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Continuing spectroscopic observations (3500-8800A) of Nova Del 2013 with the Ondrejov Observatory and the ARAS group

ATel #5312; S. N. Shore (Univ. of Pisa, INFN-Pisa); P. Skoda, D. Korcakova, P. Koubsky R. K?í?ek, P. Rutsch, M. Slechta ((Astronomical Institute, Academy of Sciences of the Czech Republic- Ondrejov, Czech Republic); O. Garde, O. Thizy , T. de France, D. Antao, J. Edlin, K. Graham, J. Guarro, F. Teyssier, P. Berard, i T. Bohlsen, E. Pollmann, T. Lemoult, A. Favaro, J.-N. Terry, E. Barbotin, F. Boubault, J. P. Masviel, R. Leadbeater, C. Buil, B. Mauclaire (contributing participants, ARAS)
on 23 Aug 2013; 01:15 UT
Distributed as an Instant Email Notice Novae
Credential Certification: S. N. Shore (shore@df.unipi.it)

Subjects: Optical, Cataclysmic Variable, Nova

Referred to by ATel #: 5378

Observations with the Ondrejov Observatory 2m Zeiss coude spectrograph (R = 18000) are continuing covering the range 3550 - 8870 A (see ATel #5282). High cadence spectroscopic monitoring by the Astronomical Ring for Access to Spectroscopy (ARAS) began on 2013 Apr. 14.8 and has continued uninterrupted covering the wavelength interval at resolutions ranging from 3684 - 7431 A with resolutions ranging from 580 - 11000 with time sequences as short as 10 minutes at resolutions up to 12000. The ARAS spectra(at this writing more than 230) are publicly available at the consortium website: http://www.astrosurf.com/aras/Aras_DataBase/Novae/Nova-Del-2013.htm Participating observers are throughout Europe, North America, and Australia. The coverage is especially dense during the period spanned by the Fermi/LAt detection and continuing observations. The rapid changes reported by the Liverpool group (ATel#5300) have not only been confirmed but resolved although the shortest interval in which significant line profile changes were detected (R > 700) was > 6 hrs with the variations being far less prominent on Aug. 20. In addition to reports in Atel #5304, ATel #5305, Balmer absorption components were detected to at least H14 on Aug. 22 (HJD 2456522.6) with vrad (abs. min) = -600+/-50 km/s. As reported, the absorption on the lower Balmer lines is also at this low velocity but the emission wings extend now to approximately +/-2000 km/s, consistent with the maximum velocity reported in the first observations from Aug. 14. The Na I D line now shows a complex absorption trough, possibly with components of both the D1 and D2 lines at -850 and -600 km/s. On Aug. 22.8 the Fe II 4921,5018 A showed absorption extending to -1400 km/s with weak indications of incipient narrow absorption at lower velocities. In the 8400-800 A region, O I 8446 may show absorption but has a profile compatible with the Na I emission and no discernible mean redshift. The changes are now relatively slower than during the first week and the nova is likely deep into the Fe-curtain phase in the UV having now passed out of the fireball. The line profiles suggest possible asphericity of the ejecta but it would be premature to speculate further. Multiwavelength spectroscopy, especially in the infrared between 2.1 =- 2.3 microns (for Na I 2.20 micron, CO 2.15 microns, etc) are extremely important now; the only feature clearly present at CN 3883, 4216 are atomic lines (e.g. Ca I 4226) but this is the period during which any molecular formation would be observed; regardless of the rate of optical decline this stage is critical to cover with R > 500 and over broad spectral range.

ARAS database for Nova Del 2013