Published July 20, 2007 | Version Published
Journal Article Open

X-Ray, UV, and Optical Observations of Supernova 2006bp with Swift: Detection of Early X-Ray Emission

  • 1. ROR icon Universities Space Research Association
  • 2. ROR icon Pennsylvania State University
  • 3. ROR icon University of Arizona
  • 4. ROR icon Trieste Astronomical Observatory
  • 5. ROR icon Max Planck Institute for Astrophysics
  • 6. ROR icon University of Virginia
  • 7. ROR icon Marquette University
  • 8. ROR icon United States Naval Research Laboratory
  • 9. ROR icon University of California, Berkeley
  • 10. ROR icon University of Tokyo
  • 11. ROR icon Max Planck Institute for Extraterrestrial Physics
  • 12. ROR icon Brera Astronomical Observatory
  • 13. ROR icon California Institute of Technology

Abstract

We present results on the X-ray and optical/UV emission from the Type II-P supernova (SN) 2006bp and the interaction of the SN shock with its environment, obtained with the X-Ray Telescope (XRT) and UV/Optical Telescope (UVOT) on board Swift. SN 2006bp is detected in X-rays at a 4.5 σ level of significance in the merged XRT data from days 1 to 12 after the explosion. If the 0.2-10 keV band X-ray luminosity of L_(0.2-10) = (1.8 ± 0.4) × 10^(39) ergs s^(-1) is caused by interaction of the SN shock with circumstellar material (CSM) deposited by a stellar wind from the progenitor's companion star, a mass-loss rate of M ≈ (1 × 10^(-5) M_⊙ yr^(-1))(v_w/10 km s^(-1)) is inferred. The mass-loss rate is consistent with the nondetection in the radio with the VLA on days 2, 9, and 11 after the explosion and is characteristic of a red supergiant progenitor with a mass of ≈12-15 M_⊙ prior to the explosion. The Swift data further show a fading of the X-ray emission starting around day 12 after the explosion. In combination with a follow-up XMM-Newton observation obtained on day 21 after the explosion, an X-ray rate of decline of L_X ∝ t^(-n) with index n = 1.2 ± 0.6 is inferred. Since no other SN has been detected in X-rays prior to the optical peak, and since Type II-P SNe have an extended "plateau" phase in the optical, we discuss the scenario that the X-rays might be due to inverse Compton scattering of photospheric optical photons off relativistic electrons produced in circumstellar shocks. However, due to the high required value of the Lorentz factor (≈10-100), which is inconsistent with the ejecta velocity inferred from optical line widths, we conclude that inverse Compton scattering is an unlikely explanation for the observed X-ray emission.

Additional Information

© 2007 The American Astronomical Society. Received 2006 November 15 , accepted for publication 2007 March 27. We gratefully acknowledge support provided by STScI grant HST-GO-10182.75-A (P. A. M.), NASA Chandra Postdoctoral Fellowship grant PF4-50035 (D. P.), and NSF grant AST 03- 07366 (R.A. C.). L.D. acknowledges support for this work from the Scientific Discovery through Advanced Computing (SciDAC) program of the DOE, grant DE-FC02-01ER41184, and from the NSF under grant AST 05-04947. K. W.W. thanks the Office of Naval Research for the 6.1 funding supporting this research. C. J. S. is a Cottrell Scholar of Research Corporation, and work on this project has been supported by the NASA Wisconsin Space Grant Consortium. This work is sponsored at Pennsylvania State University by NASA contract NAS5-00136.We wish to thank N. Schartel and the XMM-Newton SOC for approving and scheduling a XMM Newton DDT observation. The research has made use of the NASA/ IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

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Identifiers

Eprint ID
17732
Resolver ID
CaltechAUTHORS:20100315-111139220

Funding

NASA
HST-GO-10182.75-A
NASA Chandra Fellowship
PF4-50035
NSF
AST 03-07366
Department of Energy (DOE)
DE-FC02-01ER41184
NSF
AST 05-04947
Office of Naval Research (ONR)
Wisconsin Space Grant Consortium
NASA
NAS5-00136

Dates

Created
2010-03-20
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Updated
2021-11-08
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