We observed the fast-fading, red, subluminous transient AT2023zaw/ ZTF23absbqun (Astronotes 2023-335, 2023-338, 2023-339) in the nearby galaxy UGC03089 (45 Mpc) with the Keck Cosmic Web Imager spectrograph (Morrissey et al. 2018) on the Keck II telescope on UTC 2023-12-12 11:08:40. The spectrum covers the wavelength range from 3500 - 9000 A at a resolution R~1000.
The spectrum shows a reddened continuum with broad absorption features, most prominently centered at 6400 A and 8200 A. These absorption features likely correspond to He I 6678 A and the CaII NIR triplet at a velocity of ~14000 km/s respectively. The high velocities of the absorption features in the spectrum, the low luminosity and the fast lightcurve evolution of AT2023zaw broadly resemble SN 2010X (Kasliwal et al. 2010) - a candidate “.Ia” supernova arising from a helium-shell detonation on the surface of a white dwarf (Bildsten et al. 2007; Shen et al. 2010), or a nickel-free supernova from a stripped massive star (Kleiser et al. 2018).
Further follow-up observations are planned.
| Catalog | Name | Reported RA | Reported DEC | Reported Obj-Type | Reported Redshift | Host Name | Host Redshift | Remarks | TNS RA | TNS DEC | TNS Obj-Type | TNS Redshift |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TNS | 2023zaw [ZTF23absbqun] | 04:29:20.237 | +70:25:37.51 | 0.0101 | 04:29:20.235 | +70:25:37.52 | SN Ib |