J. F. Beacom
A5068174431- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Solar and Space Plasma Dynamics
- Cosmology and Gravitation Theories
- Radiation Detection and Scintillator Technologies
- Galaxies: Formation, Evolution, Phenomena
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Astronomical Observations and Instrumentation
- Particle accelerators and beam dynamics
- Geophysics and Gravity Measurements
- Particle Accelerators and Free-Electron Lasers
- Radio Astronomy Observations and Technology
- Planetary Science and Exploration
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- Radiation Therapy and Dosimetry
The Ohio State University
2016-2025
State Library of Ohio
2007-2024
California Consortium of Addiction Programs and Professionals
2011-2023
The Ohio State University at Lima
2023
Stockholm University
2021
Australian National University
2020
United States Naval Research Laboratory
2006
K Lab (United States)
2006
University of California, Berkeley
2006
Princeton University
2006
Strong constraints on the cosmic star formation history (SFH) have recently been established using ultraviolet and far-infrared measurements, refining results of numerous measurements over past decade. Taken together, most recent robust data indicate a compellingly consistent picture SFH out to redshift z~6, with especially tight for z<~1. We fit these simple analytical forms, derive conservative bands possible variations from best fits. Since z<~1 are quite precise, we investigate sequence...
After the All-Sky Automated Survey for SuperNovae (ASAS-SN) discovered a significant brightening of inner region NGC 2617, we began ~70 day photometric and spectroscopic monitoring campaign from X-ray through near-infrared (NIR) wavelengths. We report that 2617 went dramatic outburst, during which its flux increased by over an order magnitude followed increase optical/ultraviolet (UV) continuum almost magnitude. classified as Seyfert 1.8 galaxy in 2003, is now 1 due to appearance broad...
The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of neutrino mass hierarchy as primary physics goal. It is also capable observing neutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse background, geoneutrinos, atmospheric solar well exotic searches such nucleon decays, dark matter, sterile etc. We present motivations anticipated...
If dark matter (DM) is a weakly interacting massive particle (WIMP) that thermal relic of the early Universe, then its total self-annihilation cross section revealed by present-day mass density. The canonical thermally averaged for generic WIMP usually stated as 3*10^-26 cm^3s^-1, with unspecified uncertainty, and taken to be independent mass. Recent searches annihilation products DM have just reached sensitivity exclude this 100% branching ratio certain final states small masses. ultimate...
The reaction $\bar{\nu}_e + p \to e^+ n$ is very important for low-energy ($E_\nu \lesssim 60$ MeV) antineutrino experiments. In this paper we calculate the positron angular distribution, which at low energies slightly backward. We show that weak magnetism and recoil corrections have a large effect on making it isotropic about 15 MeV forward higher energies. also behavior of cross section distribution can be well-understood analytically $E_\nu by calculating to ${\cal O}(1/M)$, where $M$...
We propose modifying large water \ifmmode \check{C}\else \v{C}\fi{}erenkov detectors by the addition of 0.2% gadolinium trichloride, which is highly soluble, newly inexpensive, and transparent in solution. Since Gd has an enormous cross section for radiative neutron capture, with $\ensuremath{\sum}_{}^{}{E}_{\ensuremath{\gamma}}=8\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}$, this would make neutrons visible first time such detectors, allowing antineutrino tagging coincidence detection...
While the high-z frontier of star formation rate (SFR) studies has advanced rapidly, direct measurements beyond z ∼ 4 remain difficult, as shown by significant disagreements among different results. Gamma-ray bursts, owing to their brightness and association with massive stars, offer hope clarifying this situation, provided that GRB can be properly related SFR. The Swift data reveal an increasing evolution in relative SFR at intermediate z; taking into account, we use highest-z make a new...
The preponderance of matter over antimatter in the early universe, dynamics supernovae that produced heavy elements necessary for life, and whether protons eventually decay—these mysteries at forefront particle physics astrophysics are key to understanding evolution our its current state, eventual fate. Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated addressing these questions as it searches leptonic charge-parity symmetry violation, stands...
The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at Fermilab Long-Baseline Facility (LBNF) is described.
We present ground-based and Swift photometric spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at center PGC 043234 ($d\simeq90$ Mpc) by All-Sky Automated Survey for SuperNovae (ASAS-SN). The source had a peak bolometric luminosity $L\simeq10^{44}$ ergs s$^{-1}$ total integrated energy $E\simeq7\times10^{50}$ radiated over $\sim6$ months presented. UV/optical emission is well-fit blackbody with roughly constant temperature $T\sim35,000$ K, while...
High-redshift gamma-ray bursts (GRBs) offer an extraordinary opportunity to study aspects of the early Universe, including cosmic star formation rate (SFR). Motivated by two recent highest-z GRBs, GRB 080913 at z = 6.7 and 090423 8.1, more than four years Swift observations, we first confirm that does not trace SFR in unbiased way. Correcting for this, find implied beyond 8 is consistent with LBG-based measurements after accounting unseen galaxies faint end UV luminosity function. We show...
ASASSN-14ae is a candidate tidal disruption event (TDE) found at the center of SDSS J110840.11+340552.2 ($d\simeq200$~Mpc) by All-Sky Automated Survey for Supernovae (ASAS-SN). We present ground-based and Swift follow-up photometric spectroscopic observations source, finding that transient had peak luminosity $L\simeq8\times10^{43}$~erg~s$^{-1}$ total integrated energy $E\simeq1.7\times10^{50}$ ergs radiated over $\sim5$ months presented. The blackbody temperature remains roughly constant...
We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as most luminous supernova yet found. At redshift z = 0.2326, reached an absolute magnitude M_{u,AB} -23.5+/-0.1 and bolometric luminosity L_bol (2.2+/-0.2)x 10^45 ergs s^-1, is more than twice any previously known supernova. It has several major features characteristic hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources progenitors are currently poorly understood. In contrast to SLSNe-I that reside in...
The sensitivity of the Deep Underground Neutrino Experiment (DUNE) to neutrino oscillation is determined, based on a full simulation, reconstruction, and event selection far detector simulation parameterized analysis near detector. Detailed uncertainties due flux prediction, interaction model, effects are included. DUNE will resolve mass ordering precision 5$\sigma$, for all $\delta_{\mathrm{CP}}$ values, after 2 years running with nominal design beam configuration. It has potential observe...
Weakly interacting massive particles (WIMPs) have long reigned as one of the leading classes dark matter candidates. The observed abundance can be naturally obtained by freezeout weak-scale annihilations in early Universe. This ``thermal WIMP'' scenario makes direct predictions for total annihilation cross section that tested present-day experiments. While mass constraint high ${m}_{\ensuremath{\chi}}\ensuremath{\gtrsim}100\text{ }\text{ }\mathrm{GeV}$ particular channels, on has not been...
The Deep Underground Neutrino Experiment (DUNE) is an international, world-class experiment aimed at exploring fundamental questions about the universe that are forefront of astrophysics and particle physics research. DUNE will study pertaining to preponderance matter over antimatter in early universe, dynamics supernovae, subtleties neutrino interaction physics, a number beyond Standard Model topics accessible powerful beam. A critical component program involves changes beam neutrinos,...
The preponderance of matter over antimatter in the early universe, dynamics supernovae that produced heavy elements necessary for life, and whether protons eventually decay—these mysteries at forefront particle physics astrophysics are key to understanding evolution our its current state, eventual fate. DUNE is an international world-class experiment dedicated addressing these questions as it searches leptonic charge-parity symmetry violation, stands ready capture supernova neutrino bursts,...
The Deep Underground Neutrino Experiment (DUNE), a 40-kton underground liquid argon time projection chamber experiment, will be sensitive to the electron-neutrino flavor component of burst neutrinos expected from next Galactic core-collapse supernova. Such an observation bring unique insight into astrophysics core collapse as well properties neutrinos. general capabilities DUNE for neutrino detection in relevant few- few-tens-of-MeV energy range described. As example, DUNE's ability...
We give an overview and describe the rationale, methods, first results from NIRCam images of JWST "Prime Extragalactic Areas for Reionization Lensing Science" ("PEARLS") project. PEARLS uses up to eight filters survey several prime extragalactic areas: two fields at North Ecliptic Pole (NEP); seven gravitationally lensing clusters; high redshift proto-clusters; iconic backlit VV 191 galaxy system map its dust attenuation. also includes NIRISS spectra one NEP NIRSpec high-redshift quasars....
We present two complementary NuSTAR x-ray searches for keV-scale dark matter decaying to mono-energetic photons in the Milky Way halo. In first, we utilize known intensity pattern of unfocused stray light across detector planes -- dominant source from diffuse sources separate astrophysical emission internal instrument backgrounds using ${\sim}$7-Ms/detector deep blank-sky exposures. second, an updated parametric model full background, allowing us leverage statistical power independent...
Extragalactic transient searches have historically been limited to looking for the appearance of new sources such as supernovae. It is now possible carry out a kind survey that will do opposite, is, search disappearance massive stars. This entail systematic observation galaxies within distance 10 Mpc in order watch ~106 supergiants. Reaching this critical number ensures something occur yearly, since these stars must end their lives with core collapse yr. Using deep imaging and image...
We identify a "supernova rate problem": the measured cosmic core-collapse supernova is factor of ~ 2 smaller (with significance sigma) than that predicted from massive-star formation rate. The comparison critical for topics galaxy evolution and enrichment to abundance neutron stars black holes. systematically explore possible resolutions. accuracy precision star data conversion are well supported, proposed changes would have far-reaching consequences. dominant effect likely many supernovae...
We discuss the prospects for next generation neutrino telescopes, such as IceCube, to measure flavor ratios of high-energy astrophysical neutrinos. The expected at sources are ${\ensuremath{\varphi}}_{{\ensuremath{\nu}}_{e}}:{\ensuremath{\varphi}}_{{\ensuremath{\nu}}_{\ensuremath{\mu}}}:{\ensuremath{\varphi}}_{{\ensuremath{\nu}}_{\ensuremath{\tau}}}=1:2:0,$ and oscillations quickly transform these $1:1:1.$ can be deduced from relative rates showers $({\ensuremath{\nu}}_{e}$ charged current,...
Existing limits on the nonradiative decay of one neutrino to another plus a massless particle (e.g., singlet Majoron) are very weak. The best lifetime mass ratio come from solar observations and tau/m greater, similar 10(-4) s/eV for relevant eigenstate(s). For lifetimes even several orders magnitude longer, high-energy neutrinos distant astrophysical sources would decay. This strongly alter flavor ratios phi(nu(e)):phi(nu(mu)):phi(nu(tau))=1:1:1 expected oscillations alone should be readily...