Formation Rate Research Articles

High resolution water emission from nitromethane combustion under high pressure mono- and bipropellant conditions

Optical emission spectroscopy was used to measure rovibrationally resolved spectra of water formed during nitromethane combustion at elevated pressures in both oxidizing and inert atmospheres. Complementary kinetic models were used to predict flame temperatures, product distributions, and product formation rates, and results were compared with experimental observations. Experiments were carried out at pressures of 27.4 bar and 34.2 bar in inert atmospheres (referred to as monopropellant conditions) and air (referred to as bipropellant conditions). Dispersed emission shows many rovibrational transitions with the strongest occurring between 13,000 and 14,500 cm−1. These lines are primarily assigned to the relaxation from water's (3,0,1) vibrationally excited state to its vibrational ground state. Weaker progressions in this same region are assigned to water relaxation from the (1,0,3) and (2,2,1) vibrationally excited states. Data collected under mono- and bipropellant conditions showed very similar relative intensities of individual rovibrational lines. The spectra were fit using a simulated temperature of 2,500 K ± 500 K for both mono- and bipropellant conditions. Ex situ FTIR spectra of NM exhaust confirms the presence of H2O in both mono- and bipropellant combustion. Interestingly, analyses of these same spectra also show significant amounts of CO in monopropellant exhaust, but no detected CO in bipropellant exhaust. These latter findings show higher CO/CO2 concentration ratios compared to simulations, motivating the need for refined models describing nitromethane monopropellant combustion.

Evolution of Sequence Stratigraphy and Paleogeography, Case Study: M2 Member of the Muara Enim Formation

Sequence stratigraphy related to accommodation space as an area of potential sediment accumulation that is influenced by fluctuations in sea level and subsidence of the basin floor. Paleogeography, on the other hand, is the study of physical geographic features and their evolution throughout geological periods. The aim of this work is to shed light on the relationship between paleogeographic evolution and sequence stratigraphy, as well as coal accumulation in the South Sumatra Basin. The method used are geophysical logs and cores analysis to determine the system tracts, types of system tracts, and stratigraphic sequences, lithofacies and sedimentary facies analysis, paleogeographic analysis using modified single-factor and multi-factor and them mapped using IDW as a geostatistical method. The results indicate that the study area comprises four system tracts, namely TST-1, HST-1, TST-2 and HST-2. In TST-1 and TST-2, the rate of peat formation is balanced with the rate of accommodation space formation, resulting in continuous and very thick coal accumulation. In HST-1 and HST-2, the rate of accommodation space formation exceeds the rate of peat formation, leading to continuous coal accumulation that is quite thick to very thick. Sequence 1 consists of lagoon and tidal/mouth/distal bar paleogeographic unit with sand/shale ratio range 0.217 to 0.247. Sequence 2 consists of lagoon paleogeographic units with sand/shale ratio range 0.046 to 0.05.

Finding Passive Galaxies in H i-MaNGA: The Impact of Star Formation Rate Indicator

H i-rich galaxies typically have high star formation rates (SFRs), but there exist interesting H i-rich and low star-forming galaxies. Previous work on a sample of these galaxies identified from H i-Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) (H i follow-up to the MaNGA survey) using an infrared indicator of specific-SFR (sSFR; namely W2 − W3 < 2) could find no single physical process to explain their unusual behavior. The method by which galaxies are identified as low sSFR may be important in this conclusion. In this Research Note, we explore how an H i-rich, low sSFR sample of H i-MaNGA galaxies differs using Hα, single stellar population, and ultraviolet estimators of SFR. We find that samples are statistically similar to each other so long as W2 − W3 < 2 is interpreted as corresponding to sSFR < 10−11.15 yr−1.

A molecular synergy of non-covalent interactions facilitated via theobromine modifying the self-assembly process of type I collagen

Type I Collagen is a multifunctional fibrous protein present significantly in the connective tissues. Generally, fibril formation process of an interstitial collagen begins with a triple helix alignment to form a pentafibril, which sequentially self-assembles into a microfibril. Typically, this sequential formation can be achieved under an in vitro condition as well by maintaining certain specific physiological parameters to mimic the interstitial microenvironment of collagen. The necessity to study such a kinetically driven process is due to its implications in template fabrication particularly as a scaffold to enhance the growth of specific stem cells or accelerating nanoparticle synthesis. Drawing inspiration from this, theobromine, a methylxanthine that contributes towards the hydrogen bond network via dimerization and stacking interaction was used as a small molecule in modifying the molecular level interactions of a self-assembled collagen. Initially, rheological studies revealed certain variations in the viscous properties of collagen on addition of theobromine. Turbidity assay showed an increase in the rate of fibril formation and its topographical changes were observed through the high-resolution scanning electron microscope. The stability and probable physico-chemical interactions between collagen and theobromine were comprehended from the vibrational frequency changes recorded using (FT-IR) (ATR) and conformational changes using Circular Dichroism (CD) studies. Our results show possible multibinding sites on theobromine, which would compete to bind with the polar and non-polar residues exposed over the monomeric surfaces of triple helix causing a local conformational fluctuation modifying protein-protein interaction.

Structural Ni0-Niδ+ Pair Sites for Highly Active Hydrogenation of Nitriles to Primary Amines.

Supported metal pair sites have sparked interest due to their tremendous potential as bifunctional catalysts. Here, we report the structural Ni0-Niδ+ pair sites constructed in a well-defined nanocrystal phase of Ni3P. These Ni0-Niδ+ pair sites exhibited a remarkable product formation rate of 123 molBA/molmetal/h for the hydrogenation of benzonitrile (BN) to benzylamine (BA). The heterogeneity of surface Ni atoms over the Ni3P crystal created two types of metal centers, Ni0 and Niδ+, with a specific spatial distance of 4-5 Å. The Ni0 site acted as the center for H2 activation, while the Niδ+ site served as the adsorption and activation center for the C ≡ N group. The highly efficient cooperation effect of Ni0-Niδ+ pair sites resulted in a TOF of 2915 h-1 in BN hydrogenation, which is 2.4 and 9.7 times higher than that over the mono-Ni0 and -Niδ+ sites, respectively.

A Survey of Galaxy Pairs in the SDSS Photometric Images based on Faster-RCNN

Galaxy pairs hold significant importance in understanding the evolution of galaxies, and the extensive search for a large sample of galaxy pairs is meaningful. In this article, we develop a deep learning-based approach for the search of galaxy pairs and conduct a comprehensive search on Sloan Digital Sky Survey (SDSS) images. In nine million photometric images, 17,965 physical galaxy pairs with spectral or photometric redshifts are detected. Four sets of results are provided, including physical pairs determined by two spectral redshifts, two photometric redshifts, one spectral redshift, and one photometric redshift, and visual irregular pairs that have no precise redshift information but can be inferred as physical galaxy pairs based on the morphological changes. Then their morphological and physical characteristics are explored, the redshifts of most targets are around 0.1, and as the redshift difference between two galaxies increases, the number of galaxy pairs gradually reduces. The distributions of star formation rate (SFR) are not the same for different morphologies of galaxy pairs, irregular pairs have higher SFR than the other three types, and statistics indicate that the SFR of galaxies depends on both nearby galaxies and internal properties. Color and stellar mass are also key properties of galaxies which can reflect the status of galaxy pairs. Compared to other surveys, a greater number of galaxy pair targets are detected, and this is also the first extensive detection of galaxy pairs in SDSS images using photometric redshifts. These galaxy pair samples can greatly aid in the study of galaxy evolution.

Application of the blastomere count variations "skip value" in the embryo AI assessment

Objective: To explore the correlation between blastomere count variations "skip value" which extracted from by time-lapse technology (TLT) combined with artificial intelligence (AI) and morphological features of in vitro fertilization (IVF) embryo, and to test its feasibility in clinical applications. Methods: This study was a diagnostic experiment (AI reassessment of embryo transferred patients), a total of 6 545 embryos from 1 226 patients who underwent IVF at the Women and Children's Hospital of Chongqing Medical University from December 2020 to December 2021 were retrospectively analyzed, of which 2 869 embryos were attempted to cultured to blastocyst stage by TLT. The embryo dynamic map (EDM) was drawn by Embryo Viewer, a TLT recording software, based on embryo developmental kinetics. The self-developed AI embryo evaluation software identified and recorded the number of cleavages in real time during embryonic development, and compared with the EDM, the correlation between the skip value formed by the change of cleavage sphere counts and the outcomes of the embryos was analyzed. The correlation among skip value, morphological score of embryo, implantation rate and live birth rate were performed by Spearman and step-up logistic regression. The receiver operating characteristic (ROC) curve was selected for reporting there relationship of skip value and morphology. Finally, predicting power of skip value for implantation and live birth rate were performed by ROC analysis. Results: The total skip values extracted from the blastomere count of embryos (72 hours post-fertilization) were negatively correlated with abnormal cleavage, blastocyst formation rate, day 3 (D3)-cell score, uneven size and fragmentation (the β values were -0.268, -0.116, -0.213, -0.159 and -0.222, respectively; all P<0.001); positively correlated with D3-cell number (β=0.034; P<0.001); negatively correlated with blastocyst formation rate and implantation rate (OR=0.97, 95%CI: 0.93-0.99, P=0.034; OR=0.96, 95%CI: 0.93-0.98, P=0.044). The power of predicting implantation were similar between the order selection of skip values and traditional morphology criteria [area under curve (AUC): 0.679 vs 0.620]. Live birth rate were negatively correlated with female age (OR=0.91, 95%CI: 0.88-0.93; P<0.001), D3 general score (OR=0.77, 95%CI: 0.59-0.99; P=0.045) and order selection of skip values (OR=0.98, 95%CI: 0.96-0.99; P=0.038), while positively correlated with retrieved oocyte number and endometrial thickness in embryo transferred (OR=1.08, 95%CI:1.05-1.11, P<0.001; OR=1.09, 95%CI:1.06-0.12, P<0.001, respectively) from multivariate regression analysis, and the power of predicting live birth was 0.666 for AUC. Conclusions: The skip value and its order form is a systematic quantification of embryo development, correlated with embryo developmental quality and clinical outcome. It could be an addition parameter for embryo culture and selection.

Hydrothermal carbon reduction in the absence of minerals

Abiotic synthesis of CH4 in seafloor hydrothermal fluids is generally assumed to occur via heterogeneous reactions on mineral surfaces. Stepwise homogeneous reduction of CO2 has, however, been suggested as an alternative (but sluggish) abiotic pathway to CH4, potentially via metastable species of intermediate oxidation states. In this study, we examine the effect of two temperature-dependent methylated species − methanol (CH3OH) and methanethiol (CH3SH), on homogeneous CH4 formation rates under long-term simulated hydrothermal conditions. Aqueous solutions containing formic acid (H13COOH, generating 13CO2 and H2) were heated with and without H2S at 300–325 °C (35 MPa) in a flexible Au reaction cell over several years without added minerals. Substantial 13C-labeled CH4 and CH3OH production from 13CO2 was observed over 4.3 yr, with aqueous CH4 formation varying with CH3OH abundance – a strong function of dissolved H2 abundance and, inversely, temperature. CH4 production was slower at 325 °C with lower CH3OH concentrations (in equilibrium with CO2 and H2), and faster at 300 °C, accompanying an equilibrium-controlled increase in CH3OH. Fastest CH4 production occurred at 300 °C following injection of H2S and H13COOH, which led to rapid formation (<4 days) of 13C-labeled CH3SH that subsequently decomposed over a further 0.8 yr, partly to 13CH4. Heating aqueous 13CH4 to 345–387 °C (33–35 MPa) in the presence of an oxidizing hematite-magnetite-pyrite assemblage, however, yielded no detectable CH3SH after 112 days indicating the reverse reaction is inhibited under favorable thermodynamics. Neither direct reduction of CO2 to CH3SH nor CO2-CH3SH equilibrium were evident at 300 °C, implying CH3SH and CH3OH play disparate roles in homogeneous carbon reduction to CH4. Longer chain hydrocarbons (C2+ alkanes) remained low throughout the experiments.CH3SH abundances previously reported in vent fluids at the Von Damm hydrothermal field correlate strongly with demonstrably abiotic HCOOH there, suggesting the reduction of HCOOH to CH3SH observed in this study may also occur in vent fluids. A comparison of mineral-free 13CH4 production rates reported here with 13CO2 reduction experiments involving minerals indicates that homogeneous reduction proceeds at similar rates to purported transition metal-catalyzed 13CH4 production, and is generally faster than experiments with either added olivine or ultramafic rock. Previous claims of substantial mineral-catalyzed abiogenic CH4 production are therefore not supported by our study. Homogeneous CO2 reduction may be a significant source of methylated compounds and CH4 in hydrothermal fluids characterized by decadal (or longer) residence times, such as those found in mineral-hosted inclusions or occluded fractures in igneous basement, requiring only moderate temperatures and abundant H2 to proceed.

Controlled incorporation of Zn into nitrogen-doped porous carbon boosts the alcohol dehydrogenation to carboxylic acids

The dehydrogenation of primary alcohols to carboxylic acids is a crucial process in chemical industries such as fibers and plastics. Carboxylic acids, the resulting products, are not only important chemical raw materials but also fundamental pharmaceutical intermediates. Zn-based catalysts have gained attention as a promising option for this transformation owing to their economic cost and abundant reserves. However, stability issues, including structure collapse and morphological changes, have plagued the reported Zn-based catalysts during this transformation. In response to these challenges, this study focused on the design and development of Zn-based catalysts via controlled incorporation of Zn into nitrogen-doped porous carbon to modulate the numbers of defects and Lewis acid-base site pairs. Through extensive screening of various parameters, the best-performing catalyst, namely Zn@NC-800, exhibited high activity and remarkable stability, surpassing all the reported Zn-based catalysts. Moreover, this catalyst demonstrated great recyclability since it could maintain approximately 90 % yields after 9 cycles. Notably, the product formation rate of this catalyst could reach 3833 μmol·gcat.−1·h−1, exceeding that of most reported non-noble metal heterogeneous catalysts. Consequently, this study offers a promising approach for efficiently and stably catalyzing alcohol dehydrogenation reactions using non-noble metals.

First Detection of CO Isotopologues in a High-redshift Main-sequence Galaxy: Evidence of a Top-heavy Stellar Initial Mass Function

Recent observations and theories have presented a strong challenge to the universality of the stellar initial mass function (IMF) in extreme environments. A notable example has been found for starburst conditions, where evidence favors a top-heavy IMF, i.e., there is a bias toward massive stars compared to the IMF that is responsible for the stellar mass function and elemental abundances observed in the Milky Way. Local starburst galaxies have star formation rates similar to those in high-redshift main-sequence galaxies, which appear to dominate the stellar mass budget at early epochs. However, the IMF of high-redshift main-sequence galaxies is yet to be probed. Since 13CO and C18O isotopologues are sensitive to the IMF, we have observed these lines toward four strongly lensed high-redshift main-sequence galaxies using the Atacama Large Millimeter/submillimeter Array. Of our four targets, SDSS J0901+1814, at z ≈ 2.26, is seen clearly in 13CO and C18O, the first detection of CO isotopologues in the high-redshift main-sequence galaxy population. The observed 13C/18O ratio, 2.4 ± 0.8, is significantly lower than that of local main-sequence galaxies. We estimate the isotope ratio, oxygen abundance, and stellar mass using a series of chemical evolution models with varying star formation histories and IMFs. All models favor an IMF that is more top-heavy than that of the Milky Way. Thus, as with starburst galaxies, main-sequence galaxies in the high-redshift Universe have a greater fraction of massive stars than a Milky Way IMF would imply.

Can we reach consensus on the dominant sulfate formation pathway in China's haze?

Atmospheric sulfate aerosols contribute significantly to air pollution and climate change. Sulfate formation mechanisms during winter haze events in northern China have recently received considerable attention, with more than 10 studies published in high-impact journals. However, the conclusions from in-field measurements, laboratory studies, and numerical simulations are inconsistent and even contradictory. Here, we propose a physically based yet simple method to clarify the debate on the dominant sulfate formation pathway. Based on the hazes evolving in the synoptic scale, first, a characteristic sulfate formation rate is derived using the Eulerian mass conservation equation constrained by in situ observations. Then, this characteristic value is treated as a guideline to determine the dominant sulfate formation pathway with a 0D chemical box model. Our observation-derived results establish a linkage between studies from laboratory experiments and chemical transport model simulations. A convergent understanding could therefore be reached on sulfate formation mechanisms in China's wintertime haze. This method is universal and can be applied to various haze conditions and different secondary products.

222 nm causes greater protein damage and repair inhibition of E. coli than 254 nm for water disinfection

Germicidal ultraviolet (UV) light has been widely used to inactivate pathogens in water. Emerging alternatives to conventional low pressure (LP) mercury lamps emitting at 254 nm, such as krypton chloride (KrCl) excimer lamps emitting at 222 nm, are gaining acceptance and popularity due to advantages in human safety and disinfection mechanisms. Cyclobutane pyrimidine dimer (CPD) formation kinetics and photolyase damage kinetics were quantified in E. coli for 222 nm and 254 nm UV. Molecular damage and cell regrowth were also quantified after UV irradiation under photorepair and dark repair incubation conditions using a standardized photorepair fluence response protocol. CPDs and photolyase were measured using enzyme linked immunosorbent assays (ELISA). A novel ELISA for photolyase was developed for this study. Culture-based log inactivation UV fluence responses were similar for 254 nm and 222 nm, with Geeraerd model estimates for rate constants of 1.18±0.09 and 1.24±0.08 cm2 mJ−1 for LP and KrCl lamps, respectively. Molecular UV fluence kinetics showed that the rate of CPD formation was greater by LP, but the rate of photolyase damage was greater by KrCl, as supported by the intercepts of repair kinetics. Compared to LP irradiated samples, KrCl irradiated samples exhibited less repair overall. For a given lamp, similar repair was observed between light and dark repair incubations. Percent reactivation rates with respect to photorepair fluence were (3.7±1.4)×10−5 and (–1.3±2.5)×10−5 cm2 mJ-1 for LP and KrCl lamps, respectively. CPDs decreased at a higher rate during repair incubations in LP samples than KrCl samples, and photolyase concentration increased in LP samples but decreased in KrCl samples. The results quantify contributions of photolyase protein damage to disinfection and repair prevention mechanism of KrCl lamps. This study mechanistically demonstrates why KrCl lamps can be applied for UV water disinfection to limit photorepair after treatment. Synopsis: This study used a novel photolyase assay to demonstrate photolyase damage inflicted by krypton chloride excimer lamps contributes to disinfection of bacteria to prevent bacterial photorepair of damaged DNA and regrowth in drinking water treatment.

Role of Direct and Sensitized Photolysis in the Photomineralization of Dissolved Organic Matter and Model Chromophores to Carbon Dioxide.

This study addresses the fundamental processes that drive the photomineralization of dissolved organic matter (DOM) to carbon dioxide (CO2), deconvoluting the role of direct and sensitized photolysis. Here, a suite of DOM isolates and model compounds were exposed to simulated sunlight in the presence of various physical and chemical quenchers to assess the magnitude, rate, and extent of direct and sensitized photomineralization to CO2. Results suggest that CO2 formation occurs in a biphasic kinetic system, with fast production occurring within the first 3 h, followed by slower production thereafter. Notably, phenol model chromophores were the highest CO2 formers and, when conjugated with carboxylic functional groups, exhibited a high efficiency for CO2 formation relative to absorbed light. Simple polycarboxylated aromatic compounds included in this study were shown to be resistant to photomineralization. Quencher results suggest that direct photolysis and excited triplet state sensitization may be largely responsible for CO2 photoproduction in DOM, while singlet oxygen and hydroxyl radical sensitization may play a limited role. After 3 h of irradiation, the CO2 formation rate significantly decreased, and the role of sensitized reactions in CO2 formation increased. Together, the results from this study advance the understanding of the fundamental reactions driving DOM photomineralization to CO2, which is an important part of the global carbon cycle.

The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). VI. The High-mass Stellar Initial Mass Function of M33

We measure the high-mass stellar initial mass function (IMF) from resolved stars in M33 young stellar clusters. Leveraging the Hubble Space Telescope’s high resolving power, we fully model the IMF probabilistically. We first model the optical color–magnitude diagram of each cluster to constrain its power-law slope Γ, marginalized over other cluster parameters in the fit (e.g., cluster age, mass, and radius). We then probabilistically model the distribution of mass function (MF) slopes for a highly strict cluster sample of nine clusters more massive than log(Mass/M ⊙) = 3.6; above this mass, all clusters have well-populated main sequences of massive stars and should have accurate recovery of their MF slopes, based on extensive tests with artificial clusters. We find that the ensemble IMF is best described by a mean high-mass slope of Γ¯=1.49±0.18 , with an intrinsic scatter of σΓ2=0.020.00+0.16 , consistent with a universal IMF. We find no dependence of the IMF on environmental impacts such as the local star formation rate (SFR) or galactocentric radius within M33, which serves as a proxy for metallicity. This Γ¯ measurement is consistent with similar measurements in M31, despite M33 having a much higher SFR intensity. While this measurement is formally consistent with the canonical Kroupa (Γ = 1.30) IMF, as well as the Salpeter (Γ = 1.35) value, it is the second Local Group cluster sample to show evidence for a somewhat steeper high-mass IMF slope. We explore the impacts a steeper IMF slope has on a number of astronomical subfields.

PHANGS-MeerKAT and MHONGOOSE HI observations of nearby spiral galaxies: Physical drivers of the molecular gas fraction, Rmol

The molecular-to-atomic gas ratio is crucial to our understanding of the evolution of the interstellar medium (ISM) in galaxies. We investigated the balance between the atomic ( and molecular gas ( surface densities in eight nearby star-forming galaxies using new high-quality observations from MeerKAT and ALMA (for and CO, respectively). We defined the molecular gas ratio as mol and measured how depends on local conditions in the galaxy disks using multiwavelength observations. We find that, depending on the galaxy is detected at out to $20-120$\,kpc in galactocentric radius gal $). The typical radius at which reaches 1 is hi kpc, which corresponds to $1-3$ times the optical radius $). We note that, $R_ mol $ correlates best with the dynamical equilibrium pressure, P$_ DE $, among potential drivers studied, with a median correlation coefficient of $ Correlations between mol $ and the star formation rate surface density, total gas surface density, stellar surface density, metallicity, and (a proxy for the combined effect of the UV radiation field and number density) are present but somewhat weaker. Our results also show a direct correlation between and $ SFR $, supporting self-regulation models. Quantitatively, we measured similar scalings as previous works, and attribute the modest differences that we do find to the effect of varying resolution and sensitivity. At $r_ gal gtrsim 0.4 r_ $, atomic gas dominates over molecular gas among our studied galaxies, and at the balance of these two gas phases ($R_ mol $ = 1), we find that the baryon mass is dominated by stars, with Our study constitutes an important step in the statistical investigation of how local galaxy properties (stellar mass, star formation rate, or morphology) impact the conversion from atomic to molecular gas in nearby galaxies.

The host of GRB 171205A in 3D. A resolved multiwavelength study of a rare grand-design spiral GRB host

Long GRB hosts at $z&lt;1$ are usually low-mass, low-metallicity star-forming galaxies. Here we present the most detailed, spatially resolved study of the host of GRB 171205A so far, a grand-design barred spiral galaxy at $z=0.036$. Our analysis includes MUSE integral field spectroscopy complemented with high-spatial-resolution UV/VIS HST imaging and CO(1--0) and H i 21cm data. The GRB is located in a small star-forming region in a spiral arm of the galaxy at a deprojected distance of sim 8\,kpc from the center. The galaxy shows a smooth negative metallicity gradient and the metallicity at the GRB site is half solar, slightly below the mean metallicity at the corresponding distance from the center. Star formation in this galaxy is concentrated in a few H ii regions between 5 and 7\,kpc from the center and at the end of the bar, inwards from the GRB region; however the H ii region hosting the GRB is in the top 10&lt;!PCT!&gt; of the regions with the highest specific star-formation rate. The stellar population at the GRB site has a very young component ($&lt;$ 5\,Myr) that contributes a significant part of the light. Ionized and molecular gas show only minor deviations at the end of the bar. A parallel study found an asymmetric H i distribution and some additional gas near the position of the GRB, which might explain the star-forming region of the GRB site. Our study shows that long GRBs can occur in many types of star-forming galaxies; however the actual GRB sites have consistently low metallicity, high star formation rates, and a young population. Furthermore, gas inflow or interactions triggering the star formation producing the GRB progenitor might not be evident in ionized or even molecular gas but only in H i

The FLAMINGO simulation view of cluster progenitors observed in the epoch of reionization with JWST

ABSTRACT Motivated by the recent JWST discovery of galaxy overdensities during the Epoch of Reionzation, we examine the physical properties of high-z protoclusters and their evolution using the Full-hydro Large-scale structure simulations with All-sky Mapping for the Interpretation of Next Generation Observations (FLAMINGO) simulation suite. We investigate the impact of the apertures used to define protoclusters, because the heterogeneous apertures used in the literature have limited our understanding of the population. Our results are insensitive to the uncertainties of the subgrid models at a given resolution, whereas further investigation into the dependence on numerical resolution is needed. When considering galaxies more massive than $M_\ast \, {\simeq }\, 10^8\, {\rm M_\odot }$, the FLAMINGO simulations predict a dominant contribution from progenitors similar to those of the Coma cluster to the cosmic star formation rate density during the reionization epoch. Our results indicate the onset of suppression of star formation in the protocluster environments as early as $z\, {\simeq }\, 5$. The galaxy number density profiles are similar to NFW (Navarro–Frenk–White profile) at $z\, {\lesssim }\, 1$ while showing a steeper slope at earlier times before the formation of the core. Different from most previous simulations, the predicted star formation history for individual protoclusters is in good agreement with observations. We demonstrate that, depending on the aperture, the integrated physical properties including the total (dark matter and baryonic) mass can be biased by a factor of 2 to 5 at $z\, {=}\, 5.5$–7, and by an order of magnitude at $z\, {\lesssim }\, 4$. This correction suffices to remove the ${\simeq }\, 3\, \sigma$ tensions with the number density of structures found in recent JWST observations.

The MAGPI survey: The interdependence of the mass, star formation rate, and metallicity in galaxies at z~0.3

Star formation rates (SFRs), gas-phase metallicities, and stellar masses are crucial for studying galaxy evolution. The different relations resulting from these properties give insights into the complex interplay of gas inside galaxies and their evolutionary trajectory and current characteristics. We aim to characterize these relations at $z 0.3$, corresponding to a 3-4 Gyr lookback time, to gather insight into the galaxies' redshift evolution. We utilized optical integral field spectroscopy data from 65 emission-line galaxies from the MUSE large program MAGPI at a redshift of $0.28&lt;z&lt;0.35$ (average redshift of $z 0.3$) and spanning a total stellar mass range of $8.2&lt; /M_ odot ) &lt; 11.4$. We measured emission line fluxes and stellar masses, allowing us to determine spatially resolved SFRs, gas-phase metallicities, and stellar mass surface densities. We derived the resolved star formation main sequence (rSFMS), resolved mass metallicity relation (rMZR), and resolved fundamental metallicity relation (rFMR) at $z 0.3$, and compared them to results for the local Universe. We find a relatively shallow rSFMS slope of $ 0.014$ compared to the expected slope at this redshift for an ordinary least square (OLS) fitting routine. For an orthogonal distance regression (ODR) routine, a much steeper slope of $ 0.022$ is measured. We confirm the existence of an rMZR at $z 0.3$ with an average metallicity located $ 0.03$ dex above the local Universe's metallicity. Via partial correlation coefficients, evidence is found that the local metallicity is predominantly determined by the stellar mass surface density and has a weak secondary (inverse) dependence on the SFR surface density $ SFR $. Additionally, a significant dependence of the local metallicity on the total stellar mass $M_ $ is found. Furthermore, we find that the stellar mass surface density $ $ and $M_ $ have a significant influence in determining the strength with which $ SFR $ correlates with the local metallicity. We observe that at lower stellar masses, there is a tighter correlation between $ SFR $ and the gas-phase metallicity, resulting in a more pronounced rFMR.

Evolution of the star formation rate and Sigma_SFR of galaxies at cosmic morning (4&lt;z&lt;10)

The galaxy-integrated star formation rate (SFR) surface density measurement ($ SFR $) has been proposed as a valuable diagnostic of the mass accumulation in galaxies given it is more tightly related to the physics of star formation and stellar feedback than other indicators. In this work, we assembled a statistical sample of $230$ galaxies observed with JWST in the GLASS and CEERS spectroscopic surveys to estimate Balmer line-based dust attenuations and SFRs (i.e., from Halpha , Hbeta , and Hgamma ), along with the UV rest-frame effective radii. We studied the evolution of galaxy SFR and $ SFR $ in the first $1.5$ billion years of our Universe, from a redshift of $z to $z We found that $ SFR $ is mildly increasing with redshift with a linear slope of $0.16 0.06$. We explored the dependence of SFR and $ SFR $ on stellar mass, showing that a star-forming main sequence and a $ SFR $ main sequence are present out to $z=10$. This dependence exhibits a similar slope compared to the same relations at lower redshifts, but with a higher normalization. We find that the specific SFR (sSFR) and $ SFR $ are correlated with the ratio and with indirect estimates of the escape fraction of Lyman continuum photons; hence, they are likely to play an important role in the evolution of ionization conditions at higher redshifts and in the escape of ionizing radiation. We also searched for spectral outflow signatures in the Halpha and emission lines in a subset of galaxies observed at high resolution (R$=2700$) by the GLASS survey, finding an outflow incidence of $2/11$ 32&lt;!PCT!&gt; 9&lt;!PCT!&gt; $) at $z&lt;6$, but no evidence at $z&gt;6$ ($0/6$, $&lt;26&lt;!PCT!&gt;$). Finally, we find a positive correlation between A$_V$ and $ SFR $, and a flat trend as a function of sSFR, indicating that there is no evidence of a drop in A$_V$ in extremely star-forming galaxies between $z 4$ and $ 10$. This result might be at odds with a dust-clearing outflow scenario, which may instead take place at redshifts of $z 10$, as suggested by some theoretical models.

The COS-Holes Survey: Connecting Galaxy Black Hole Mass with the State of the CGM

We present an analysis of Hubble Space Telescope COS/G160M observations of C IV in the inner circumgalactic medium (CGM) of a novel sample of eight z ∼ 0, L ≈ L ⋆ galaxies, paired with UV-bright QSOs at impact parameters (R proj) between 25 and 130 kpc. The galaxies in this stellar-mass-controlled sample (log10 M ⋆/M ⊙ ∼ 10.2–10.9 M ⊙) host supermassive black holes (SMBHs) with dynamically measured masses spanning log10 M BH/M ⊙ ∼ 6.8–8.4; this allows us to compare our results with models of galaxy formation where the integrated feedback history from the SMBH alters the CGM over long timescales. We find that the C IV column density measurements (N C IV; average log10 N C IV,CH = 13.94 ± 0.09 cm−2) are largely consistent with existing measurements from other surveys of N C IV in the CGM (average log10 N C IV,Lit = 13.90 ± 0.08 cm−2), but do not show obvious variation as a function of the SMBH mass. By contrast, specific star formation rate (sSFR) is highly correlated with the ionized content of the CGM. We find a large spread in sSFR for galaxies with log10 M BH/M ⊙ > 7.0, where the CGM C IV content shows a clear dependence on galaxy sSFR but not M BH. Our results do not indicate an obvious causal link between CGM C IV and the mass of the galaxy’s SMBH; however, through comparisons to the EAGLE, Romulus25, and IllustrisTNG simulations, we find that our sample is likely too small to constrain such causality.