Near-infrared observations of Nova Sgr 2015 #2 (PNV J18365700-2855420)
ATel #7265; D. P. K. Banerjee, M. Srivastava, N. M. Ashok (Physical Research Laboratory, Ahmedabad, India)
on 21 Mar 2015; 05:22 UT
Credential Certification: Dipankar P.K. Banerjee (email@example.com)
Subjects: Infra-Red, Nova
Near-IR spectra of Nova Sgr 2015 #2 (PNV J18365700-2855420, discovered
on 15.634 March 2015) are reported for 2014 March 18.0, 19.0 and 20.0 UT
with the Mount Abu 1.2 meter telescope and the Near-Infrared Imager/Spectrograph (NICS)
at R ~ 1000 in the 0.85-2.4 micron region.
The spectra are typical of the Fe II class of novae, NIR templates of which are
given in Banerjee & Ashok 2012, BASI, 40, 243 (also see ATel #7230). The observed emission lines include
Hydrogen lines of the Paschen and Brackett
series, several CI and NI lines and relatively weak Lyman beta fluoresced
OI 1.1287. The strongest of the He lines expected in the NIR region, HeI 1.083 and and 2.058,
have yet to build up. All the lines show deep and strong P Cygni features. Both the P Cygni and
emission components are uncommonly narrow,
and the FWHM of both seem to be evolving with time
(more details of profile parameters to be presented later). The
spectra resemble those of a Fe II nova near or on its rise to maximum.
Photometry on March 18.0 UT shows it to be one of the brighter novae
in recent times with J = 4.85, H = 4.67, K = 4.81.