J/A+A/580/A45 Nova M31N 2008-12a 2014 eruption in optical/UV (Darnley+, 2015)
A remarkable recurrent nova in M31: Discovery and optical/UV observations of the
predicted 2014 eruption.
Darnley M.J., Henze M., Steele I.A., Bode M.F., Ribeiro V.A.R.M.,
Rodriguez-Gil P., Shafter, A.W., Williams S.C., Baer D., Hachisu I.,
Hernanz M., Hornoch K., Hounsell R., Kato M., Kiyota S., Kucakova H.,
Maehara H., Ness J.-U., Piascik A.S., Sala G., Skillen I., Smith R.J.,
Wolf M.
<Astron. Astrophys. 580, A45 (2015)>
=2015A&A...580A..45D 2015A&A...580A..45D
ADC_Keywords: Galaxies, nearby ; Novae ; Photometry, CCD
Keywords: galaxies: individual: M31 - novae, cataclysmic variables -
stars: individual: M31N 2008-12a
Abstract:
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-year, 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 multicolour
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.
Description:
Optical and near-UV photometric observations of the 2014 eruption of
the M31 recurrent nova M31N 2008-12a are presented. For each set of
observations the date (UT), time with respect to the optical maximum,
JD of the start and end of the observation (if the same, these
represent the midpoint), telescope & instrument, number of exposures,
exposure time of each exposure, filter, detection signal to noise
ratio (if detect), photometry, and photometric error (if =99 the
photometry is an upper limit) is provided.
Color information is also provided separately, here the data (UT),
time with respect to the optical maximum, JD of the start and end of
the observation, telescope & instrument, filters, color, and color
error is provided.
Objects:
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RA (2000) DE Designation(s)
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00 45 28.80 +41 54 10.1 M31N 2008-12a = M31N 2008-12a
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 85 156 Optical/UV photometric observations of the
2014 eruption of M31N 2008-12a
tablea2.dat 73 69 Color evolution of the 2014 eruption of
M31N 2008-12a
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 "date" Date Midpoint data of observation (UT)
17- 23 F7.3 d Time [-66/40] Time after optical peak of the
observation midpoint
25- 31 F7.3 d Start Julian Date (JD-2456000.5) of start of
observation
33- 39 F7.3 d End Julian Date (JD-2456000.5) of end of observation
41- 54 A14 --- Tel Telescope and instrumentation used (G1)
56- 57 I2 --- Obs [1/50]?=0 Number of single exposures making up
the observation (0= unknown)
59- 62 I4 s Texp [60/1200]?=0 Exposure time of each of the single
exposures (0= unknown)
64- 65 A2 --- Filter Filter used: B, Ha, I, R, U, V, g, i' and r'
67- 71 F5.1 --- SNR [5/127]?=0 Signal to noise ratio of the detection
(0= unknown or undetected (if l_mag='<'))
73 A1 --- l_mag Limit flag on mag
74- 79 F6.3 mag mag [16.9/22.4] Apparent magnitude in Filter
81- 85 F5.3 mag e_mag [0.01/0.3]?=0 Apparent magnitude uncertainty
(0 if upper photometric limit)
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Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 "date" Date Midpoint data of observation (UT)
17- 23 F7.3 d Time [-0.2/6.4] Time after optical peak of the
observation midpoint
25- 31 F7.3 d Start Julian Date (JD-2456000.5) of start of
observation
33- 39 F7.3 d End Julian Date (JD-2456000.5) of end of
observation
41- 54 A14 --- Tel Telescope and instrumentation used (G1)
56- 60 A5 --- Filters Filter pair used to determine color
(B-V, V-r' and r'-i')
62- 67 F6.3 mag Col Apparent color
69- 73 F5.3 mag e_Col [0.01/0.3] Apparent color uncertainty
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Global Notes:
Note (G1): telescopes are:
Danish 1.54m = Telescope at ESO, La Silla (Chile)
Kiso 1.05m = Schmidt telescope in Japan
LT IO:O = Liverpool 2m robotic Telescope on La Palma, Canary Islands
MLO 1.0m = Mount Laguna Observatory (California)
Ondrejov 0.65m = Telescope in Czech Republic
iPTF = intermediate Palomar Transient Factory
iTelescope T11 = 50cm (20inch) telescope at Mayhill, New Mexico
(http://itelescope.int/)
iTelescope T24 = 60cm (24inch) telescope at Sierra Remote Obs., Auberry
(http://itelescope.int/)
Acknowledgements:
Matt Darnley, M.J.Darnley(at)ljmu.ac.uk
History:
* 28-Jul-2015: on-line version
* 11-Oct-2016: tables 1 and 2 renamed tables A1 and A2, respectively
(End) Matt Darnley [LJMU, UK], Patricia Vannier [CDS] 16-Jul-2015