VizieR Online Data Catalog: Photometry and spectroscopy of ASASSN-17jz (Holoien+, 2022)

Here we study the nuclear outburst ASASSN-17jz spanning from 88 days prior to peak light through 1081 days after peak. ASASSN-17jz was discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) on UT 2017 July 27 in the galaxy SDSS J171955.84+414049.4, at a redshift of z=0.1641.

We retrieved archival ugriz images of the host galaxy SDSS J171955 from the Sloan Digital Sky Survey (SDSS) Data Release 16 (DR16) and JHKS images from the Two Micron All-Sky Survey (2MASS). We also obtained near-UV (NUV) and far-UV (FUV) magnitudes from the Galaxy Evolution Explorer (GALEX) All-Sky Imaging Survey (AIS) catalog and infrared W1 and W2 magnitudes from the Wide-field Infrared Survey Explorer AllWISE catalog. We also checked archival survey data from the Catalina Real-Time Transient Survey (CRTS; Drake+ 2009, J/ApJ/696/870) to search for signs of previous variability from SDSS J171955. CRTS obtained observations of the galaxy beginning on UT 2005 July 1, roughly 12yr prior to our first detection of ASASSN-17jz in ASAS-SN V-band data, and there is no evidence of prior flaring in these data. See Section 2.1.

ASAS-SN monitors the visible sky nightly to find bright, nearby transients using units of four 14 cm telescopes. Currently, ASAS-SN consists of five units in Hawaii, Chile, Texas, and South Africa hosted by the Las Cumbres Observatory global telescope network using g-band filters, but at the time of the discovery of ASASSN-17jz, it was composed of only single units in Chile and in Hawaii using V-band filters. Roughly two months after ASASSN-17jz was discovered, our Texas unit began survey operations, and also started to observe ASASSN-17jz in the g-band. See Section 2.2.

The Asteroid Terrestrial-impact Last Alert System (ATLAS) is an ongoing survey that uses fully robotic 0.5m telescopes located on the summit of Haleakala and Mauna Loa Observatory in Hawaii. ATLAS uses two broad filters for its survey operations: "cyan" (c), covering 420-650nm, and "orange" (o) covering 560-820nm. We present the stacked o-band photometry and 3σ limits in Table 3. See Section 2.3.

During our initial follow-up campaign of ASASSN-17jz, we obtained 23 epochs of Swift TOO observations spanning from 1 day before peak light through 212 days after peak. We later obtained one epoch of observations on 2018 September 16, and two epochs on 2020 July 21 and 2020 July 22 to monitor the long-term UV and X-ray evolution of this transient. UVOT observations were obtained in the V (5468Å), B (4392Å), U (3465Å), UVW1 (2600Å), UVM2 (2246Å), and UVW2 (1928Å) filters (Poole et al. 2008) at most epochs, with later epochs only using the UV and U filters, as the transient had faded in the optical. See Section 2.4.

We obtained additional BVgri observations from the Las Cumbres Observatory 1m telescopes located at McDonald Observatory, Texas, and from the 24 inch Post Observatory robotic telescopes located in Mayhill, New Mexico, and Sierra Remote Observatory in California. We further obtained BVRI images from the 0.76m Katzman Automatic Imaging Telescope (KAIT) and the 1m Anna L. Nickel telescope at Lick Observatory. See Section 2.5.

The telescopes and instruments used to obtain follow-up optical spectra included the Spectrograph for the Rapid Acquisition of Transients (SPRAT) on the 2m Liverpool Telescope (LT), the Kast Spectrograph on the 3m Shane telescope at Lick Observatory, the Double Spectrograph (DBSP) on the 5.1m Hale telescope at Palomar Observatory, the Multi-Object Double Spectrograph (MODS) on the dual 8.4m Large Binocular Telescope (LBT), the Low-Resolution Imaging Spectrometer (LRIS) on the Keck I 10m telescope, and the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II 10m telescope. See Section 2.6, table A1 and Figure 2.

We also obtained 4 observations on 2017 September, October and November using the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST; GO-14781; PI: C. Kochanek). We used the FUV/NUV MAMA detectors with the G140L (1150-1730Å, FUV-MAMA) and G230L (1570-3180Å, NUV-MAMA) gratings and 52.0"x0.2" slit. See Section 2.7 and Figure 3.

Finally, we obtained radio observations of ASASSN-17jz using Director's Discretionary Time observations at 10GHz with the Karl G. Jansky Very Large Array (VLA; legacy code AR981) in its BnA configuration on 2018 February 23, and TOO observations at 5GHz with the electronic European very long baseline interferometry Network (e-EVN) on 2018 April 11 (project code RR011). See Section 2.8.

(4 data files).