News and Events

Linda Cabrales
Please join us for a colloquium titled “Beyond Academia – Opportunities to turn your next idea or research project into a business” at 12:00 PM in C215 ESC.
Thumbnail of Odysseus and The Dish
Murriyang, the CSIRO’s Parkes radio telescope points toward a nearly Full Moon in this image from New South Wales, Australia, planet Earth. Bathed in moonlight, the 64 meter dish is receiving weak radio signals from Odysseus, following the robotic lander's February 22 touch down some 300 kilometers north of the Moon's south pole. The landing of Odysseus represents the first U.S. landing on the Moon since the Apollo 17 mission in 1972. Odysseus' tilted orientation on the lunar surface prevents its high-gain antenna from pointing toward Earth. But the sensitivity of the large, steerable Parkes dish significantly improved the reception of data from the experiments delivered to the lunar surface by the robotic moon lander. Of course the Parkes Radio Telescope dish became famous for its superior lunar television reception during the Apollo 11 mission in 1969, allowing denizens of planet Earth to watch the first moonwalk.
Mount Timpanogos with sky above
Check current conditions and historical weather data at the ESC.
Image for 2024 Student Research Conference
The 2024 SRC will be held on February 24. Abstracts are due January 26. Come present your research, compete for prizes, and have a pizza lunch.
Image for BYU Women in Physics Students Thrive at CUWiP
Conference for Undergraduate Women in Physics provides support and opportunities for female BYU physics students
Image for New Faculty Member, Dr. Micah Shepherd
Dr. Micah Shepherd, Acoustic Physicist, joins faculty

Selected Publications

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BYU Authors: M D Joner, M Holland, J Jensen, and D Watts, published in Mon. Not. Roy. Astron. Soc.

In 2022 the BL Lac object S4 0954+65 underwent a major variability phase, reaching its historical maximum brightness in the optical and γ-ray bands. We present optical photometric and polarimetric data acquired by the Whole Earth Blazar Telescope (WEBT) Collaboration from 2022 April 6 to July 6. Many episodes of unprecedented fast variability were detected, implying an upper limit to the size of the emitting region as low as 10−4 parsec. The WEBT data show rapid variability in both the degree and angle of polarization. We analyse different models to explain the polarization behaviour in the framework of a twisting jet model, which assumes that the long-term trend of the flux is produced by variations in the emitting region viewing angle. All the models can reproduce the average trend of the polarization degree, and can account for its general anticorrelation with the flux, but the dispersion of the data requires the presence of intrinsic mechanisms, such as turbulence, shocks, or magnetic reconnection. The WEBT optical data are compared to γ-ray data from the Fermi satellite. These are analysed with both fixed and adaptive binning procedures. We show that the strong correlation between optical and γ-ray data without measurable delay assumes different slopes in faint and high brightness states, and this is compatible with a scenario where in faint states we mainly see the imprint of the geometrical effects, while in bright states the synchrotron self-Compton process dominates.

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BYU Authors: Jeffrey Taggart Durrant, Mark C. Anderson, Michael S. Bassett, Kent L. Gee, and Grant W. Hart, published in Proc. Meet. Acoust.

The last two years have seen more orbital rocket launches than any period in history, exposing launch pads, natural environments, and communities to large acoustical loads. This paper is part of an ongoing effort by BYU to disseminate the results of acoustical measurements of these launch vehicles. Specifically, this paper summarizes BYU’s measurement and analysis of the Falcon-9 SARah-1 launch and landing out of Vandenberg Space Force Base in June 2022. This measurement differs from typical launch measurements due to the sonic boom created by the reentry and landing of the first-stage booster. In total, 9 measurement stations were set up at locations between 400 m and 15000 m from the launch pad, and each station successfully recorded the launch noise and reentry sonic boom. Several metrics are reported for both the launch and sonic boom at each station and compared with a previous measurement. Additionally, spectral analysis shows the sonic booms to peak at a lower frequency than the launch noise, and that they spread cylindrically rather than spherically. No evidence is found of a decrease in peak frequency at stations farther from the pad.

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BYU Authors: Joshua Vawdrey, published in Proc. SPIE

The optical edges of a starshade define its outermost perimeter. During astronomical measurements, the edges are exposed to sunlight resulting in glint seen by the telescope. Clean, sharply etched edges are capable of meeting the stringent solar glint scatter requirement. We report on the increased glint that arises from particulate contamination clinging to the edges. We measure the relationship between surface contamination and edge contamination and compare to a simple edge contaminant population model where the edge acts like a line drawn across the continuous surface. We correlate the level of edge contamination to the degree of increased scatter and derive an on-orbit contamination requirement that is compatible with the detection of exo-Earths.

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BYU Authors: Taylor J. Buckway, Aaron Redd, Devin Lewis, Joshua Vawdrey, Karine Chesnel, David Allred, and Richard L. Sandberg, published in Proc. SPIE

Tabletop extreme ultraviolet (EUV) sources based on high harmonic generation (HHG) have been used as a powerful tool for probing magnetism. Obtaining magnetic information via magneto-optical contrast often requires the energy of the light to be tuned to magnetic resonance energies of the magnetic element present in the material; therefore, it is essential to calibrate the HHG spectrum to well defined absorption energies of materials. We have designed and assembled a HHG based EUV source for studying transition metal magnetic materials at their resonant M-absorption edges (35-75 eV of photon energy). One material of interest is iron, for which the iron M2,3 edge is 52.7 eV (23.5 nm wavelength) according to CXRO. We prepared and characterized a thin sample of iron for absorption spectroscopy and calibration of the absorption edge with beamline 6.3.2 at the Advance Light Source (ALS) in Lawrence Berkeley National Laboratory. This well characterized sample was capped with gold to prevent oxidation. From these measurements we extracted the absorption part of the index of refraction β spectrally and confirmed that the absorption edge of iron is 52.7 eV. With this information, we can better calibrate the HHG spectrum of our tabletop EUV source. Calibration of the HHG spectrum was achieved using model fitting the HHG spectrum using the grating equation and law of cosines while taking account into the results of the ALS data. We have determined that driving wavelength of the HHG process to be 773 nm. We also conclude that the chirp of the driving laser pulse can cause an energy shift to a HHG spectrum.

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BYU Authors: Joshua J. Vawdrey and David D. Allred, published in Proc. SPIE

First Contact (FC) Polymer™, developed by Photonic Cleaning Technologies, is used to clean and protect surfaces from contamination. The polymer creates a peelable coating that renders the surface clean while not leaving visible residues. To investigate the effectiveness of FC at the subnanometer level, we used variable-angle, spectroscopic ellipsometry (VASE) to measure sample top-layer thickness after repeated application/storage/removal cycles of standard (red) FC with three sample sets (CVD Si3N4 on Si, bare Si, and SiO2 on Si). The samples were measured via VASE after every FC removal to understand contaminant thickness changes with “peel-off” count. Control samples were also measured at each iteration. Ellipsometric analysis revealed FC removed, during the first peel-off, impurity from the surface of samples treated with impure isopropyl alcohol. Linear regressions and t-tests comparing samples with and without FC were employed for evaluating changes with peel-off counts. There is evidence for the very slight build-up of material which is not removed by iterative FC application/removal cycles on these samples. It is slight, <0.1 nm after 17 iterations, in the case of native oxide on Si.

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BYU Authors: Moriah F. Garate, Carson K. Chandler, Adam H. Bennion, Clark R. Snelgrove, and Tracianne B. Neilsen, published in Phys. Teach.