M31N 2007-12b: An Extragalactic Recurrent Nova Characterised from Optical and X-ray Observations
Feb, 2009Citations per year
Abstract: (arXiv)
We report combined optical and X-ray observations of nova M31N 2007-12b. Positional coincidence and optical light curve similarities strongly suggest that this object had a previously recorded outburst in 1969 and is therefore a Recurrent Nova. Optical spectroscopy obtained 5 days after the 2007 December outburst shows evidence of very high ejection velocities (FWHM H km s). In addition, X-ray data show that M31N 2007-12b is associated with a Super-Soft Source which appeared between 21 and 35 days post-outburst and turned off between then and day 169. These optical and X-ray data further strengthen the identification of the source as a Recurrent Nova and indicate that it most likely belongs to the U Sco sub-class. Our analysis implies that M_{\rm WD} \ga 1.3 M in this system. Overall, we show that suitable complementary X-ray and optical observations can be used not only to unambiguously identify Recurrent Novae in M31, but also to determine subtypes and important physical parameters of these systems. Prospects are therefore good for extending studies of Recurrent Novae to M31 with the potential to explore in more detail such important topics as their proposed link to Type Ia Supernovae.References(26)
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