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1. The ALPINE-ALMA [C  ii ] survey: Investigation of 10 galaxies at z ∼ 4.5 with [O  ii ] and [C  ii ] line emission − ISM properties and [O  ii ]−SFR relation

   https://doi.org/10.1093/mnras/stac071  

   Vanderhoof, Brittany N.; Faisst, A. L.; Shen, L.; Lemaux, B. C.; Béthermin, M.; Capak, P. L.; Cassata, P.; Le Fèvre, O.; Schaerer, D.; Silverman, J.; et al (January 2022, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We present 10 main-sequence ALPINE galaxies (log (M/M⊙) = 9.2−11.1 and $${\rm SFR}=23-190\, {\rm M_{\odot }\, yr^{-1}}$$) at z ∼ 4.5 with optical [O ii] measurements from Keck/MOSFIRE spectroscopy and Subaru/MOIRCS narrow-band imaging. This is the largest such multiwavelength sample at these redshifts, combining various measurements in the ultraviolet, optical, and far-infrared including [C ii]158 $$\mu$$m line emission and dust continuum from ALMA and H α emission from Spitzer photometry. For the first time, this unique sample allows us to analyse the relation between [O ii] and total star-formation rate (SFR) and the interstellar medium (ISM) properties via [O ii]/[C ii] and [O ii]/H α luminosity ratios at z ∼ 4.5. The [O ii]−SFR relation at z ∼ 4.5 cannot be described using standard local descriptions, but is consistent with a metal-dependent relation assuming metallicities around $$50{{\ \rm per\ cent}}$$ solar. To explain the measured dust-corrected luminosity ratios of $$\log (L_{\rm [OII]}/L_{\rm [CII]}) \sim 0.98^{+0.21}_{-0.22}$$ and $$\log (L_{\rm [OII]}/L_{\rm H\alpha }) \sim -0.22^{+0.13}_{-0.15}$$ for our sample, ionization parameters log (U) < −2 and electron densities $$\log (\rm n_e / {\rm [cm^{-3}]}) \sim 2.5-3$$ are required. The former is consistent with galaxies at z ∼ 2−3, however lower than at z > 6. The latter may be slightly higher than expected given the galaxies’ specific SFR. The analysis of this pilot sample suggests that typical log (M/M⊙) > 9 galaxies at z ∼ 4.5 to have broadly similar ISM properties as their descendants at z ∼ 2 and suggest a strong evolution of ISM properties since the epoch of reionization at z > 6. 

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2. The H α luminosity and stellar mass dependent clustering of star-forming galaxies at 0.7 < z < 1.5 with 3D- HST

   https://doi.org/10.1093/mnras/stac1889  

   Clontz, Callie; Wake, David; Zheng, Zheng (July 2022, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We present measurements of the dependence of the clustering amplitude of galaxies on their star formation rate (SFR) and stellar mass (M*) at 0.7 < z < 1.5 to assess the extent to which environment affects these properties. While these relations are well determined in the local Universe, they are much more poorly known at earlier times. For this analysis, we make use of the near-infrared HST WFC3 grism spectroscopic data in the five CANDELS fields obtained as part of the 3D-HST survey. We make projected two-point correlation function measurements using ∼6000 galaxies with accurate redshifts, M*, and H α luminosities. We find a strong dependence of clustering amplitude on H α luminosity and thus SFR. However, at fixed M*, the clustering dependence on H α luminosity is largely eliminated. We model the clustering of these galaxies within the halo occupation distribution framework using the conditional luminosity function model and the newly developed conditional stellar mass and H α luminosity distribution model. These show that galaxies with higher SFRs tend to live in higher mass haloes, but this is largely driven by the relationship between SFR and M*. Finally, we show that the small residual correlation between clustering amplitude and H α luminosity at fixed M* is likely being driven by a broadening of the SFR–M* relationship for satellite galaxies. 

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3. The MOSDEF survey: the dependence of H α-to-UV SFR ratios on SFR and size at z ∼ 2

   https://doi.org/10.1093/mnras/stab2570  

   Fetherolf, Tara; Reddy, Naveen A; Shapley, Alice E; Kriek, Mariska; Siana, Brian; Coil, Alison L; Mobasher, Bahram; Freeman, William R; Sanders, Ryan L; Price, Sedona H; et al (October 2021, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We perform an aperture-matched analysis of dust-corrected H α and UV star formation rates (SFRs) using 303 star-forming galaxies with spectroscopic redshifts 1.36 < zspec < 2.66 from the MOSFIRE Deep Evolution Field survey. By combining H α and H β emission line measurements with multiwaveband resolved Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey/3D-HST imaging, we directly compare dust-corrected H α and UV SFRs, inferred assuming a fixed attenuation curve shape and constant SFHs, within the spectroscopic aperture. Previous studies have found that H α and UV SFRs inferred with these assumptions generally agree for typical star-forming galaxies, but become increasingly discrepant for galaxies with higher SFRs (≳100 M⊙ yr−1), with H α-to-UV SFR ratios being larger for these galaxies. Our analysis shows that this trend persists even after carefully accounting for the apertures over which H α and UV-based SFRs (and the nebular and stellar continuum reddening) are derived. Furthermore, our results imply that H α SFRs may be higher in the centres of large galaxies (i.e. where there is coverage by the spectroscopic aperture) compared to their outskirts, which could be indicative of inside-out galaxy growth. Overall, we suggest that the persistent difference between nebular and stellar continuum reddening and high H α-to-UV SFR ratios at the centres of large galaxies may be indicative of a patchier distribution of dust in galaxies with high SFRs. 

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4. The ALPINE-ALMA [C II] survey: Little to no evolution in the [C II]–SFR relation over the last 13 Gyr

   https://doi.org/10.1051/0004-6361/202037617  

   Schaerer, D.; Ginolfi, M.; Béthermin, M.; Fudamoto, Y.; Oesch, P. A.; Le Fèvre, O.; Faisst, A.; Capak, P.; Cassata, P.; Silverman, J. D.; et al (November 2020, Astronomy & Astrophysics)

   The [C  II ] 158 μ m line is one of the strongest IR emission lines, which has been shown to trace the star formation rate (SFR) of galaxies in the nearby Universe, and up to z  ∼ 2. Whether this is also the case at higher redshift and in the early Universe remains debated. The ALPINE survey, which targeted 118 star-forming galaxies at 4.4 <   z  <  5.9, provides a new opportunity to examine this question with the first statistical dataset. Using the ALPINE data and earlier measurements from the literature, we examine the relation between the [C  II ] luminosity and the SFR over the entire redshift range from z  ∼ 4 − 8. ALPINE galaxies, which are both detected in [C  II ] and in dust continuum, show good agreement with the local L ([CII])–SFR relation. Galaxies undetected in the continuum by ALMA are found to be over-luminous in [C  II ] when the UV SFR is used. After accounting for dust-obscured star formation, by an amount of SFR(IR) ≈ SFR(UV) on average, which results from two different stacking methods and SED fitting, the ALPINE galaxies show an L ([CII])–SFR relation comparable to the local one. When [C  II ] non-detections are taken into account, the slope may be marginally steeper at high- z , although this is still somewhat uncertain. When compared homogeneously, the z  >  6 [C  II ] measurements (detections and upper limits) do not behave very differently to the z  ∼ 4 − 6 data. We find a weak dependence of L ([CII])/SFR on the Ly α equivalent width. Finally, we find that the ratio L ([CII])/ L IR ∼ (1 − 3) × 10 −3 for the ALPINE sources, comparable to that of “normal” galaxies at lower redshift. Our analysis, which includes the largest sample (∼150 galaxies) of [C  II ] measurements at z  > 4 available so far, suggests no or little evolution of the [C  II ]–SFR relation over the last 13 Gyr of cosmic time. 

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5. High-redshift JWST predictions from IllustrisTNG: II. Galaxy line and continuum spectral indices and dust attenuation curves

   https://doi.org/10.1093/mnras/staa1423  

   Shen, Xuejian; Vogelsberger, Mark; Nelson, Dylan; Pillepich, Annalisa; Tacchella, Sandro; Marinacci, Federico; Torrey, Paul; Hernquist, Lars; Springel, Volker (July 2020, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We present predictions for high redshift (z = 2−10) galaxy populations based on the IllustrisTNG simulation suite and a full Monte Carlo dust radiative transfer post-processing. Specifically, we discuss the H α and H β + $$[\rm O \,{\small III}]$$ luminosity functions up to z = 8. The predicted H β + $$[\rm O \,{\small III}]$$ luminosity functions are consistent with present observations at z ≲ 3 with $${\lesssim} 0.1\, {\rm dex}$$ differences in luminosities. However, the predicted H α luminosity function is $${\sim }0.3\, {\rm dex}$$ dimmer than the observed one at z ≃ 2. Furthermore, we explore continuum spectral indices, the Balmer break at 4000 Å; (D4000) and the UV continuum slope β. The median D4000 versus specific star formation rate relation predicted at z = 2 is in agreement with the local calibration despite a different distribution pattern of galaxies in this plane. In addition, we reproduce the observed AUV versus β relation and explore its dependence on galaxy stellar mass, providing an explanation for the observed complexity of this relation. We also find a deficiency in heavily attenuated, UV red galaxies in the simulations. Finally, we provide predictions for the dust attenuation curves of galaxies at z = 2−6 and investigate their dependence on galaxy colours and stellar masses. The attenuation curves are steeper in galaxies at higher redshifts, with bluer colours, or with lower stellar masses. We attribute these predicted trends to dust geometry. Overall, our results are consistent with present observations of high-redshift galaxies. Future James Webb Space Telecope observations will further test these predictions. 

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