First Spectroscopic Confirmation of Faint ZUDS Transients with the Keck I Telescope
ATel #13514; Danny Goldstein (Caltech), Peter Nugent (LBNL), Ariel Goobar (Stockholm), Suhail Dhawan (Stockholm), Christoffer Fremling (Caltech)
on 22 Feb 2020; 20:34 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Danny Goldstein (danny@caltech.edu)
Subjects: Optical, Supernovae
D. A. Goldstein, P. E. Nugent, A. Goobar, S. Dhawan, and C. Fremling report the first spectroscopic confirmation of faint transients from the ZTF Uniform Depth Survey (ZUDS; Goldstein et al. 2020, in preparation) using the Low-Resolution Imaging Spectrograph (LRIS) on the Keck I 10-m telescope.
ZUDS is a ZTF partnership experiment designed to search for strongly gravitationally lensed supernovae using stacked ZTF images. The ZUDS survey covers 2,000 deg2 of the Legacy Survey DR8 footprint in each of the g, r, and i-band filters, with a cadence of two visits per filter per night. Using a custom image processing pipeline to combine survey images into 7-day stacks, ZUDS achieves weekly limiting magnitudes of ~21.5 - 22 in all three of its search bandpasses. This infrastructure enables ZUDS to be sensitive to fainter, more distant transients than the nominal ZTF survey.
Real-time subtractions are performed on the stacked images to search for transients, using the Cori supercomputer at the National Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory.
The observations reported below were made on 19 Feburary 2020 UT. Classifications were performed with Superfit (Howell et al. 2005).
| Name | IAU Name| RA (J2000) | DEC (J2000) | z | Type | Phase | Notes
| ZUDS20dyxde | 2020dau | 14h58m55.3734s | +51d03m34.1211s | 0.27 | SN Ia | Post-peak | (1)
| ZUDS20eaies | 2020dav | 14h34m48.4126s | +50d01m15.5126s | 0.35 | 91T | +10 |
| ZUDS20dpvgu | 2020daw | 13h31m08.5013s | +52d36m54.5173s | 0.29 | SN Ia | +5 |
| ZUDS20egnws | 2020dax | 13h40m46.6066s | +40d03m28.2525s | 0.17 | SN Ia | -5 | (1)
| ZUDS20drtvq | 2020day | 12h41m58.1998s | +60d38m46.4606s | 0.16 | 11kx | +30 |
| ZUDS20dqkdq | 2020daz | 14h45m31.5077s | +58d18m16.1612s | 0.27 | SN IIn| Post-peak | (2)
| ZUDS20dohna | 2020dba | 14h56m33.2728s | +46d34m34.3585s | 0.32 | SLSN I| Peak | (3)
| ZUDS20dofxx | 2020dcm | 14h56m07.725s | +46d19m35.2836s | 0.27 | 91T | +10 |
| ZUDS20dlgrv | 2020dcn | 13h45m22.5824s | +39d44m16.6046s | 0.2177 | 99aa | -3 |
Notes: When the redshift is given to 2 decimal places, it is derived from the SN spectrum. Otherwise, the redshift is determined from the host galaxy. (1) Heavily extincted. (2). Strong Na I D absorption. (3) MgII @ 17k km/s.
