J/ApJ/833/149ivo://CDS.VizieR/J/ApJ/833/149doi:10.26093/cds/vizier.18330149CDSDarnley M.J.Henze M.Bode M.F.Hachisu I.Hernanz M.Hornoch K.,Hounsell R.Kato M.Ness J.-U.Osborne J.P.Page K.L.,Ribeiro V.A.R.M.Rodriguez-gil P.Shafter A.W.Shara M.M.Steele I.A.,Williams S.C.Arai A.Arcavi I.Barsukova E.A.Boumis P.Chen T.,Fabrika S.Figueira J.Gao X.Gehrels N.Godon P.Goranskij V.P.,Harman D.J.Hartmann D.H.Hosseinzadeh G.Horst J.C.Itagaki K.,Jose J.Kabashima F.Kaur A.Kawai N.Kennea J.A.Kiyota S.,Kucakova H.Lau K.M.Maehara H.Naito H.Nakajima K.Nishiyama K.,O'Brien T.J.Quimby R.Sala G.Sano Y.Sion E.M.Valeev A.F.,Watanabe F.Watanabe M.Williams B.F.Xu Z.2017-07-03T13:14:59Z2017-05-12T07:40:57ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frnovaeinfrared-photometryvisible-astronomybroad-band-photometryultraviolet-photometryx-ray-sourcesThe Andromeda Galaxy recurrent nova M31N 2008-12a had been observed in eruption 10 times, including yearly eruptions from 2008 to 2014. With a measured recurrence period of P_rec_=351+/-13days (we believe the true value to be half of this) and a white dwarf very close to the Chandrasekhar limit, M31N 2008-12a has become the leading pre-explosion supernova type Ia progenitor candidate. Following multi-wavelength follow-up observations of the 2013 and 2014 eruptions, we initiated a campaign to ensure early detection of the predicted 2015 eruption, which triggered ambitious ground- and space-based follow-up programs. In this paper we present the 2015 detection, visible to near-infrared photometry and visible spectroscopy, and ultraviolet and X-ray observations from the Swift observatory. The LCOGT 2m (Hawaii) discovered the 2015 eruption, estimated to have commenced at August 28.28+/-0.12UT. The 2013-2015 eruptions are remarkably similar at all wavelengths. New early spectroscopic observations reveal short-lived emission from material with velocities ~13000km/s, possibly collimated outflows. Photometric and spectroscopic observations of the eruption provide strong evidence supporting a red giant donor. An apparently stochastic variability during the early supersoft X-ray phase was comparable in amplitude and duration to past eruptions, but the 2013 and 2015 eruptions show evidence of a brief flux dip during this phase. The multi-eruption Swift/XRT spectra show tentative evidence of high-ionization emission lines above a high-temperature continuum. Following Henze+ (2015A&A...582L...8H), the updated recurrence period based on all known eruptions is P_rec_=174+/-10days, and we expect the next eruption of M31N 2008-12a to occur around 2016 mid-September.2016ApJ...833..149Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/833/149CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)J/AJ/152/62 : Revised LGGS UBVRI photom. of M31 & M33 stars (Massey+, 2016)J/ApJ/811/32 : BVRcIcJHK and X-ray LCs of the U Sco nova (Pagnotta+, 2015)J/A+A/580/A45 : Nova M31N 2008-12a 2014 eruption in opt/UV (Darnley+, 2015)J/A+A/563/A2 : X-ray monitoring of M31 novae (Henze+, 2014)J/ApJS/197/31 : Swift X-ray obs. of classical novae. II. (Schwarz+, 2011)J/A+A/533/A52 : X-ray monitoring of M31 novae (Henze+, 2011)J/ApJ/734/12 : Survey of novae in M31 (Shafter+, 2011)J/AJ/140/34 : Classification of novae light curves (Strope+, 2010)J/ApJS/187/275 : Photometric histories of recurrent novae (Schaefer, 2010)J/A+A/477/67 : Search for M31 novae from Schmidt plates (Henze+, 2008)J/A+A/465/375 : X-ray monitoring of optical novae in M31 (Pietsch+, 2007)J/A+A/418/869 : M31-RV evolution (1942-1993) (Boschi+, 2004)http://www.mpe.mpg.de/~m31novae/opt/m31 : Optical novae in M31https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/833/149https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/833/149http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/833/149https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/833/149https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/833/149http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/833/149GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapAssociated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/ApJ/833/149InfraredOpticalUVX-raydefaultJ/ApJ/833/149/table13Swift observations of nova M31N 2008-12a following the 2015 eruptionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObsIDIdentification of Swift observationmeta.id;obs.param;obscharExpDead-corrected Swift/XRT exposure timekstime.duration;obs.exposurefloatDateUT Date of observation midpointtime.epoch;obsnullableStartJulian Date of observation start +2457000.5dtime.start;obsdoubleTimeTime after optical peak of observation startdtime.epochfloatl_m2magUpper limit flag on m2magmeta.code.errorcharm2mag[16.8/19]? Swift/UVOT uvm2 band apparent magnitudemagphot.mag;em.UVfloatnullablee_m2mag[0.2]? Uncertainty in m2magmagstat.error;phot.magfloatnullablel_w1magUpper limit flag on w1magmeta.code.errorcharw1mag[17/20.5]? Swift/UVOT uvw1 band apparent magnitudemagphot.mag;em.UVfloatnullablee_w1mag[0.1/0.4]? Uncertainty in w1magmagstat.error;phot.magfloatnullablel_CRateUpper limit flag on CRatemeta.code.errorcharCRate[0.7/31] Swift/XRT count rate0.01count.s**-1phot.count;em.X-rayfloate_CRate[0.3/0.9]? Uncertainty in CRate0.01count.s**-1stat.errorfloatnullablel_LXUpper limit flag on LXmeta.code.errorcharLX[0.5/23] X-ray luminosity; 1e38 erg/s1e+31Wphys.luminosity;em.X-rayfloate_LX[0.2/0.7]? Uncertainty in LX1e+31Wstat.errorfloatnullableJ/ApJ/833/149/table11Visible and near infrared photometric observations of the 2015 eruption of M31N 2008-12arecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObsUT Date of observation midpointtime.epoch;obsnullableTimeTime after optical peak of observation midpointdtime.epochfloatStartJulian Date of observation start +2457000.5dtime.start;obsfloatEndJulian Date of observation end +2457000.5dtime.end;obsfloatTelTelescope+Instrumentation used; where knowninstr.setupcharNexp[0/75] Number of single exposures making up observation (0=unknown)meta.numberintExp[0/600] Exposure time of each of single exposures (0=unknown)stime.duration;obs.exposureintFiltFilter used (BVRIHu'r'i'z')instr.setup;instr.filtercharSNR[0/176] Signal to noise ratio of detection (0=unknown or undetected (if no e_mag))stat.snrfloatl_magUpper limit flag on magmeta.code.errorcharmag[12.5/23.7] Apparent magnitude in Filt (or upper limit)magphot.magfloate_mag[0.008/0.5]? Uncertainty in magmagstat.error;phot.magfloatnullableRefReference associated with data point (1)meta.ref;pos.framecharJ/ApJ/833/149/table12Color evolution of the 2015 eruption of M31N 2008-12arecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObsUT Date of observation midpointtime.epochnullableTimeTime after optical peak of observation midpointdtime.epochfloatStartJulian Date of observation start +2457000.5dtime.start;obsfloatEndJulian Date of observation end +2457000.5dtime.end;obsfloatTelTelescope+Instrumentation used; where knowninstr.setupcharFiltFilter pair used to determine color (B-V, V-r', i'-z', r'-i', u'-B and uvw1-u')instr.setupcharColor[-1.8/0.7] Apparent color in Filtmagphot.colorfloate_Color[0.01/0.4] Uncertainty in Colormagstat.error;phot.colorfloat