AstroNote 2021-59

The Zwicky Transient Facility (ZTF; Bellm et al. 2019; Graham et al. 2019) Infant Supernova Science Program (Gal-Yam 2019) reports the early discovery, rapid follow-up and classification of SN2021can (ZTF21aaiaqhh), following the methodology outlined by Gal-Yam et al. (2011).

The object was first detected on ZTF r-band images obtained on February 07, 2021 at 07:55 UT, about 1.8 days after the last non-detection, and was picked up by a custom Fritz filter. The object was first saved by Jesper Sollerman and rapid follow-up was triggered. The object was publicly announced by Daniel Perley, Anna Ho and Lucy Astles via the TNS. 

Assuming the redshift of the apparent host (z=0.0207), the SN was discovered around absolute magnitude Mr=-15.6. An early spectrum obtained with SEDm (Blagorodnova et al., 2018) showed flash ionisation features (i.e.: H, He II, N III). The object was classified as a SN II. Swift photometry has been triggered and additional observations are ongoing.

We will continue to distribute alerts on such early SN detections via AstroNotes; additional follow-up observations of this transient are encouraged.

ZTF is a project led by PI S. R. Kulkarni at Caltech, and includes IPAC; WIS, Israel; OKC, Sweden; JSI/UMd, USA; UW,USA; DESY, Germany; NRC, Taiwan; UW Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. Alert distribution service provided by DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system (Kasliwal et al. 2019), supported by NSF PIRE grant 1545949.