AstroNote 2024-231

The Neural Engine for Discovering Luminous Events (NEEDLE) classifier (Sheng et al. 2024) is a machine-learning tool for identifying rare astronomical transients from real-time alerts. NEEDLE is trained to identify Superluminous Supernova (SLSN) and Tidal Disruption Events (TDE) candidates in data from the Zwicky Transient Facility (ZTF; Bellm et al. 2019; Graham et al. 2019). We are running NEEDLE daily on public ZTF alerts, streamed via the Lasair alert broker (Williams et al. 2024), and publicly providing classification predictions as annotations on Lasair.

We provide three SQL filters on Lasair with our candidates (also output as Kafka streams): NEEDLE SLSN candidates, NEEDLE TDE candidates, and all NEEDLE annotations. Lasair users can also incorporate NEEDLE outputs into their own custom SQL filters.

We manually vet all alerts with a SLSN or TDE score > 0.5, and will highlight the most promising candidates in these AstroNotes. A complete set of candidates can be found in the Lasair streams. This report includes recent 2 SLSN and 2 TDE candidates, and one ambiguous object.

2024sbm [ZTF24aaybwcs] shows a slow rise similar to SLSNe, but is quite red (g-r~0.3). Its host galaxy shows an irregular morphology but may be blended with a foreground star.

2024rny[ZTF24aazlori] was initially suggested as a SLSN candidate by NEEDLE (AstroNote 2024-222), however, given its location at the centre of its host and persistent blue colour, it is now more confidently predicted as a TDE candidate.

2023aclf [ZTF23abscfuu] was first discovered on 2023-11-10, and has been rising for over 290 days. Its smooth rise and lack of previous variability are unlike AGN activity. 

 We encourage spectroscopic classification and follow-up.