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Browsing University of Hertfordshire by Author "Worrall, D.M."
Now showing items 21-40 of 68
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The fading of two transient ultraluminous x-ray sources to below the stellar mass Eddington limit
Burke, M.J.; Kraft, R.P.; Soria, R.; Maccarone, T. J.; Raychaudhury, S.; Sivakoff, G.R.; Birkinshaw, M.; Brassington, Nicola; Forman, W.R.; Hardcastle, M.J.; Jones, C.; Murray, S.S.; Worrall, D.M. (2013-09-20)We report new detections of the two transient ultraluminous X-ray sources (ULXs) in NGC 5128 from an ongoing series of Chandra observations. Both sources have previously been observed L (2-3) × ∼10 erg s, at the lower end ... -
A flare in the jet of Pictor A
Marshall, H.L.; Hardcastle, M.J.; Birkinshaw, M.; Croston, J.H.; Evans, D.; Landt, H.; Lenc, E.; Massaro, F.; Perlman, E.; Schwartz, D.A.; Siemiginowska, A.; Stawarz, L.; Urry, C.M.; Worrall, D.M. (2010)A Chandra X-ray imaging observation of the jet in Pictor A showed a feature that appears to be a flare that faded between 2000 and 2002. The feature was not detected in a follow-up observation in 2009. The jet itself is ... -
FRII sources at z>0.5: X-ray properties of the core and extended emission
Belsole, E.; Croston, J.H.; Worrall, D.M.; Hardcastle, M.J. (2005) -
High resolution X-ray observation and monitoring of the x-ray jet and radio lobes of Centaurus A
Kraft, R.P.; Hardcastle, M.J.; Forman, W.R.; Jones, C.; Murray, S.S.; Worrall, D.M. (2003)We summarize the results of our Chandra AO-1 observations of the X-ray jet in the nearby radio galaxy Centaurus A, and discuss preliminary results from our ongoing monitoring campaign, the first observation of which was ... -
High-energy particle acceleration at the radio-lobe shock of Centaurus A
Croston, J.H.; Kraft, R.P.; Hardcastle, M.J.; Birkinshaw, M.; Worrall, D.M.; Nulsen, P.E.J.; Penna, R.F.; Sivakoff, G.R.; Jordan, R.; Brassington, Nicola; Evans, D.A.; Forman, W.R.; Gilfanov, M.; Goodger, Joanna; Harris, W.E.; Jones, C.; Juett, A.M.; Murray, S.S.; Raychaudhury, S.; Sarazin, C.L.; Voss, R.; Woodley, K.A. (2009)We present new results on the shock around the south-west radio lobe of Centaurus A using data from the Chandra Very Large Programme observations (740 ks total observing time). The X-ray spectrum of the emission around the ... -
High-redshift Fanaroff-Riley type II radio sources: large-scale X-ray environment
Belsole, E.; Worrall, D.M.; Hardcastle, M.J.; Croston, J.H. (2007) -
High-redshift Faranoff Riley type II radio galaxies: X-ray properties of the cores
Belsole, E.; Worrall, D.M.; Hardcastle, M.J. (2006) -
The infrared jet in 3C 66B
Tansley, D.; Birkinshaw, M.; Hardcastle, M.J.; Worrall, D.M. (2000) -
The infrared jet in Centaurus A: multiwavelength constraints on emission mechanisms and particle acceleration
Hardcastle, M.J.; Kraft, R.P.; Worrall, D.M. (2006) -
The interaction between radio lobes and hot gas in the nearby radio galaxies 3C285 and 3C442A
Hardcastle, M.J.; Kraft, R.P.; Worrall, D.M.; Croston, J.H.; Evans, D.A.; Birkinshaw, M.; Murray, S.S. (2007) -
Interactions of low-power radio galaxies with their hot-gas environments
Croston, J.H.; Hardcastle, M.J.; Birkinshaw, M.; Worrall, D.M. (2004) -
The jet heated x-ray filament in the Centaurus A northern middle radio lobe
Kraft, R.P.; Forman, W.R.; Hardcastle, M.J.; Birkinshaw, M.; Croston, J.H.; Jones, C.; Nulsen, P.E.J.; Worrall, D.M.; Murray, S.S. (2009)We present results from a 40 ks XMM-Newton observation of the X-ray filament coincident with the southeast edge of the Centaurus A Northern Middle Radio Lobe (NML). We find that the X-ray filament consists of five spatially ... -
Jet/Environment Interactions of FRI and FRII Radio Galaxies.
Croston, J.H.; Hardcastle, M.J.; Birkinshaw, M.; Worrall, D.M. (2004)We present the results of new XMM-Newton observations of FRI and FRII radio galaxies that show the importance of jet/environment interactions for both radiosource structure and the properties of the surrounding gas. The ... -
The Jet/ISM Interaction in Three Nearby Radio Galaxies as Seen with Chandra.
Kraft, R.P.; Forman, W.R.; Churazov, E.; Eilek, J.; Hardcastle, M.J.; Heinz, S.; Jones, C.; Markevitch, M.; Murray, S.S.; Nulsen, P.E.J.; Owen, F.; Vikhlinin, V.; Worrall, D.M. (2004)Chandra observations of radio galaxies have demonstrated a wide range of complex interactions between their jets and the ambient interstellar/intracluster medium (ISM/ICM). In this paper, we discuss results from Chandra ... -
Kinematics of the parsec-scale radio jet in 3C 48
An, T.; Hong, X.Y.; Hardcastle, M.J.; Worrall, D.M.; Venturi, T.; Pearson, T.J.; Shen, Z.Q.; Zhao, W.; Feng, W.X. (2010)We present results on the compact steep-spectrum quasar 3C 48 from observations with the Very Long Baseline Array (VLBA), the Multi-Element Radio Linked Interferometer Network (MERLIN) and the European Very long baseline ... -
Long-term monitoring of the dynamics and particle acceleration of knots in the jet of Centaurus A
Goodger, Joanna; Hardcastle, M.J.; Croston, J.H.; Kraft, R.P.; Birkinshaw, M.; Evans, D.A.; Jordan, A.; Nulsen, P.E.J.; Sivakoff, G.R.; Worrall, D.M.; Brassington, Nicola; Forman, W.R.; Gilfanov, M.; Jones, C.; Murray, S.S.; Raychaudhury, S.; Sarazin, C.L.; Voss, R.; Woodley, K.A. (2010)We present new and archival multi-frequency radio and X-ray data for Centaurus A obtained over almost 20 years at the Very Large Array and with Chandra, with which we measure the X-ray and radio spectral indices of jet ... -
Luminosity functions of LMXBs in Centaurus A: globular clusters versus the field
Voss, R.; Gilfanov, M.; Sivakoff, G.R.; Kraft, R.P.; Jordan, A.; Raychaudhury, S.; Birkinshaw, M.; Brassington, Nicola; Croston, J.H.; Evans, D.A.; Forman, W.R.; Hardcastle, M.J.; Harris, W.E.; Jones, C.; Juett, A.M.; Murray, S.S.; Sarazin, C.L.; Woodley, K.A.; Worrall, D.M. (2009)We study the X-ray luminosity function (XLF) of low-mass X-ray binaries (LMXB) in the nearby early-type galaxy Centaurus A, concentrating primarily on two aspects of binary populations: the XLF behavior at the low-luminosity ... -
Magnetic Field Strengths in the Hot Spots and Lobes of Three Powerful Fanaroff-Riley Type II Radio Sources
Hardcastle, M.J.; Birkinshaw, M.; Cameron, R.A.; Harris, D.E.; Looney, L.W.; Worrall, D.M. (2002-12) -
Magnetic field strengths in the hotspots of 3C 33 and 111..
Hardcastle, M.J.; Birkinshaw, M.; Worrall, D.M. (1998)We report on ROSAT HRI observations of the nearby powerful radio galaxies 3C33 and 3C111, which both have detected optical hot spots. We find nuclear X-ray sources in both objects, but no X-ray emission from the hot spots. ... -
Modeling x-ray emission of a straight jet : PKS 0920-397
Schwartz, D.A.; Massaro, F.; Siemiginowska, A.; Worrall, D.M.; Birkinshaw, M.; Marshall, H.L.; Evans, D.; Perlman, E.; Gelbord, J.M.; Lovell, J.E.J.; Godfrey, L.; Bicknell, G.; Ojha, R.; Hardcastle, M.J.; Jester, S.; Jorstad, S.G.; Stawarz, L. (2010)We summarize a study of PKS 0920-397 using our 42 ks Chandra observation in conjunction with our ATCA 20GHz image, and HST/ACS F814W and F475W images. We investigate the hypothesis that the jet X–ray emission is due to ...