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  1. Free, publicly-accessible full text available April 1, 2025
  2. ABSTRACT Recent works have suggested that energy balance spectral energy distribution (SED) fitting codes may be of limited use for studying high-redshift galaxies for which the observed ultraviolet and far-infrared emission are offset (spatially ‘decoupled’). It has been proposed that such offsets could lead energy balance codes to miscalculate the overall energetics, preventing them from recovering such galaxies’ true properties. In this work, we test how well the SED fitting code magphys can recover the stellar mass, star formation rate (SFR), specific SFR, dust mass, and luminosity by fitting 6706 synthetic SEDs generated from four zoom-in simulations of dusty, high-redshift galaxies from the FIRE project via dust continuum radiative transfer. Comparing our panchromatic results (using wavelengths 0.4–500 μm, and spanning 1 < z < 8) with fits based on either the starlight ($\lambda _\mathrm{eff} \le 2.2\, \mu$m) or dust ($\ge 100\, \mu$m) alone, we highlight the power of considering the full range of multiwavelength data alongside an energy balance criterion. Overall, we obtain acceptable fits for 83 per cent of the synthetic SEDs, though the success rate falls rapidly beyond z ≈ 4, in part due to the sparser sampling of the priors at earlier times since SFHs must be physically plausible (i.e. shorter than the age of the universe). We use the ground truth from the simulations to show that when the quality of fit is acceptable, the fidelity of magphys estimates is independent of the degree of UV/FIR offset, with performance very similar to that previously reported for local galaxies. 
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  3. Abstract

    We present cosmological analysis of 12 nearby (z< 0.06) Type IIP supernovae (SNe IIP) observed with the ROTSE-IIIb telescope. To achieve precise photometry, we present a new image-differencing technique that is implemented for the first time on the ROTSE SN photometry pipeline. With this method, we find up to a 20% increase in the detection efficiency and significant reduction in residual rms scatter of the SN lightcurves when compared to the previous pipeline performance. We use the published optical spectra and broadband photometry of well-studied SNe IIP to establish temporal models for ejecta velocity and photospheric temperature evolution for our SNe IIP population. This study yields measurements that are competitive with other methods even when the data are limited to a single epoch during the photospheric phase of SNe IIP. Using the fully reduced ROTSE photometry and optical spectra, we apply these models to the respective photometric epochs for each SN in the ROTSE IIP sample. This facilitates the use of the Expanding Photosphere Method (EPM) to obtain distance estimates to their respective host galaxies. We then perform cosmological parameter fitting using these EPM distances, from which we measure the Hubble constant to be72.94.3+5.7kms1Mpc1, which is consistent with the standard ΛCDM model values derived using other independent techniques.

     
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  4. Abstract

    Fluvial erosion of cohesive soil is mediated by interactions between soil physical, biological, and chemical characteristics such as soil aggregate stability and extracellular polymeric substances (EPS). While labile organic matter (OM) stimulates microbial EPS production and significantly improves soil aggregate stability in agricultural soils, these interactions remain unexplored in streambank soils. The study goal was to quantify the impact of OM on aggregate stability, EPS, and fluvial erosion rates of cohesive streambank soil. Increasing amounts of 1‐mm sieved dry grass were incorporated at rates of 0, 1, and 4 g per 100 g of 2‐mm sieved silt‐loam soil (treatments T0, T1, and T4, respectively). Samples (eight replicates per treatment) were matured in a greenhouse for 50 days prior to flume erosion testing. EPS carbohydrates were significantly (p < 0.05) lower in T1 (324 ± 63 μg/g) compared to T0 (388 ± 37 μg/g) and T4 (376 ± 44 μg/g). EPS proteins were significantly higher in T1 (194 ± 15 μg/g) and T4 (223 ± 61 μg/g) compared to T0 (101 ± 20 μg/g) and positively correlated with mean weight diameter (MWD), a measure of soil stability against slaking. MWD was 16% and over 100% higher for T1 and T4, respectively, than for T0. Similarly, the average soil erodibility coefficient of T1 and T4 was 25% and 61% lower than the erodibility of T0; however, only the reduction for T4 was significant. The data presented here underscore the important role labile OM plays in improving soil physical stability and increasing the resistance of cohesive soil to fluvial erosion of streambanks.

     
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