Astroinformatics Proceedings IAU Symposium No. 325, 2016 M. Brescia, S.G. Djorgovski, E. Feigelson, G. Longo & S. Cavuoti, eds. c  International Astronomical Union 2017 doi:10.1017/S174392131601303X AlertSim - Serbian Contribution to the LSST Darko Jevremovi´ c 1 , Veljko Vujˇ ci´ c 1,2 , Vladimir A. Sre´ ckovi´ c 3 , Jovan Aleksi´ c 1 , Sanja Erkapi´ c 1 and Nenad Milovanovi´ c 1 1 Astronomical Observatory, Volgina 7, 11060 Belgrade, Serbia email: darko, veljko, jaleksic, serkapic, nmilovanovic@aob.rs 2 Faculty of Organizational Sciences, Univesity of Belgrade, Serbia 3 Institute of Physics Belgrade, University of Belgrade, P.O. Box 57, 11001, Belgrade, Serbia email: vlada@ipb.ac.rs Abstract. We present simulator of alerts for the Large Synoptic Survey Telescope (LSST) developed by Belgrade group. This simulator will be used in testing the functionality of external event brokers/Complex Event Processing (CEP) engines. It is based on current LSST Simulation framework and allows for different classes of objects to be ‘alerted’. A Web service based on our simulator is prototyped and can be accessed by developers of brokers/CEP engines. Keywords. LSST, simulations, transients, alerts, web service 1. Introduction The Large Synoptic Survey Telescope (LSST, http://lsst.org) is a large-aperture, wide- field, ground-based survey system that will image the sky in six optical bands from 320 to 1050 nm, uniformly covering approximately 18,000deg 2 of the sky over 800 times (Ivezi´ c et al. 2008). The LSST is currently under construction on Cerro Pach´ on in Chile, and expected to enter operations in 2022. The LSST will generate on average 15 TB of data per night, and will require a compre- hensive Data Management system to reduce the raw data to scientifically useful catalogs and images with minimum human intervention. These reductions will result in a real-time alert stream, and eleven data releases over the 10-year duration of LSST operations. As a part of its nightly operations, LSST is expected to generate a transient alert stream of ˜ 10,000 events/visit. That stream is planned to be forwarded a) unfiltered, to a number of public event brokers/CEP engines, and b) to an internal simple transient filtering service designed to support the end-users (per Section 3.5 of the Science Requirement Document, Ivezi´ c et al. 2011). It is anticipated that due to bandwidth constraints only a limited number of public brokers (on order of ∼2 to ∼4) will be able to connect directly to LSST. Given the limited number of external brokers that will serve as the primary delivery mechanism of LSST transient data to the public, it is important to assure they are ca- pable of receiving and processing the LSST event stream, both initially and throughout operations. An inefficient or buggy event broker results in opportunity loss for the LSST user community, and in helpdesk/technical support costs to LSST. To achieve the pro- jected return of investment for LSST transient science, it is important to initially validate each external broker’s capability, continually monitor it, and have the tools and support personnel to understand and resolve any issues as they arise. In order to do so, the group in Belgrade develops transient alert simulator (AlertSim) and will contribute, in time for LSST Early Operations, an event broker validation suite. 122 https://www.cambridge.org/core/terms. https://doi.org/10.1017/S174392131601303X Downloaded from https://www.cambridge.org/core. IP address: 3.90.28.136, on 30 Apr 2021 at 07:28:51, subject to the Cambridge Core terms of use, available at