Continuing spectroscopic observations (3600-8800A) of V339 Del = Nova Del 2013 in the early nebular stage with the Nordic Optical Telescope, Ondrejov Observatory and the ARAS group
ATel #5546; S. N. Shore (Univ. of Pisa, INFN-Pisa); J. Cechura, D. Korcakova, J. Kubat, P. Skoda, M. Slechta, V. Votruba (Charles Univ. and Astronomical Institute, Academy of Sciences of the Czech Republic- Ondrejov, Czech Republic); K. Alton, D. Antao, E. Barbotin, P. Berardi, T. Blank, P. Bohlsen, F. Boubault, D. Boyd, J. Briol, Y. Buchet, C. Buil, S. Charbonnel, P. Dubreuil, M. Dubs, J. Edlin, T. de France, A. Favaro, P. Gerlach, O. Garde, K. Graham, D. Greenan, J. Guarro, T. Hansen, D. Hyde, T. Lemoult, R. Leadbeater, G. Martineau, J. P. Masviel, B. Mauclaire, J. Montier, E. Pollmann, M. Potter, J. Ribeiro, B. Schramm, O. Thizy, J.-N. Terry, F. Teyssier (contributing participants, ARAS)
on 5 Nov 2013; 01:12 UT
Distributed as an Instant Email Notice Novae
Credential Certification: S. N. Shore (shore@df.unipi.it)
We have been continuing almost nightly spectroscopic observations of V339 Del (see ATel#5378) with the 2.6 m Nordic Optical Telecope (NOT) FIbre-fed Echelle Spectrograph (FIES) (R ~ 67000), the Ondrejov Observatory 2m Zeiss coude spectrograph (R = 18000), and a variety of grating and echelle spectrographs of the ARAS group in the wavelength range 3684 - 7431A with resolutions ranging from 580 - 12000. As noted by Munari et al. (ATel#5533), the ejecta have now turned optically thin and entered the nebula phase but there are intriguing details. The strong lines include: [O I] 6300,6364,8446A, [O II] 7320/7330A, [O III] 4363,4959,5007A, C II 7235A and [N II] 5755A (the 6548,6583A lines are still strongly blended with Halpha), N II 4639, He I (especially 4471, 5876, and 7065), and He II 4686A (peak flux 5.9E-13 erg/s/cm^2/A on Oct. 28). He II was clearly present as early as Oct. 10 (but see Woodward et al. ATel#5493). There is no further indication of either Na I D or any Fe II (or related) emission in the spectrum. The line profiles remained nearly symmetrical and identical to the [O I] 6300A, 6364A lines until Oct. 11. A drastic change in the Balmer line profiles occurred between Oct. 12 (Day 59) and Oct. 14 (Day 61) -- the interval from -500 to -800 km/s increased by a factor of about 3 relative to the red wing (in the velocity interval 500 to 800 km/s). This transition occurred around the time of the supersoft X-ray detection (Osborne et al. ATel#5505). This same profile change was reproduced in all ionized species lines, only the [O I] lines have remained unchanged. On the Oct. 28 NOT spectrum (Day 76), comparisons of Hbeta and Hdelta reveals narrow emission features with halfwidths of ~100 km/s throughout the profile, suggesting that the broad emission is composed of individual knots with possibly low filling factor, the same narrow features appear on [N II] 5755A. The [O III] 5007A line blue and red peaks are at more negative (positive, respectively) velocities than Hbeta by ~150 km/s while the FWZI is the same for both profiles; the same contrast is seen with respect to [N II] 5755A, which shows a weaker red peak (500-800 km/s) than Hbeta. The He I triplets show a similar profile to Hbeta, the singlets (e.g., 5016A, 6678A) are either weak (showing only the -500 to -800 km/s peak) or absent. To date (Nov. 5), there is no evidence of [Ar III] 7135A, [Fe VII] 6086A or any higher ionization emission lines. A weak continuum is present, ~ 6E-14 erg/s/cm^2/A at 4000-7000A. At this point, the publicly available ARAS archive contains more than 1000 spectra, many flux calibrated.
Based, in part, on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.
ARAS database for Nova Del 2013
