About

John Evans is an Associate Professor in the Ann and H.J. Smead Aerospace Engineering Sciences at the University of Colorado Boulder. His research focuses on computational mechanics with an emphasis on fluid dynamics, fluid-structure interaction, and turbulence modeling and simulation. He specializes in high-order and structure-preserving methods. Evans has a strong academic background with a PhD and MS in Computational and Applied Mathematics from The University of Texas at Austin, and a BS and MS in Mathematics and Applied Mathematics from Rensselaer Polytechnic Institute. He has been recognized for his contributions to the field through numerous awards, including the Educator of the Year by the Rocky Mountain Section of the American Institute of Aeronautics and Astronautics in 2021, the Gallagher Young Investigator Medal from the United States Association for Computational Mechanics in 2021, and the Outstanding Junior Faculty Award from the Smead Aerospace Engineering Sciences in 2020. Evans has also been distinguished as a Clarivate Analytics Highly Cited Researcher multiple years and has held prestigious fellowships such as the Institute for Computational Engineering and Sciences Postdoctoral Fellowship and the Department of Energy Computational Science Graduate Fellowship. His professional experience includes positions as a Visiting Assistant Professor and Assistant Professor at the University of Colorado Boulder, and a Postdoctoral Fellow at the University of Texas at Austin. Evans is actively involved in research related to computational mechanics, fluid dynamics, and turbulence, contributing to advancements in high-order numerical methods and structure-preserving computational techniques.

Research topics

• Particle physics
• Astrophysics
• Computer Science
• Physics
• Artificial Intelligence
• Astronomy
• Cardiology
• Radiology
• Pathology
• Optics
• Medicine
• Nuclear medicine

Selected publications

• Ultra-High-Energy Transient Source Search using IceCube Neutrinos and Pierre Auger Photon Candidates

  2025-09-23

  articleOpen access

  The origins of ultra-high-energy particles remain one of the most profound mysteries in astrophysics. If nearby transient sources of ultra-high-energy particles exist, we might expect correlated emission of neutrinos and photons, arriving in close temporal and spatial coincidence. The IceCube Neutrino Observatory, located at the South Pole, is sensitive to neutrinos from TeV to EeV energies, while the Pierre Auger Observatory, in Argentina, detects cosmic rays and has the capability of observing ultra-high-energy photons using surface and fluorescence detectors. The ultra-high-energy photon candidates reported by the Auger Collaboration, though consistent with cosmic ray backgrounds, provide a compelling opportunity to search for correlated neutrino-photon events. In this contribution, we present the framework to search for ultra-high-energy transients by combining multi-flavour neutrino data from IceCube with photon candidates from the Auger Detector from 2011 to 2017. We will report the sensitivities that we expect to achieve from the search and the astrophysical implications of the possible outcomes.

  PublisherOA PDFDOI

• All-sky Neutrino Point-source Search with IceCube Combined Track and Cascade Data

  The Astrophysical Journal · 2025-12-02 · 1 citations

  articleOpen access

  Abstract Despite extensive efforts, discovery of high-energy astrophysical neutrino sources remains elusive. We present an event-level simultaneous maximum likelihood analysis of tracks and cascades using IceCube data collected from 2008 April 6 to 2022 May 23 to search the whole sky for neutrino sources, and using a source catalog, for coincidence of neutrino emission with gamma-ray emission. This is the first time a simultaneous fit of different detection channels is used to conduct a time-integrated all-sky scan with IceCube. Combining all-sky tracks, with superior pointing power and sensitivity in the northern sky, with all-sky cascades, with good energy resolution and sensitivity in the southern sky, we have developed the most sensitive point-source search to date by IceCube that targets the entire sky. The most significant point in the northern sky aligns with NGC 1068, a Seyfert II galaxy, which, from the catalog search, shows a 3.5 σ excess over background after accounting for trials. The most significant point in the southern sky does not align with any source in the catalog and is not significant after accounting for trials. A search for the single most significant Gaussian flare at the locations of NGC 1068, PKS 1424+240, and the southern highest-significance point shows results consistent with expectations for steady emission. Notably, this is the first time that a flare shorter than four years has been excluded as being responsible for NGC 1068’s emergence as a neutrino source. Our results show that combining tracks and cascades when conducting neutrino source searches improves sensitivity and can lead to new discoveries.

  PublisherDOI

• Performance of the Prototype Station of the IceCube Surface Array Enhancement

  2025-09-24

  articleOpen access

  The prototype station of the Surface Array Enhancement at the IceCube Neutrino Observatory has been taking data in its final design since 2023. This station is part of the planned extension within the footprint of the existing surface array, IceTop. One station consists of 8 scintillator detectors, 3 radio antennas, and a central DAQ. The final upgrade of the scintillation detectors and their firmware at the prototype station has extended the dynamic range and increased the data-taking up-time, thereby expanding the observation window for air showers. This contribution will discuss the performance of the upgraded prototype station after commissioning and its angular resolution capabilities when observing air showers with the scintillation detectors and in coincidence with IceTop. Furthermore, the integration of additional stations during the most recent deployment will be discussed.

  PublisherOA PDFDOI

• School absence and (primary) school connectedness: evidence from the Millennium Cohort Study

  London Review of Education · 2025-03-04 · 3 citations

  articleOpen access

  School-mandated exclusion, or school absence, is on the increase in England. Earlier analyses focused on the characteristics of children, rather than the relationship with school. Using the Millennium Cohort Study, we explore the relationship between school exclusion/school absence and school satisfaction. The Millennium Cohort Study is a UK birth cohort study of around 19,000 children born at the start of the twenty-first century and includes measures relating to school satisfaction, including liking school, being interested in school and being happy. We ask: What are the exclusion risk factors? What is the predictive relationship between school satisfaction and school exclusion and school absence? And what is the predictive relationship between school exclusion and school absence and subsequent school satisfaction over time? Our analysis applied fixed effect models based on within-child comparisons across time (age 11, 14 and 17). Results confirm that Millennium Cohort Study children miss school through exclusion (9 per cent) and absence (14 per cent), are disproportionately male and have special educational needs. School satisfaction was protective; a high level of satisfaction with school at age 7 and 11 reduced the likelihood of exclusion and truancy at age 14 in secondary school. Girls who experienced primary school exclusion reported significantly lower satisfaction with secondary school. We discuss the relationship between school satisfaction and school connectedness measures, with a view to a more nuanced understanding of the interaction between school attitudes to children and children’s attitudes to school. We conclude with tentative implications for policy and future research.

  PublisherOA PDFDOI

• Model Based Systems Engineering for CubeSat Mission Reliability

  Digital Commons - USU (Utah State University) · 2025-08-21

  articleOpen accessSenior author

  Model Based Systems Engineering (MBSE) is moving to the forefront of small spacecraft development. The benefits of SysML as a language for the elucidation of the system architecture for CubeSats is well understood and is implemented in standard model formats. Concurrently, the benefits of the evolving development of MBSE for assurance has been recognized and is emerging as Model Based Mission Assurance (MBMA), which promises the development of integral assurance stakeholder views into the model as well as the production of useful products from the model. In this regard, the assurance organizations of NASA, ESA, and JAXA are exploring jointly the potential benefits of MBSE and MBMA in anticipation of future joint projects in which an architecture for a flight mission will be shared in a SysML model. Traditionally, only mission-critical aspects of large systems have been able to justify the time and expense of creating reliability analyses. This work aims to make these analyses practical for a wide range of missions, from small to large to support architectural design decisions, rapidly and cost effectively, across organizations. In additions to exploring basic modeling concepts and communicating over the model, the partners have shown that reliability analysis can be generated from the model. These include early Failure Modes, Effects, and Critically Analysis (FMECA) and Fault Tree Analysis (FTA) based on the simulated mission. The intent is to test basic meta-model frameworks and compare these results across the agencies. One such basic framework employs SysML state machines as the basis for developing FMEAs and FTAs. When failures are modeled using this framework, plugins (developed by NASA under a Small Business Innovation Research project) for the SysML tool are able to automatically to generate a FMECA table and Fault Trees. The expected outcome of this project is a compilation of lessons learned across the 3 agencies (NASA-ESA-JAXA) to be shared with their assurance communities. In addition, comparisons and utility of SysML derived products from the model are planned. Finally, a framework for standardization to the extent possible will be proposed to facilitate model sharing in the future for more complex scenarios, as a result of lessons learned herein.

  PublisherDOI

• Search for GeV-scale Dark Matter from the Galactic Center with IceCube-DeepCore

  ArXiv.org · 2025-01-01

  articleOpen access

  Models describing dark matter as a novel particle often predict that its annihilation or decay into Standard Model particles could produce a detectable neutrino flux in regions of high dark matter density, such as the Galactic Center. In this work, we search for these neutrinos using $\sim$9 years of IceCube-DeepCore data with an event selection optimized for energies between 15 GeV to 200 GeV. We considered several annihilation and decay channels and dark matter masses ranging from 15 GeV up to 8 TeV. No significant deviation from the background expectation from atmospheric neutrinos and muons was found. The most significant result was found for a dark matter mass of 201.6 GeV annihilating into a pair of $b\bar{b}$ quarks assuming the Navarro-Frenk-White halo profile with a post-trial significance of $1.08 \;σ$. We present upper limits on the thermally-averaged annihilation cross-section of the order of $10^{-24} \mathrm{cm}^3 \mathrm{s}^{-1}$, as well as lower limits on the dark matter decay lifetime up to $10^{26} \mathrm{s}$ for dark matter masses between 5 GeV up to 8 TeV. These results strengthen the current IceCube limits on dark matter masses above 20 GeV and provide an order of magnitude improvement at lower masses. In addition, they represent the strongest constraints from any neutrino telescope on GeV-scale dark matter and are among the world-leading limits for several dark matter scenarios.

  PublisherOA PDFDOI

• Investigation of Electromagnetic and Muonic Air-Shower Components using IceTop Simulations

  2025-09-24

  articleOpen access

  The IceCube Neutrino Observatory studies cosmic-ray initiated extensive air showers (EASs) using the IceTop surface array, which is sensitive to the electromagnetic component and low-energy (∼ GeV) muonic component of EASs. The contribution from the two components is reconstructed on an event-by-event basis by simultaneously fitting separate lateral distribution functions (LDFs) for both the electromagnetic and muonic components of each shower. In this work, we demonstrate the ability of the two-component LDF reconstruction to recreate the muon distribution in IceTop accurately. The parameters characterizing the reconstructed muonic LDF can vary significantly based on the choice of hadronic interaction model. Thus, the dependence of the reconstructed muon LDF and other parameters on the hadronic interaction models is investigated.

  PublisherOA PDFDOI

• Search for Extremely-High-Energy Neutrinos and First Constraints on the Ultrahigh-Energy Cosmic-Ray Proton Fraction with IceCube

  Desy publication database (The Deutsches Elektronen-Synchrotron) · 2025-01-01 · 2 citations

  preprintOpen access

  We present a search for the diffuse extremely-high-energy neutrino flux using 12.6 years of IceCube data. The nonobservation of neutrinos with energies well above 10 PeV constrains the all-flavor neutrino flux at 1018 eV to a level of $E^2Φ_{ν_{e}}$+$ν_μ$$+ν_τ≃$10$^{−8}$ GeV cm$^{-2}$ s-1 sr$^{-1}$, the most stringent limit to date. Using these data, we constrain the proton fraction of ultrahigh-energy cosmic rays (UHECRs) above ≃30 EeV to be ≲70% (at 90% CL) if the cosmological evolution of the sources is comparable to or stronger than the star formation rate. This is the first result to disfavor the “proton-only” hypothesis for UHECR in this evolution regime using neutrino data. This result complements direct air-shower measurements by being insensitive to uncertainties associated with hadronic interaction models. We also evaluate the tension between IceCube’s nonobservation and the ∼200 PeV KM3NeT neutrino candidate (KM3-230213A), finding it to be ∼2.9σ based on a joint-livetime fit between neutrino datasets.

  PublisherDOI

• Mapping the ice stratigraphy in IceCube using camera deployment footage

  2025-09-24

  articleOpen access

  The IceCube Neutrino Observatory is a cubic-kilometer Cherenkov array deployed in the deep, glacial ice at the geographic South Pole. An important feature of the instrumented ice are undulations of layers of constant optical properties over the footprint of the detector. During detector construction, these layers were mapped using stratigraphy measurements obtained from a stand-alone laser dust logger. While this system is very precise, its cost does not scale to the instrumented volume envisioned for the proposed IceCube-Gen2 Observatory. Here, we explore the possibility of obtaining equivalent stratigraphy data from camera footage recorded during the deployment of IceCube more than a decade ago. If successful, this could be an alternative technique to be considered for IceCube-Gen2.

  PublisherOA PDFDOI

• IceCube Search for Neutrino Emission from X-Ray Bright Seyfert Galaxies

  The Astrophysical Journal · 2025-07-18 · 22 citations

  articleOpen access

  Abstract The recent IceCube detection of TeV neutrino emission from the nearby active galaxy NGC 1068 suggests that active galactic nuclei (AGNs) could make a sizable contribution to the diffuse flux of astrophysical neutrinos. The absence of TeV γ -rays from NGC 1068 indicates neutrino production in the vicinity of the supermassive black hole, where the high radiation density leads to γ -ray attenuation. Therefore, any potential neutrino emission from similar sources is not expected to correlate with high-energy γ -rays. Disk-corona models predict neutrino emission from Seyfert galaxies to correlate with keV X-rays because they are tracers of coronal activity. Using through-going track events from the Northern Sky recorded by IceCube between 2011 and 2021, we report results from a search for individual and aggregated neutrino signals from 27 additional Seyfert galaxies that are contained in the Swift's Burst Alert Telescope AGN Spectroscopic Survey. Besides the generic single power law, we evaluate the spectra predicted by the disk-corona model assuming stochastic acceleration parameters that match the measured flux from NGC 1068. Assuming all sources to be intrinsically similar to NGC 1068, our findings constrain the collective neutrino emission from X-ray bright Seyfert galaxies in the northern sky, but, at the same time, show excesses of neutrinos that could be associated with the objects NGC 4151 and CGCG 420-015. These excesses result in a 2.7 σ significance with respect to background expectations.

  PublisherDOI

Frequent coauthors

• Kwok Lung Fan

  199 shared

• C. H. Wiebusch

  144 shared

• S. R. Klein

  142 shared

• Patrick Reichherzer

  139 shared

• S. Sarkar

  139 shared

• L. Halve

  139 shared

• Philipp Fürst

  Clark Atlanta University

  138 shared

• Erik Ganster

  137 shared

Labs

• Computational Mechanics and Geometry LaboratoryPI

Education

• Ph.D., Computational and Applied Mathematics

  The University of Texas at Austin

  2011

• M.S., Computational and Applied Mathematics

  The University of Texas at Austin

  2008

• M.S., Applied Mathematics

  Rensselaer Polytechnic Institute

  2006

• B.S., Mathematics

  Rensselaer Polytechnic Institute

  2006

Awards & honors

• Educator of the Year (College/University), Rocky Mountain Se…
• Gallagher Young Investigator Medal, United States Associatio…
• Outstanding Junior Faculty Award, Smead Aerospace Engineerin…
• Outstanding Graduate Teaching and Mentoring Award, Smead Aer…
• Simons Visiting Professor, Oberwolfach Research Institute, 2…