Session AA03: V: Future Prospects and Open Questions in Astrophysics

Next-generation multi-PMT Optical Modules and Data Acquisition for IceCube-Gen2

A new in-ice optical sensor is under development for IceCube-Gen2, the proposed expansion to the IceCube South Pole Neutrino Observatory. With 4 times the sensitivity of the current Digital Optical Modules (DOMs), the “Gen2-DOM” encloses multiple 4-inch Photomultiplier Tubes (PMTs) in a borosilicate glass pressure vessel, distributed homogeneously to guarantee full angular coverage. Challenges arise for the mechanical design from the requirement to minimize the size of each module, which requires close packing of the PMTs and associated electronics. An internal support structure has been designed to enable precise alignment and coupling of the PMTs to the pressure vessel using moulded optical gel ‘pads’. Modular electronics have been custom-designed to fit into the available space and to minimize cost and power requirements for the ~10000  modules to be installed. As IceCube-Gen2 aims to increase sensitivity to PeV-scale neutrino events,the electronics have been designed for a high linear dynamic range by adding a second channel dynode readout on each PMT. An in-module memory buffering system has been implemented, enabling a multi-level trigger design that focuses data transmission on the most interesting events. Prototype modules will be installed in the upcoming IceCube Upgrade.   

Parameterization of Photon Yields In Idealized Ice for Pixelated Reconstruction

IceCube Neutrino Observatory currently uses single-PMT Digital Optical Modules (DOMs) for data collection. Future expansions (IceCube-Upgrade, IceCube-Gen2) will enhance detection by employing multi-PMT DOMs, improving sensitivity and accuracy in locating neutrino sources. However, the adoption of multi-pixel sensors presents challenges due to high memory usage. Utilizing deep neural networks relies on generating extensive Monte Carlo datasets using GPUs. To address this, we propose a maximum likelihood method, analytically parameterizing photon propagation in a homogenous medium for arrival timing and flux distribution. For a given detector geometry and DOM PMT configuration, events were simulated by Poisson sampling from the parameterization. We show preliminary results for idealized angular resolution gain by utilization of pixelated sensors.   

Consistent directional likelihoods for IceCube realtime alerts

The IceCube Neutrino Observatory instruments a cubic-kilometer of ice at the South Pole. A primary science goal is the detection of high-energy neutrinos from astrophysical sources. In order to facilitate such discoveries, IceCube issues alerts in real time for specific categories of high-energy events, thus allowing rapid follow up by the multimessenger community. As an example, follow up observations initiated by the alert IC170922A found a flaring blazar, TXS 0506+056, in the direction of the alert, ultimately leading to the first astrophysical source detected by IceCube. However, the construction of likelihood contours for this and other historical alerts is outdated and inconsistent across per-event topologies. In this talk, several updates to the reconstruction model, based on the tremendous progress made recently towards a refined understanding of the ice, will be presented that lead to more consistent likelihood spaces across different categories of realtime alerts.   

Computational Insights into the IC-59 Nebula: Probing the Dynamics of Stellar Interactions in Cassiopeia

The IC-59 nebula, nestled within the constellation Cassiopeia, offers a captivating glimpse into the aftermath of stellar processes and their impact on the surrounding interstellar environment. This research embarks on a computational odyssey to simulate the multifaceted evolution of the IC-59 nebula, employing state-of-the-art hydrodynamics and magnetohydrodynamics (MHD) techniques. By reconstructing the progenitor stars' interactions and subsequent feedback with the nebular material, our study elucidates the underlying mechanisms driving the nebula's morphology, shockwave dynamics, and magnetic field structures. Through meticulous data analysis and immersive visualizations, we unveil the intricate patterns and physical phenomena manifested within the IC-59 nebula, fostering a deeper appreciation for the dynamic interplay between stars and their cosmic surroundings. This computational endeavor serves as a pivotal educational resource, illuminating the complexities of stellar evolution and the profound influence of stellar processes on the fabric of the universe.   

Beyond the universe

Are the stars a beautiful but useless filling of the universe or do they still have some kind of power and deep hidden meaning? This is not about mysticism, but about a very real, physical problem. The Austrian physicist and philosopher Ernst Mach raised this problem, later called Mach's principle, more than a century ago. Albert Einstein hoped to introduce Mach's principle into general relativity but failed. We offer a concise and logical embodiment of Mach's principle in modern physics. The universe is surrounded by a special space in which the laws of motion become completely uncertain, and distance and time lose their physical meaning. We called such a condition of space Chaos, by analogy with the term used by ancient thinkers. The laws of physics and fundamental physical constants change dramatically in Chaos. The entire mass of the stars in the universe acquires a fundamental meaning and determines the values of physical constants. The presentation will present formulas relating the distribution of matter in the universe and the fundamental physical constants, including the speed of light and Planck's constant.   

A New Calculation of the Speed of Objects in Nested Paths in the Universe

Given that each moon orbits around its planet and each planet orbits around its central sun, the combination of orbits 1 and 2 creates a helical pathway for a moon. If a star’s orbit around its central galactic black hole, which is a closed curve path, is added to the moon's path, the final path will be a combination of paths 1, 2, and 3. And, the path of moon will be a nested helical orbit.

But celestial objects have different speed at different orbits. to calculate the total velocity of objects in these helixes, we have used the following method:

Resultant velocity = Sum of the velocities in helical paths + Linear velocity (speed in biggest orbit)

In this paper we will explain more about this theory, drive a formula for calculation of speed of objects in nested paths in the universe and give some real examples.   

Deep-Sea and Lunar 244Pu: A New Messenger Probing the r-Process in Recent Near-Earth Explosions

The geological and lunar record represent natural archives that contain new messengers from cosmic explosions:  live (not decayed) radioisotopes ejected in these outbursts.  Events sufficiently nearby will drive blast waves that engulf the solar system and deliver the radioisotopes to the Earth and Moon.  Thanks to their low or terrestrial backgrounds, these astrophysical radioisotopes can be detected with ultrasensitive accelerator mass spectrometry (AMS) techniques.   The first such messenger is now well-established:  a wealth of ⁶⁰Fe (half-life 2.6 Myr) detections around the Earth and on the Moon demonstrate that at least two supernovae exploded near the Earth around 3 and 7 Myr ago.  Recently, a new messenger has come into our grasp:  the r-process actinide ²⁴⁴Pu (half-life 80 Myr) has been detected a deep-sea sample where ⁶⁰Fe is also found.  We will review the status of these detections and present models of r-process nucleosynthesis to interpret their significance.  The current deep-sea allows for the ²⁴⁴Pu to originate either in one or both of the recnet supernova(e), or in separate nearby kilonova event.  We will discuss future observations that can discriminate these possibilities and thus shed new light on the origin of the r-process.  In particular we will highlight  the value of future lunar measurements from samples returned by the Chang'e and Artemis missions.