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We investigate how feedback and environment shapes the X-ray scaling relations of early-type galaxies (ETGs), especially at the low-mass end. We select central-ETGs from the TNG100 box of IllustrisTNG that have stellar masses $\log _{10}(M_{\ast }/\mathrm{M_{\odot }})\in [10.7, 11.9]$. We derive mock X-ray luminosity (LX, 500) and spectroscopic-like temperature (Tsl, 500) of hot gas within R500 of the ETG haloes using the MOCK-X pipeline. The scaling between LX, 500 and the total mass within 5 effective radii ($M_{5R_{\rm e}}$) agrees well with observed ETGs from Chandra. IllustrisTNG reproduces the observed increase in scatter of LX, 500 towards lower masses, and we find that ETGs with $\log _{10} (M_{5R_{\rm e}}/\mathrm{M_{\odot }}) \leqslant 11.5$ with above-average LX, 500 experienced systematically lower cumulative kinetic AGN feedback energy historically (vice versa for below-average ETGs). This leads to larger gas mass fractions and younger stellar populations with stronger stellar feedback heating, concertedly resulting in the above-average LX, 500. The LX, 500–Tsl, 500 relation shows a similar slope to the observed ETGs but the simulation systematically underestimates the gas temperature. Three outliers that lie far below the LX–Tsl relation all interacted with larger galaxy clusters recently and demonstrate clear features of environmental heating. We propose that the distinct location of these backsplash ETGs in the LX–Tsl plane could provide a new way of identifying backsplash galaxies in future X-ray surveys.

 

It has been claimed that traditional models struggle to explain the tentative detection of the 21 cm absorption trough centered atz∼ 17 measured by the EDGES collaboration. On the other hand, it has been shown that the EDGES results are consistent with an extrapolation of a declining UV luminosity density, following a simple power law of deep Hubble Space Telescope observations of 4 <z< 9 galaxies. We here explore the conditions by which the EDGES detection is consistent with current reionization and post-reionization observations, including the neutral hydrogen fraction atz∼ 6–8, Thomson-scattering optical depth, and ionizing emissivity atz∼ 5. By coupling a physically motivated source model derived from radiative transfer hydrodynamic simulations of reionization to a Markov Chain Monte Carlo sampler, we find that it is entirely possible to reconcile existing high-redshift (cosmic dawn) and low-redshift (reionization) constraints. In particular, we find that high contributions from low-mass halos along with high photon escape fractions are required to simultaneously reproduce cosmic dawn and reionization constraints. Our analysis further confirms that low-mass galaxies produce a flatter emissivity evolution, which leads to an earlier onset of reionization with a gradual and longer duration, resulting in a higher optical depth. While the models dominated by faint galaxies successfully reproduce the measured globally averaged quantities over the first one billion years, they underestimate the late redshift-instantaneous measurements in efficiently star-forming and massive systems. We show that our (simple) physically motivated semianalytical prescription produces results that are consistent with the (sophisticated) state-of-the-artTHESANradiation-magnetohydrodynamic simulation of the reionization.

 

Modelling galaxy formation in hydrodynamic simulations has increasingly adopted various radiative transfer methods to account for photoionization feedback from young massive stars. However, the evolution of H ii regions around stars begins in dense star-forming clouds and spans large dynamical ranges in both space and time, posing severe challenges for numerical simulations in terms of both spatial and temporal resolution that depends strongly on gas density (∝n−1). In this work, we perform a series of idealized H ii region simulations using the moving-mesh radiation-hydrodynamic code arepo-rt to study the effects of numerical resolution. The simulated results match the analytical solutions and the ionization feedback converges only if the Strömgren sphere is resolved by at least 10–100 resolution elements and the size of each time integration step is smaller than 0.1 times the recombination time-scale. Insufficient spatial resolution leads to reduced ionization fraction but enhanced ionized gas mass and momentum feedback from the H ii regions, as well as degrading the multiphase interstellar medium into a diffuse, partially ionized, warm (∼8000 K) gas. On the other hand, insufficient temporal resolution strongly suppresses the effects of ionizing feedback. This is because longer time-steps are not able to resolve the rapid variation of the thermochemistry properties of the gas cells around massive stars, especially when the photon injection and thermochemistry are performed with different cadences. Finally, we provide novel numerical implementations to overcome the above issues when strict resolution requirements are not achievable in practice.

 

Using high-resolution cosmological radiation-hydrodynamic (RHD) simulations (thesan-hr), we explore the impact of alternative dark matter (altDM) models on galaxies during the Epoch of Reionization. The simulations adopt the IllustrisTNG galaxy formation model. We focus on altDM models that exhibit small-scale suppression of the matter power spectrum, namely warm dark matter (WDM), fuzzy dark matter (FDM), and interacting dark matter (IDM) with strong dark acoustic oscillations (sDAO). In altDM scenarios, both the halo mass functions and the ultraviolet luminosity functions at z ≳ 6 are suppressed at the low-mass/faint end, leading to delayed global star formation and reionization histories. However, strong non-linear effects enable altDM models to ‘catch up’ with cold dark matter (CDM) in terms of star formation and reionization. The specific star formation rates are enhanced in halos below the half-power mass in altDM models. This enhancement coincides with increased gas abundance, reduced gas depletion times, more compact galaxy sizes, and steeper metallicity gradients at the outskirts of the galaxies. These changes in galaxy properties can help disentangle altDM signatures from a range of astrophysical uncertainties. Meanwhile, it is the first time that altDM models have been studied in RHD simulations of galaxy formation. We uncover significant systematic uncertainties in reionization assumptions on the faint-end luminosity function. This underscores the necessity of accurately modeling the small-scale morphology of reionization in making predictions for the low-mass galaxy population. Upcoming James Webb Space Telescope imaging surveys of deep lensed fields hold potential for uncovering the faint low-mass galaxy population, which could provide constraints on altDM models.

 

Abstract The darkling beetle tribe Adesmiini (Tenebrionidae: Pimeliinae) is a prominent part of African and western Palearctic desert faunas, with most species being day-active fast-running detritivores. Taxonomic diversity within the tribe is highest in the southern Afrotropical realm (where all genera are present); only 1 genus, the species-rich Adesmia, occurs north of the Sahara. Despite notable species, such as the fog-basking beetle Onymacris unguicularis (a focal taxon in desert ecological research), Adesmiini has undergone few modern taxonomic or phylogenetic studies. Hence, generic concepts and pronounced diurnal activity, rare in the primarily nocturnal family Tenebrionidae, remain poorly explored. To investigate evolutionary relationships and diurnal origins within the tribe, we generated a genomic dataset of 529 protein-coding genes across 43 species spanning 10 of 11 Adesmiini genera. Our resulting phylogeny for the tribe rejects the monophyly of 5 currently recognized Adesmiini genera (i.e., Adesmia, Metriopus, Onymacris, Physadesmia, and Stenocara). Ancestral state reconstruction of diurnal activity using eye shape as a proxy supports the hypothesis that Adesmiini were primitively diurnal, followed by at least 4 shifts to nocturnal or crepuscular activity. 

The feedback loop between the galaxies producing the background radiation field for reionization and their growth is crucial, particularly for low-mass haloes. Despite this, the vast majority of galaxy formation studies employ a spatially uniform, time-varying reionizing background, with the majority of reionization studies employing galaxy formation models only required to work at high redshift. This paper uses the well-studied TNG galaxy formation model, calibrated at low redshift, coupled to the arepo-rt code, to self-consistently solve the coupled problems of galaxy evolution and reionization, evaluating the impact of patchy (and slow) reionization on early galaxies. thesan-hr is an extension of the thesan project to higher resolution (a factor of 50 increase, with a baryonic mass of mb ≈ 104 M⊙), to additionally enable the study of ‘mini-haloes’ with virial temperatures Tvir < 104 K. Comparing the self-consistent model to a uniform UV background, we show that galaxies in thesan-hr are predicted to be larger in physical extent (by a factor ∼2), less metal enriched (by ∼0.2 dex), and less abundant (by a factor ∼10 at M1500 =   − 10) by z = 5. We show that differences in star formation and enrichment patterns lead to significantly different predictions for star formation in low mass haloes, low-metallicity star formation, and even the occupation fraction of haloes. We posit that cosmological galaxy formation simulations aiming to study early galaxy formation (z ≳ 3) must employ a spatially inhomogeneous UV background to accurately reproduce galaxy properties.

 

Abstract A fundamental requirement for reionizing the Universe is that a sufficient fraction of the ionizing photons emitted by galaxies successfully escapes into the intergalactic medium. However, due to the scarcity of high-redshift observational data, the sources driving reionization remain uncertain. In this work, we calculate the ionizing escape fractions (fesc) of reionization-era galaxies from the state-of-the-art thesan simulations, which combine an accurate radiation-hydrodynamic solver (arepo-rt) with the well-tested IllustrisTNG galaxy formation model to self-consistently simulate both small-scale galaxy physics and large-scale reionization throughout a large patch of the universe ($L_\text{box} = 95.5\, \text{cMpc}$). This allows the formation of numerous massive haloes ($M_\text{halo} \gtrsim 10^{10}\, {\text{M}_{\odot }}$), which are often statistically underrepresented in previous studies but are believed to be important to achieving rapid reionization. We find that low-mass galaxies ($M_\text{stars} \lesssim 10^7\, {\text{M}_{\odot }}$) are the main drivers of reionization above z ≳ 7, while high-mass galaxies ($M_\text{stars} \gtrsim 10^8\, {\text{M}_{\odot }}$) dominate the escaped ionizing photon budget at lower redshifts. We find a strong dependence of fesc on the effective star formation rate (SFR) surface density defined as the SFR per gas mass per escape area, i.e. $\bar{\Sigma }_\text{SFR} = \text{SFR}/M_\text{gas}/R_{200}^2$. The variation in halo escape fractions decreases for higher mass haloes, which can be understood from the more settled galactic structure, SFR stability, and fraction of sightlines within each halo significantly contributing to the escaped flux. Dust is capable of reducing the escape fractions of massive galaxies, but the impact on the global fesc depends on the dust model. Finally, active galactic nuclei are unimportant for reionization in thesan and their escape fractions are lower than stellar ones due to being located near the centres of galaxy gravitational potential wells. 

The early release science results from JWST have yielded an unexpected abundance of high-redshift luminous galaxies that seems to be in tension with current theories of galaxy formation. However, it is currently difficult to draw definitive conclusions form these results as the sources have not yet been spectroscopically confirmed. It is in any case important to establish baseline predictions from current state-of-the-art galaxy formation models that can be compared and contrasted with these new measurements. In this work, we use the new large-volume ($L_\mathrm{box}\sim 740 \, \mathrm{cMpc}$) hydrodynamic simulation of the MillenniumTNG project, suitably scaled to match results from higher resolution – smaller volume simulations, to make predictions for the high-redshift (z ≳ 8) galaxy population and compare them to recent JWST observations. We show that the simulated galaxy population is broadly consistent with observations until z ∼ 10. From z ≈ 10–12, the observations indicate a preference for a galaxy population that is largely dust-free, but is still consistent with the simulations. Beyond z ≳ 12, however, our simulation results underpredict the abundance of luminous galaxies and their star-formation rates by almost an order of magnitude. This indicates either an incomplete understanding of the new JWST data or a need for more sophisticated galaxy formation models that account for additional physical processes such as Population III stars, variable stellar initial mass functions, or even deviations from the standard ΛCDM model. We emphasize that any new process invoked to explain this tension should only significantly influence the galaxy population beyond z ≳ 10, while leaving the successful galaxy formation predictions of the fiducial model intact below this redshift.

 

Backsplash galaxies are galaxies that once resided inside a cluster, and have migrated back outside as they move towards the apocentre of their orbit. The kinematic properties of these galaxies are well understood, thanks to the significant study of backsplashers in dark matter-only simulations, but their intrinsic properties are not well-constrained due to modelling uncertainties in subgrid physics, ram pressure stripping, dynamical friction, and tidal forces. In this paper, we use the IllustrisTNG300-1 simulation, with a baryonic resolution of Mb ≈ 1.1 × 107 M⊙, to study backsplash galaxies around 1302 isolated galaxy clusters with mass 1013.0 < M200,mean/M⊙ < 1015.5. We employ a decision tree classifier to extract features of galaxies that make them likely to be backsplash galaxies, compared to nearby field galaxies, and find that backsplash galaxies have low gas fractions, high mass-to-light ratios, large stellar sizes, and low black hole occupation fractions. We investigate in detail the origins of these large sizes, and hypothesize their origins are linked to the tidal environments in the cluster. We show that the black hole recentring scheme employed in many cosmological simulations leads to the loss of black holes from galaxies accreted into clusters, and suggest improvements to these models. Generally, we find that backsplash galaxies are a useful population to test and understand numerical galaxy formation models due to their challenging environments and evolutionary pathways that interact with poorly constrained physics.

 

Abstract The spectacular radiation of insects has produced a stunning diversity of phenotypes. During the past 250 years, research on insect systematics has generated hundreds of terms for naming and comparing them. In its current form, this terminological diversity is presented in natural language and lacks formalization, which prohibits computer-assisted comparison using semantic web technologies. Here we propose a Model for Describing Cuticular Anatomical Structures (MoDCAS) which incorporates structural properties and positional relationships for standardized, consistent, and reproducible descriptions of arthropod phenotypes. We applied the MoDCAS framework in creating the ontology for the Anatomy of the Insect Skeleto-Muscular system (AISM). The AISM is the first general insect ontology that aims to cover all taxa by providing generalized, fully logical, and queryable, definitions for each term. It was built using the Ontology Development Kit (ODK), which maximizes interoperability with Uberon (Uberon multi-species anatomy ontology) and other basic ontologies, enhancing the integration of insect anatomy into the broader biological sciences. A template system for adding new terms, extending, and linking the AISM to additional anatomical, phenotypic, genetic, and chemical ontologies is also introduced. The AISM is proposed as the backbone for taxon-specific insect ontologies and has potential applications spanning systematic biology and biodiversity informatics, allowing users to (1) use controlled vocabularies and create semi-automated computer-parsable insect morphological descriptions; (2) integrate insect morphology into broader fields of research, including ontology-informed phylogenetic methods, logical homology hypothesis testing, evo-devo studies, and genotype to phenotype mapping; and (3) automate the extraction of morphological data from the literature, enabling the generation of large-scale phenomic data, by facilitating the production and testing of informatic tools able to extract, link, annotate, and process morphological data. This descriptive model and its ontological applications will allow for clear and semantically interoperable integration of arthropod phenotypes in biodiversity studies.