Overview and First Results of EUSO-SPB2

Abstract

Observing ultra-high energy cosmic rays (UHECR) and very high energy (VHE) neutrinos from space is a promising way to measure their extremely low fluxes by significantly increasing the observed volume. The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2), the next, most advanced pathfinder for such a mission, was launched May 13th 2023 from Wanaka New Zealand. The pioneering EUSO-SPB2 payload flew a Fluorescence Telescope (FT) with a PMT camera pointed in nadir to record fluorescence light from cosmic ray extensive air shower (EAS) with energies above 1 EeV, and a Cherenkov telescope (CT) with a silicon photomultiplier focal surface for observing Cherenkov emission of cosmic ray EAS with energies above 1 PeV with an above-the-limb geometry and of PeV-scale EAS initiated by neutrinosourced tau decay. As the CT is a novel instrument, optical background measurements for space neutrino observation are an important goal of the mission. Any data collected during the mission will influence and improve the development of a space-based multi-messenger observatory such as the Probe of Extreme Multi-Messenger Astrophysics (POEMMA). We present an overview of the EUSO-SPB2 mission and its science goals and summarize results as available, from the 2023 flight.

Mini-EUSO on Board the International Space Station: Mission Status and Results

“…During the last ten years, the JEM-EUSO collaboration has accomplished many successful missions (see Figure 1) by operating on ground (EUSO-TA [6] (2013-Current)), on stratospheric balloons (EUSO-Balloon [7,8] (2014), EUSO-SPB1 [9] (2017), EUSO-SPB2 [10,11] (2023)) and in space (TUS [12,13] (2016), Mini-EUSO [1] (2019)). Other missions are foreseen for the coming years: K-EUSO [14] and POEMMA [15].…”

“…On 13 May 2023, EUSO-SPB2 [10,11], a second NASA super pressure balloon, was launched from Wanaka but, again due to a leak in the balloon, the flight lasted only about 32 h, and sank in the Pacific Ocean. It aimed to search for UHECRs (E > EeV) and very high-energy neutrinos (E > PeV) using ultraviolet fluorescence and Cherenkov radiation, respectively.…”

EUSO-Offline: A comprehensive simulation and analysis framework

“…Since 2019, Mini-EUSO [7] has been taking data on board the International Space Station. A second long duration super pressure balloon flight, EUSO-SPB2 was launched on May 13th from Wanaka, NZ [8,9] but was prematurely terminated over the Pacific ocean due to a balloon leak after only 37 hours at float. The first four of these pathfinders comprised telescopes capable of sensing the fluorescence light produced by excited atmospheric nitrogen as the UHECR-induced cascade of particles develops and deposits energy as it traverses the Earth's atmosphere.…”

Neutrino Target-of-Opportunity Sky Coverage and Scheduler for EUSO-SPB2

“…The field of view (FOV) of the CT extends Δ𝛼 = 6.4 • in altitude and Δ𝜙 = 12.8 • in azimuth. Additional details describing the EUSO-SPB2 CT can be found in these proceedings [5,6]. To fulfil criteria 1 and 2, the pointing of the CT is such that the upper part of the field of view corresponds to the limb of Earth.…”