Browsing by Author "Evans, D.A."

Now showing items 1-20 of 31

    • The active nuclei of z < 1.0 3CRR radio sources 

      Hardcastle, M.J.; Evans, D.A.; Croston, J.H. (2009)
      We combine Chandra and XMM–Newton X-ray data from our previous papers with new X-ray observations and with Spitzer mid-infrared (mid-IR) data in order to study the nature of the nuclei of radio galaxies and radio-loud ...

    • Chandra and XMM-Newton observations of NGC 6251 

      Evans, D.A.; Hardcastle, M.J.; Croston, J.H.; Worrall, D.M.; Birkinshaw, M. (2005)

    • Chandra and XMM-Newton Observations of the Nucleus of Centaurus A 

      Evans, D.A.; Kraft, R.P.; Worrall, D.M.; Hardcastle, M.J.; Jones, C.; Forman, W.R.; Murray, S.S. (2004-09)
      We present X-ray spectra of the nucleus of the nearby radio galaxy Centaurus A from observations with the XMM-Newton EPIC CCD cameras (two exposures separated by 12 months) and the Chandra HETGS. For the first time in an ...

    • A Chandra observation of 3C 288 - reheating the cool core of a 3 keV cluster from a nuclear outburst at z=0.246 

      Lal, D.V.; Kraft, R.P.; Forman, W.R.; Hardcastle, M.J.; Jones, C.; Nulsen, P.E.J.; Evans, D.A.; Croston, J.H.; Lee, J.C. (2010)
      We present results from a 42 ks Chandra/ACIS-S observation of the transitional FR I/FR II radio galaxy 3C 288 at z = 0.246. We detect ~3 keV gas extending to a radius of ~0.5 Mpc with a 0.5-2.0 keV luminosity of 6.6 × 1043 ...

    • The Chandra, HST and VLA view of the circumnuclear extended emission in the narrow emission line galaxy NGC 2110 

      Evans, D.A.; Lee, J.C.; Kamenetska, M.; Gallagher, S.C.; Kraft, R.P.; Hardcastle, M.J.; Weaver, K.A. (2006)

    • Deep Chandra Observations of the Centaurus A Jet 

      Hardcastle, M.J.; Kraft, R.P.; Goodger, Joanna; Croston, J.H.; Sivakoff, G.R.; Jordan, A.; Evans, D.A. (Astronomical Society of the Pacific, 2008)
      Chandra has observed the jet of Centaurus A for 560 ks in 2007, giving a total on-source observation time since the launch of Chandra of 720 ks. Combining these datasets gives us a uniquely detailed X-ray view of the jet ...

    • Evidence for Non-Hydrostatic Gas Motions in the Hot Interstellar Medium of Centaurus A 

      Kraft, R.P.; Hardcastle, M.J.; Sivakoff, G.R.; Jordan, A.; Nulsen, P.E.J.; Birkinshaw, M.; Forman, W.R.; Jones, C.; Worrall, D.M.; Croston, J.H.; Evans, D.A.; Raychaudhury, S.; Murray, S.S.; Brassington, Nicola; Goodger, Joanna; Harris, W.E.; Juett, A.M.; Sarazin, C.L.; Woodley, K.A. (2008)
      We present preliminary results from a deep (600 ks) Chandra observation of the hot interstellar medium of the nearby early-type galaxy Centaurus A. We find a surface brightness discontinuity in the gas ~3.5 kpc from the ...

    • The gas dynamics of NGC 4472 revealed by XMM-Newton 

      Kraft, R.P.; Forman, W.R.; Jones, C.; Nulsen, P.E.J.; Hardcastle, M.J.; Raychaudhury, S.; Evans, D.A.; Sivakoff, G.R.; Sarazin, C.L. (2011)
      We present results from a 100 ks XMM-Newton observation of the hot gas in the Virgo cluster elliptical galaxy NGC 4472. We find a surface brightness discontinuity ∼21 kpc north of the nucleus, consistent with being a contact ...

    • The hard x-ray view of reflection, absorption and the disk-jet connection in the radio-loud AGN 3C 33 

      Evans, D.A.; Reeves, J.N.; Hardcastle, M.J.; Kraft, R.P.; Lee, J.C.; Virani, S. (2010)
      We present results from Suzaku and Swift observations of the nearby radio galaxy 3C 33, and investigate the nature of absorption, reflection, and jet production in this source. We model the 0.5-100 keV nuclear continuum ...

    • 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 ...

    • Hot and cold gas accretion and feedback in radio-loud active galaxies 

      Hardcastle, M.J.; Evans, D.A.; Croston, J.H. (2007)
      We have recently shown that X-ray observations of the population of ‘low-excitation’ radio galaxies, which includesmost low-power, Fanaroff-Riley class I sources as well as some more powerful Fanaroff-Riley class II objects, ...

    • 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)

    • A large-scale shock surrounding a powerful radio galaxy? 

      Croston, J.H.; Hardcastle, M.J.; Mingo, B.; Evans, D.A.; Dicken, D.; Morganti, R.; Tadhunter, C.N. (2011)
      We report Chandra evidence for a 200 kpc scale shock in the cluster surrounding the powerful radio galaxy 3C444. Our 20 ks observation allows us to identify a clear surface brightness drop around the outer edge of the radio ...

    • 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 ...

    • Low-Mass X-ray Binaries and Globular Clusters in Centaurus A 

      Jordan, A.; Sivakoff, G.R.; McLaughlin, D.E.; Blakeslee, J.P.; Evans, D.A.; Kraft, R.P.; Hardcastle, M.J.; Peng, E.W.; Cote, P.; Croston, J.H.; Juett, A.M.; Minniti, D.; Raychaudhury, S.; Sarazin, C.L.; Worrall, S.M.; Harris, W.E.; Woodley, K.A.; Birkinshaw, M.; Brassington, Nicola; Forman, W.R.; Jones, C.; Murray, S.S. (2007)
      We present results of Hubble Space Telescope and Chandra X-Ray Observatory observations of globular clusters (GCs) and low-mass X-ray binaries (LMXBs) in the central regions of Centaurus A. Out of 440 GC candidates, we ...

    • 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 ...

    • Markarian 6 : shocking the environment of an intermediate Seyfert 

      Mingo, B.; Hardcastle, M.J.; Croston, J.H.; Evans, D.A.; Hota, A.; Kharb, P.; Kraft, R.P. (2011)
      Markarian 6 is a nearby (D ~ 78 Mpc) Seyfert 1.5, early-type galaxy, with a double set of radio bubbles. The outer set spans similar to 7.5 kpc and is expanding into the halo regions of the host galaxy. We present an ...

    • 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 ...

    • Probing quasar shutdown timescales with Hanny's Voorwerp 

      Evans, D.A.; Schawinski, K.; Virani, S.; Urry, C.M.; Keel, W.C.; Natarajan, P.; Lintott, C.J.; Manning, A.; Coppi, P.; Kaviraj, S.; Bamford, S.P.; Józsa, G.I.G.; Garrett, M.; Van Arkel, H.; Gay, P.; Fortson, L. (American Institute of Physics (AIP), 2012)
      Galaxy formation is significantly modulated by energy output from supermassive black holes at the centers of galaxies which grow in highly efficient luminous quasar phases. The timescale on which black holes transition ...

    • 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)