The first tidal disruption flare in ZTF: from photometric selection to multi-wavelength characterization

Sjoert van Velzen; Suvi Gezari; S. Bradley Cenko; Erin Kara; James C. Miller-Jones; Tiara Hung; Joe Bright; Nathaniel Roth; Nadejda Blagorodnova; Daniela Huppenkothen; Lin Yan; Eran Ofek; Jesper Sollerman; Sara Frederick; Charlotte Ward; Matthew J. Graham; Rob Fender; Mansi M. Kasliwal; Chris Canella; Robert Stein; Matteo Giomi; Valery Brinnel; Jakob Santen; Jakob Nordin; Eric C. Bellm; Richard Dekany; Christoffer Fremling; V. Zach Golkhou; Thomas Kupfer; Shrinivas R. Kulkarni; Russ R. Laher; Ashish Mahabal; Frank J. Masci; Adam A. Miller; James D. Neill; Reed Riddle; Mickael Rigault; Ben Rusholme; Maayane T. Soumagnac; Yutaro Tachibana

doi:10.3847/1538-4357/aafe0c

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arXiv · 1809.02608

The first tidal disruption flare in ZTF: from photometric selection to multi-wavelength characterization

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Abstract

We present Zwicky Transient Facility (ZTF) observations of the tidal disruption flare AT2018zr/PS18kh reported by Holoien et al. and detected during ZTF commissioning. The ZTF light curve of the tidal disruption event (TDE) samples the rise-to-peak exceptionally well, with 50 days of g- and r-band detections before the time of maximum light. We also present our multi-wavelength follow-up observations, including the detection of a thermal (kT~100 eV) X-ray source that is two orders of magnitude fainter than the contemporaneous optical/UV blackbody luminosity, and a stringent upper limit to the radio emission. We use observations of 128 known active galactic nuclei (AGN) to assess the quality of the ZTF astrometry, finding a median host-flare distance of 0.2" for genuine nuclear flares. Using ZTF observations of variability from known AGN and supernovae we show how these sources can be separated from TDEs. A combination of light-curve shape, color, and location in the host galaxy can be used to select a clean TDE sample from multi-band optical surveys such as ZTF or LSST.

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Sjoert van Velzen, Suvi Gezari, S. Bradley Cenko, Erin Kara, James C. Miller-Jones, Tiara Hung, Joe Bright, Nathaniel Roth, Nadejda Blagorodnova, Daniela Huppenkothen, Lin Yan, Eran Ofek, Jesper Sollerman, Sara Frederick, Charlotte Ward, Matthew J. Graham, Rob Fender, Mansi M. Kasliwal, Chris Canella, Robert Stein, Matteo Giomi, Valery Brinnel, Jakob Santen, Jakob Nordin, Eric C. Bellm, Richard Dekany, Christoffer Fremling, V. Zach Golkhou, Thomas Kupfer, Shrinivas R. Kulkarni, Russ R. Laher, Ashish Mahabal, Frank J. Masci, Adam A. Miller, James D. Neill, Reed Riddle, Mickael Rigault, Ben Rusholme, Maayane T. Soumagnac, Yutaro Tachibana. 2018-09-07. The first tidal disruption flare in ZTF: from photometric selection to multi-wavelength characterization. https://doi.org/10.3847/1538-4357/aafe0c

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