ATLAS and Liverpool Telescope observations and classification of the peculiar type II SN 2018anu
ATel #12014; S. J. Prentice, K. Maguire, S. J. Smartt, O. McBrien, K. W. Smith, (Queen's University Belfast), J. Tonry, L. Denneau, A. Heinze, H. Weiland, H. Flewelling (IfA, University of Hawaii), B. Stalder (LSST) A. Rest (STScI), P. Clark, E. Kankare, M. Magee, D. O'Neill, D. R. Young (QUB)
on 6 Sep 2018; 16:32 UT
Credential Certification: Simon Prentice (s.prentice@qub.ac.uk)
Subjects: Optical, Supernovae
SN 2018anu was discovered by CRTS on 2018-03-29 (TNS Astronomical Transient Report
No.17554) at V=18.8. ATLAS detected the source on 2018-04-05 at o=18.5, and it
faded to ~19 mag before rising again over the past 80 days to 18.2 mag (o-band).
The transient was observed with SPRAT (Piascik et al. 2014) on the Liverpool Telescope (Steele et al, 2004) on 2018-September 05.86 (UT). The spectrum is similar to SNe II, showing a strong H alpha P-Cygni line with an expansion velocity of -6500 km/s.
SNID gives a best match to Type IIP SN 2005cs, 15 d past explosion at a z=0.039. The SN is offset from the galaxy, GALEXASC J173615.16+185850.6. A nearby galaxy (CGCG 112-011 NED02) has a NED spectroscopic redshift of z=0.039120, consistent with that from the SN spectral fit and an offset of ~30 kpc from the SN position, suggestive of a galaxy group environment. Assuming this redshift gives a current absolute magnitude of -18.
The potential multiple peaks and normal Type II SN spectrum are similar to the behaviour of the unusual long-lived Type II SN, iPTF14hls (Arcavi et al. 2017, Nature, 551, 210).
