Buscombe & de Vaucouleurs ( 1955) suggested that all novae reach roughly the same absolute photographic magnitude, M pg,15 ∼ −5.2 ± 0.1, 14–16 d after maximum light. There is another methodology that has been proposed to use novae as distance indicators. Ferrarese, Côté & Jordán ( 2003) reached the same conclusion, based on a smaller and less densely sampled group of nine novae in the Virgo cluster elliptical galaxy M49.
2016), increasing the observed scatter in the MMRD to 3 mag, it is now evident from observations that the above-noted predictions from theory were correct: The MMRD has no value as a distance indicator (Shara et al. With the discovery of ‘faint, fast novae’ in M31 (Kasliwal et al. 17 that the observational scatter in an MMRD plot is far from negligible.
The many observed MMRD relations in the literature are summarized in Downes & Duerbeck ( 2000). 2017), the scatter in the MMRD was predicted to be significant (Prialnik & Kovetz 1995 Yaron et al. More importantly, they could determine distances to, for example, elliptical galaxies with no Cepheids, to low-luminosity dwarf galaxies (Conroy & Bullock 2015), and even to intergalactic ‘tramp novae’ (Shara 2006 Teyssier, Johnston & Shara 2009), which act as tracers of stars unbound to any galaxy.īecause it is not just WD mass, but also total accreted envelope mass that control nova thermonuclear runaways, and because different accretion rates can produce a significant range of accreted envelope masses (Yaron et al. If the MMRD relation did indeed calibrate novae as standard candles, then they could be used to independently measure distances to galaxies with Cepheids. Zwicky's initial correlation between the maximum magnitude of a nova and its rate of decline, was improved upon by Mclaughlin ( 1945) and Arp ( 1956). After the announcement of their discovery in the Andromeda galaxy (Hubble 1929), Zwicky ( 1936) claimed that novae behave as standard candles, with light curves that can be interpreted to yield the distances to their host galaxies. 2009) – that they can be detected with the Hubble Space Telescope ( HST) out to cosmologically interesting distances, well beyond the useful ranges of RR Lyrae stars, Cepheids and planetary nebulae. Novae near maximum light are so luminous – ranging from M V ∼ −5 to −10.7 (Shafter et al. Techniques: imaging spectroscopy, novae, cataclysmic variables 1 INTRODUCTION If very fast novae with decline times t 2 < 10 d are excluded, the distances to novae in elliptical galaxies with stellar binary populations similar to those of M87 should be determinable with 1σ accuracies of ± 20 per cent with the above calibrations. For 13 novae with daily sampled light curves, well determined times of maximum light in both the F606W and F814W filters, and decline times t 2 > 10 d we find that M87 novae display M 606 W,15 = −6.37 ± 0.46 and M 814 W,15 = −6.11 ± 0.43. Here, we demonstrate that a modified Buscombe–de Vaucouleurs hypothesis, namely that novae with decline times t 2 > 10 d converge to nearly the same absolute magnitude about two weeks after maximum light in a giant elliptical galaxy, is supported by our M87 nova data. We have recently used these light curves to demonstrate that the observational scatter in the so-called maximum-magnitude rate of decline (MMRD) relation for classical novae is so large as to render the nova-MMRD useless as a standard candle.
Ten weeks of daily imaging of the giant elliptical galaxy M87 with the Hubble Space Telescope ( HST) has yielded 41 nova light curves of unprecedented quality for extragalactic cataclysmic variables.
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