Gaia16alo is a Type II SN
ATel #9037; M. Fraser, S. T. Hodgkin, S. Mattila, D. Harrison (IoA), L. Wyrzykowski (Warsaw), Z. Kostrzewa-Rutkowska (Warsaw/SRON), N. Blagorodnova (Caltech)
on 10 May 2016; 18:52 UT
Credential Certification: Morgan Fraser (mf@ast.cam.ac.uk)
Subjects: Optical, Supernovae
Gaia16alo (aka PS16cct) was observed using the robotic Liverpool Telescope + SPRAT (R~350; 400-800 nm) on the night of 2016 May 6. The spectrum was compared to a set of templates using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024), and we find a best match to a range of Type II SNe at z=0.03. We see a clear broad Halpha line in emission, with FWHM ~7000 km/s. There is a weak, P-Cygni absorption in Halpha similar to that typically seen in either a young Type IIP SN, or a Type IIL SN. Given that this spectrum was taken 2 weeks after the discovery of Gaia16alo, we suggest the latter is more likely. Broad NaD, Hbeta, and Fe lines in the blue are also seen. The absolute magnitude of ~-17.8 is also relatively bright for a Type IIP SN, and more consistent with a IIL SN.
We acknowledge ESA Gaia, DPAC and the Photometric Science Alerts Team (http://gsaweb.ast.cam.ac.uk/alerts).
