VizieR Online Data Catalog: Photometry & spectroscopy follow-up of ASASSN-20hx (Hinkle+, 2022)

ASASSN-20hx was discovered in the g-band data from the ASAS-SN "Brutus" unit on Haleakala Hawai'i on 2020 July 10.3 UTC. Shortly after discovery, we obtained several spectroscopic observations. Spectra from both the SPectrograph for the Rapid Acquisition of Transients (SPRAT) on the 2m Liverpool Telescope and the Low-Resolution Imaging Spectrometer (LRIS) on the 10m Keck I telescope. We triggered spectroscopic and ground-based photometric follow-up of ASASSN-20hx.

We reduced images from ASAS-SN, a fully automated transient survey consisting of 20 individual telescopes on 5 robotic mounts. The five ASAS-SN units are located at Haleakala Observatory, McDonald Observatory, the South African Astrophysical Observatory, and two at Cerro Tololo Inter-American Observatory. See section 2.2.

The host galaxy of ASASSN-20hx, NGC 6297, lies in the TESS northern continuous viewing zone near the North Ecliptic Pole, so it was observed continuously between 2019 July 18 and 2020 July 04. See Section 2.3.

In addition to the ASAS-SN and TESS survey photometry, we obtained photometric follow-up observations from several ground-based observatories. We used the Las Cumbres Observatory Global Telescope (LCOGT) network 1m and 2m telescopes located at Haleakala and McDonald Observatory for BVgri observations, the Liverpool 2m telescope at Observatorio del Roque de los Muchachos for ugriz observations, the Wendelstein Observatory 2m Fraunhofer telescope for ugizJH observations, and images from amateur astronomer Richard Post (RP) for BVgri observations taken with a 24-in and 32-in telescope. See Section 2.4.

Sixty-two total Neil Gehrels Swift Gamma-Ray Burst Mission (Swift) target-of-opportunity observations were carried out between 2020-Jul-19 and 2021-Apr-15 (Swift target ID 13617, PIs: Holoien, Hinkle). Some of these epochs were obtained from Swift guest investigator program 1619122 (PI: Holoien). These observations used the UVOT and the XRT to study the multiwavelength properties of the ambiguous nuclear transient (ANT). See Section 2.5.

ASASSN-20hx was also observed using the X-ray timing instrument on board the Neutron star Interior Composition ExploreR (NICER), which is an external payload on the International Space Station. NICER offers high spectral (~85eV at 1keV) and time resolution (~100ns) observations in the 0.2-12keV energy range. ASASSN-20hx was observed a total of 41 times between 2020 July 25 and 2020 November 01 (ObsIDs: 3573010101-3573014102, PI: Auchettl), for a total cumulative exposure of 67.6ks. See Section 2.6.

In addition to our classification spectra obtained from SPRAT and LRIS, we obtained follow-up spectra of ASASSN-20hx with the SuperNova Integral Field Spectrograph (SNIFS) on the 88-inch University of Hawaii telescope (UH88), LRIS on the 10m Keck I telescope, SPRAT on the 2m Liverpool Telescope, and the Multi-Object Double Spectrographs (MODS) on the Large Binocular Telescope (LBT). See Section 2.7.

We obtained submillimeter observations in the 850um band (353GHz) using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) on the James Clerk Maxwell Telescope (JCMT). See Section 2.8.

(5 data files).