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Near-infrared observations of recurrent nova V745 Sco

ATel #5865; Dipankar P. K. Banerjee, V. Venkataraman, Vishal Joshi, Ashish Raj and N. M. Ashok; (Physical Research Laboratory, Ahmedabad, India)
on 9 Feb 2014; 06:47 UT
Credential Certification: Dipankar P.K. Banerjee (orion@prl.res.in)

Subjects: Infra-Red, Cataclysmic Variable, Nova

Referred to by ATel #: 5870, 5871, 5874

Near-IR photometry (JHK bands) and spectroscopy have been obtained of recurrent nova V745 Sco on 8.021 and 9.021 February 2014 with the Mount Abu 1.2 meter telescope and the Near-Infrared Imager/Spectrograph (NICS; detector employed is a 1Kx1K Hawaii array). The spectral coverage is 1.58 - 2.4 micron and 0.85-2.4 micron respectively on the first and second night. The 9th February spectrum is dominated by Hydrogen lines of the Paschen and Brackett series and strong HeI lines at 1.083 and and 2.058 (HeI 1.7002 is also seen). The Lyman beta fluoresced OI 1.1287 line is just building up. The H and He lines show a broad pedestal from the nova ejecta on which is superposed a prominent narrow, spiky emission component likely emanating from the secondary giant's wind. Gaussian profiles poorly fit the HI or HeI lines but a formal gaussian fit gives a FWHM of ~4000 km/s for Paschen beta at 1.2818 micron. The FWZI's are better estimated and show the lines to be very broad (FWZI of Pa beta is 9130 km/s).

Further observations will be attempted but conditions are challenging. V745 Sco is a pre-dawn object with the threat of a rapidly brightening sky which offers about an hours observational slot. Further complications arise from its low elevation for northern telescopes (Abu 24 degree N; V745 Sco 33 degree S). "At my back I always hear, Time's winged chariot hurrying near" describes the observer's race against time in observing this object.