Multi-dimensional modelling of X-ray spectra for AGN accretion-disk outflows (2008)
Sim, S. A., Long, K. S., Miller, L., Turner, T. J.
We use a multi-dimensional Monte Carlo code to compute X-ray spectra for a variety of active galactic nucleus (AGN) disk-wind outflow geometries. We focus on the formation of blue-shifted absorption...
An absorption origin for the X-ray spectral variability of MCG-6-30-15 (2008)
Miller, L., Turner, T. J., Reeves, J. N.
The Seyfert I galaxy MCG-6-30-15 shows one of the best examples of a broad "red wing" of emission in its X-ray spectrum at energies 2 < E < 6.4 keV, commonly interpreted as being caused by...
Fourier-resolved energy spectra of the Narrow Line Seyfert 1 Mkn 766 (2008)
Arevalo, P., McHardy, I. M., Markowitz, A., Papadakis, I. E., Turner, T. J., Miller, L., ...
We compute Fourier-resolved X-ray spectra of the Seyfert 1 Markarian 766 to study the shape of the variable components contributing to the 0.3-10 keV energy spectrum and their time-scale dependence....
Tracing a Disk Wind in NGC 3516 (2008)
Turner, T. J., Reeves, J. N., Kraemer, S. B., Miller, L.
X-ray spectra of AGN often contain signatures indicative of absorption in multiple layers of gas whose ionization-state and covering fraction may vary with time. It has been unclear to date how much...
Deo, R. P., Crenshaw, D. M., Kraemer, S. B., Dietrich, M., Elitzur, M., Teplitz, H., ...
We present Spitzer Space Telescope mid-infrared spectra of 12 Seyfert 1.8 and 1.9 galaxies over the 5-38 um region. We compare the spectral characteristics of this sample to those of 58 Seyfert 1 and...
Low accretion rates at the AGN cosmic downsizing epoch (2007)
Babic, A., Miller, L., Jarvis, M. J., Turner, T. J., Alexander, D. M., Croom, S. M.
Context: X-ray surveys of Active Galactic Nuclei (AGN) indicate `cosmic downsizing', with the comoving number density of high-luminosity objects peaking at higher redshifts (z about 2) than...
The Variable X-ray Spectrum of Markarian 766 - II. Time-Resolved Spectroscopy (2007)
Turner, T. J., Miller, L., Reeves, J. N., Kraemer, S. B.
CONTEXT: The variable X-ray spectra of AGN systematically show steep power-law high states and hard-spectrum low states. The hard low state has previously been found to be a component with only weak...
Relativistic Iron K Emission and absorption in the Seyfert 1.9 galaxy MCG-5-23-16 (2007)
Braito, V., Reeves, J. N., Dewangan, G. C., George, I., Griffiths, R. E., Markowitz, A., ...
We present the results of the simultaneous deep XMM and Chandra observations of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is thought to have one of the best known examples of a...
A Photoionization Model For The Soft X-Ray Spectrum Of NGC 4151 (2007)
Armentrout, B. K., Kraemer, S. B., Turner, T. J.
We present analysis of archival data from multiple XMM-Newton observations of the Seyfert 1 galaxy NGC 4151. Spectral data from the RGS instruments reveal several strong soft X-ray emission lines,...
An XMM-Newton view of the X-ray flat radio-quiet quasar PG 1416-129 (2007)
Porquet, D., Reeves, J. N., Markowitz, A., Turner, T. J., Miller, L., Nandra, K.
Low accretion rates at the AGN cosmic downsizing epoch. (2007)
Babic, A., Miller, L., Jarvis, M.J., Turner, T.J., Alexander, D.M., Croom, S.M.
An XMM-Newton view of the X-ray flat radio-quiet quasar PG 1416-129 (2006)
Porquet, D., Reeves, J. N., Markowitz, A., Turner, T. J., Miller, L., Nandra, K.
(abridged) The radio-quiet quasar PG1416-129 (z=0.129) exhibits atypical optical and X-ray properties. Between 1990 and 2000, in response to its optical continuum decrease, the ``classical'' broad...
The variable X-ray spectrum of Markarian 766 - I. Principal components analysis (2006)
Miller, L., Turner, T. J., Reeves, J. N., George, I. M., Kraemer, S. B., Wingert, B.
Aims: We analyse a long XMM-Newton spectrum of the narrow-line Seyfert 1 galaxy Mrk 766, using the marked spectral variability on timescales >20ks to separate components in the X-ray spectrum....
The Energy-dependent X-ray Timing Characteristics of the Narrow Line Seyfert 1 Mkn 766 (2006)
Markowitz, A., Papadakis, I. E., Arevalo, P., Turner, T. J., Miller, L., Reeves, J. N.
We present the energy-dependent power spectral density (PSD) and cross-spectral properties of Mkn 766, obtained from combining data obtained during an XMM-Newton observation spanning six revolutions...
An XMM-Newton survey of broad iron lines in AGN (2006)
Nandra, K., O'Neill, P. M., George, I. M., Reeves, J. N., Turner, T. J.
We report on the iron K-alpha line properties of a sample of Seyfert galaxies observed with the XMM-Newton EPIC pn instrument. Using a systematic and uniform analysis, we find that complexity at...
Kraemer, S. B., Crenshaw, D. M., Gabel, J. R., Kriss, G. A., Netzer, H., Peterson, B. M., ...
We present a detailed analysis of the intrinsic absorption in the Seyfert 1 galaxy NGC 4151 using UV spectra from the HST/STIS and FUSE, obtained 2002 May as part of a set of contemporaneous...
A Cloudy/Xspec Interface (2006)
Porter, R. L., Ferland, G. J., Kraemer, S. B., Armentrout, B. K., Arnaud, K. A., Turner, T. J.
We discuss new functionality of the spectral simulation code CLOUDY which allows the user to calculate grids with one or more initial parameters varied and formats the predicted spectra in the...
Variable iron-line emission near the black hole of Markarian 766 (2006)
Miller, L., Turner, T. J., Reeves, J. N., George, I. M., Porquet, D., Nandra, K., ...
We investigate the link between ionised Fe X-ray line emission and continuum emission in the bright nearby AGN, Mrk 766. A new long (433 ks) XMM-Newton observation is analysed, together with archival...
The iron emission line complex of MCG-5-23-16: the long XMM-Newton look (2006)
Braito, V., Reeves, J. N., Dewangan, G., George, I., Griffiths, R., Markowitz, A., ...
Variable iron-line emission near the black hole of Markarian 766 (2006)
Miller, L., Turner, T. J., Reeves, J. N., George, I. M., Porquet, D., Nandra, K., ...
The Highly Red-Shifted Fe Kα Line in ESO 113-G010 (2006)
Porquet, D., Reeves, J.N., Uttley, P., Turner, T.J.
Not Available
Collaborate to compete: a strategic weapon for SMEs (2006)
Bititci, U.*, Turner, T.J., Kearney, D.
This paper reports on the value of collaboration in helping SMEs identify more clearly their positions in their markets and to provide pointers to strategies that might lead to increased...
Reeves, J.N., Pounds, Kenneth A., Uttley, P., Kraemer, S., Mushotzky, R., Yaqoob, T., ...
The definitive version of this paper, with enhancements, is available from http://www.journals.uchicago.edu/ApJ/journal/issues/ApJL/v633n2/19868/19868.html
Ionization structure of the warm wind in NGC 5548 (2005)
Steenbrugge, K. C., Kaastra, J. S., Crenshaw, D. M., Kraemer, S. B., Arav, N., George, I. M., ...
We present the results from our 140 ks XMM-Newton and 500 ks Chandra observation of NGC 5548. The velocity structure of the X-ray absorber is consistent with the velocity structure measured in the...
The Spectral Energy Distribution of the Seyfert galaxy Ton S180 (2005)
Turner, T. J., Romano, P., Kraemer, S. B., George, I. M., Yaqoob, T., Crenshaw, D. M., ...
We present spectral results from a multi-satellite, broad-band campaign on the Narrow-line Seyfert 1 galaxy Ton S180 performed at the end of 1999. We discuss the spectral-energy distribution of the...
Reeves, J. N., Pounds, K., Uttley, P., Kraemer, S., Mushotzky, R, Yaqoob, T., ...
We report the detection of redshifted iron K-alpha absorption lines in the Chandra LETG spectrum of the narrow-line quasar, PG 1211+143. The absorption lines are observed at 4.22 keV and 4.93 keV in...
Kraemer, S. B., George, I. M., Crenshaw, D. M., Gabel, J. R., Turner, T. J., Gull, T. R., ...
We present a detailed analysis of the intrinsic X-ray absorption in the Seyfert 1 galaxy NGC 4151 using Chandra/HETGS data obtained 2002 May, as part of a program which included simultaneous UV...
Gabel, J. R., Kraemer, S. B., Crenshaw, D. M., George, I. M., Brandt, W. N., Hamann, F. W., ...
We present results on the location, physical conditions, and geometry of the outflow in the Seyfert 1 galaxy NGC 3783 from a study of the variable intrinsic UV absorption. Based on 18 observations...
Evidence for Orbital Motion of Material Close to the Central Black Hole of Mrk 766 (2005)
Turner, T. J., Miller, L., George, I. M., Reeves, J. N.
Time-resolved X-ray spectroscopy has been obtained for the narrow line Seyfert galaxy Mrk766 from XMM-Newton observations. We present analysis in the energy-time plane of EPIC pn data in the 4-8 keV...
XMM-Newton Spectroscopy of the Starburst Dominated Ultra Luminous Infrared Galaxy NGC 6240 (2005)
Netzer, Hagai, Lemze, Doron, Kaspi, Shai, George, I. M., Turner, T. J., Lutz, D., ...
We present new XMM-Newton observation of the Ultra Luminous Infrared Galaxy (ULIRG) NGC 6240. We analyze the reflecting grating spectrometer (RGS) data, and data from the other instruments, and find...
Steenbrugge, K. C., Kaastra, J. S., Crenshaw, D. M., Kraemer, S. B., Arav, N., George, I. M., ...
We present the results from a 500 ks Chandra observation of the Seyfert 1 galaxy NGC 5548. We detect broadened emission lines of O VII and C VI in the spectra, similar to those observed in the...
XMM-Newton spectroscopy of the starburst-dominated ultraluminous infrared galaxy NGC 6240 (2005)
Netzer, Hagai, Lemze, Doron, Kaspi, Shai, George, I. M., Turner, T. J., Lutz, D., ...
Imlementation and impact of performance measures in two SMEs in Central Scotland (2005)
Turner, T.J., Bititci, U., Nudurupati, S.S.
This paper describes how performance measures were selected and then implemented in two small to medium size enterprises (SMEs) in Central Scotland. It then goes on to consider the impact of these...
Imlementation and impact of performance measures in two SMEs in Central Scotland (2005)
Turner, T.J., Bititci, U., Nudurupati, S.S.
This paper describes how performance measures were selected and then implemented in two small to medium size enterprises (SMEs) in Central Scotland. It then goes on to consider the impact of these...
Complex X-ray Absorption and the Fe Kalpha Profile in NGC 3516 (2004)
Turner, T. J., Kraemer, S. B., George, I. M., Reeves, J. N., Bottorff, M. C.
We present data from simultaneous Chandra, XMM-Newton and BeppoSAX observations of the Seyfert 1 galaxy NGC 3516, taken during 2001 April and Nov. We have investigated the nature of the very flat...
Reeves, J. N., Porquet, D., Turner, T. J.
We report on a short XMM-Newton observation of the radio-quiet Narrow Line Seyfert 1 PG 1402+261. The EPIC X-ray spectrum of PG 1402+261 shows a strong excess of counts between 6-9 keV in the rest...
Crenshaw, D. M., Kraemer, S. B., Gabel, J. R., Schmitt, H. R., Filippenko, A. V., Ho, L. C., ...
We present ultraviolet spectra of the dwarf Seyfert 1 nucleus of NGC 4395, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope's Space Telescope Imaging...
The Properties and the Evolution of the Highly Ionized Gas in MR2251-178 (2004)
Kaspi, Shai, Netzer, Hagai, Chelouche, Doron, George, Ian M., Nandra, Kirpal, Turner, T. J.
(abridged) We present the first XMM-Newton observations of the radio-quiet quasar MR2251-178 obtained in 2000 and 2002. The EPIC-pn spectra show a power-law continuum with a slope of 1.6 at high...
Kaastra, J. S., Steenbrugge, K. C., Crenshaw, D. M., Kraemer, S. B., Arav, N., George, I. M., ...
The Seyfert 1 galaxy NGC 5548 was observed for a week by Chandra using both the HETGS and LETGS spectrometers. In this paper we study the time variability of the continuum radiation. During our...
The XMM-Newton iron line profile of NGC 3783 (2004)
Reeves, J.N., Nandra, K., George, I.M., Pounds, Kenneth A., Turner, T.J., Yaqoob, T.
The definitive version of this paper is that available at http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v602n2/58961/58961.html
Managing the value delivery process (2004)
Turner, T.J., Martinez, V., Bititci, U.
This paper introduces a reference model for the life cycle of a logical business unit (LBU). It goes on to explain how the model was deduced from empirical data generated during participation by the...
Implementing a web enabled performance measurement system (2004)
Turner, T.J., Bititci, U., Creighton, S., Nudurupati, S.S.
A Web-enabled-performance-measurement system was designed, implemented and used to improve the business performance of a company processing aluminum foil in central Scotland. The benefits of the...
Implementing a web enabled performance measurement system (2004)
Turner, T.J., Bititci, U., Creighton, S., Nudurupati, S.S.
A Web-enabled-performance-measurement system was designed, implemented and used to improve the business performance of a company processing aluminum foil in central Scotland. The benefits of the...
Managing the value delivery process (2004)
Turner, T.J., Martinez, V., Bititci, U.
This paper introduces a reference model for the life cycle of a logical business unit (LBU). It goes on to explain how the model was deduced from empirical data generated during participation by the...
The Properties and the Evolution of the Highly Ionized Gas in MR2251-178 (2003)
Kaspi, S., Netzer, H., Chelouche, D., George, I. M., Turner, T. J., Nandra, K.
We present the first XMM-Newton observations of the radio-quiet quasar MR2251-178. We model the X-ray spectrum with two power laws, one at high energies with a slope of \Gamma=1.6 and the other to...
Transient Relativistically-Shifted Lines as a Probe of Black Hole Systems (2003)
Turner, T. J., Kraemer, S. B., Reeves, J. N.
X-ray spectra of Seyfert galaxies have revealed a new type of X-ray spectral feature, one which appears to offer important new insight into the black hole system. XMM/Chandra revealed several narrow...
The XMM-Newton Iron Line Profile of NGC 3783 (2003)
Reeves, J. N, Nandra, K., George, I. M., Pounds, K. A., Turner, T. J., Yaqoob, T.
We report on observations of the iron K line in the nearby Seyfert 1 galaxy, NGC 3783, obtained in a long, 2 orbit (240 ks) XMM-Newton observation. The line profile obtained exhibits two strong...
A warm hot intergalactic medium towards 3C 120? (2003)
McKernan, B., Yaqoob, T., Mushotzky, R., George, I. M., Turner, T. J.
We observed the Seyfert I active galaxy/broad line radio galaxy 3C120 with the Chandra high energy transmission gratings and present an analysis of the soft X-ray spectrum. We identify the strongest...
Netzer, H., Kaspi, S., Behar, E., Brandt, W. N., Chelouche, D., George, I. M., ...
We present a detailed spectral analysis of the data obtained from NGC 3783 during the period 2000-2001 using Chandra. This analysis leads us to the following results. 1) NGC 3783 fluctuated in...
XMM-Newton Observation of Fe Kalpha emission from a BAL QSO: Mrk 231 (2003)
We present results from a 20 ksec XMM observation of Mrk 231. EPIC data reveal strong line emission due to Fe Ka, which has rarely been detected in this class. The line energy is consistent with an...
Yaqoob, T., George, I. M., Kallman, T. R., Padmanabhan, U., Weaver, K. A., Turner, T. J.
We report the detection of Fe XXV and Fe XXVI $K\alpha$ emission lines from a Chandra HETGS observation of the Seyfert~1 galaxy NGC 7314, made simultaneously with RXTE. The lines are redshifted (cz ~...
Gabel, J. R., Crenshaw, D. M., Kraemer, S. B., Brandt, W. N., George, I. M., Hamann, F. W., ...
We report an intrinsic absorber with decreasing outflow velocity in the Seyfert 1 galaxy NGC 3783. This is the first detection of a change in radial velocity in an outflow associated with a Seyfert...
Elemental Abundances in NGC 3516 (2003)
Turner, T. J., Kraemer, S. B., Mushotzky, R. F., George, I. M., Gabel, J. R.
We present RGS data from an XMM-Newton observation of the Seyfert 1 galaxy NGC 3516, taken while the continuum source was in an extreme low state. The spectrum shows numerous emission lines including...
Crenshaw, D. M., Kraemer, S. B., Gabel, J. R., Kaastra, J. S., Steenbrugge, K. C., Brinkman, A. C., ...
We present new UV spectra of the nucleus of the Seyfert 1 galaxy NGC 5548, which we obtained with the Space Telescope Imaging Spectrograph at high spectral resolution, in conjunction with...
McKernan, B., Yaqoob, T., George, I. M., Turner, T. J.
We observed the Seyfert 1 galaxy NGC 4593 with the Chandra high energy transmission gratings and present a detailed analysis of the soft X-ray spectrum. We measure strong absorption lines from...
The Ionized Gas and Nuclear Environment in NGC 3783 II. Averaged HST/STIS and FUSE Spectra (2002)
Gabel, Jack R., Crenshaw, D. Michael, Kraemer, Steven B., Brandt, W. N., George, Ian M., Hamann, Frederick W., ...
We present observations of the intrinsic absorption in the Seyfert 1 galaxy NGC 3783 obtained with the STIS/HST and FUSE. We have coadded multiple STIS and FUSE observations to obtain a high S/N...
SHEEP: The Search for the High Energy Extragalactic Population (2002)
Nandra, K., Georgantopoulos, I., Ptak, A., Turner, T. J.
We present the SHEEP survey for serendipitously-detected hard X-ray sources in ASCA GIS images. In a survey area of $\sim 40$ deg$^{2}$, 69 sources were detected in the 5-10 keV band to a limiting...
Yaqoob, T., McKernan, B., Kraemer, S. B., Crenshaw, M., Gable, J., George, I. M., ...
We observed the Seyfert 1 galaxy Mrk 509 simultaneously with Chandra/HETG, HST/STIS and RXTE. We measure strong absorption lines from He-like Ne and Mg, and from H-like N, O, and Ne. The lines are...
Kraemer, S. B., Crenshaw, D. M., Yaqoob, T., McKernan, B., Gabel, J. R., George, I. M., ...
We present observations of the UV absorption lines in the luminous Seyfert 1 galaxy Mrk 509, obtained with the medium resolution (lambda/Delta-lambda ~ 40,000) echelle gratings of the Space Telescope...
Turner, T.J., Mendibil, K., Mendibil, K., Bititci, U.S., Daisley, P., Breen, T. H. J.
This paper explains how the improvement of a key business process in a manufacturing company can be interpreted in terms of reliability engineering concepts. A case study is presented to illustrate...
Turner, T. J., Mushotzky, R. F., Yaqoob, T., George, I. M., Snowden, S. L., Netzer, H., ...
We present results from a simultaneous Chandra HETG and XMM-Newton observation of NGC 3516. We find evidence for several narrow components of Fe Kalpha along with a broad line. We consider the...