Dust Model Research Articles

The Ultraviolet Slopes of Early Universe Galaxies: The Impact of Bursty Star Formation, Dust, and Nebular Continuum Emission

Abstract JWST has enabled the detection of the ultraviolet (UV) continuum of galaxies at z > 10, revealing extremely blue, potentially dust-free galaxies. However, interpreting UV spectra is complicated by the well-known degeneracy between stellar ages, dust reddening, and nebular continuum. The main goal of this paper is to develop a theoretical model for the relationship between galaxy UV slopes (β), bursty star formation histories, dust evolution, and nebular contributions using cosmological zoom-in simulations. We build a layered model where we simulate increasingly complex physics, including the impact of (i) unattenuated intrinsic stellar populations, (ii) reddened populations using a new on-the-fly evolving dust model, and (iii) populations including dust and nebular continuum. Unattenuated stellar populations with no nebular emission exhibit a diverse range of intrinsic UV slopes (β 0 ≈ −3 → −2.2), with an inverse correlation between UV slope and specific star formation rate. When including dust, our model galaxies demonstrate a rapid rise in dust obscuration between z ≈ 8 and 10. This increase in dust mass is due to high grain–grain shattering rates, and enhanced growth per unit dust mass in very small grains, resulting in UV-detected galaxies at z ∼ 12 descending into Atacama Large Millimeter/submillimeter Array–detectable galaxies by z ∼ 6. The rapid rise in dust content at z ≈ 8–10 leads to a systematic reddening of the UV slopes during this redshift range. Nebular continuum further reddens UV slopes by a median Δβ neb ≈ 0.2–0.4, though notably the highest-redshift galaxies (z ≈ 12) are insufficiently blue compared to observations; this may imply an evolving escape fraction from H ii regions with redshift.

Source Limitation Could Have Major Implications to Dust Emission Estimates

AbstractA model for source‐limited dust emission is proposed. The model accounts for the evolution of the supply of soil dust depleted by dust emission and enriched by the process of surface renewal, together with several other new developments. The model is tested with a field dataset. The impact of source limitation to dust emission is profound. Our tests show that by considering source limitation, the model predicted dust emission can reduce by one order of magnitude in a real‐case simulation period of less than 20 days. We show that the process of dust emission is much more complex and variable than considered in previous dust models. Our findings have far‐reaching implications, for example, to the global dust emission estimates. Because source‐limited dust emission has so far not been represented in global dust models, the model estimated dust emission is only its potential and may be a substantial overestimate.

Connecting Dust and Outflows in Active Galactic Nuclei: The Intriguing Case of NGC 6860

Abstract Cosmic dust plays a crucial role in the evolution of galaxies, significantly influencing star formation and the interstellar medium. However, in active galactic nuclei (AGNs), the role and origin of dust remain poorly understood. High-resolution X-ray spectroscopy is a powerful tool for probing the properties of dust in AGN. NGC 6860, an X-ray bright type-1 quasar, is an ideal target for investigating the connection between dust and winds in AGN. It exhibits reddening and X-ray absorption by both dust and winds. By modeling high-resolution X-ray spectra from XMM-Newton and Chandra observations, we determine the properties of dust and outflows in this AGN. Our analysis finds four photoionized components, outflowing with velocities of 50–300 km s−1. The first two are relatively highly ionized with log ξ = 3.4 and log ξ = 2.9 . The results of our photoionization modeling suggest that these two components are thermally unstable. The third component is ionized, with log ξ = 2.3 , and is located farther away from the central black hole. The fourth component is less ionized and is possibly located in the host galaxy. The application of dust models enables us to probe the abundance and location of the dust in NGC 6860. Our findings suggest that dust absorption and reddening originates from the extended narrow-line region and its host galaxy.

Exploring the Impact of Dynamic Dust Source on the East Asian Dust Cycle Using WRF‐Chem

AbstractDust emission is a prerequisite to accurately describe the physical processes of dust and is closely associated with dust sources; however, the spatial and temporal variation of East Asian dust sources has not been accurately quantified. Herein, we show the effects of the dominant factors associated with the dynamic dust source on dust modeling with multiple aspects. We found that the dynamic dust source in East Asia in 2001–2020 demonstrates a pronounced monthly and annual variability, showing wider spatial distribution in March than that in July and lower probability of dust uplifting in summer than that in spring. The dust source functions of the Gobi Desert and Taklimakan Desert decrease at rates of 5.8 × 10−3 and 4.7 × 10−3 decade−1, respectively. Using the Weather Research and Forecasting model coupled with Chemistry, we further assess the joint control of surface bareness and topographical depression feature on the spatial distribution and value of the dynamic dust source. The East Asian dust source function generally increases with increasing surface bareness threshold, whereas that in the western Taklimakan Desert and central Gobi Desert decreases with coarse topography calculation resolution. These study findings show the importance of the dynamic dust source on dust simulation and deeply dive into exploring the effect of surface bareness and topographical depression feature on dust cycle simulation, which provide more options for better dust simulations in the future.

The mass-dependent UVJ diagram at cosmic noon

Context. The UVJ color-color diagram is a widely used diagnostic to separate star-forming and quiescent galaxies. Observational data from photometric surveys reveal a strong stellar mass trend, with higher-mass star-forming galaxies being systematically more dust-reddened. Aims. We analyze the UVJ diagram in the TNG100 cosmological simulation at cosmic noon (z ≈ 2). Specifically, we focus on the trend between UVJ colors and mass, which has not been reproduced in any cosmological simulation thus far. Methods. We applied the SKIRT dust radiative transfer code to the TNG100 simulation to generate rest-frame UVJ fluxes. These UVJ colors were then compared to observational data from several well-studied extragalactic fields from the CANDELS/3D-HST programs, augmented by recent JWST/NIRCam photometry. Results. Quiescent and low-mass (M⋆ ≲ 1010.5 M⊙) galaxies at cosmic noon do not require significant levels of dust reddening, as opposed to massive (M⋆ ≳ 1011 M⊙) star-forming galaxies. An extensive range of possible dust models fall short of the required dust reddening in V − J color for massive star-forming galaxies, with the simulated galaxies being too blue by ≈0.9 mag. Conclusions. We find that only variations in the star-to-dust geometries of the simulated galaxies are able to yield V − J colors that are red enough to match the observations. A toy model with isolated dust screens around younger stellar populations (with ages below ∼1 Gyr) can reproduce the observational data, while all “conventional” dust radiative transfer models (where the dust distribution follows the metals in the interstellar medium) fail to achieve the required V − J colors.

Experiment study on the source identification and dust forecast based on the atmospheric electric field during urban dust pollution.

Experiment study on the source identification and dust forecast based on the atmospheric electric field during urban dust pollution.

The centimeter emission from planet-forming disks in Taurus

The last decade has witnessed remarkable advances in the characterization of the (sub-)millimeter emission from planet-forming disks. Conversely, the study of (sub-)centimeter emission has made more limited progress, to the point that only a few exceptional disk-bearing objects have been characterized in the centimeter regime. This work takes a broad view of the centimeter emission from a large sample with Karl G. Jansky Very Large Array (VLA) observations that is selected from previous Atacama Large (sub-)Millimeter Array (ALMA) surveys of more representative disks in brightness and extent . We report on the detection and characterization of flux at centimeter wavelengths from 21 sources in the Taurus star-forming region. Complemented by literature and archival data, the entire photometry from 0.85 mm to 6 cm is fit by a two-component model that determines the ubiquitous presence of free-free emission entangled with the dust emission. The flux density of the free-free emission is found to scale with the accretion rate but is independent of the outer-disk morphology depicted by ALMA. The dust emission at 2 cm is still appreciable and offers the possibility to extract an unprecedented large set of dust spectral indices in the centimeter regime. A pronounced change between the median millimeter indices (2.3) and centimeter indices (2.8) suggests that a large portion of the disk emission is optically thick up to 3 mm. The comparison of both indices and fluxes with the ALMA disk extent indicates that this portion can be as large as 40 au and suggests that the grain population within this disk region that emits the observed centimeter emission is similar in disks with different sizes and morphologies. All these results await confirmation and dedicated dust modeling once facilities such as next generation VLA (ngVLA) or Square Kilometre Array (SKA)-mid are able to resolve the centimeter emission from planet-forming disks and disentangle the various components.

Dust Scattering Albedo at Millimeter Wavelengths in the TW Hya Disk

Abstract Planetary bodies are formed by coagulation of solid dust grains in protoplanetary disks. Therefore, it is crucial to constrain the physical and chemical properties of the dust grains. In this study, we measure the dust albedo at millimeter wavelength, which depends on dust properties at the disk midplane. Since the albedo and dust temperature are generally degenerate in observed thermal dust emission, it is challenging to determine them simultaneously. We propose to break this degeneracy by using multiple optically thin molecular lines as a dust–albedo-independent thermometer. In practice, we employ pressure-broadened CO line wings that provide an exceptionally high signal-to-noise ratio as an optically thin line. We model the CO J = 2–1 and 3–2 spectra observed by the Atacama Large Millimeter/submillimeter Array at the inner region (r < 6 au) of the TW Hya disk and successfully derive the midplane temperature. Combining multiband continuum observations, we constrain the albedo spectrum at 0.9–3 mm for the first time without assuming a dust opacity model. The albedo at these wavelengths is high, ~0.5–0.8, and broadly consistent with the L. Ricci et al., DIANA, and DSHARP dust models. Even without assuming dust composition, we estimate the maximum grain size to be ~340 μm, the power-law index of the grain size distribution to be >−4.1, and the porosity to be <0.96. The derived dust size may suggest efficient fragmentation with a threshold velocity of ~0.08 m s−1. We also note that the absolute flux uncertainty of ~10% (1σ) is measured and used in the analysis, which is approximately twice the usually assumed value.

Luminosity Distance and Extinction by Submicrometer-sized Grains

Abstract The distance to the stars is a fundamental parameter, which is determined via two primary methods—parallax and luminosity. While the parallax is a direct trigonometric method, the luminosity distance is usually influenced by interstellar extinction. As long as the optical properties of dust grains are wavelength-dependent this contamination can be corrected. However, as the grain size increases, the extinction properties become gray, meaning these particles contribute by a constant at wavelengths ≲ 1 μm, making them undetectable by photometry in the optical. In this study, we compare the parallactic and luminosity distances of a pristine sample of 33 well-known early-type stars with nonpeculiar reddening curves and find that the luminosity distance overestimates the parallactic distance in 80% of the cases. This discrepancy can be removed when incorporating a population of large, submicrometer-sized dust grains in a dust model that provides gray extinction, which diminishes the luminosity distance accordingly.

Fuzzy Galaxies or Cirrus? Decomposition of Galactic Cirrus in Deep Wide-field Images

Abstract Diffuse Galactic cirrus, or diffuse Galactic light (DGL), can be a prominent component in the background of deep wide-field imaging surveys. The DGL provides unique insights into the physical and radiative properties of dust grains in our Milky Way, and it also serves as a contaminant on deep images, obscuring the detection of background sources such as low surface brightness galaxies. However, it is challenging to disentangle the DGL from other components of the night sky. In this paper, we present a technique for the photometric characterization of Galactic cirrus based on (1) extraction of its filamentary or patchy morphology and (2) incorporation of color constraints obtained from Planck thermal dust models. Our decomposition method is illustrated using a ~10 deg2 imaging data set obtained by the Dragonfly Telephoto Array, and its performance is explored using various metrics that characterize the flatness of the sky background. As a concrete application of the technique, we show how removal of cirrus allows low surface brightness galaxies to be identified on cirrus-rich images. We also show how modeling the cirrus in this way allows optical DGL intensities to be determined with high radiometric precision.

Airborne Soil-Derived Dust Hazards in Aviation

Abstract Airborne mineral dust poses a safety challenge for aviation. Several fatal accidents have happened in dust-laden air due to reduced visibility, strong gusty winds, and wind shear. Dust-induced icing also contributed at least to two fatal accidents. Furthermore, atmospheric dust has long- and short-term effects on aircraft operating conditions due to corrosion and abrasion on the aircraft surfaces and molten ingress deterioration of engine hot section components. The combined impact can increase operating and maintenance costs and increase the overall cost of ownership. While the scientific community has started preparing and providing products based on atmospheric dust modeling and observation, there are still important data and information gaps in the fundamental science. These include (i) insufficient data which could be used to better understand the effects of dust on aircraft as well as on ground systems and operations (e.g., four-dimensional information of dust mineralogy, cost–benefit analysis of the impact of dust on aviation along flight routes), (ii) the identification of airborne dust monitoring and modeling products and services that could enable the flow of relevant information in commercial aviation and in decision-making workflows, and (iii) the underdeveloped, unclear, or absent role of dust hazards in regulations and operational procedures as well as in the training, skill set, and knowledge base of pilots. This review is aimed at both academic and aviation stakeholders and presents the current state-of-the-art knowledge at the intersection of dust hazards, aviation safety, and impacts on flight operations and aircraft maintenance.

Intermediate mass T Tauri disk masses and a comparison to their Herbig disk descendants

Context. Herbig disks are prime sites for the formation of massive exoplanets and looking into the precursors of these disks can offer clues for determining planet formation timescales. The precursors of Herbig stars, called intermediate-mass T Tauri (IMTT) stars, have spectral types later than F, but stellar masses between 1.5 and 5 M⊙. These stars will eventually become Herbig stars of spectral types A and B. Aims. The aim of this work is to obtain the dust and gas masses and radii of all IMTT disks with ALMA archival data. The obtained disk masses are then compared to Herbig disks and T Tauri disks and the obtained disks sizes to those of Herbig disks. Methods. ALMA Band 6 and 7 archival data were obtained for 34 IMTT disks with continuum observations, 32 of which have at least 12CO, 13CO, or C18O observations, but with most of them at quite shallow integrations. The disk integrated flux together with a stellar luminosity-scaled disk temperature were used to obtain a total disk dust mass by assuming optically thin emission. Using thermochemical Dust And LInes (DALI) models drawn from previous works, we also obtained gas masses of 10 out of 35 of the IMTT disks based on the CO isotopologues. From the disk masses and sizes, we obtained the cumulative distributions. Results. The IMTT disks in this study have the same dust mass and radius distributions as Herbig disks. The dust mass of the IMTT disks is higher compared to that of the T Tauri disks, as also found for the Herbig disks. No differences in dust mass were found for group I versus group II disks, in contrast to Herbig disks. The disks for which a gas mass could be determined display a similarly high-mass as to the Herbig disks. Comparing the disk dust and gas mass distributions to the mass distribution of exoplanets shows that there also is not enough dust mass in disks around intermediate-mass stars to form massive exoplanets. On the other hand, there is more than enough gas to form the atmospheres of exoplanets. Conclusions. We conclude that the sampled IMTT disk population is almost indistinguishable compared to Herbig disks, as their disk masses are the same, even though the former objects are younger. Based on this study, we conclude that planet formation is already well underway in these objects and, thus, planet formation is expected to start early on in the lifetime of Herbig disks. Combined with our findings on group I and group II disks, we conclude that most disks around intermediate-mass pre-main sequence stars converge quickly to small disks, unless they are prevented from doing so by a nearby massive exoplanet.

The Volatile Composition and Activity Evolution of Main-belt Comet 358P/PANSTARRS

We report the detection of water vapor associated with main-belt comet 358P/PANSTARRS on UT 2024 January 8–9 using the NIRSPEC instrument on board JWST. We derive a water production rate of QH2O=(5.0±0.2)×1025 molecules s−1, marking only the second direct detection of sublimation products of any kind from a main-belt comet, after 238P/Read. Similar to 238P, we find a remarkable absence of hypervolatile species, finding QCO2<7.6×1022 molecules s−1, corresponding to QCO2/QH2O<0.2 %. Upper limits on CH3OH and CO emission are also estimated. Photometry from ground-based observations shows that the dust coma brightened and faded slowly over ∼250 days in 2023–2024, consistent with photometric behavior observed in 2012–2013, but also indicates a ∼2.5× decline in the dust production rate between these two periods. Dynamical dust modeling shows that the coma’s morphology as imaged by JWST's NIRCam instrument on 2023 November 22 can be reproduced by asymmetric dust emission from a nucleus with a midrange obliquity (ε ∼ 80°) with a steady-state mass-loss rate of ∼0.8 kg s−1. Finally, we find similar Af ρ-to-gas ratios of log10(Afρ/QH2O)=−24.8±0.2 for 358P and log10(Afρ/QH2O)=−24.4±0.2 for 238P, suggesting that Af ρ could serve as an effective proxy for estimating water production rates in other active main-belt comets. The confirmation of water vapor outgassing in both main-belt comets observed by JWST to date reinforces the use of recurrent activity near perihelion as an indicator of sublimation-driven activity in active asteroids.

An infrared and far-UV study of jet-induced star formation in the halo of Centaurus A

Centaurus A (Cen A) is the nearest galaxy hosting an active galactic nucleus (AGN), which produces powerful radio and X-ray jets extending to hundreds of kiloparsecs from the center. At 15 kpc northeast (NE) and 12 kpc southwest (SW) in the halo along the jet from the nucleus of Cen A, dust clouds accompanying the Hα emission are detected. For both NE and SW clouds, past studies suggested that star formation may have been induced through interactions between the AGN jet and the surrounding intergalactic media. For these clouds, we performed dust model fitting of infrared (IR) spectral energy distributions (SEDs) created from the archival data of WISE, Spitzer, and Herschel. Then we compare the IR emission properties of the dust clouds with the far-ultraviolet (UV) emission using the archival data of GALEX/FUV. As a result, we find that the interstellar radiation field intensity G0 (and thus the dust temperature) in the NE cloud suggests star formation activity, while that in the SW cloud does not. The local far-UV intensity and G0 in the NE region are significantly larger than those expected for the far-UV radiation originating from the central region of Cen A and its dust-scattered component, respectively. In contrast, the local far-UV intensity and G0 in the SW region are compatible with them. The polycyclic aromatic hydrocarbon (PAH) emission is detected for both NE and SW clouds. The mass abundance ratios of PAH to dust are similar for both clouds and significantly lower than that in the central region of Cen A. We suggest that the dust clouds and the PAHs in the clouds are associated with the broken ring-like structure of H I gas which is thought to be a remnant of the past gas-rich merger and that shocks by the jet responsible for the middle lobe on the north side may have triggered the star formation in the NE cloud.

Developing a non-Newtonian fluid model for dust, for application to astrophysical flows

Developing a non-Newtonian fluid model for dust, for application to astrophysical flows

The distribution of the near-solar bound dust grains detected with Parker Solar Probe

Context. Parker Solar Probe (PSP) counts dust impacts in the near-solar region, but modeling effort is needed to understand the dust population’s properties. Aims. We aim to constrain the dust cloud’s properties based on the flux observed by PSP. Methods. We developed a forward model for the bound dust detection rates using the formalism of 6D phase space distribution of the dust. We applied the model to the location table of different PSP solar encounter groups. We explain some of the near-perihelion features observed in the data as well as the broader characteristic of the dust flux between 0.15 AU and 0.5 AU. We compare the measurements of PSP to the measurements of Solar Orbiter near 1 AU to expose the differences between the two spacecraft. Results. We found that the dust flux observed by PSP between 0.15 AU and 0.5 AU in post-perihelia can be explained by dust on bound orbits and is consistent with a broad range of orbital parameters, including dust on circular orbits. However, the dust number density as a function of the heliocentric distance and the scaling of detection efficiency with relative speed are important to explain the observed flux variation. The data suggest that the slope of differential mass distribution, δ, is between 0.14 and 0.49. The near-perihelion observations, however, show the flux maxima, which are inconsistent with the circular dust model, and additional effects may play a role. We found an indication that the sunward side of PSP is less sensitive to the dust impacts than PSP’s other surfaces. Conclusions. We show that the dust flux on PSP can be explained by noncircular bound dust and the detection capabilities of PSP. The scaling of flux with impact speed is especially important, and shallower than previously assumed.

Valid time shifting ensemble Kalman filter (VTS-EnKF) for dust storm forecasting

Abstract. Dust storms pose significant risks to health and property, necessitating accurate forecasting for preventive measures. Despite advancements, dust models grapple with uncertainties arising from emission and transport processes. Data assimilation addresses these by integrating observations to rectify model error, enhancing forecast precision. The ensemble Kalman filter (EnKF) is a widely used assimilation algorithm that effectively optimize model states, particularly in terms of intensity adjustment. However, the EnKF's efficacy is challenged by position errors between modeled and observed dust features, especially under substantial position errors. This study introduces the valid time shifting ensemble Kalman filter (VTS-EnKF), which combines stochastic EnKF with a valid time shifting mechanism. By recruiting additional ensemble members from neighboring valid times, this method not only accommodates variations in dust load but also explicitly accounts for positional uncertainties. Consequently, the enlarged ensemble better represents both the intensity and positional errors, thereby optimizing the utilization of observational data. The proposed VTS-EnKF was evaluated against two severe dust storm cases from spring 2021, demonstrating that position errors notably deteriorated forecast performance in terms of root mean square error (RMSE) and normalized mean bias (NMB), impeding the EnKF's effective assimilation. Conversely, the VTS-EnKF improved both the analysis and forecast accuracy compared to the conventional EnKF. Additionally, to provide a more rigorous assessment of its performance, experiments were conducted using fewer ensemble members and different time intervals.

Differential Cytotoxicity, Inflammatory Responses, and Aging Effects of Human Skin Cells in Response to Fine Dust Exposure

Airborne fine dust pollution poses a significant threat to both respiratory and skin health, yet the skin’s physiological response to such exposure has been underexplored. This study investigates the impact of fine dust on skin cells, focusing on their metabolic activity, inflammatory responses, and aging-related changes. We found that exposure to fine dust model compounds led to dose-dependent cytotoxicity, with PM2.5-Ions exhibiting higher toxicity compared to PM10-PAHs. Human epithelial keratinocytes (HEKn) showed heightened sensitivity to fine dust, marked by increased inflammation, particularly with elevated IL-8 expression in response to PM2.5-Ions. Additionally, fine dust exposure resulted in reduced cell density, slower proliferation, and decreased migration, notably at higher concentrations of PM2.5-Ions. These changes are indicative of accelerated aging processes, including compromised cell function and structural integrity. Live cell imaging and correlation analyses highlighted significant links between metabolic activity, cell morphology, and IL-8 secretion. These findings provide critical insights into the differential impacts of fine dust components on skin cells, emphasizing the potential acceleration of aging processes and underscoring the need for further research on cellular responses to environmental stress and the development of protective measures against urban fine dust exposure. Overall, this study, which contributes to addressing the skin health risks posed by air pollutants, could be actively used in environmental science, dermatology, and public health.

What is the amount of baryonic dark matter in galaxies?

What is the amount of baryonic dark matter in galaxies?

Cross-sectional analysis of dyslipidemia risk in coal mine workers: from epidemiology to animal models

Objective: To investigate the association between coal dust exposure and the occurrence of dyslipidemia in coal mine workers, and identify relevant risk factors. Methods: We selected a population who underwent occupational health examinations at Huainan Yangguang Xinkang Hospital from March 2020 to July 2022. Participants were divided into two groups based on the presence or absence of dyslipidemia, and their baseline information was collected, including records of coal dust exposure. We employed single-factor analysis to identify risk factors for dyslipidemia and adjusted for confounding factors in the adjusted models. Additionally, we explored the effects in different populations using stratified analysis, smooth curve fitting, and propensity score matching. Finally, we confirmed the causal relationship between coal dust exposure and dyslipidemia by examining tissue sections and lipid-related indicators in a mouse model of coal dust exposure. Results A total of 5,657 workers were included in the study, among whom 924 individuals had dyslipidemia and 4,743 individuals did not have dyslipidemia. The results of the single-factor analysis revealed that dust exposure, age, BMI, blood pressure, and smoking were statistically significant risk factors for dyslipidemia (p < 0.05). Additionally, the three multivariate models, adjusted for different confounders, consistently showed a significant increase in the risk of dyslipidemia associated with coal dust exposure (Model 1: OR, 1.869; Model 2: OR, 1.863; Model 3: OR, 2.033). After conducting stratified analysis, this positive correlation remained significant. Furthermore, propensity score matching analysis revealed that with increasing years of work, the risk of dyslipidemia gradually increased, reaching 50% at 11 years. In the mouse model of coal dust exposure, significant coal dust deposition was observed in the lungs and livers of the mice, accompanied by elevated levels of total cholesterol (TC), alanine transaminase (ALT), aspartate transaminase (AST), and low-density lipoprotein cholesterol (LDL-C). Conclusion Exposure to coal dust significantly increases the risk of developing dyslipidemia, and this positive correlation exists in different populations, particularly with increasing years of work, resulting in a higher risk. Keywords: Dust, occupational health, dyslipidemia, risk factors, cross-sectional study.