Optical and NIR observations of SN 2014J
ATel #5876; Shubham Srivastav (Indian Institute of Astrophysics), Joe Philip Ninan (Tata Institute of Fundamental Research), G. C. Anupama, D. K. Sahu (Indian Institute of Astrophysics), D. K. Ojha (Tata Institute of Fundamental Research)
on 11 Feb 2014; 06:37 UT
Credential Certification: G.C. Anupama (gca@iiap.res.in)
Subjects: Infra-Red, Optical, Supernovae
We report that SN 2014J, the nearby type Ia supernova in M82 (ATel #5786) is being monitored from the Indian Astronomical Observatory (IAO) in the optical and NIR bands, using the HFOSC and TIRSPEC instruments on the Himalayan Chandra Telescope (HCT).
The B-band maximum occurred at an apparent magnitude of 11.95 +/- 0.02 on Jan 31.29 UT, and the observed (B-V) color at this epoch was ~1.4. JHK magnitudes at 4 epochs near maximum, estimated after accounting for the galactic contribution using archival 2MASS images, are summarized below:
Jan 25.02 UT J=9.59 H=9.64 K=9.53
Jan 29.91 UT J=9.40 H=9.49 K=9.34
Jan 30.84 UT J=9.42 H=9.59 K=9.37
Jan 31.91 UT J=9.52 H=9.61 K=9.42
Low resolution spectra (350-920 nm) show a red continuum with prominent Si II, Ca II, S II and Fe II features along with deep Na I D absorption and DIBs at 5780, 5797 and 6284, similar to that reported in ATel #5797, #5816. The measured Si II absorption velocities indicate a decrease from ~13,300 km/sec on Jan 24.96 UT to ~11,800 km/sec on Feb 07.91 UT. The measured velocities are consistent with those reported in ATel #5791, #5818, #5827, #5829 and #5843.
A NIR spectrum (1.01-2.45 micron) obtained on Jan 29.92 UT shows broad absorption features of Mg II 1.09 micron (blueshifted by ~13,000 km/sec) and Si II / Mg II blend near 1.6 micron. A blend of features near 1.2 micron attributable to Ca II is also detected.
