Optical spectroscopy of SN2014J

ATel #5816; R. Kotak (QUB)
on 25 Jan 2014; 23:21 UT
Credential Certification: Rubina Kotak (r.kotak@qub.ac.uk)

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Authors: J. Polshaw, R. Kotak, J. R. Maund, S. J. Smartt (QUB), M. Fraser, N. Walton (IoA), J. M. Abreu (IAC), M. Balcells, C. Benn, J. Mendez, A. Oscoz, O. Zamora, C. Zurita (ING) A spectrum of the supernova SN 2014J in the nearby galaxy M82 was obtained on Jan. 23.2 2014 (UT) at the 2.54m Isaac Newton Telescope (INT) with IDS and the grating R1200R (approximate wavelength range 5600 - 7500A, at 2A resolution). The spectrum is dominated by strong NaI D lines, indicating significant extinction. The equivalent widths of the NaI D lines are 2.6 A (D1, 5896A) and 2.9 A (D2, 5890A), each with an uncertainty of +/- 0.2A. This is in agreement with Cox el al. (ATel #5797), and exceeds the range of the relation for estimating extinction in extragalactic sources as specified in Poznanski et al. (2012). We additionally identify narrow features associated with diffuse interstellar bands in M82 at the following rest wavelengths: 5797 6203 (blend), 6270, 6379, 6660, 6993, and 7224 A. Despite the extremely strong NaD absorption, the lightcurve of SN 2014J is consistent with an E(B-V) < 1. For a distance modulus of m-M = 27.7 mag to M82, and a current magnitude of mag ~11 for SN 2014J, the SN is currently at -16.7. For a normal SN Ia, this suggests an upper limit to E(B-V) of ~0.8, or less if the SN continues to rise as expected.