The Zwicky Transient Facility (ZTF) is a new robotic time-domain survey
currently in progress using the Palomar 48-inch Schmidt Telescope. ZTF uses a
47 square degree field with a 600 megapixel camera to scan the entire northern
visible sky at rates of ~3760 square degrees/hour to median depths of g ~ 20.8
and r ~ 20.6 mag (AB, 5sigma in 30 sec). We describe the Science Data System
that is housed at IPAC, Caltech. This comprises the data-processing pipelines,
alert production system, data archive, and user interfaces for accessing and
analyzing the products. The realtime pipeline employs a novel
image-differencing algorithm, optimized for the detection of point source
transient events. These events are vetted for reliability using a
machine-learned classifier and combined with contextual information to generate
data-rich alert packets. The packets become available for distribution
typically within 13 minutes (95th percentile) of observation. Detected events
are also linked to generate candidate moving-object tracks using a novel
algorithm. Objects that move fast enough to streak in the individual exposures
are also extracted and vetted. The reconstructed astrometric accuracy per
science image with respect to Gaia is typically 45 to 85 milliarcsec. This is
the RMS per axis on the sky for sources extracted with photometric S/N >= 10.
The derived photometric precision (repeatability) at bright unsaturated fluxes
varies between 8 and 25 millimag. Photometric calibration accuracy with respect
to Pan-STARRS1 is generally better than 2%. The products support a broad range
of scientific applications: fast and young supernovae, rare flux transients,
variable stars, eclipsing binaries, variability from active galactic nuclei,
counterparts to gravitational wave sources, a more complete census of Type Ia
supernovae, and Solar System objects.

Zwicky Transient Facility (ZTF) is a time-domain survey utilizing a unique image-differencing algorithm, sensitive photometry, and data-rich alert packets to detect and track variable sources of all varieties, in real time, for a wide range of scientific applications.

Zwicky 瞬变设施：数据处理、产品和档案

The Zwicky Transient Facility: Data Processing, Products, and Archive

The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that
uses the Palomar 48-inch Schmidt telescope. A custom-built wide-field camera
provides a 47 deg$^2$ field of view and 8 second readout time, yielding more
than an order of magnitude improvement in survey speed relative to its
predecessor survey, the Palomar Transient Factory (PTF). We describe the design
and implementation of the camera and observing system. The ZTF data system at
the Infrared Processing and Analysis Center provides near-real-time reduction
to identify moving and varying objects. We outline the analysis pipelines, data
products, and associated archive. Finally, we present on-sky performance
analysis and first scientific results from commissioning and the early survey.
ZTF's public alert stream will serve as a useful precursor for that of the
Large Synoptic Survey Telescope.

Zwicky Transient Facility (ZTF) 是一项新的光学时域巡天，使用 Palomar 48 英寸 Schmidt 望远镜，所采用的自定义广角相机提供了 47 平方度的视场和 8 秒的读出时间，相对于其前身巡天 Palomar Transient Factory（PTF），提高了一个数量级的观测速度。该研究描述了相机和观测系统的设计和实现，以及数据处理和分析方案，最终给出了 ZTF 的初步科学结果和性能分析。