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We report on our plans to upgrade the detector systems in the 2022–2024 time frame for three of the workhorse instruments (NIRC2, DEIMOS, and NIRES) operated by the W. M. Keck Observatory. The upgrades are done in collaboration with Observatory partner institutions and other Maunakea observatories. The main motivating factors behind these upgrades are to tackle obsolescence of hardware and software components, to boost observing efficiency, to enhance the instrument throughput, and to add new observing functionality. 

Abstract. Western US wildlands experience frequent and large-scale wildfires which arepredicted to increase in the future. As a result, wildfire smoke emissionsare expected to play an increasing role in atmospheric chemistry whilenegatively impacting regional air quality and human health. Understanding theimpacts of smoke on the environment is informed by identifying andquantifying the chemical compounds that are emitted during wildfires and byproviding empirical relationships that describe how the amount andcomposition of the emissions change based upon different fire conditions andfuels. This study examined particulate organic compounds emitted from burningcommon western US wildland fuels at the US Forest Service Fire ScienceLaboratory. Thousands of intermediate and semi-volatile organic compounds(I/SVOCs) were separated and quantified into fire-integrated emission factors(EFs) using a thermal desorption, two-dimensional gas chromatograph withonline derivatization coupled to an electron ionization/vacuum ultraviolethigh-resolution time-of-flight mass spectrometer(TD-GC × GC-EI/VUV-HRToFMS). Mass spectra, EFs as a function ofmodified combustion efficiency (MCE), fuel source, and other definingcharacteristics for the separated compounds are provided in the accompanyingmass spectral library. Results show that EFs for total organic carbon (OC),chemical families of I/SVOCs, and most individual I/SVOCs span 2–5 orders ofmagnitude, with higher EFs at smoldering conditions (low MCE) than flaming.Logarithmic fits applied to the observations showed that log (EFs) forparticulate organic compounds were inversely proportional to MCE. Thesemeasurements and relationships provide useful estimates of EFs for OC,elemental carbon (EC), organic chemical families, and individual I/SVOCs as afunction of fire conditions. 

Abstract Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counterintuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfvén waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold,α= 2 as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed >600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: preflare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine thatα= 1.63 ± 0.03. This is below the critical threshold, suggesting that Alfvén waves are an important driver of coronal heating.