ZTF Discovery of ZTF18abukavn (AT2018gep): a Rapidly Rising, Luminous Blue Transient
ATel #12030; A. Y. Q. Ho (Caltech), S. Schulze (WIS), D. A. Perley (LJMU), S. Adams (Caltech), J. den Brok (ETH), N. Kamraj (Caltech), M. M. Kasliwal (Caltech), M. Koss (UW Seattle), A. A. Miller (Northwestern), D. Stern (JPL) on behalf of the Zwicky Transient Facility collaboration
on 11 Sep 2018; 15:53 UT
Credential Certification: Adam Miller (amiller@astro.caltech.edu)
Subjects: Optical, Supernovae, Transient
The Zwicky Transient Facility (ZTF; ATel #11266) reports the discovery of ZTF18abukavn (AT2018gep), a rapidly rising blue transient located at
16:43:48.22 +41:02:43.4 (J2000)
250.950926 +41.045380 (J2000)
The source was first discovered on 2018-09-09.17 (UT) at r=20.5 mag, and rose 4 magnitudes in under 2 days. Early spectra obtained by D. A. Perley with SPRAT on the Liverpool Telescope and by J. den Brok, N. Kamraj, M. Koss, and D. Stern with DBSP on the 200-inch Hale telescope at Palomar Observatory show a blue continuum with narrow galaxy emission lines at z=0.033, making this a luminous transient (M = -19.7). The spectra show a broad absorption feature around 5300 Å. The rapid rise, blue continuum, and luminosity are reminiscent of AT2018cow (ATel #11727), but further observations are needed to clarify the comparison. Notably, the broad feature seen in AT2018gep is redder and narrower than that seen in AT2018cow.
Swift has been triggered for UVOT and XRT imaging and further follow-up observations are underway.
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.