Peak brightnesses of historical supernovae and the hubble constant

This paper reports on the peak magnitudes (m(max)) and peak absolute magnitudes (M(max)) of SN 1604, SN 1572, SN 1006, and SN 185 utilizing three techniques that have not been previously applied to the historical supernovae. SN 1604 is at a distance (D) of 3.4 +/- 0.3 kpc, with a visual extinction (A) of 3.27 +/- 0.14 and is unlikely to be a Type Ia supernova. Its light curve shape is like that of a fast Type Ia event with m(max) = -3.02 +/- 0.10 and M(max) = -18.95 +/- 0.26. SN 1572 is at D = 2.35 +/- 0.20 kpc, with A = 2.25 +/- 0.16, and is likely to be a Type Ia or Ib supernova. Its light curve shape is like that of a very fast Type Ia event with m(max) = -4.53 +/- 0.18 and M(max) = -18.64 +/- 0.31. SN 1006 is most likely a Type Ia event at 1.59 +/- 0.13 kpc with an extinction of 0.32 +/- 0.03 and a peak near -5 mag. Even though the available light curve is sparse and crude, the supernova is certainly subluminous with a peak absolute magnitude of approximately -17. SN 185 has a peak magnitude that can only be constrained to be brighter than roughly -7.5, has an uncertain remnant, and is unlikely to even be a supernova. These four historical supernovae are useless for solving the Hubble constant question for three reasons: First, none of them is guaranteed to be a Type Ia event and SN 185 is unlikely to even be a supernova. Second, the various calibration, template, and procedural problems combine to make the uncertainties large. Third, the measurement errors alone yield uncertainties that are sufficiently large to preclude a solution of the Hubble constant problem.