We propose a regular way to construct lattice versions of W -algebras, both for quantum and classical cases. In the classical case we write the algebra explicitly and derive the lattice analogue of Boussinesq equation from the Hamiltonian equations of motion. Connection between the lattice Faddeev-Takhtadjan-Volkov algebra [1] and q-deformed Virasoro is also discussed.

Mini-EUSO is a telescope observing the Earth in the ultraviolet band from the International Space Station. It is a part of the JEM-EUSO program, paving the way to future larger missions, such as K-EUSO and POEMMA, devoted primarily to the observation of ultrahigh-energy cosmic rays from space. Mini-EUSO is capable of observing extensive air showers generated by ultrahigh-energy cosmic rays with an energy above 1021 eV and to detect artificial showers generated with lasers from the ground. Other main scientific objectives of the mission are the search for nuclearites and strange quark matter, the study of atmospheric phenomena such as transient luminous events, meteors, and meteoroids, the observation of sea bioluminescence and of artificial satellites and man-made space debris. Mini-EUSO will map the nighttime Earth in the UV range (290–430 nm), with a spatial resolution of about 6.3 km and a temporal resolution of 2.5 μs, through a nadir-facing UV-transparent window in the Russian Zvezda module. The instrument, launched on 2019 August 22, from the Baikonur Cosmodrome, is based on an optical system employing two Fresnel lenses and a focal surface composed of 36 multianode photomultiplier tubes, 64 channels each, for a total of 2304 channels with single-photon counting sensitivity and an overall field of view of 44°. Mini-EUSO also contains two ancillary cameras to complement measurements in the near-infrared and visible ranges. In this paper, we describe the detector and present the various phenomena observed in the first months of operations.

The Mini-EUSO instrument is a UV telescope to be placed inside the International Space Station (ISS), looking down on the Earth from a nadir-facing window in the Russian Zvezda module. Mini-EUSO will map the earth in the UV range (300 -400 nm) with a spatial resolution of 6.11 km and a temporal resolution of 2.5 µs, offering the opportunity to study a variety of atmospheric events such as transient luminous events (TLEs) and meteors, as well as searching for strange quark matter and bioluminescence. Furthermore, Mini-EUSO will be used to detect space debris to verify the possibility of using a EUSO-class telescope in combination with a high energy laser for space debris remediation.The high-resolution mapping of the UV emissions from Earth orbit allows Mini-EUSO to serve as a pathfinder for the study of Extreme Energy Cosmic Rays (EECRs) from space by the JEM-EUSO collaboration.

A natural definition of q-deformation of Virasoro and superconformal algebras is proposed. New Lie algebraic symmetries are shown to describe the lattice version of the original theory. On the classical (Poisson brackets) level these two-loop algebras are shown to be isomorphic to the Faddeev-Takhtadjan-Volkov lattice Virasoro algebra.

The Mini-EUSO telescope is designed by the JEM-EUSO Collaboration to observe the UV emission of the Earth from the vantage point of the International Space Station (ISS) in low Earth orbit. The main goal of the mission is to map the Earth in the UV, thus increasing the technological readiness level of future EUSO experiments and to lay the groundwork for the detection of Extreme Energy Cosmic Rays (EECRs) from space. Due to its high time resolution of 2.5 us, Mini-EUSO is capable of detecting a wide range of UV phenomena in the Earth's atmosphere. In order to maximise the scientific return of the mission, it is necessary to implement a multi-level trigger logic for data selection over different timescales. This logic is key to the success of the mission and thus must be thoroughly tested and carefully integrated into the data processing system prior to the launch. This article introduces the motivation behind the trigger design and details the integration and testing of the logic.Comment: 24 pages, 11 figures. Accepted for publication in AS

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EUSO-Balloon is a pathfinder mission for the Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO). It was launched on the moonless night of the 25 th of August 2014 from Timmins, Canada. The flight ended successfully after maintaining the target altitude of 38 km for five hours. One part of the mission was a 2.5 hour underflight using a helicopter equipped with three UV light sources (LED, xenon flasher and laser) to perform an inflight calibration and examine the detectors capability to measure tracks moving at the speed of light. We describe the helicopter laser system and details of the underflight as well as how the laser tracks were recorded and found in the data. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. Finally, we present a first reconstruction of the direction of the laser tracks relative to the detector.

EUSO-TA is a on-ground telescope, installed at the Telescope Array (TA) site in Black Rock Mesa, Utah, USA in 2013. The main aim of the project is observation of Ultra High Energy Cosmic Rays (UHECR) through detection of ultraviolet light generated by cosmic-ray showers. EUSO-TA consists of two, 1 m 2 square Fresnel lenses with a field of view of about 10.6 • × 10.6 •. Light is focused on the Photo Detector Module (PDM), identical to the ones that are employed in the other EUSO missions' focal surfaces. The PDM is composed of 36 Hamamatsu multi-anode photomultipliers (64 channels per tube), for a total of 2304 channels. Front-End readout is performed by 36 ASICS, with trigger and readout tasks done by two acquisition boards that send the data to a CPU and storage system. The telescope is housed in a shed located in front of one of the fluorescence detectors of the TA experiment, pointing in the direction of the Electron Light Source and Central Laser Facility. After the installation in February 2013, the performance of the detector has been very good, with little (about one photoelectron) electronic noise and a Point Spread Function of stars compatible with expectations. Several ultra high energy cosmic rays and meteors have been observed. The limiting magnitude of 5.5 on summed frames has been established, with PSF of ∼ 2.5 pixels FWHM. Measurements of the UV background in different darkness conditions and moon phases and positions have been completed. EUSO-TA has been used for development of balloon and space flights within the EUSO framework.