23 GHz VLBI Observations of SN 2008ax

 Title: 23 GHz VLBI Observations of SN 2008ax Author: Marti-Vidal, I.; Alberdi, A.; Ros, E.; Shapiro, Irwin Ira; Beswick, R.J.; Pedlar, A.; Immler, S.; Panagia, N.; Van Dyk, S.; Marcaide, J. M.; Guirado, J. C.; Perrez-Torres, M. A.; Muxlow, T. W. B.; Argo, M. K.; Stockdale, C. J.; Sramek, R. A.; Weiler, K. W. Note: Order does not necessarily reflect citation order of authors. Citation: Marti-Vidal, I., J. M. Marcaide, A. Alberdi, J. C. Guirado, M. A. Pérez-Torres, E. Ros, Irwin Ira Shapiro, et al. 2009. 23 GHz VLBI Observations of SN 2008ax. Astronomy & Astrophysics 499(3): 649-652. Full Text & Related Files: Shapiro Weiler 0904.pdf (140.0Kb; PDF) Abstract: We report on phase-referenced 23 GHz Very-Long-Baseline-Interferometry (VLBI) observations of the type IIb supernova SN 2008ax, made with the Very Long Baseline Array (VLBA) on 2 April 2008 (33 days after explosion). These observations resulted in a marginal detection of the supernova. The total ﬂux density recoveredfrom our VLBI image is $$0.8 \pm 0.3 mJy$$ (one standard deviation). As it appears, the structure may be interpreted as either a core-jet or a double source. However, the supernova structure could be somewhat confused with a possible close by noise peak. In such a case, the recovered ﬂux density would decrease to $$0.48 \pm 0.12 mJy$$, compatible with the ﬂux densities measured with the VLA at epochs close in time to our VLBI observations. The lowest average expansion velocities derived from our observations are $$(1.90 \pm 0.30) \times 10^{5} km$$ $$s^{-1}$$ (case of a double source) and $$(5.2 \pm 1.3) \times 10^{4} km$$ $$s^{-1}$$ (taking the weaker source component as a spurious, close by, noise peak, which is the more likely interpretation). These velocities are 7.3 and 2 times higher, respectively, than the maximum ejecta velocity inferred from optical-line observations. Published Version: doi:10.1051/0004-6361/200912034 Other Sources: http://arxiv.org/pdf/0904.0337v1.pdf Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:8919559 Downloads of this work: