Discovery and Spectroscopic Classification of iPTFemh as a Classical Nova in M31

ATel #9347; K. Chinetti (Caltech), M. J. Darnley (LJMU), N. Blagorodnova (Caltech), J. D. Neill (Caltech), S. C. Williams (Lancaster)
on 9 Aug 2016; 00:17 UT
Credential Certification: Matt Darnley (M.J.Darnley@ljmu.ac.uk)

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We report the discovery of nova candidate iPTFemh with the CFH12k instrument taken on 2016 Aug 01.45 UT on the Palomar 48-in telescope. The new object is located at RA 00:43:57.77, DEC +41:34:52.6 (J2000.0), and was not detected in images taken 2016 July 26.49. A search of PTF data yielded prediscovery photometry data for 2016 Jul 28 - 31. Full photometry, including prediscovery, of the transient is summarized in the table below:

 
Date (UT)       Filter  Magnitude 
2016 Jul 28.42  r       19.15 ± 0.13 
2016 Jul 29.47  r       19.04 ± 0.12 
2016 Jul 30.46  r       18.58 ± 0.11 
2016 Jul 31.46  r       18.13 ± 0.11 
2016 Aug 01.45  r       18.36 ± 0.11 
2016 Aug 02.46  r       18.17 ± 0.11 
2016 Aug 03.46  r       18.37 ± 0.10 
2016 Aug 04.49  r       18.44 ± 0.11 
2016 Aug 05.44  r       18.55 ± 0.10 

We also obtained a spectrum with the SPRAT spectrograph (Piascik et al. 2014) on the 2m Liverpool Telescope (Steele et al. 2004) on 2016 Aug 5.18 UT. The spectrum shows strong Balmer lines (Hα-δ), with FWHM 1000±100 km/s. There are also Fe II (multiplets 37, 38, 42, 48, 49, 74), Na-D (5892 Å), and Na I (6159 Å) emission lines. This spectrum is consistent with spectra obtained with the SEDM spectrograph on the Palomar 60-in telescope on 2016 Aug 2 and 4. As such, we conclude iPTF16emh is a classical nova in M31 belonging to the Fe II taxonomic class.

This work is part of an international undergraduate internship supported by the NSF PIRE GROWTH program.