energy distributions (SEDs). We report on the results from spectral modelling of the X-ray and optical/UV afterglow of eight GRBs detected by Swift. The sample are all at redshifts z<1.75, and were detected with the X-Ray (XRT) and UV/Optical Telescopes (UVOT) on-board. We use the observed SMC, LMC and Galactic extinction curves to model the GRB host galaxy dust and determine the amount of rest-frame visual extinction present in the afterglow. For three GRBs a distinction could not be made between the goodness of fit between the models. Four were best fit by a model with SMC or LMC dust at the host galaxy, and only GRB050802 was better fit by a model with the Galactic absorption feature at 2175 A. The dust-to-gas ratio spanned over three orders of magnitude, and was typically larger than the dust-to-gas ratio observed in pre-Swift GRBs. We investigate the factors that contribute to the extinction and absorption observed in GRB afterglows, and the implications this has on the properties of GRB host galaxies.
2-4 Kim Page (Leicester)
The UK Swift Science Data Centre
The UK Swift Science Data Centre, based at the University of Leicester, is the first point of contact for UK scientists wishing to analyse Swift data. We host quick-look science data from the Swift satellite (usually available within a few hours of the observation), as well as a data archive which will contain the full complement of observations from the mission; the data are publicly accessible to all. As well as providing routine support for Swift operations, we offer training in the retrieval and analysis of the data and an online help facility. We are also happy to advise on, and support, Target of Opportunity Observations.
| Session 3: Binary objects (and X-ray astronomy heritage) | |||||||
3-1 Jenny Carter (Leicester)
An XMM-Newton search for X-ray emission from Wolf-Rayet stars in the Magellanic Clouds
Wolf-Rayet stars (WR) have fast stellar winds with high mass loss rates. The energetic WR wind can dynamically interact with the winds of massive companions and/or with the ambient interstellar medium. Strong interactions are also possible within the stellar wind itself. In all these cases, hot gas emitting X-rays can be produced. The study of the X-ray emission from Galactic WR stars is hampered by their uncertain distances and by the heavy absorption in the Galactic plane. The Magellanic Clouds (MCs) contain ~150 known WR stars, all at known distances and with small foreground extinction. Therefore, the MCs are ideal locations to study the X-ray properties of WR stars per se and the interaction of their winds with companion stars or ambient medium. Using the Chandra and ROSAT archives, we have indeed detected X-ray emission associated with ~25 MCs WR stars with X-ray luminosities in the range 2e10^32 to 2e10^35 erg/s. In this contribution, we report our on-going search for X-ray emission from MCs WR stars using XMM-Newton archival observations. The large collecting area of XMM-Newton make it possible to sensitively search for X-ray emission from MCs WR stars that previously had only ROSAT observations. For MCs WR stars with previous Chandra observations, the current XMM-Newton can be used to study their spectral properties and/or X-ray variability. Using appropriate data from the XMM-Newton Science Archive (XSA), we have found X-ray emission in 4 LMC WR stars and 2 SMC WR stars, all of which occur in binary systems. In this poster we present the spectra and images from these detected sources, and discuss the implications of these detections for the MCs WR population.
3-2 Roberto Soria (UCL/MSSL)
X-ray spectra and black hole masses in ULXs
Abstract not available
3-3 Alex Blustin (UCL/MSSL)
Genealogy of UK X-ray astronomy
This poster presents a partial genealogy of UK X-ray astronomy, taking records of previous PhD students at MSSL as a starting point. It shows which research areas have been transmitted across multiple generations of supervisors and students, and how space science has spread out into different universities over the course of the last five decades. The reader is encouraged to write him or herself onto the poster if not already listed.