The radio emission, X-ray emission, and hydrodynamics of G328.4+0.2: A comprehensive analysis of a luminous pulsar wind nebula, its neutron star, and the progenitor supernova explosion

Joseph D. Gelfand, B. M. Gaensler, Patrick O. Slane, Daniel J. Patnaude, John P. Hughes, Fernando Camilo

Research output: Contribution to journalArticle


We present new observational and modeling results obtained for the Galactic nonthermal radio source G328.4+0.2. Using X-ray data obtained by XMM-Newton, we confirm that its X-ray emission is heavily absorbed, has a spectrum best fitted by a power-law model of photon index Γ = 2 with no evidence for a thermal component, comes from a region significantly smaller than the radio emission, and that the X-ray and radio emissions are significantly offset from each other. We also present the results of a new high-resolution (7″) 1.4 GHz image of G328.4+0.2 obtained using ATCA and a deep search for radio pulsations using the Parkes radio telescope. By comparing this 1.4 GHz image with a similar resolution image at 4.8 GHz, we find that the radio emission has a flat spectrum (α ≈ 0; Sv ∝ vα). Additionally, we are able to limit the pseudoluminosity of any pulsar to L1400 ≡ S1400d2 ≲ 30 mJy kpc2 for the central radio pulsar, assuming a distance of 17 kpc. In light of these observational results, we test whether G328.4+0.2 is a pulsar wind nebula or an SNR that contains a large pulsar wind nebula using a simple hydrodynamic model for the evolution of a pulsar wind nebula inside an SNR. As a result of this analysis, we conclude that G328.4+0.2 is a young (≲10,000 years old) pulsar wind nebula formed by a low magnetic field (≲1012G) neutron star born spinning rapidly (≲10 ms) expanding into an undetected SNR formed by an energetic (≳1051 ergs), low ejecta mass (Mej ≲ 5 M) supernova explosion that occurred in a low-density (n ∼ 0.03 cm-3) environment.

Original languageEnglish (US)
Pages (from-to)468-486
Number of pages19
JournalAstrophysical Journal
Issue number1 I
StatePublished - Jul 1 2007



  • Pulsars: general
  • Radio continuum: ISM
  • Stars: neutron
  • Supernova remnants
  • X-rays: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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