T. Kennedy

Publications (7)4.9 Total impact

• Article: Further calibration of the Swift ultraviolet/optical telescope

  A. A. Breeveld, P. A. Curran, E. A. Hoversten, S. Koch, W. Landsman, F. E. Marshall, M. J. Page, T. S. Poole, P. Roming, P. J. Smith, [......], S. Immler, M. Ivanushkina, T. Kennedy, K. O. Mason, A. N. Morgan, S. Oates, M. De Pasquale, P. Schady, M. Siegel, D. Vanden Berk
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  ABSTRACT: The Ultraviolet/Optical Telescope (UVOT) is one of three instruments onboard the Swift observatory. The photometric calibration has been published, and this paper follows up with details on other aspects of the calibration including a measurement of the point spread function with an assessment of the orbital variation and the effect on photometry. A correction for large-scale variations in sensitivity over the field of view is described, as well as a model of the coincidence loss which is used to assess the coincidence correction in extended regions. We have provided a correction for the detector distortion and measured the resulting internal astrometric accuracy of the UVOT, also giving the absolute accuracy with respect to the International Celestial Reference System. We have compiled statistics on the background count rates, and discuss the sources of the background, including instrumental scattered light. In each case, we describe any impact on UVOT measurements, whether any correction is applied in the standard pipeline data processing or whether further steps are recommended.
  Monthly Notices of the Royal Astronomical Society 06/2010; 406(3):1687 - 1700. · 4.90 Impact Factor
• Source

  Available from: P. W. A. Roming

  Article: Paper II: Calibration of the Swift ultraviolet/optical telescope

  A. A. Breeveld, P. A. Curran, E. A. Hoversten, S. Koch, W. Landsman, F. E. Marshall, M. J. Page, T. S. Poole, P. Roming, P. J. Smith, [......], S. Immler, M. Ivanushkina, T. Kennedy, K. O. Mason, A. N. Morgan, S. Oates, M. De Pasquale, P. Schady, M. Siegel, D. Vanden Berk
  [show abstract] [hide abstract]
  ABSTRACT: The Ultraviolet/Optical Telescope (UVOT) is one of three instruments onboard the Swift observatory. The photometric calibration has been published, and this paper follows up with details on other aspects of the calibration including a measurement of the point spread function with an assessment of the orbital variation and the effect on photometry. A correction for large scale variations in sensitivity over the field of view is described, as well as a model of the coincidence loss which is used to assess the coincidence correction in extended regions. We have provided a correction for the detector distortion and measured the resulting internal astrometric accuracy of the UVOT, also giving the absolute accuracy with respect to the International Celestial Reference System. We have compiled statistics on the background count rates, and discuss the sources of the background, including instrumental scattered light. In each case we describe any impact on UVOT measurements, whether any correction is applied in the standard pipeline data processing or whether further steps are recommended. Comment: Accepted for publication in MNRAS. 15 pages, 21 figures, 4 tables
  04/2010;
• Article: GRB 081203A: Swift UVOT captures the earliest ultraviolet spectrum of a gamma‐ray burst

  N. P. M. Kuin, W. Landsman, M. J. Page, P. Schady, M. Still, A. A. Breeveld, M. De Pasquale, P. W. A. Roming, P. J. Brown, M. Carter, [......], E. A. Hoversten, S. Hunsberger, T. Kennedy, S. Koch, H. Lamoureux, F. E. Marshall, S. R. Oates, A. Parsons, D. M. Palmer, P. J. Smith
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  ABSTRACT: We present the earliest ultraviolet (UV) spectrum of a gamma-ray burst (GRB) as observed with the Swift Ultra-Violet/Optical Telescope (UVOT). The GRB 081203A spectrum was observed for 50 s with the UV-grism starting 251 s after the Swift-Burst-Alert-Telescope (BAT) trigger. During this time, the GRB was ≈13.4 mag (u filter) and was still rising to its peak optical brightness. In the UV-grism spectrum, we find a damped Lyα line, Lyβ and the Lyman continuum break at a redshift z= 2.05 ± 0.01. A model fit to the Lyman absorption implies a gas column density of log NH i= 22.0 ± 0.1 cm−2, which is typical of GRB host galaxies with damped Lyα absorbers. This observation of GRB 081203A demonstrates that for brighter GRBs (v≈ 14 mag) with moderate redshift (0.5 < z < 3.5) the UVOT is able to provide redshifts, and probe for damped Lyα absorbers within 4–6 min from the time of the Swift-BAT trigger.
  Monthly Notices of the Royal Astronomical Society Letters 04/2009; 395(1):L21 - L24.
• Source

  Available from: P. W. A. Roming

  Article: Swift-UVOT captures the earliest ultraviolet spectrum of a Gamma Ray Burst

  N. P. M. Kuin, W. B. Landsman, M. J. Page, P. Schady, M. Still, A. A. Breeveld, M. De Pasquale, P. J. Brown, M. Carter, C. James, [......], S. Hunsberger, T. Kennedy, S. Koch, H. Lamoureux, F. E. Marshall, S. R. Oates, A. Parsons, D Palmer, P. Roming, P. J. Smith
  [show abstract] [hide abstract]
  ABSTRACT: We present the earliest ever ultraviolet spectrum of a gamma-ray burst (GRB) as observed with the Swift-UVOT. The GRB 081203A spectrum was observed for 50 seconds with the UV grism starting 251 seconds after the Swift-BAT trigger when the GRB was of u ~13.4 mag and still rising to its peak optical brightness. The UV grism spectrum shows a damped Ly-alpha line, Ly-beta, and the Lyman continuum break at a redshift z = 2.05 +/- 0.01. A model fit to the Lyman absorption implies log N(HI) = 22.0 +/- 0.2 cm-2, which is typical for GRB host galaxies with damped Ly-alpha absorbers. This observation of GRB 081203A demonstrates that for GRBs brighter than v ~14 mag and with 0.5 < z < 3.5 the UVOT will be able to provide redshifts, and probe for damped Ly-alpha absorbers within 4-6 minutes from the time of the Swift-BAT trigger. Comment: 4 pages, 4 figures, accepted by MNRAS letters
  12/2008;
• Source

  Available from: P. W. A. Roming

  Article: Photometric Calibration of the Swift Ultraviolet/Optical Telescope

  T. S. Poole, A. A. Breeveld, M. J. Page, W. Landsman, S. T. Holland, P. Roming, N. P. M. Kuin, P. J. Brown, C. Gronwall, S. Hunsberger, [......], H. Huckle, S. Immler, M. Ivanushkina, T. Kennedy, F. Marshall, A. Morgan, S. Pandey, M. De Pasquale, P. J. Smith, M. Still
  [show abstract] [hide abstract]
  ABSTRACT: We present the photometric calibration of the Swift UltraViolet/Optical Telescope (UVOT) which includes: optimum photometric and background apertures, effective area curves, colour transformations, conversion factors for count rates to flux, and the photometric zero points (which are accurate to better than 4 per cent) for each of the seven UVOT broadband filters. The calibration was performed with observations of standard stars and standard star fields that represent a wide range of spectral star types. The calibration results include the position dependent uniformity, and instrument response over the 1600-8000A operational range. Because the UVOT is a photon counting instrument, we also discuss the effect of coincidence loss on the calibration results. We provide practical guidelines for using the calibration in UVOT data analysis. The results presented here supersede previous calibration results. Comment: Minor improvements after referees report. Accepted for publication in MNRAS
  08/2007;
• Source

  Available from: arxiv.org

  Article: The XMM-Newton Optical/UV Monitor Telescope

  K. O. Mason, A. A. Breeveld, R. Much, M. Carter, F. A. Cordova, M. S. Cropper, J. Fordham, H. Huckle, C. Ho, H. Kawakami, J. Kennea, T. Kennedy, J. Mittaz, D. Pandel, W. C. Priedhorsky, T. Sasseen, R. Shirey, P. Smith, J. -M. Vreux
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  ABSTRACT: The XMM-OM instrument extends the spectral coverage of the XMM-Newton observatory into the ultraviolet and optical range. It provides imaging and time-resolved data on targets simultaneously with observations in the EPIC and RGS. It also has the ability to track stars in its field of view, thus providing an improved post-facto aspect solution for the spacecraft. An overview of the XMM-OM and its operation is given, together with current information on the performance of the instrument. Comment: Accepted by A&A for publication in the Special Issue on 1st science with XMM Newton, 9 pages
  11/2000;
• Article: GRB 050318: Swift/UVOT detection of afterglow emission.

  K. McGowan, M. de Pasquale, P. Boyd, S. T. Holland, M. Still, W. Landsman, S. Hunsberger, A. Breeveld, P. Roming, K. Mason, [......], S. Koch, M. Carter, H. Huckle, P. Broos, T. Kennedy, P. Smith, B. Hancock, H. Krimm, J. Nousek, N. Gehrels
  GRB Coordinates Network. 3115:1.