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Chandra Observations of SN 2004et and the X-Ray Emission of Type II-P Supernovae

Rho, J. and Jarrett, T. H. and Chugai, N. N. and Chevalier, R. A. (2007) Chandra Observations of SN 2004et and the X-Ray Emission of Type II-P Supernovae. Astrophysical Journal, 666 (2). pp. 1108-1115. ISSN 0004-637X. doi:10.1086/520336.

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We report the X-ray detection of the Type II-P (plateau) supernova SN 2004et in the spiral galaxy NGC 6946, using the Chandra X-Ray Observatory. The position of the X-ray source was found to agree with the optical position within ~0.4". Chandra also surveyed the region before the 2004 event, finding no X-ray emission at the location of the progenitor. For the postexplosion observations, a total of 202, 151, and 158 photons were detected in three pointings, each 29 ks in length, on 2004 October 22, November 6, and December 3, respectively. The spectrum of the first observation is best fit by a thermal model with a temperature of kT = 1.3^(+∞)_(-0.8) keV and a line-of-sight absorption of N_H = (1.0 ± 1.0) × 10^(22) cm^(-2). The inferred unabsorbed luminosity (0.4-8 keV) is ~4 × 10^(38) erg s^(-1), adopting a distance of 5.5 Mpc. A comparison between hard and soft counts on the first and third epochs indicates a softening over this time, although there is an insufficient number of photons to constrain the variation of temperature and absorption by spectral fitting. We model the emission as arising from the reverse-shock region in the interaction between the supernova ejecta and the progenitor wind. For a Type II-P supernova with an extended progenitor, the cool shell formed at the time of shock wave breakout from the star can affect the initial evolution of the interaction shell and the absorption of radiation from the reverse shock. The observed spectral softening might be due to decreasing shell absorption. We find a presupernova mass-loss rate of (2-2.5) × 10^(-6) M_⊙ yr^(-1) for a wind velocity of 10 km s^(-1), which is in line with expectations for a Type II-P supernova.

Item Type:Article
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Jarrett, T. H.0000-0002-4939-734X
Additional Information:© 2007 The American Astronomical Society. Received 2007 March 30; accepted 2007 May 19. We are grateful to the referee for a very helpful report. This research was supported in part by NSF grant AST 03-07366 (N. N. C. and R. A. C.). J. R. and T. H. J. acknowledge the support of California Institute of Technology, the Jet Propulsion Laboratory, which is operated under contract with NASA. This work is based on Chandra archival data.
Funding AgencyGrant Number
NSFAST 03-07366
Subject Keywords:stars : mass loss; supernovae : general; supernovae : individual (SN 2004et)
Issue or Number:2
Record Number:CaltechAUTHORS:20091113-110534464
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Official Citation:Chandra Observations of SN 2004et and the X-Ray Emission of Type II-P Supernovae J. Rho, T. H. Jarrett, N. N. Chugai, and R. A. Chevalier 2007 ApJ 666 1108-1115 doi: 10.1086/520336
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16700
Deposited By: Tony Diaz
Deposited On:25 Nov 2009 20:14
Last Modified:08 Nov 2021 23:29

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