On the Progenitors of Local Group Novae. Ii. The Red Giant Nova Rate of M31

Abstract

In our preceding paper, Liverpool Telescope data of M31 novae in eruption were used to facilitate a search for their progenitor systems within archival Hubble Space Telescope data, with the aim of detecting systems with red giant secondaries (RG-novae) or luminous accretion disks. From an input catalog of 38 spectroscopically confirmed novae with archival quiescent observations, likely progenitors were recovered for 11 systems. Here we present the results of the subsequent statistical analysis of the original survey, including possible biases associated with the survey and the M31 nova population in general. As part of this analysis, we examine the distribution of optical decline times (t 2 ) of M31 novae, how the likely bulge and disk nova distributions compare, and how the M31 t 2 distribution compares to that of the Milky Way. Using a detailed Monte Carlo simulation, we determine that 30 % 10 13 -+ of all M31 nova eruptions can be attributed to RG-nova systems, and at the 99% confidence level, 10% > of all M31 novae are RG-novae. This is the first estimate of a RG-nova rate of an entire galaxy. Our results also imply that RG-novae in M31 are more likely to be associated with the M31 disk population than the bulge; indeed, the results are consistent with all RG-novae residing in the disk. If this result is confirmed in other galaxies, it suggests that any Type Ia supernovae that originate from RG-nova systems are more likely to be associated with younger populations and may be rare in old stellar populations, such as early-type galaxies.

On a century of extragalactic novae and the rise of the rapid recurrent novae

“…This work confirmed that the M 31 proportion of Fe ii (82%) and He/N (18%) novae was consistent with that measured in the Milky Way (Della Valle & Livio, 1998;Shafter, 2007). By combining their data set with that of Capaccioli et al (1989) −10 % (> 10% at the 99% confidence level; Williams et al, 2016). This analysis also indicated that these luminous progenitors were more likely to be associated with the disk population, and the authors could not formally exclude the possibility that all of these systems were disk novae .…”

The Peculiar Multiwavelength Evolution Of V1535 Sco

“…However, recent studies on the nova population in M31 indicate that there may be many novae with red giants that are not detected, and they may constitute ∼30% of the nova eruptions in the Milky Way (Williams et al 2016). There is particular interest in discovering more of these novae because they are possible progenitors to Type Ia supernovae (e.g., Starrfield et al 2012).…”

M31N 2008-12a—THE REMARKABLE RECURRENT NOVA IN M31: PANCHROMATIC OBSERVATIONS OF THE 2015 ERUPTION

“…But it is the nearby Andromeda Galaxy (M 31), with an annual nova rate of -+ 65 15 16 yr −1 (Darnley et al 2006), that provides the leading laboratory for the study of galaxy-wide nova populations (see, for example, Ciardullo et al 1987Ciardullo et al , 1990aShafter & Irby 2001;Darnley et al 2004Darnley et al , 2006Henze et al 2008Henze et al , 2010Henze et al , 2011Henze et al , 2014bShafter et al 2011aShafter et al , 2011bShafter et al , 2015aWilliams et al 2014Williams et al , 2016. Since the discovery of the first M 31 nova by Ritchey (1917, also spectroscopically confirmed) and the pioneering work of Hubble (1929), more than 1000 nova candidates have been discovered (see Pietsch et al 2007;Pietsch 2010, and their on-line database 46 ), with over 100 now spectroscopically confirmed (see, for example, Shafter et al 2011b).…”

“…The subsequent analysis predicted a historic M 31 RN discovery efficiency of just 10% and that as many as 33% of M 31 nova eruptions may arise from RN systems (  P 100 rec years). Williams et al (2014Williams et al ( , 2016 employed a different approach: by recovering the progenitor systems of 11 M 31 RG-novae, they determined that -+ 30 % 10 13 of all M 31 nova eruptions occur in RG-nova systems, a sub-population that also appears to be strongly associated with the M 31 disk.…”