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Published November 2019 | Published + Submitted
Journal Article Open

Transient processing and analysis using AMPEL: alert management, photometry, and evaluation of light curves


Both multi-messenger astronomy and new high-throughput wide-field surveys require flexible tools for the selection and analysis of astrophysical transients. We here introduce the Alert Management, Photometry and Evaluation of Lightcurves (AMPEL) system, an analysis framework designed for high-throughput surveys and suited for streamed data. AMPEL combines the functionality of an alert broker with a generic framework capable of hosting user-contributed code, that encourages provenance and keeps track of the varying information states that a transient displays. The latter concept includes information gathered over time and data policies such as access or calibration levels. We describe a novel ongoing real-time multi-messenger analysis using AMPEL to combine IceCube neutrino data with the alert streams of the Zwicky Transient Facility (ZTF). We also reprocess the first four months of ZTF public alerts, and compare the yields of more than 200 different transient selection functions to quantify efficiencies for selecting Type Ia supernovae that were reported to the Transient Name Server (TNS). We highlight three channels suitable for (1) the collection of a complete sample of extragalactic transients, (2) immediate follow-up of nearby transients and (3) follow-up campaigns targeting young, extragalactic transients. We confirm ZTF completeness in that all TNS supernovae positioned on active CCD regions were detected. AMPEL can assist in filtering transients in real time, running alert reaction simulations, the reprocessing of full datasets as well as in the final scientific analysis of transient data. This text introduces how users can design their own channels for inclusion in the AMPEL live instance that parses the ZTF stream and the real-time submission of high quality extragalactic supernova candidates to the TNS.

Additional Information

© 2019 ESO. Article published by EDP Sciences. Received 5 April 2019; Accepted 10 June 2019. Published online 11 November 2019. Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW. The authors are grateful to the IceCube Collaboration for providing the neutrino dataset and supporting its use with AMPEL. N.M. acknowledges the support of the Helmholtz Einstein International Berlin Research School in Data Science (HEIBRiDS), Deutsches Elektronensynchrotron (DESY), and Humboldt-Universität zu Berlin. M.R. acknowledges the support from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement no. 759194 – USNAC).

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Published - aa35634-19.pdf

Submitted - 1904.05922.pdf


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August 19, 2023
October 18, 2023