Classification of AT2018lna/ZTF19aabbnzo as a tidal disruption flare
ATel #12509; S. van Velzen (UMd and NYU), S. Gezari (UMd), S. Frederick (UMd), T. Hung (UCSC), S. B. Cenko (GSFC), S. R. Kulkarni (Caltech), I. Andreoni (Caltech), M. Hankins (Caltech), A. Dugas (Caltech), C. Fremling (Caltech), J. C. A. Miller-Jones (Curtin), A. Horesh (Hebrew University)
on 16 Feb 2019; 23:10 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Sjoert van Velzen (sjoert@astro.umd.edu)
Subjects: Radio, Optical, Ultra-Violet, X-ray, Tidal Disruption Event
We report the discovery of AT2018lna/ZTF19aabbnzo in ZTF imaging data. The transient was found near the center of the galaxy PSO J105.8277+23.0291.
The first detection was obtained on 2018-Dec-12, while the source was on the rise. Follow-up spectroscopy with DBSP on the Palomar P200 telescope was obtained 2019-Jan-26 and showed a blue continuum with broad Halpha emission. We determine a redshift of z~0.08.
Observations with the Neil Gehrels Swift telescope, obtained on 2019-Feb-10, show the transient is UV-bright. We measure UVW2=18.04 +/- 0.05 (AB), implying a very blue UV-optical color: UVW2-g ~ -1. The source is not detected in XRT (3-sigma upper limit on the X-ray count rate is 6e-3 counts/s).
The TDE classification is based on the location in the center of the host galaxy (offset 0.15 +/- 0.16 arcsec with respect to the coordinates of the host), a blue and constant color post peak, the detection of broad emission lines in the optical spectrum, and the UV detection with Swift/UVOT. The source shows no prior variability in ZTF or CRTS data.
Follow-up with VLA, AMI, and XMM has been triggered. We encourage further follow-up of this source, in particular spectroscopic monitoring and multi-band imaging.
ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266), and includes IPAC; WIS, Israel; OKC, Sweden; JSI/UMd, USA; UW,USA; DESY, Germany; NRC, Taiwan; UW Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. Alert distribution service provided by DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system, supported by NSF PIRE grant 1545949.