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We compare recent observations of the supernova remnant G11.2-0.3 taken with the VLA during 2001-02 with images from VLA archives (1984-85) to detect and measure the amount of expansion that has occurred during 17 years. The bright, circular outer shell shows a mean expansion of (0.71 +/- 0.15)% and (0.50 +/- 0.17)%, from 20- and 6-cm data, respectively, which corresponds to a rate of 0.057 +/- 0.012/yr at 20 cm and 0.040 +/- 0.013/yr at 6 cm. From this result, we estimate the age of the remnant to be roughly between 960 and 3400 years old, according to theoretical models of supernova evolution. This is highly inconsistent with the 24000 yr characteristic age of PSR J1811-1925, located at the remnants center, but, rather, is consistent with the time since the historical supernova observed in 386 AD. We also predict that G11.2-0.3 is currently in a pre-Sedov evolutionary state, and set constraints on the distance to the remnant based on Chandra X-ray spectral results.
We present a high-resolution radio study of the supernova remnant (SNR) G11.2-0.3 using archival VLA data. Spectral tomography is performed to determine the properties of this composite-type SNRs individual components, which have only recently been d
We present results of a 400-ks Chandra observation of the young shell supernova remnant (SNR) G11.2-0.3, containing a pulsar and pulsar-wind nebula (PWN). We measure a mean expansion rate for the shell since 2000 of 0.0277+/-0.0018% per yr, implying
We present radio maps of the historical supernova remnant G11.2-0.3 in the frequency range from 4.85 GHz to 32 GHz. The integrated spectrum with alpha = -0.50 (S ~ u^alpha) is dominated by its steep spectrum shell emission (alpha ~ -0.57), although
We present 1 to 10GHz radio continuum flux density, spectral index, polarisation and Rotation Measure (RM) images of the youngest known Galactic Supernova Remnant (SNR) G1.9+0.3, using observations from the Australia Telescope Compact Array (ATCA). W
We report measurements of X-ray expansion of the youngest Galactic supernova remnant, G1.9+0.3, using Chandra observations in 2007, 2009, and 2011. The measured rates strongly deviate from uniform expansion, decreasing radially by about 60% along the