Spectroscopic classification of AT2018aes as a supernova impostor
ATel #11441; Jennifer Andrews, Nathan Smith (University of Arizona), Schuyler D. Van Dyk (Caltech/IPAC)
on 19 Mar 2018; 21:49 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Jennifer Andrews (jandrews@as.arizona.edu)
Subjects: Optical, Supernovae, Transient, Variables
A visual-wavelength optical spectrum of AT2018aes obtained on UT 2018 Mar 13 (JD 2458190.84) with the Magellan Clay telescope (+ LDSS3 spectrograph, VPH-all grism) reveals a narrow H-alpha emission line with a velocity of 525 km/s, with wings extending to roughly +/-1000 km/s. This suggests a Type IIn classification. Additionally, however, narrow emission lines of [Ca II] 7291,7324 and intermediate-width emission lines of Ca II 8498, 8542, 8662 are seen. The presence of the calcium emission lines combined with an absolute magnitude of -12.6 (using a distance modulus of NGC5300 from NED of 30.96) indicate that this object may be a supernova impostor or intermediate-luminosity optical transient, similar to events like SN 2002bu, SN 2008S, or SN 2010dn (Prieto 2008, ATel #1550; Smith et al., 2011, MNRAS, 415, 773).
