TY - JOUR
T1 - VLBI observations of SN 2008iz
T2 - I. Expansion velocity and limits on anisotropic expansion
AU - Brunthaler, A.
AU - Martí-Vidal, I.
AU - Menten, K. M.
AU - Reid, M. J.
AU - Henkel, C.
AU - Bower, G. C.
AU - Falcke, H.
AU - Feng, H.
AU - Kaaret, P.
AU - Butler, N. R.
AU - Morgan, A. N.
AU - Weiß, A.
PY - 2010/6
Y1 - 2010/6
N2 - We present observations of the recently discovered supernova 2008iz in M 82 with the VLBI High Sensitivity Array at 22 GHz, the Very Large Array at frequencies of 1.4, 4.8, 8.4, 22 and 43 GHz, and the Chandra X-ray observatory. The supernova was clearly detected in two VLBI images separated by 11 months. The source shows a ring-like morphology and expands with a velocity of ∼23 000 km s-1. The most likely explosion date is in mid-February 2008. The measured expansion speed is a factor of ∼2 higher than expected under the assumption that synchrotron self-absorption dominates the light curve at the peak, indicating that this absorption mechanism may not be important for the radio emission. We find no evidence for an asymmetric explosion. The VLA spectrum shows a broken power law, indicating that the source was still optically thick at 1.4 GHz in April 2009. Finally, we report upper limits on the X-ray emission from SN 2008iz and a second radio transient recently discovered by MERLIN observations.
AB - We present observations of the recently discovered supernova 2008iz in M 82 with the VLBI High Sensitivity Array at 22 GHz, the Very Large Array at frequencies of 1.4, 4.8, 8.4, 22 and 43 GHz, and the Chandra X-ray observatory. The supernova was clearly detected in two VLBI images separated by 11 months. The source shows a ring-like morphology and expands with a velocity of ∼23 000 km s-1. The most likely explosion date is in mid-February 2008. The measured expansion speed is a factor of ∼2 higher than expected under the assumption that synchrotron self-absorption dominates the light curve at the peak, indicating that this absorption mechanism may not be important for the radio emission. We find no evidence for an asymmetric explosion. The VLA spectrum shows a broken power law, indicating that the source was still optically thick at 1.4 GHz in April 2009. Finally, we report upper limits on the X-ray emission from SN 2008iz and a second radio transient recently discovered by MERLIN observations.
KW - galaxies: individual: M 82
KW - radio continuum: general
KW - stars: supernovae: general
KW - stars: supernovae: individual: SN2008iz
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U2 - 10.1051/0004-6361/201014133
DO - 10.1051/0004-6361/201014133
M3 - Article
AN - SCOPUS:77957848563
SN - 0004-6361
VL - 516
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
IS - 18
M1 - A27
ER -