2022MNRAS.517.6150S

I derive the overall best distances for all 402 known Galactic novae, and I collect their many properties. The centrepiece is the 74 novae with accurate parallaxes from the new Gaia data release. For the needed priors, I have collected 171 distances based on old methods (including expansion parallaxes and extinction distances). Further, I have collected the V-magnitudes at peak and the extinction measures, so as to produce absolute magnitudes at peak and then derive a crude distance as a prior. Further, I have recognized that 41 per cent of the known novae are concentrated in the bulge, with 68 per cent of these <5.4° from the Galactic Centre, so the 165 bulge novae must have distances of 8000 ± 750 parsecs. Putting this all together, I have derived distances to all 402 novae, of which 220 have distances to an accuracy of better than 30 per cent. I find that the disc novae have an exponential scale height of 140 ± 10 pc. The average peak absolute V-magnitude is -7.45, with an RMS scatter of 1.33 mag. These peak luminosities are significantly correlated with the decline rate (t₃ in days) as M_V, peak_ = -7.6 + 1.5log (t₃/30). The huge scatter about this relation masks the correlation in many smaller data sets, and makes this relation useless for physical models. The bulge novae are indistinguishable from the disc novae in all properties, except that the novae with red giant companion stars have a strong preference for residing in the bulge population.