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1. The MOSFIRE Deep Evolution Field Survey: Implications of the Lack of Evolution in the Dust Attenuation–Mass Relation to z ∼ 2*

   https://doi.org/10.3847/1538-4357/ac4742  

   Shapley, Alice E. ; Sanders, Ryan L. ; Salim, Samir ; Reddy, Naveen A. ; Kriek, Mariska ; Mobasher, Bahram ; Coil, Alison L. ; Siana, Brian ; Price, Sedona H. ; Shivaei, Irene ; et al ( February 2022 , The Astrophysical Journal)

   We investigate the relationship between dust attenuation and stellar mass (M_*) in star-forming galaxies over cosmic time. For this analysis, we compare measurements from the MOSFIRE Deep Evolution Field survey atz∼ 2.3 and the Sloan Digital Sky Survey (SDSS) atz∼ 0, augmenting the latter optical data set with both UV Galaxy Evolution Explorer (GALEX) and mid-infrared Wide-field Infrared Survey Explorer (WISE) photometry from the GALEX-SDSS-WISE Catalog. We quantify dust attenuation using both spectroscopic measurements of Hαand Hβemission lines, and photometric measurements of the rest-UV stellar continuum. The Hα/Hβratio is used to determine the magnitude of attenuation at the wavelength of Hα,A_Hα. Rest-UV colors and spectral energy distribution fitting are used to estimateA₁₆₀₀, the magnitude of attenuation at a rest wavelength of 1600 Å. As in previous work, we find a lack of significant evolution in the relation between dust attenuation andM_*over the redshift rangez∼ 0 toz∼ 2.3. Folding in the latest estimates of the evolution ofM_dust, (M_dust/M_gas), and gas surface density at fixedM_*, we find that the expectedM_dustand dust mass surface density are both significantly higher atz∼ 2.3 than atz∼ 0. These differences appear at odds with the lack of evolution in dust attenuation. To explain the striking constancy in attenuation versusM_*, it is essential to determine the relationship between metallicity and (M_dust/M_gas), the dust mass absorption coefficient and dust geometry, and the evolution of these relations and quantities fromz∼ 0 toz∼ 2.3.

    

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2. An Updated Dust-to-Star Geometry: Dust Attenuation Does Not Depend on Inclination in 1.3 ≤z ≤2.6 Star-forming Galaxies from MOSDEF

   https://doi.org/10.3847/1538-4357/accdd1  

   Lorenz, Brian ; Kriek, Mariska ; Shapley, Alice E. ; Reddy, Naveen A. ; Sanders, Ryan L. ; Barro, Guillermo ; Coil, Alison L. ; Mobasher, Bahram ; Price, Sedona H. ; Runco, Jordan N. ; et al ( June 2023 , The Astrophysical Journal)

   We investigate dust attenuation and its dependence on viewing angle for 308 star-forming galaxies at 1.3 ≤z≤ 2.6 from the MOSFIRE Deep Evolution Field survey. We divide galaxies with a detected Hαemission line and coverage of Hβinto eight groups by stellar mass, star formation rate (SFR), and inclination (i.e., axis ratio), and we then stack their spectra. From each stack, we measure the Balmer decrement and gas-phase metallicity, and then we compute the medianA_Vand UV continuum spectral slope (β). First, we find that none of the dust properties (Balmer decrement,A_V, orβ) varies with the axis ratio. Second, both stellar and nebular attenuation increase with increasing galaxy mass, showing little residual dependence on SFR or metallicity. Third, nebular emission is more attenuated than stellar emission, and this difference grows even larger at higher galaxy masses and SFRs. Based on these results, we propose a three-component dust model in which attenuation predominantly occurs in star-forming regions and large, dusty star-forming clumps, with minimal attenuation in the diffuse ISM. In this model, nebular attenuation primarily originates in clumps, while stellar attenuation is dominated by star-forming regions. Clumps become larger and more common with increasing galaxy mass, creating the above mass trends. Finally, we argue that a fixed metal yield naturally leads to mass regulating dust attenuation. Infall of low-metallicity gas increases the SFR and lowers the metallicity, but leaves the dust column density mostly unchanged. We quantify this idea using the Kennicutt–Schmidt and fundamental metallicity relations, showing that galaxy mass is indeed the primary driver of dust attenuation.

    

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3. High-redshift JWST predictions from IllustrisTNG: dust modelling and galaxy luminosity functions

   https://doi.org/10.1093/mnras/staa137  

   Vogelsberger, Mark ; Nelson, Dylan ; Pillepich, Annalisa ; Shen, Xuejian ; Marinacci, Federico ; Springel, Volker ; Pakmor, Rüdiger ; Tacchella, Sandro ; Weinberger, Rainer ; Torrey, Paul ; et al ( March 2020 , Monthly Notices of the Royal Astronomical Society)

   ABSTRACT The James Webb Space Telescope (JWST) promises to revolutionize our understanding of the early Universe, and contrasting its upcoming observations with predictions of the Λ cold dark matter model requires detailed theoretical forecasts. Here, we exploit the large dynamic range of the IllustrisTNG simulation suite, TNG50, TNG100, and TNG300, to derive multiband galaxy luminosity functions from z = 2 to z = 10. We put particular emphasis on the exploration of different dust attenuation models to determine galaxy luminosity functions for the rest-frame ultraviolet (UV), and apparent wide NIRCam bands. Our most detailed dust model is based on continuum Monte Carlo radiative transfer calculations employing observationally calibrated dust properties. This calibration results in constraints on the redshift evolution of the dust attenuation normalization and dust-to-metal ratios yielding a stronger redshift evolution of the attenuation normalization compared to most previous theoretical studies. Overall we find good agreement between the rest-frame UV luminosity functions and observational data for all redshifts, also beyond the regimes used for the dust model calibrations. Furthermore, we also recover the observed high-redshift (z = 4–6) UV luminosity versus stellar mass relation, the H α versus star formation rate relation, and the H α luminosity function at z = 2. The bright end (MUV > −19.5) cumulative galaxy number densities are consistent with observational data. For the F200W NIRCam band, we predict that JWST will detect ∼80 (∼200) galaxies with a signal-to-noise ratio of 10 (5) within the NIRCam field of view, $2.2\times 2.2 \, {\rm arcmin}^{2}$, for a total exposure time of $10^5\, {\rm s}$ in the redshift range z = 8 ± 0.5. These numbers drop to ∼10 (∼40) for an exposure time of $10^4\, {\rm s}$. 

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4. The dust-to-gas mass ratio of luminous galaxies as a function of their metallicity at cosmic noon

   Popping, Gergö ; Shivaei, Irene ; Sanders, Ryan L. ; Jones, Tucker ; Pope, Alexandra ; Reddy, Naveen A. ; Shapley, Alice E. ; Coil, Alison L. ; Kriek, Mariska ( February 2023 , Astronomy & Astrophysics)

   Aims. We aim to quantify the relation between the dust-to-gas mass ratio (DTG) and gas-phase metallicity of z  = 2.1 − 2.5 luminous galaxies and contrast this high-redshift relation against analogous constraints at z  = 0. Methods. We present a sample of ten star-forming main-sequence galaxies in the redshift range 2.1 <  z  < 2.5 with rest-optical emission-line information available from the MOSDEF survey and with ALMA 1.2 millimetre and CO J  = 3 − 2 follow-up observations. The galaxies have stellar masses ranging from 10 10.3 to 10 10.6   M ⊙ and cover a range in star-formation rate from 35 to 145 M ⊙ yr −1 . We calculated the gas-phase oxygen abundance of these galaxies from rest-optical nebular emission lines (8.4 < 12 + log(O/H) < 8.8, corresponding to 0.5−1.25 Z ⊙ ). We estimated the dust and H 2 masses of the galaxies (using a metallicity-dependent CO-to-H 2 conversion factor) from the 1.2 mm and CO J  = 3 − 2 observations, respectively, from which we estimated a DTG. Results. We find that the galaxies in this sample follow the trends already observed between CO line luminosity and dust-continuum luminosity from z  = 0 to z  = 3, extending such trends to fainter galaxies at 2.1 <  z  < 2.5 than observed to date. We find no second-order metallicity dependence in the CO – dust-continuum luminosity relation for the galaxies presented in this work. The DTGs of main-sequence galaxies at 2.1 <  z  < 2.5 are consistent with an increase in the DTG with gas-phase metallicity. The metallicity dependence of the DTG is driven by the metallicity dependence of the CO-to-H 2 conversion factor. Galaxies at z  = 2.1 − 2.5 are furthermore consistent with the DTG-metallicity relation found at z  = 0 (i.e. with no significant evolution), providing relevant constraints for galaxy formation models. These results furthermore imply that the metallicity of galaxies should be taken into account when estimating cold-gas masses from dust-continuum emission, which is especially relevant when studying metal-poor low-mass or high-redshift galaxies. 

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5. Introducing the thesan project: radiation-magnetohydrodynamic simulations of the epoch of reionization

   https://doi.org/10.1093/mnras/stab3710  

   Kannan, R. ; Garaldi, E. ; Smith, A. ; Pakmor, R. ; Springel, V. ; Vogelsberger, M. ; Hernquist, L. ( December 2021 , Monthly Notices of the Royal Astronomical Society)

   We introduce the thesan project, a suite of large volume ($L_\mathrm{box} = 95.5 \, \mathrm{cMpc}$) radiation-magnetohydrodynamic simulations that simultaneously model the large-scale statistical properties of the intergalactic medium during reionization and the resolved characteristics of the galaxies responsible for it. The flagship simulation has dark matter and baryonic mass resolutions of $3.1 \times 10^6\, {\rm M_\odot }$ and $5.8 \times 10^5\, {\rm M_\odot }$, respectively. The gravitational forces are softened on scales of 2.2 ckpc with the smallest cell sizes reaching 10 pc at z = 5.5, enabling predictions down to the atomic cooling limit. The simulations use an efficient radiation hydrodynamics solver (arepo-rt) that precisely captures the interaction between ionizing photons and gas, coupled to well-tested galaxy formation (IllustrisTNG) and dust models to accurately predict the properties of galaxies. Through a complementary set of medium resolution simulations we investigate the changes to reionization introduced by different assumptions for ionizing escape fractions, varying dark matter models, and numerical convergence. The fiducial simulation and model variations are calibrated to produce realistic reionization histories that match the observed evolution of the global neutral hydrogen fraction and electron scattering optical depth to reionization. They also match a wealth of high-redshift observationally inferred data, including the stellar-to-halo-mass relation, galaxy stellar mass function, star formation rate density, and the mass–metallicity relation, despite the galaxy formation model being mainly calibrated at z = 0. We demonstrate that different reionization models give rise to varied bubble size distributions that imprint unique signatures on the 21 cm emission, especially on the slope of the power spectrum at large spatial scales, enabling current and upcoming 21 cm experiments to accurately characterize the sources that dominate the ionizing photon budget.

    

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