| 1. |
- Abdellaoui, G., et al.
(författare)
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An overview of the JEM-EUSO program and results
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The field of UHECRs (Ultra-High energy cosmic Rays) and the understanding of particle acceleration in the cosmos, as a key ingredient to the behaviour of the most powerful sources in the universe, is of outmost importance for astroparticle physics as well as for fundamental physics and will improve our general understanding of the universe. The current main goals are to identify sources of UHECRs and their composition. For this, increased statistics is required. A space-based detector for UHECR research has the advantage of a very large exposure and a uniform coverage of the celestial sphere. The aim of the JEM-EUSO program [1] is to bring the study of UHECRs to space. The principle of observation is based on the detection of UV light emitted by isotropic fluorescence of atmospheric nitrogen excited by the Extensive Air Showers (EAS) in the Earth's atmosphere and forward-beamed Cherenkov radiation reflected from the Earth's surface or dense cloud tops. In addition to the prime objective of UHECR studies, JEM-EUSO will do several secondary studies due to the instruments' unique capacity of detecting very weak UV-signals with extreme time-resolution around 1 μs: meteors, Transient Luminous Events (TLE), bioluminescence, maps of human generated UV-light, searches for Strange Quark Matter (SQM) and high-energy neutrinos, and more. The JEM-EUSO program includes several missions from ground (EUSO-TA [2]), from stratospheric balloons (EUSO-Balloon [3], EUSO-SPB1 [4], EUSO-SPB2 [5]), and from space (TUS [6], Mini-EUSO [7]) employing fluorescence detectors to demonstrate the UHECR observation from space and prepare the large size missions K-EUSO [8] and POEMMA [9]. A review of the current status of the program, the key results obtained so far by the different projects, and the perspectives for the near future are presented.
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| 2. |
- Abdellaoui, G., et al.
(författare)
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Science and mission status of EUSO-SPB2
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The Extreme Universe Space Observatory on a Super Pressure Balloon II (EUSO-SPB2) is a second generation stratospheric balloon instrument for the detection of Ultra High Energy Cosmic Rays (UHECRs, E > 1 EeV) via the fluorescence technique and of Very High Energy (VHE, E > 10 PeV) neutrinos via Cherenkov emission. EUSO-SPB2 is a pathfinder mission for instruments like the proposed Probe Of Extreme Multi-Messenger Astrophysics (POEMMA). The purpose of such a space-based observatory is to measure UHECRs and UHE neutrinos with high statistics and uniform exposure. EUSO-SPB2 is designed with two Schmidt telescopes, each optimized for their respective observational goals. The Fluorescence Telescope looks at the nadir to measure the fluorescence emission from UHECR-induced extensive air shower (EAS), while the Cherenkov Telescope is optimized for fast signals (∼10 ns) and points near the Earth's limb. This allows for the measurement of Cherenkov light from EAS caused by Earth skimming VHE neutrinos if pointed slightly below the limb or from UHECRs if observing slightly above. The expected launch date of EUSO-SPB2 is Spring 2023 from Wanaka, NZ with target duration of up to 100 days. Such a flight would provide thousands of VHECR Cherenkov signals in addition to tens of UHECR fluorescence tracks. Neither of these kinds of events have been observed from either orbital or suborbital altitudes before, making EUSO-SPB2 crucial to move forward towards a space-based instrument. It will also enhance the understanding of potential background signals for both detection techniques. This contribution will provide a short overview of the detector and the current status of the mission as well as its scientific goals.
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| 3. |
- Abdellaoui, G., et al.
(författare)
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Towards observations of nuclearites in Mini-EUSO
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is a small orbital telescope with a field of view of 44◦ × 44◦, observing the night-time Earth mostly in 320-420 nm band. Its time resolution spanning from microseconds (triggered) to milliseconds (untriggered) and more than 300 × 300 km of the ground covered, already allowed it to register thousands of meteors. Such detections make the telescope a suitable tool in the search for hypothetical heavy compact objects, which would leave trails of light in the atmosphere due to their high density and speed. The most prominent example are the nuclearites – hypothetical lumps of strange quark matter that could be stabler and denser than the nuclear matter. In this paper, we show potential limits on the flux of nuclearites after collecting 42 hours of observations data.
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| 4. |
- Bianciotto, Marta, et al.
(författare)
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Expected performance of the K-EUSO space-based observatory
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- K-EUSO is a planned mission of the JEM-EUSO program for the study of ultra-high energy cosmic rays (UHECR) from space, to be deployed on the International Space Station. The K-EUSO observatory consists of a UV telescope with a wide field of view, which aims at the detection of fluorescence light emitted by extensive air showers (EAS) in the atmosphere. The EAS events will be sampled with a time resolution of 1-2.5 μs to reconstruct the entire shower profile with high precision. The detector consisting of ∼ 105 independent pixels will allow a spatial resolution of ∼700 m on ground. From a 400 km altitude, K-EUSO will achieve a large and full sky exposure to sample the highest energy range of the UHECR spectrum. In this contribution, we present estimates of the performance of the observatory: an estimation of the expected exposure and triggered event rate as a function of energy and the event reconstruction performance, including resolution of arrival directions and energy of UHECRs.
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| 5. |
- Casolino, M., et al.
(författare)
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The Mini-EUSO telescope on board the International Space Station : Launch and first results
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is a telescope launched on board the International Space Station in 2019 and currently located in the Russian section of the station. 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. It is also capable of observing Extensive Air Showers generated by Ultra-High Energy Cosmic Rays with an energy above 1021 eV and detect artificial showers generated with lasers from the ground. Mini-EUSO can map the night-time 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, observing our planet through a nadir-facing UV-transparent window in the Russian Zvezda module. The instrument, launched on 2019/08/22 from the Baikonur cosmodrome, is based on an optical system employing two Fresnel lenses and a focal surface composed of 36 Multi-Anode 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 year of operation.
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| 6. |
- Diesing, R., et al.
(författare)
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UCIRC2: EUSO-SPB2’s Infrared Cloud Monitor
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The second generation of the Extreme Universe Space Observatory on a Super Pressure Balloon (EUSO-SPB2) is a balloon instrument for the detection of ultra high energy cosmic rays (UHECRs) with energies above 1 EeV and very high energy neutrinos with energies above 10 PeV. EUSOSPB2 consists of two telescopes: a fluorescence telescope pointed downward for the detection of UHECRs and a Cherenkov telescope pointed towards the limb for the detection of tau lepton-induced showers produced by up-going tau neutrinos and background signals below the limb. Clouds inside the field of view of these telescopes reduce EUSO-SPB2’s geometric aperture, in particular that of the fluorescence telescope. For this reason, cloud coverage and cloud-top altitude within the field of view of the fluorescence telescope must be monitored throughout data-taking. The University of Chicago Infrared Camera (UCIRC2) will monitor these clouds using two infrared cameras with response centered at wavelengths 10 and 12 microns. By capturing images at wavelengths spanning the cloud thermal emission peak, UCIRC2 will measure cloud color-temperatures and thus cloud-top altitudes. In this contribution, we provide an overview of UCIRC2, including an update on its construction and a discussion of the techniques used to calibrate the instrument.
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| 7. |
- Fenu, Francesco, et al.
(författare)
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Estimation of the exposure of the TUS space-based cosmic ray observatory
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The TUS observatory was the first orbital detector aimed at the detection of ultra-high energy cosmic rays (UHECRs). It was launched on April 28, 2016, from the Vostochny cosmodrome in Russia and operated until December 2017. It collected ∼ 80, 000 events with a time resolution of 0.8 μs. A fundamental parameter to be determined for cosmic ray studies is the exposure of an experiment. This parameter is important to estimate the average expected event rate as a function of energy and to calculate the absolute flux in case of event detection. Here we present results of a study aimed to calculate the exposure that TUS accumulated during its mission. The role of clouds, detector dead time, artificial sources, storms, lightning discharges, airglow and moon phases is studied in detail. An exposure estimate with its geographical distribution is presented. We report on the applied technique and on the perspectives of this study in view of the future missions of the JEM-EUSO program.
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| 8. |
- Golzio, Alessio, et al.
(författare)
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A study on UV emission from clouds with Mini-EUSO
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is the first mission of the JEM-EUSO program located on the International Space Station. One of the main goals of the mission is to provide valuable scientific data in view of future large missions devoted to study Ultra-High Energy Cosmic Rays (UHECRs) from space by exploiting the fluorescence emission generated by Extensive Air Showers (EAS) developing in the atmosphere. A space mission like Mini-EUSO experiences continuous changes in atmospheric conditions, including the cloud presence. The influence of clouds on space-based observation is, therefore, an important topic to investigate as it might alter the instantaneous exposure for EAS detection or deteriorate the quality of the EAS images with consequences on the reconstructed EAS parameters. For this purpose, JEM-EUSO is planning to have an IR camera and a lidar as part of its Atmospheric Monitoring System. At the same time, it would be extremely beneficial if the UV camera itself would be able to detect the presence of clouds, at least in some specific conditions. For this reason, we analyze a few case studies by comparing the pixel count rates from Mini-EUSO during orbits with the cloud cover (as cloud fraction). This quantity is retrieved from the Global Forecast System (GFS) model at different height levels over the Mini-EUSO trajectory. The results of this analysis are reported.
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| 9. |
- Heaton, C., et al.
(författare)
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Expected Performance of the EUSO-SPB2 Fluorescence Telescope
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
-
Konferensbidrag (refereegranskat)abstract
- The Extreme Universe Space Observatory Super Pressure Balloon 2 (EUSO-SPB2) is under development, and will prototype instrumentation for future satellite-based missions, including the Probe of Extreme Multi-Messenger Astrophysics (POEMMA). EUSO-SPB2 will consist of two telescopes. The first is a Cherenkov telescope (CT) being developed to identify and estimate the background sources for future below-the-limb very high energy (E>10 PeV) astrophysical neutrino observations, as well as above-the-limb cosmic ray induced signals (E>1 PeV). The second is a fluorescence telescope (FT) being developed for detection of Ultra High Energy Cosmic Rays (UHECRs). In preparation for the expected launch in 2023, extensive simulations tuned by preliminary laboratory measurements have been performed to understand the FT capabilities. The energy threshold has been estimated at 1018.2 eV, and results in a maximum detection rate at 1018.6 eV when taking into account the shape of the UHECR spectrum. In addition, onboard software has been developed based on the simulations as well as experience with previous EUSO missions. This includes a level 1 trigger to be run on the computationally limited flight hardware, as well as a deep learning based prioritization algorithm in order to accommodate the balloon's telemetry budget. These techniques could also be used later for future, space-based missions.
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| 10. |
- Kungel, Viktoria, et al.
(författare)
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EUSO-SPB2 Telescope Optics and Testing
- 2022
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Ingår i: 37th International Cosmic Ray Conference, ICRC 2021. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The Extreme Universe Space Observatory - Super Pressure Balloon (EUSO-SPB2) mission will fly two custom telescopes that feature Schmidt optics to measure Čerenkov- and fluorescence-emission of extensive air-showers from cosmic rays at the PeV and EeV-scale, and search for τ-neutrinos. Both telescopes have 1-meter diameter apertures and UV/UV-visible sensitivity. The Čerenkov telescope uses a bifocal mirror segment alignment, to distinguish between a direct cosmic ray that hits the camera versus the Čerenkov light from outside the telescope. Telescope integration and laboratory calibration will be performed in Colorado. To estimate the point spread function and efficiency of the integrated telescopes, a test beam system that delivers a 1-meter diameter parallel beam of light is being fabricated. End-to-end tests of the fully integrated instruments will be carried out in a field campaign at dark sites in the Utah desert using cosmic rays, stars, and artificial light sources. Laser tracks have long been used to characterize the performance of fluorescence detectors in the field. For EUSO-SPB2 an improvement in the method that includes a correction for aerosol attenuation is anticipated by using a bi-dynamic Lidar configuration in which both the laser and the telescope are steerable. We plan to conduct these field tests in Fall 2021 and Spring 2022 to accommodate the scheduled launch of EUSO-SPB2 in 2023 from Wanaka, New Zealand.
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