TY - JOUR
T1 - A remarkable recurrent nova in M31
T2 - Discovery and optical/UV observations of the predicted 2014 eruption
AU - Darnley, M. J.
AU - Henze, M.
AU - Steele, I. A.
AU - Bode, M. F.
AU - Ribeiro, V. A.R.M.
AU - Rodríguez-Gil, P.
AU - Shafter, A. W.
AU - Williams, S. C.
AU - Baer, D.
AU - Hachisu, I.
AU - Hernanz, M.
AU - Hornoch, K.
AU - Hounsell, R.
AU - Kato, M.
AU - Kiyota, S.
AU - Kučáková, H.
AU - Maehara, H.
AU - Ness, J. U.
AU - Piascik, A. S.
AU - Sala, G.
AU - Skillen, I.
AU - Smith, R. J.
AU - Wolf, M.
N1 - Funding Information:
The Liverpool Telescope is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias with financial support from STFC. The William Herschel Telescope is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. Based (in part) on data collected with the Danish 1.54-m telescope at the ESO La Silla Observatory. We would like to thank the LT group at LJMU for their help, and patience, in obtaining these data from the newly commissioned SPRAT spectrograph. We are grateful to the Swift Team for making the ToO observations possible, in particular N. Gehrels, the duty scientists, as well as the science planners. The authors would like to specially thank Adam Muzzin and Mauro Stefanon for graciously donating a portion of their WHT time to this study. We thank Andrew M. Shafter (Magnolia Science Academy) for assistance with the MLO observations, Karl Misselt for taking and graciously donating the Bok data, and Phil James for advice on continuum subtraction from H imaging. This work used the pamela and molly software packages written by Tom Marsh. PRG acknowledges support from the MINECO under the Ramón y Cajal programme (RYC–2010–05762). K.H. was supported by the project RVO:67985815. M.H. acknowledges support from an ESA fellowship. V.A.R.M.R. acknowledges financial support from the Radboud Excellence Initiative. A.W.S. acknowledges support from NSF grant AST1009566. M.W. was supported by the Czech Science Foundation, grant P209/10/0715. This research has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under the grants ESP2013-41268-R, AYA2011–23102, and AYA2012–38700. The comments of the referee were appreciated in identifying areas that benefited from additional discussion and clarification.
Publisher Copyright:
© ESO, 2015.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - The Andromeda Galaxy recurrent nova M31N 2008-12a had been caught in eruption eight times. The inter-eruption period of M31N 2008-12a is ~1 yr, making it the most rapidly recurring system known, and a strong single-degenerate Type Ia supernova progenitor candidate. Following the 2013 eruption, a campaign was initiated to detect the predicted 2014 eruption and to then perform high cadence optical photometric and spectroscopic monitoring using ground-based telescopes, along with rapid UV and X-ray follow-up with the Swift satellite. Here we report the results of a high cadence multi-colour optical monitoring campaign, the spectroscopic evolution, and the UV photometry. We also discuss tantalising evidence of a potentially related, vastly-extended, nebulosity. The 2014 eruption was discovered, before optical maximum, on October 2, 2014. We find that the optical properties of M31N 2008-12a evolve faster than all Galactic recurrent novae known, and all its eruptions show remarkable similarity both photometrically and spectroscopically. Optical spectra were obtained as early as 0.26 days post maximum, and again confirm the nova nature of the eruption. A significant deceleration of the inferred ejecta expansion velocity is observed which may be caused by interaction of the ejecta with surrounding material,possibly a red giant wind. We find a low ejected mass and low ejection velocity, which are consistent with high mass-accretion rate, high mass white dwarf, and short recurrence time models of novae. We encourage additional observations, especially around the predicted time of the next eruption, towards the end of 2015.
AB - The Andromeda Galaxy recurrent nova M31N 2008-12a had been caught in eruption eight times. The inter-eruption period of M31N 2008-12a is ~1 yr, making it the most rapidly recurring system known, and a strong single-degenerate Type Ia supernova progenitor candidate. Following the 2013 eruption, a campaign was initiated to detect the predicted 2014 eruption and to then perform high cadence optical photometric and spectroscopic monitoring using ground-based telescopes, along with rapid UV and X-ray follow-up with the Swift satellite. Here we report the results of a high cadence multi-colour optical monitoring campaign, the spectroscopic evolution, and the UV photometry. We also discuss tantalising evidence of a potentially related, vastly-extended, nebulosity. The 2014 eruption was discovered, before optical maximum, on October 2, 2014. We find that the optical properties of M31N 2008-12a evolve faster than all Galactic recurrent novae known, and all its eruptions show remarkable similarity both photometrically and spectroscopically. Optical spectra were obtained as early as 0.26 days post maximum, and again confirm the nova nature of the eruption. A significant deceleration of the inferred ejecta expansion velocity is observed which may be caused by interaction of the ejecta with surrounding material,possibly a red giant wind. We find a low ejected mass and low ejection velocity, which are consistent with high mass-accretion rate, high mass white dwarf, and short recurrence time models of novae. We encourage additional observations, especially around the predicted time of the next eruption, towards the end of 2015.
KW - Galaxies: individual: M31
KW - Novae, cataclysmic variables
KW - Stars: individual: M31N 2008-12a
UR - http://www.scopus.com/inward/record.url?scp=84943746978&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84943746978&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201526027
DO - 10.1051/0004-6361/201526027
M3 - Article
AN - SCOPUS:84943746978
SN - 0004-6361
VL - 580
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A45
ER -