arXiv subjects

Tonia M. Venters

Publications and source records attributed to Tonia M. Venters.

At least 19 recordsLinked to original sources

arXiv2026

NASA ASTRA Initiative White Paper: Space-Based Mission for Ultrahigh Energy Particles

Ultra-high-energy cosmic rays ($E_{\rm CR} \gtrsim 1$ EeV) are the highest-energy particles known, signaling extreme particle processes at work in the universe. However, many aspects of their nature remain largely unknown, even after more than a century of study. Very-high-energy ($E_ν\gtrsim 1$ PeV neutrinos associated with cosmic-ray interactions, both during the acceleration process and propagation, would provide new insight into these extreme particles, as we have seen at lower energies with the dawn of TeV neutrino astronomy. Nevertheless, only a handful of such neutrinos have been observed thus far. A space-based observatory dedicated to studying cosmic rays, neutrinos, and photons would provide an unprecedented platform for observations of these extreme-energy messengers.

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arXiv2026

Scheduling follow-up observations of energetic transients with the neutrino target scheduler (NuTS)

Space missions offer unique opportunities for studying ultra-high-energy (UHE) cosmic rays and neutrinos by leveraging secondary emissions generated by extensive air showers (EAS) resulting from their interactions with the Earth's atmosphere or crust. Detecting UHE neutrinos associated with transient sources holds great potential for unraveling the origins of UHE cosmic rays and the physical processes driving their production. Stratospheric balloon missions, illustrated recently by the Extreme Universe Space Observatory on a Super Pressure Balloon II Mission, serve as crucial precursors to space missions. Due to slewing abilities of their telescopes, they can perform follow-up observations of transient sources foreseen as potential candidates for detectable UHE neutrino emissions. Strategies tailored to stratospheric and space missions are essential for optimizing follow-up observations aimed at detecting these elusive neutrinos for the first time. To address this challenge, we have developed flexible software dedicated to scheduling transient source observations. The software comprises three main modules: a listener module that aggregates alerts from existing alert systems to construct a comprehensive source database, an observability module that factors in the detection system's properties and trajectory to determine a list of observable sources during a specific time frame, and a scheduler module that prioritizes observations and proposes an optimized observation schedule. The initial release of the neutrino target scheduler software is tailored to the requirements of stratospheric balloon missions, with mock observation examples provided for various flight scenarios. This version will be employed for the upcoming POEMMA Balloon with Radio flight in 2028. Future developments will extend its capabilities, and ensure its relevance for various types of missions.

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arXiv2026

Foundations for Discovery: A Coordinated Fleet Approach to NASA Astrophysics

This white paper presents an analysis of Astro2020 science priorities and NASA's future astrophysics mission architecture, advocating for a coordinated fleet of \$1--2B missions, smaller than typical Flagship observatories, but strategically designed to complement them, i.e. a ``Next Generation Great Observatories" program. The study addresses opportunities in current mission planning, design, and implementation and proposes a strategic approach to maximize scientific return on investment while strengthening partnerships across NASA divisions, other government organizations, universities, and industry.

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arXiv2026

Constraining light dark matter in vector-scalar portals with COSI and AMEGO-X

Detecting gamma-ray signals that could be due to dark matter (DM) particles would give us invaluable information about the nature of DM. In particular, gamma-ray lines could provide a way to measure the DM mass. The excellent energy resolution of the upcoming Compton Spectrometer and Imager (COSI) will allow us to probe underexplored regions of the DM parameter space while being sensitive to distinctive spectral features of potential DM signals. In this work, we consider a fermionic sub-GeV DM charged under a new U(1) gauge symmetry. Both the DM and the new gauge boson $Z'$ acquire mass from a new singlet scalar. The masses of the new particles in this class of vector-scalar portal models are naturally at the MeV scale, enabling detectable gamma-ray lines in the bandpasses of COSI and proposed missions such as the All-sky Medium Energy Gamma-ray Observatory eXplorer (AMEGO-X). We estimate the sensitivities of COSI and AMEGO-X to sub-GeV DM in this context, considering a B-L and a purely axial $Z'$ as benchmark examples. We find regions of the parameter space where COSI will provide leading constraints, beyond the strong CMB limits. On the other hand, AMEGO-X would probe most of the viable parameter space leading to continuum gamma rays. The implementation of our generic vector-scalar portal model in the Hazma toolkit is available at GitHub.

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arXiv2025

EUSO-SPB2 Cherenkov Telescope: Overview and First Neutrino Constraints

Earth-skimming tau neutrinos with energies above $\sim 10$ PeV can convert to tau leptons that decay in the atmosphere and initiate upward-going extensive air showers that generate optical Cherenkov signals. On a curtailed NASA balloon flight in May 2023, the Cherenkov telescope (CT) on the Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) was launched and had a short flight at $\sim 30$ km altitude. With some time pointing below the Earth's limb, EUSO-SPB2 CT data allow searches for neutrino events that yield optical flashes from the forward-beamed Cherenkov light. We present an overview of the CT and provide upper limits for the diffuse astrophysical neutrino flux from flight data as a proof-of-principle demonstration. We also briefly describe how the methodology is extended to potential transient neutrino point sources.

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arXiv2025

Using the Cherenkov Telescope onboard EUSO-SPB2 for Target of Opportunity searches of very high energy neutrino sources

The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) mission launched from Wanaka New Zealand on May 13, 2023. The mission ended after 36 h due to a balloon leak that resulted in the payload being lost in the Pacific Ocean. Over the course of the mission, the onboard Cherenkov Telescope (CT) was pointed just below the Earth's limb to search for optical signals from upward-moving extensive air showers that were induced by decaying tau-leptons that were generated by the conversion of $>10$ PeV tau-neutrinos in Earth. Such very-high energy (VHE) neutrinos may be produced in several classes of astrophysical sources that are suspected of possibly accelerating particles to ultra-high energies. In this contribution, we discuss the EUSO-SPB2 Target-of-Opportunity (ToO) campaign to search for VHE neutrino signals coming from astrophysical sources that crossed the CT's field of view ($6.4^\circ \times 12.8^\circ$). We also present a new software tool designed for scheduling observations, the Neutrino Target Scheduler, that we developed to support the ToO campaign. We also calculate upper limits on the neutrino fluences from sources observed during the ToO campaign. Our observations demonstrate the viability of conducting ToO follow-up observations from a near space environment with future balloon missions, such as the pathfinder mission POEMMA-Balloon with Radio.

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arXiv2025

Prospects for PBR detection of KM3-230213A-like events

POEMMA-Balloon with Radio (PBR) is a scaled-down version of the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) design, optimized to be flown as a payload on one of NASA's sub-orbital super pressure balloons circling the Earth above the southern oceans for a mission duration of more than 20 days. One of the main science objectives of PBR is to follow up astrophysical event alerts in search of neutrinos with very high energy ($10^8 \lesssim E_ν/{\rm GeV} \lesssim 10^{10}$). Of particular interest for anticipated PBR observations, the KM3NeT Collaboration has recently reported the detection of the neutrino KM3-230213A with $10^{7.8} \lesssim E_ν/{\rm GeV} \lesssim 10^{9.0}$. Such an unprecedented event is in tension with upper limits on the cosmic neutrino flux from IceCube and the Pierre Auger Observatory: for a diffuse isotropic neutrino flux there is a $3.5σ$ tension between KM3NeT and IceCube measurements, and about $2.6σ$ if the neutrino flux originates in transient sources. Therefore, if KM3-230213A was not beginner's luck, it becomes compelling to consider beyond Standard Model (BSM) possibilities which could lead to a signal at KM3NeT-ARCA but not at IceCube/Auger. We calculate the PBR horizon-range sensitivity to probe BSM physics compatible with observation at KM3NeT-ARCA and non-observation at IceCube/Auger. As an illustration, we consider a particular class of BSM physics models which has been described in the literature as a possible explanation of KM3-230213A.

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arXiv2025

The Extreme Universe Observatory on a Super-Pressure Balloon II: Mission, Payload, and Flight

The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) is a pathfinder mission toward a space-based observatory such as the Probe of Extreme Multi-Messenger Astrophysics (POEMMA). The aim of POEMMA is the observation of Ultra High Energy COsmic Rays (UHECRs) in order to elucidate their nature and origins and to discover $\gtrsim$ 20 PeV very high energy neutrinos that originate from transient and steady astrophysical sources. EUSO-SPB2 was launched from Wānaka New Zealand on May 13th, 2023 as a NASA Balloon Program Office test flight. The mission goals included making the first near-space altitude observations of the fluorescence emission from UHECR-induced extensive air showers (EASs) and making the first direct Cherenkov light emission from PeV cosmic rays traversing Earth's atmosphere. In addition, a Target of Opportunity program was developed for selecting and scheduling observations of potential neutrino sources as they passed just below the Earth's limb. Although a leaky balloon forced termination over the Pacific Ocean after 37 hours, data was collected to demonstrate the successful commissioning and operation of the instruments. This paper includes a description of the payload and the key instruments, pre-flight instrument characterizations in the lab and in the desert, flight operations and examples of the data collected. The flight was too short to catch a UHECR event via fluorescence, however about 10 candidate EAS events from cosmic rays were recorded via Cherenkov light.

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arXiv2024

The EUSO-SPB2 Fluorescence Telescope for the Detection of Ultra-High Energy Cosmic Rays

The Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) flew on May 13$^{\text{th}}$ and 14$^{\text{th}}$ of 2023. Consisting of two novel optical telescopes, the payload utilized next-generation instrumentation for the observations of extensive air showers from near space. One instrument, the fluorescence telescope (FT) searched for Ultra-High Energy Cosmic Rays (UHECRs) by recording the atmosphere below the balloon in the near-UV with a 1~$μ$s time resolution using 108 multi-anode photomultiplier tubes with a total of 6,912 channels. Validated by pre-flight measurements during a field campaign, the energy threshold was estimated around 2~EeV with an expected event rate of approximately 1 event per 10 hours of observation. Based on the limited time afloat, the expected number of UHECR observations throughout the flight is between 0 and 2. Consistent with this expectation, no UHECR candidate events have been found. The majority of events appear to be detector artifacts that were not rejected properly due to a shortened commissioning phase. Despite the earlier-than-expected termination of the flight, data were recorded which provide insights into the detectors stability in the near-space environment as well as the diffuse ultraviolet emissivity of the atmosphere, both of which are impactful to future experiments.

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arXiv2023

The Targets of Opportunity Source Catalog for the EUSO-SPB2 Mission

The Extreme Universe Space Observatory on a Super Pressure Balloon 2, EUSO SPB2, mission was designed to take optical measurements of extensive air showers, EASs, from suborbital space. The EUSO SPB2 payload includes an optical Cherenkov Telescope, CT, which searches above and below the Earth's limb. Above the limb, the CT measures Cherenkov light from PeV scale EASs induced by cosmic rays. Below the limb, the CT searches for upwards going Cherenkov emission from PeV scale EASs induced by tau neutrinos, to follow up on astrophysical Targets of Opportunity, ToO. Target candidates include gamma ray bursts, tidal disruption events, and, after the start of the O4 obervation run from Ligo, Virgo, Kagra, binary neutron star mergers. Reported here is the selection and prioritization of relevant ToOs from alert networks such as the General Coordinates Network, Transient Name Server, and Astronomer Telegrams, and the translation to a viewing schedule for EUSO SPB2. EUSO SPB2 launched on a NASA super pressure balloon in May of 2023 from Wanaka, NZ.

hep-ex↗

arXiv2023

Overview of the EUSO-SPB2 Target of Opportunity program using the Cherenkov Telescope

During the Extreme Universe Space Observatory on a Super Pressure Balloon 2 (EUSO-SPB2) mission, we planned Target of Opportunity (ToO) operations to follow up on possible sources of $\gtrsim 10 \, {\rm PeV}$ neutrinos. The original plan before flight was to point the onboard Cherenkov Telescope (CT) to catch the source's path on the sky just below Earth's horizon. By using the Earth as a tau-neutrino to tau-lepton converter, the CT would then be able to look for optical extensive air shower signals induced by tau-lepton decays in the atmosphere. The CT had a field of view of $6.4^\circ$ vertical $\times$ $12.8^\circ$ horizontal. Possible neutrino source candidates include gamma ray bursts, tidal disruption events and other bursting or flaring sources. In addition, follow-ups of binary neutron star mergers would have been possible after the start of the O4 observation run from LIGO-Virgo-KAGRA. The resulting exposure is modeled using the NuSpaceSim framework in ToO mode. With the launch of the EUSO-SPB2 payload on the 13th May 2023, this summarizes the ToO program status and preliminary data, as available.

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arXiv2023

Neutrino propagation through Earth: modeling uncertainties using nuPyProp

Using the Earth as a neutrino converter, tau neutrino fluxes from astrophysical point sources can be detected by tau-lepton-induced extensive air showers (EASs). Both muon neutrino and tau neutrino induced upward-going EAS signals can be detected by terrestrial, sub-orbital and satellite-based instruments. The sensitivity of these neutrino telescopes can be evaluated with the nuSpaceSim package, which includes the nuPyProp simulation package. The nuPyProp package propagates neutrinos ($ν_μ$, $ν_τ$) through the Earth to produce the corresponding charged leptons (muons and tau-leptons). We use nuPyProp to quantify the uncertainties from Earth density models, tau depolarization effects and photo-nuclear electromagnetic energy loss models in the charged lepton exit probabilities and their spectra. The largest uncertainties come from electromagnetic energy loss modeling, with as much as a 20-50% difference between the models. We compare nuPyProp results with other simulation package results.

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arXiv2023

Neutrino propagation in the Earth and emerging charged leptons with $\texttt{nuPyProp}$

Ultra-high-energy neutrinos serve as messengers of some of the highest energy astrophysical environments. Given that neutrinos are neutral and only interact via weak interactions, neutrinos can emerge from sources, traverse astronomical distances, and point back to their origins. Their weak interactions require large target volumes for neutrino detection. Using the Earth as a neutrino converter, terrestrial, sub-orbital, and satellite-based instruments are able to detect signals of neutrino-induced extensive air showers. In this paper, we describe the software code $\texttt{nuPyProp}$ that simulates tau neutrino and muon neutrino interactions in the Earth and predicts the spectrum of the $τ$-lepton and muons that emerge. The $\texttt{nuPyProp}$ outputs are lookup tables of charged lepton exit probabilities and energies that can be used directly or as inputs to the $\texttt{nuSpaceSim}$ code designed to simulate optical and radio signals from extensive air showers induced by the emerging charged leptons. We describe the inputs to the code, demonstrate its flexibility and show selected results for $τ$-lepton and muon exit probabilities and energy distributions. The $\texttt{nuPyProp}$ code is open source, available on Github.

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arXiv2022

Neutrino Target-of-Opportunity Observations with Space-based and Suborbital Optical Cherenkov Detectors

Cosmic-ray accelerators capable of reaching ultra-high energies are expected to also produce very-high energy neutrinos via hadronic interactions within the source or its surrounding environment. Many of the candidate astrophysical source classes are either transient in nature or exhibit flaring activity. Using the Earth as a neutrino converter, suborbital and space-based optical Cherenkov detectors, such as POEMMA and EUSO-SPB2, will be able to detect upward-moving extensive air showers induced by decaying tau-leptons generated from cosmic tau neutrinos with energies $\sim 10$ PeV and above. Both EUSO-SPB2 and POEMMA will be able to quickly repoint, enabling rapid response to astrophysical transient events. We calculate the transient sensitivity and sky coverage for both EUSO-SPB2 and POEMMA, accounting for constraints imposed by the Sun and the Moon on the observation time. We also calculate both detectors' neutrino horizons for a variety of modeled astrophysical neutrino fluences. We find that both EUSO-SPB2 and POEMMA will achieve transient sensitivities at the level of modeled neutrino fluences for nearby sources. We conclude with a discussion of the prospects of each mission detecting at least one transient event for various modeled astrophysical neutrino sources.

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arXiv2022

The NASA Multi-Messenger Astrophysics Science Support Center (MOSSAIC)

The era of multi-messenger astrophysics has arrived, leading to key new discoveries and revealing a need for coordination, collaboration, and communication between world-wide communities using ground and space-based facilities. To fill these critical needs, NASA's Goddard Space Flight Center and Marshall Space Flight Center are jointly proposing to establish a virtual Multi-Messenger Astrophysics Science Support Center that focuses entirely on community-directed services. In this article, we describe the baseline plan for the virtual Support Center which will position the community and NASA as an Agency to extract maximum science from multi-messenger events, leading to new breakthroughs and fostering increased coordination and collaboration.

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arXiv2022

Advancing the Landscape of Multimessenger Science in the Next Decade

The last decade has brought about a profound transformation in multimessenger science. Ten years ago, facilities had been built or were under construction that would eventually discover the nature of objects in our universe could be detected through multiple messengers. Nonetheless, multimessenger science was hardly more than a dream. The rewards for our foresight were finally realized through IceCube's discovery of the diffuse astrophysical neutrino flux, the first observation of gravitational waves by LIGO, and the first joint detections in gravitational waves and photons and in neutrinos and photons. Today we live in the dawn of the multimessenger era. The successes of the multimessenger campaigns of the last decade have pushed multimessenger science to the forefront of priority science areas in both the particle physics and the astrophysics communities. Multimessenger science provides new methods of testing fundamental theories about the nature of matter and energy, particularly in conditions that are not reproducible on Earth. This white paper will present the science and facilities that will provide opportunities for the particle physics community renew its commitment and maintain its leadership in multimessenger science.

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arXiv2022

Neutrino constraints on long-lived heavy dark sector particle decays in the Earth

Recent theoretical work has explored dark matter accumulation in the Earth and its drift towards the center of the Earth that, for the current age of the Earth, does not necessarily result in a concentration of dark matter ($χ$) in the Earth's core. We consider a scenario of long-lived ($τ_χ\sim 10^{28}$ s), super heavy ($m_χ=10^7-10^{10}$ GeV) dark matter that decays via $χ\to ν_τ\barν_τ$ or $χ\to ν_μ\barν_μ$. We show that an IceCube-like detector over 10 years can constrain a dark matter density that mirrors the Earth's density or has a uniform density with density fraction $ε_ρ$ combined with the partial decay width $B_{χ\to ν_τ\barν_τ}Γ_χ$ in the range of $(ε_ρ/10^{-10}) B_{χ\to ν_τ}Γ_χ\lesssim 1.5\times 10^{-29}-1.5\times 10^{-28}$ s$^{-1}$. For $χ\to ν_μ\barν_μ$, $m_χ= 10^8-10^{10}$ GeV and $E_μ>10^7$ GeV, the range of constraints is $(ε_ρ/10^{-10}) B_{χ\to ν_μ}Γ_χ\lesssim 3\times 10^{-29}-7\times 10^{-28}$ s$^{-1}$.

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arXiv2021

Probing the properties of superheavy dark matter annihilating or decaying into neutrinos with ultra-high energy neutrino experiments

The evidence for dark matter particles, $χ$, is compelling based on Galactic to cosmological scale observations. Thus far, the promising weakly interacting massive particle scenario have eluded detection, motivating alternative models of dark matter. We consider scenarios involving superheavy dark matter (SHDM) that potentially can decay or annihilate to neutrinos and antineutrinos. In the mass range $m_χ=10^7-10^{15}\,{\rm GeV}$, we evaluate the sensitivities of future observatories POEMMA and GRAND for indirect dark matter detection via the measurement of neutrino-induced extensive air showers (EAS), compute the Auger and ANITA limits using their last up-to-date sensitivities, and compare them with IceCube limits. We also show that the uncertainties related to the dark matter distribution in the Galactic halo have a large impact on the neutrino flux. We show that a ground-based radio detector such as GRAND can achieve high sensitivities due to its large effective area and high duty cycle. Space-based Cherenkov detectors such as POEMMA that measure the EAS optical Cherenkov signal have the advantage of full-sky coverage and rapid slewing, enabling an optimized SHDM observation strategy focusing on the Galactic Center. We show that increasing the field of view of the Cherenkov detectors can significantly enhance the sensitivity. Moreover, POEMMA's fluorescence observation mode that measures EAS above $20\,$EeV will achieve state-of-the-art sensitivity to SHDM properties at the highest mass scales.

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