SIMBAD references

An attempt is made to determine the degree of completeness of the historical supernova record by comparing a sample of supernovae observed over a 2000 year period with an independently constructed set of candidate young supernova remnants with corresponding ages. It is demonstrated that remnant age can be estimated from radio or X-ray diameter and nebular kinematics, as well as from the characteristic age of an associated pulsar or the date of the supernova outburst, if recorded. The samples so constructed cover objects up to about 5 kpc from the solar system. From the overlap between the supernova and remnant samples, the total number of young, nearby supernovae is estimated at 11.4±3, or a rate of one supernova every 175 years. The number implies that the Oriental record, which mentions eight events, is 70% complete. (By intercomparing comets, novae and supernovae from 1000 years of Chinese and Japanese annals, one can show that the entire record is also two-thirds complete.) Most of the unobserved supernovae were, for several reasons, probably associated with massive stars (i.e., of Type Ib or II). The mean distance from the galactic plane of their probable supernova remnants (92 pc) is not inconsistent with that of OB stars, but it is clearly different from Type Ia supernovae (308 pc). The data suggest a supernova rate for the entire Galaxy of 5.7±1.7 (100 yr)^–1 which can be reconciled with that expected on the basis of extragalactic supernovae if 70~<H₀~<90km/s/Mpc. The rate of core-collapse supernovae appears to be high given the local population of massive stars, although the observed and expected values can probably be reconciled if the limiting mass of their OB progenitors is as low as M_lim~=5M_Sun.