M31N 2008-12a, the remarkable recurrent nova in Andromeda: a monitoring campaign with the IAC80, INT, and LCOGT telescopes

ATel #15902; E. Reyes Rodriguez, G. Aznar Menargues, Y. Calatayud-Borras, A. Casasbuenas, M. Cervera Cortes, I. Cortes-Perez, J. del Socorro Prieto, M. Delgado Mancheno, A. Ferrer I Burjachs, R. Flores le Roux, D. Galan, S. Geraldia Gonzalez, P. Grebol-Tomas, S. Navarro Umpierrez, A. Pelaez-Torres, P. Sosa-Guillen, A. Vielba Trillo (ULL), E. Esparza-Borges, F. Poidevin and I Perez-Fournon (IAC and ULL)
on 13 Feb 2023; 22:48 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Ismael Perez-Fournon (ipf@iac.es)

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In ATel #15786 we reported the discovery of the 2022 eruption of the remarkable recurrent nova in Andromeda M31N 2008-12a, that presents annual eruptions that have been studied in detail (see, e.g. Darnley et al. 2016). However, the annual eruption date varies from year to year. Here, we report additional photometry based on a three-month monitoring campaign with the IAC80 and Isaac Newton (INT) telescopes, and with the Las Cumbres Observatory global telescope network (LCOGT). At the IAC80, we observed the field of M31N 2008-12a with the CAMELOT2 camera on the nights of 2022 October 14, 15, 21, 22, 28, and 29, in visitor mode. At the INT, we observed the nova field with the Wide Field Camera on the nights of 2022 November 11 and 12, also in visitor mode. The nova was not detected in any of these observations, with varying limiting magnitudes that will be reported elsewhere. We continued the monitoring using the northern hemisphere LCOGT 1m telescopes and their Sinistro cameras with observations on the nights of 2022 November 18 and 23 and December 1, 2, 3, 4, 5, 6, 8, 11, and 14. The nova was not detected in any of the LCOGT observations until the first detection on 2022 December 2.8264 reported by us in ATEL #15786. We report here the limiting magnitude of the last LCOGT non detection and the photometry of the LCOGT detections, calibrated using Pan-STARRS DR2.

 
  Date [UT]       | Mag    | Err  | Filter | Exposure Time (sec)  | Telescope 
2022-12-01.9580   | < 20.8 |      | r'     | 180                  | LCOGT (Teide Observatory, 1m) 
2022-12-02.8264   | 19.18  | 0.07 | r'     | 180                  | LCOGT (Teide Observatory, 1m)   
2022-12-03.2434   | 18.35  | 0.03 | r'     | 180                  | LCOGT (McDonald Observatory, 1m) 
2022-12-03.9573   | 18.38  | 0.05 | r'     | 180                  | LCOGT (Teide Observatory, 1m)    
2022-12-03.9748   | 18.50  | 0.05 | r'     | 180                  | LCOGT (Teide Observatory, 1m)     
2022-12-04.8469   | 18.94  | 0.14 | r'     | 100                  | LCOGT (Teide Observatory, 1m)      
2022-12-05.0353   | 19.61  | 0.30 | r'     | 300                  | LCOGT (McDonald Observatory, 1m)   
2022-12-06.8396   | 20.67  | 0.36 | r'     | 180                  | LCOGT (Teide Observatory, 1m)      
  

After our report of the discovery of the 2022 eruption, observations from other follow-up programs have been reported in the optical (ATel's #15787, #15788, #15789, #15795, #15797, and #15802), as well as with Swift (ATel #15798) and AstroSat (ATel #15810). Spectroscopic confirmation of the nova has been reported in ATel's #15788 and #15790. The combined light curve from our LCOGT photometry and other reported results resembles in peak magnitude and shape the light curves of other eruptions of M31N 2008-12a (e.g. the 2015 eruption discussed in Darnley et al. 2016).

More information on previous eruptions of M31N 2008-12a with links to related ATel's is available here.

Based on observations made in the Observatorios de Canarias del IAC with the IAC80 and Isaac Newton Telescope. This work makes use also of observations from the Las Cumbres Observatory global telescope network.
These observations are part of a training course in observational astronomy of the Master in Astrophysics of the University of La Laguna (ULL, Tenerife, Spain).  We thank the IAC, ULL, Teide Observatory, and Isaac Newton Group of Telescopes staff for their support of the observing trips and help with the observations. We are also grateful to David Bishop for his compilation of supernovae and extragalactic novae.

Las Cumbres Observatory images: last non detection and first detection