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Browsing University of Hertfordshire by Author "Worrall, D.M."
Now showing items 41-60 of 68
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New insights on Radio-Galaxy X-ray Emission Components from Chandra
Worrall, D.M.; Birkinshaw, M.; Hardcastle, M.J. (Astronomical Society of the Pacific, 2001) -
New radio-galaxy X-ray results from Chandra
Worrall, D.M.; Birkinshaw, M.; Hardcastle, M.J. (Astronomical Society of the Pacific, 2001)The superior spatial resolution of the Chandra X-ray Observatory is sharpening our X-ray vision of extragalactic radio sources. Our recent Guest Observer observations of a small sample of B2 radio galaxies show jet X-ray ... -
New results on particle acceleration in the Centaurus A jet and counterjet from a deep Chandra observation
Hardcastle, M.J.; Kraft, R.P.; Sivakoff, G.R.; Goodger, Joanna; Croston, J.H.; Jordan, A.; Evans, D.A.; Worrall, D.M.; Birkinshaw, M.; Raychaudhury, S.; Brassington, Nicola; Forman, W.R.; Harris, W.E.; Jones, C.; Juett, A.M.; Murray, S.S.; Nulsen, P.E.J.; Sarazin, C.L.; Woodley, K.A. (2007)We present new deep Chandra observations of the Centaurus A jet, with a combined on-source exposure time of 719 ks. These data allow detailed X-ray spectral measurements to be made along the jet out to its disappearance ... -
The Origins of X-Ray Emission from the Hot Spots of FR II Radio Sources
Hardcastle, M.J.; Worrall, D.M.; Harris, D.E.; Birkinshaw, M. (2004-09) -
Particle acceleration and jet dynamics in Centaurus A
Hardcastle, M.J.; Worrall, D.M.; Kraft, R.P.; Forman, W.R.; Jones, C.; Murray, S.S. (2004-06)New multi-epoch Chandra observations, combined with multi-epoch, high-dynamic range VLA data, have allowed us to relate the radio and X-ray structure of the jet in Cen A to the jet dynamics. We present evidence that a ... -
Radio and X-Ray Observations of the Jet in Centaurus A
Hardcastle, M.J.; Worrall, D.M.; Kraft, R.P.; Forman, W.R.; Jones, C.; Murray, S.S. (2003-08)We present new, high dynamic range VLA images of the inner jet of the closest radio galaxy, Centaurus A. Over a 10 yr baseline we detect apparent subluminal motions (v ~ 0:5c) in the jet on scales of hundreds of parsecs. ... -
A radio through x-ray study of the hot spots, active nucleus and environment of the nearby FR II radio galaxy 3C 33
Kraft, R.P.; Birkinshaw, M.; Hardcastle, M.J.; Evans, D.A.; Croston, J.H.; Worrall, D.M.; Murray, S.S. (2007) -
A Radio through X-Ray Study of the Jet/Companion-Galaxy Interaction in 3C 321
Evans, D.A.; Fong, W-F.; Hardcastle, M.J.; Kraft, R.P.; Lee, J.C.; Worrall, D.M.; Birkinshaw, M.; Croston, J.H.; Muxlow, T.W.B. (2008) -
Radio, optical and X-ray nuclei in nearby 3CRR radio galaxies
Hardcastle, M.J.; Worrall, D.M. (2000)HST observations have shown that low-redshift 3CR radio galaxies often exhibit a point-like optical component positionally coincident with the GHz-frequency radio core. In this paper we discuss the correlation between the ... -
The relationship between the X-ray and radio components in the compact steep-spectrum quasar 3c 48
Worrall, D.M.; Hardcastle, M.J.; Pearson, T.J.; Readhead, A.C.S. (2004-01) -
ROSAT X-ray observations of 3CRR radio sources
Hardcastle, M.J.; Worrall, D.M. (1999)Over half the 3CRR sample of radio galaxies and quasars has been observed in X-rays with ROSAT pointed observations, and we present results from these observations, discussing many of the sources in detail. The improved ... -
Spectral properties of X-ray binaries in Centaurus A
Burke, M.J.; Raychaudhury, S.; Kraft, R.P.; Forman, W.R.; Jones, C.; Murray, S.S.; Birkinshaw, M.; Evans, D.A.; Jordán, A.; Worrall, D.M.; Maccarone, T. J.; Croston, J.H.; Brassington, Nicola; Hardcastle, M.J.; Goodger, J.L.; Kainulainen, J.; Woodley, K.A.; Sivakoff, G.R.; Gilfanov, M.; Zhang, Z.; Sarazin, C.L.; Voss, R. (2013-04-01)We present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100 ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states ... -
A Transient Black-Hole Low-Mass X-Ray Binary Candidate in Centaurus A
Sivakoff, G.R.; Kraft, R.P.; Jordan, A.; Juett, A.M.; Evans, D.A.; Forman, W.R.; Hardcastle, M.J.; Sarazin, C.L.; Birkinshaw, M.; Brassington, Nicola; Croston, J.H.; Harris, W.F.; Jones, C.; Murray, S.S.; Raychaudhury, S.; Woodley, K.A.; Worrall, D.M. (2008)We report the discovery of a bright transient X-ray source, CXOU J132518.2–430304, toward Centaurus A (Cen A) using six new Chandra X-Ray Observatory observations in 2007 March-May. Between 2003 and 2007, its flux has ... -
A transient sub-Eddington black hole X-ray binary candidate in the dust lanes of Centaurus A
Burke, M.J.; Raychaudhury, S.; Kraft, R.P.; Forman, W.R.; Jones, C.; Murray, S.S.; Evans, D.A.; Jordán, A.; Brassington, Nicola; Hardcastle, M.J.; Goodger, J.L.; Sivakoff, G.R.; Woodley, K.A.; Kainulainen, J.; Birkinshaw, M.; Worrall, D.M.; Croston, J.H.; Gilfanov, M.; Zhang, Z.; Sarazin, C.L.; Voss, R. (2012-04-20)We report the discovery of a bright X-ray transient CXOU J132527.6-430023 in the nearby early-type galaxy NGC5128. The source was first detected over the course of five Chandra observations in 2007, reaching an unabsorbed ... -
Unifying B2 radio galaxies with BL Lacertae objects
Hardcastle, M.J.; Worrall, D.M.; Birkinshaw, M.; Canosa, C.M. (2003-01) -
Where Centaurus A gets its X-ray knottiness
Worrall, D.M.; Birkinshaw, M.; Kraft, R.P.; Sivakoff, G.R.; Jordan, A.; Hardcastle, M.J.; Brassington, Nicola; Croston, J.H.; Evans, D.A.; Forman, W.R.; Harris, W.E.; Jones, C.; Juett, A.M.; Murray, S.S.; Nulsen, P.E.J.; Raychaudhury, S.; Sarazin, C.L.; Woodley, K.A. (2008)We report an X-ray spectral study of the transverse structure of the Centaurus A jet using new data from the Chandra Cen A Very Large Project. We find that the spectrum steepens with increasing distance from the jet axis, ... -
X-Ray Emission from the Hot Interstellar medium and Southwest Radio Lobe of the Nearby Radio Galaxy Centaurus A
Kraft, R.P.; Vazquez, S.E.; Forman, W.R.; Jones, C.; Murray, S.S.; Hardcastle, M.J.; Worrall, D.M.; Churazov, E. (2003-07) -
X-ray emission from the nuclei, lobes and hot-gas environments of two FR II radio galaxies
Croston, J.H.; Birkinshaw, M.; Hardcastle, M.J.; Worrall, D.M. (2004-09) -
The X-ray Emission of Low-Power Radio Galaxies
Worrall, D.M.; Birkinshaw, M.; Hardcastle, M.J. (Astronomical Society of the Pacific, 2003)A low-power radio galaxy generally emits X-rays from a compact X-ray core, its brighter kpc-scale radio jet, and a galaxy atmosphere. The core emission is normally predominantly radio related. The kpc-scale jet emission ... -
The X-ray jet and central structure of the active galaxy NGC 315
Worrall, D.M.; Birkinshaw, M.; Hardcastle, M.J. (2003-08)We report the Chandra detection of resolved X-ray emission of luminosity 3.5 × 1040 ergs s−1 (0.4–4.5 keV) and power-law energy spectral index = 1.5 ± 0.7 from a roughly 10 arcsec length of the north-west radio jet in ...