ZTF releases Zubercal
The Zwicky Transient Facility has released Zubercal (ZTF-ubercal), a new set of photometry based on a detailed recalibration of ZTF Science image-based PSF photometry. This dataset includes all ZTF detections from DR20 that have been matched to Pan-STARRS1 (PS1) sources (> 1.2”) and contain color information. For more details, refer to the Zubercal documentation. Zubercal is now available for bulk download on the IRSA ZTF mission page.
ZTF Summer School 2025
Thanks to the continued support of the NSF, we will organize our signature summer school in 2025 and 2026. As in previous years, we continue with the same successful hybrid format, with both in-person and virtual attendance possible. We expect to accept up to 20 in-person and 40 online participants. In 2025, the school will take place on Jul 21-25 and will be hosted by the University of Minnesota, USA.
This year, the theme of the school is " Astronomy Data Science in the Rubin Observatory Era". Modern optical surveys, in combination with data science principles, are transforming astrophysics with detections of very rare phenomena. Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) will soon see first light, and it is expected that the combination of its depth and entendue will revolutionize the field. To maximize our sensitivity to fast transients, other wide field systems, such as the Zwicky Transient Facility (ZTF), will be following the footprint of LSST to probe otherwise inaccessible timescales down to a few hours, enabling us to study previously unobserved physics of well-known transients, e.g., supernovae (SNe), while also discovering rare, fast evolving sources, e.g., kilonovae. However, this brings to us the challenge of using multiple surveys to identify the nature of transients in alert streams, as detection does not mean identification, and identification does not mean understanding. In this summer school, we will focus on data science techniques for classification and characterization necessary for maximizing science with ZTF in this era of the LSST.
Public Data Release in ZTF3
ZTF continues science observations in 2025 and 2026 thanks to extended funding by the National Science Foundation. There will be two yearly public releases that will become available in the January 2026 and 2027. Public releases are announced on our website and soial media X account @ztfsurvey.
Science Highlights
Potentially Hazardous Asteriods in the Taurid swarm
Authors present a dedicated telescopic search for potentially hazardous asteroids and other macroscopic objects in the Taurid swarm using the Zwicky Transient Facility survey. No such objects were detected suggesting that there are no more than 9–14 H ≤ 24 (equivalent to a diameter of D > 100 m) objects in the swarm. This implies that the Encke–Taurid progenitor was approximately 10 km in size, which is compatible with the prediction of state-of-the-art solar system dynamical models.
Low-Luminosity supernovae from ZTF's CLU survey
Authors present the luminosity function and volumetric rate of a sample of Type IIP supernovae (SNe) from the Zwicky Transient Facility Census of the Local Universe survey (CLU). This is the largest sample of Type IIP SNe from a systematic volume-limited survey to-date. The final sample includes 330 Type IIP SNe and 36 low-luminosity Type II (LLIIP) SNe with peak >−16 mag, which triples the literature sample of LLIIP SNe.
A catalog with 5 million quasars from the Zwicky Transient Facility
In this paper, authors explore machine learning methods for the classification of quasars (QSOs). The goal is to use the Zwicky Transient Facility (ZTF) to create a catalog of QSOs. The team processed the ZTF DR20 light curves with a transformer artificial neural network and combined the Pan-STARRS (PS), AllWISE, and Gaia surveys with extreme gradient boosting. They found that ZTF classification is superior to the PS static bands, and on par with WISE and Gaia measurements.
Inferring circumstellar medium properties of type II supernovae
Astronomers present a detailed light curve analysis of a magnitude-limited sample of 639 Type II SNe from the Zwicky Transient Facility Bright Transient Survey. They find a high fraction of progenitors with dense CSM. This finding supported by photometric and spectroscopic evidence of previous SNe, reveals mass-loss rates significantly exceeding those measured in local group red supergiants or predicted by current theoretical models.
ZTF-observed late-time signals of pre-ZTF transients
Authors search for late-time signals in a sample of 7718 transients, mainly supernovae (SNe), which were first detected during the 10 years before the start of ZTF, aiming to find objects showing signs of late-time interaction with CSM.This study demonstrates the ability of large-scale surveys to find faint transient signals for a variety of objects, uncovering a population of previously unknown sources. However, the large number of non-detections show that strong late-time CSM interaction occurring years after the SN explosion is extremely rare.
ZTF Faces
Here are our amazing scanners who help us find near-earth asteroids.
Tanvi Batra
(UC Berkeley, USA)
I am a 3rd year Physics and Astrophysics double major, looking to pursue grad school.
Samridh Tiwari
(Indian Institute of Technology Bombay)
I am a sophomore majoring in Engineering Physics. I was interested in astronomy from a young age thanks to the books lent to me by my sister.
Divya Kulkarni
(IN2P3, France)
I have a background in astronomy and joined ZTF as a scanner in 20222 out of my passion for near-Earth objects. It’s exciting to contribute to planetary defense in a hands-on way. In my free time, I enjoy reading and stargazing.
Yogesh Wagh
(Indian Institute of Technology Bombay)
I am a graduate in MSc in Physics. I began my academic journey with a bachelor's degree in mechanical engineering but my growing interest in physics led me to pursue a master’s at IIT Bombay, where I joined STARLab. That’s where my research path began to take shape.
ZTF Science Vlog
The ZTF vlog brings you the latest ZTF results presented by the authors themselves.
Peculiar binaries within planetary nebulae
Soumyadeep Bhattacharjee et al.,
In this science vlog, PhD student at Caltech Soumyadeep Bhattacharjee presents a number of peculiar discoveries of binary systems within planetary nebulae. The ZTF observatory now allows us to study such systems on long time scales of several years, revealing exciting new features in their behavior.
Community science with ZTF
We highlight scientific publications from individuals and groups outside of the ZTF partnership that use ZTF public data
The First Search for Optical Transient as a Counterpart of a Month-timescale IceCube Neutrino Multiplet Event
[Abstract]
Optical transients with timescale of months, such as supernovae (SNe) and tidal disruption events (TDEs),
are candidates of high-energy neutrino sources. Multiple neutrino detections from the same direction within
a month timescale provide a unique opportunity to identify such optical counterparts in the nearby Universe.
In this work, we conduct archival search for the optical counterpart of an IceCube triplet event using the
data of Zwicky Transient Facility. We develop a dedicated alert filtering system and validate the performance
by following a blind analysis method. Applying this filtering system to the data after the detections of the
IceCube triplet event, we find no transient candidates within the localization area. Assuming that the IceCube
triplet event originates from an astrophysical source, we constrain parameters of optical transient, a peak
luminosity and a decay timescale, using a simple signal model that is motivated by TDEs and superluminous
SNe (SLSNe). Assuming the case with no time lag between neutrino detections and optical peak, almost
entire parameter space of the known TDEs and SLSNe would be constrained. To give constraints on
transients with a rapidly evolving light curve, quick follow-up observations for future neutrino
multiplet events are crucial.
ZTF is supported by the National Science Foundation and a collaboration including the following universities
: University of
Maryland, College Park, USA; University of Wisconsin,
Milwaukee, USA; Drexel University, USA; Cornell University, USA; University of California, Berkeley; University of North Caroline Chapel Hill, USA;
Institute of Science and Technology, Austria;
IPAC, Caltech, USA; Caltech, USA. Operations are conducted
by COO, IPAC and University of Washington.
Any opinions, findings, and conclusions or
recommendations expressed in this material are those of the
author(s) and do not necessarily reflect the views of the National Science Foundation.