UFFO/Lomonosov: The Payload for the Observation of Early Photons from Gamma Ray Bursts

Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The payload of the UFFO (Ultra-Fast Flash Observatory)-pathfinder now onboard the Lomonosov spacecraft (hereafter UFFO/Lomonosov) is a dedicated instrument for the observation of GRBs. Its primary aim is to capture the rise phase of the optical light curve, one of the least known aspects of GRBs. Fast response measurements of the optical emission of GRB will be made by a Slewing Mirror Telescope (SMT), a key instrument of the payload, which will open a new frontier in transient studies by probing the early optical rise of GRBs with a response time in seconds for the first time. The SMT employs a rapidly slewing mirror to redirect the optical axis of the telescope to a GRB position prior determined by the UFFO Burst Alert Telescope (UBAT), the other onboard instrument, for the observation and imaging of X-rays. UFFO/Lomonosov was launched successfully from Vostochny, Russia on April 28, 2016, and will begin GRB observations after completion of functional checks of the Lomonosov spacecraft. The concept of early GRB photon measurements with UFFO was reported in 2012. In this article, we will report in detail the first mission, UFFO/Lomonosov, for the rapid response to GRB observations. © The Author(s) 2017. The Korean work is supported by the National Research Foundation grants funded by MSIP of Korea (Creative Research Initiatives program for RCMST, No. 2015R1A2A1A01006870, and No. 2015R1A2A1A15055344). The Russian work was partially supported by ROSCOSMOS grants and by RFFI grants No. 13-02-12175 and No. 15-35-21038 and acknowledges support from the Development Program of Lomonosov Moscow State University. AJCT acknowledges support from the Spanish MINECO Projects AYA 2009-14000-C03-01/ESP and AYA 2015-71718R (including EU/FEDER funds). The Taiwanese authors thank Taiwan's National Science Council Vanguard Program (100-2119-M-002-025) and Ministry of Science and Technology (MOST) funding (104-2811-M-002-160). SJ acknowledges the support from the Korea Basic Science Research Program through NRF-2014R1A6A3A03057484 and NRF-2015R1D1A4A01020961. MBK acknowledges the support from NRF-2015-GPF.