VizieR Online Data Catalog: Final moments. I. Type II SN 2020tlf (Jacobson-Galan+, 2022)

SN 2020tlf was first reported to the Transient Name Server by the Asteroid Terrestrial-impact Last Alert System (ATLAS; Tonry+ 2018PASP..130f4505T) on 2020 September 16, but the earliest detections of the SN are from the Young Supernova Experiment (YSE; Jones+ 2021ApJ...908..143J) with the PS1 telescope on 2020-Sept-5. See Section 2.1.

Pre-explosion imaging of SN 2020tlf was also acquired by the Zwicky Transient Facility (ZTF) and ATLAS. See Section 2.2.

We started observing SN 2020tlf with the Ultraviolet Optical Telescope (UVOT) on board the Neil Gehrels Swift Observatory on 2020-September-9 until 2021-February-18 (δt=11.0-165.2days since first light).

Additional griz-band imaging of SN 2020tlf was obtained through the YSE sky survey with the Pan-STARRS telescope (PS1) between 2020-Sept-8 and 2021-Jun-26 (δt=1.5-292.3days since first light).

SN 2020tlf was observed with ATLAS (δt=-9.40-157.8days since first light), a twin 0.5m telescope system installed on Haleakala and Mauna Loa in the Hawai'ian islands that robotically surveys the sky in cyan (c) and orange (o) filters.

We also observed SN 2020tlf with the Las Cumbres Observatory (LCO) Global Telescope Network 1m telescopes and Las Cumbres Observatory imagers from 2020-Sept-21 to 2021-Mar-29 (δt=14.34-203.5days since first light) in ugri-bands.

Observations of SN 2020tlf were obtained with the 1m Lulin telescope located at Lulin Observatory on 2020-Oct-9 (δt=32.71days since first light) in BVgr bands.

The complete light curve of SN 2020tlf is presented in Figure 4, and all photometric observations are listed in Appendix Table A4. In addition to our observations, we include g/r-band photometry from the ZTF forced-photometry service, which span from 2020-Nov-27 to 2021-Jun-28 (δt=81.81-294.5days since first light).

In Figure 5, we present the complete series of optical spectroscopic observations of SN 2020tlf from -9 to +257days relative to the B-band maximum (δt=10-270days relative to first light). A full log of spectroscopic observations is presented in Appendix Table A1.

SN 2020tlf was observed with Shane/Kast and Keck/LRIS between -9 and +257days relative to the B-band maximum. Spectra of SN 2020tlf were also obtained with Keck NIRES and DEIMOS, as well as Binospec on MMT and the Dual Imaging Spectrograph (DIS) on the Astrophysical Research Consortium (ARC) 3.5-m telescope at Apache Point Observatory (APO).

The X-Ray Telescope (XRT) on board the Swift spacecraft started observing the field of SN 2020tlf on 2020-Sept-9 until 2021-Feb-18 (δt=11.0-165.2days since first light) with a total exposure time of 35.2ks, (Source IDs 11337 and 11339). We find no evidence for significant X-ray emission in any of the individual Swift-XRT epochs, nor in merged images near optical/UV peak and at all observed phases. See Section 3.3.

We acquired deep radio observations of SN 2020tlf with the Karl G. Jansky Very Large Array (VLA) at δt=146-320days since first light through project SD1096 (PI Margutti). All observations have been obtained at 10GHz (X band). SN 2020tlf is not detected in our observations. See Section 3.4.

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