DRAFT
2024-09-21 05:01:50
Type: Announcement-Campaign/Survey
ZTF Experiment: The Nightly-cadence Three-band Extragalactic Survey
Authors: Christoffer Fremling (Caltech), Yu-Jing Qin (Caltech), Jakob Nordin (HU Berlin), Anamaria Gkini (Stockholm U.), Jesper Sollerman (Stockholm U.), Steve Schulze (Northwestern), Adam Miller (Northwestern), Daniel Perley (LJMU), on behalf of the Physics of Supernovae and Relativistic Transients Working Group
Source Group: ZTF
Abstract:
We announce an upcoming extragalactic experiment with the Zwicky Transient Facility (ZTF), scheduled to take place over three consecutive nights beginning on 2024-09-22 at 02:38 UT. Each night, the experiment will image a total area of 12,000 square degrees in the northern sky in three filters (g, r, i), aiming to discover new extragalactic transients brighter than g/r~19.8 mag (AB). The transients will be classified through coordinated spectroscopic observations, with all discoveries and classifications made publicly available.

The Zwicky Transient Facility (ZTF) is currently in an extended operational phase (ZTF-O4) aligned with the fourth gravitational wave observing run of the LIGO-Virgo-KAGRA network. During this phase, the ZTF collaboration carries out a three-night experiment each month, focusing on different scientific objectives and survey designs. (AstroNotes 2023-349, 2024-59, 2024-96, 2024-123, 2024-135, 2024-172, 2024-216, and 2024-261)

The next ZTF experiment is scheduled from 2024-09-22 at 02:38 UT to 2024-09-24 at 12:43 UT. This experiment will survey a contiguous extragalactic region of about 12,000 square degrees in the northern sky, with nightly-cadence 30-sec exposures in the g, r, and i bands. The primary goal is to identify and classify newly emerging extragalactic transients (with the last non-detection 5 days before the experiment) brighter than g/r~19.8 mag (AB) for a coherent sample. The experiment will also test new observing strategies for future ZTF operations. Compared to the ZTF public survey, this special three-night experiment will also include the i-band filter and utilize all available on-sky time across the three nights to ensure complete coverage.

During and after this experiment, we will use the Palomar 200-inch telescope (DBSP) and the Palomar 60-inch telescope (SEDMachine) for coordinated spectroscopic classification of new extragalactic transients, aiming for a complete sample for transients reaching g/r~19.5 mag. As a public experiment, transient candidates and classification spectra will be promptly reported to the Transient Name Server. Real-time alerts will be released through the public ZTF alert stream; images and other data products will be accessible through the NASA/IPAC Infrared Science Archive. (https://irsa.ipac.caltech.edu/Missions/ztf.html).

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