The gas-to-dust ratio of reddened stars in the Milky Way (MW), the Magellanic Clouds, and in general is usually expressed as a linear relation between the hydrogen column density, N(H), and the reddening, E(B-V), or extinction in the V band (A(V)). If the extinction curve was truly universal, the strength of the relationship and the linearity would naturally be maintained for extinction at any wavelength, and also for N(H) vs. E(B-V). However, extinction curves vary within the Milky Way, and there is no reason why, except by chance, either E(B-V) or A(V) would be the most physical measure of dust column density. In this paper, we utilize for the first time full extinction curves to 41 MW sightlines and find that the scatter between N(H) and extinction is minimized -- and the relation becomes linear -- for extinction at 2900 +/- 160 A. Scatter and nonlinearity increase at longer wavelengths and are especially large for near-IR extinction. We conclude that near-UV extinction is a superior measure of the dust column density for MW dust. We provide new, non-linear gas-to-dust relations for various dust tracers. We also find that the very large discrepancy between MW and SMC gas-to-dust ratios of 0.9 dex in N(H)/E(B-V) is reduced to 0.7 dex for far-UV extinction, which matches the difference in cosmic abundances of carbon between the two galaxies, and therefore confirms that N(C) is the preferred measure of the gas in the gas-to-dust ratio, even though it may not be a convenient one.
To understand the evolution of extinction curve, we calculate the dust evolution in a galaxy using smoothed particle hydrodynamics simulations incorporating stellar dust production, dust destruction in supernova shocks, grain growth by accretion and coagulation, and grain disruption by shattering. The dust species are separated into carbonaceous dust and silicate. The evolution of grain size distribution is considered by dividing grain population into large and small gains, which allows us to estimate extinction curves. We examine the dependence of extinction curves on the position, gas densit…
Extinction curves, especially those in the Milky Way (MW), the Large Magellanic Cloud (LMC), and the Small Magellanic Cloud (SMC), have provided us with a clue to the dust properties in the nearby Universe. We examine whether or not these extinction curves can be explained by well known dust evolution processes. We treat the dust production in stellar ejecta, destruction in supernova shocks, dust growth by accretion and coagulation, and dust disruption by shattering. To make a survey of the large parameter space possible, we simplify the treatment of the grain size distribution evolution by ad…
We present a study of the extinction and depletion-derived dust properties of gamma-ray burst (GRB) absorbers at $1<z<3$ showing the presence of neutral carbon (\ion{C}{I}). By modelling their parametric extinction laws, we discover a broad range of dust models characterizing the GRB \ion{C}{I} absorption systems. In addition to the already well-established correlation between the amount of \ion{C}{I} and visual extinction, $A_V$, we also observe a correlation with the total-to-selective reddening, $R_V$. All three quantities are also found to be connected to the presence and strength of the 2…
It is well known that the extinction properties along lines of sight to Type Ia supernovae are described by steep extinction curves with unusually low total-to-selective extinction ratios of Rv = 1.0-2.0. In order to reveal the properties of interstellar dust that causes such peculiar extinction laws, we perform the fitting calculations to the measured extinction curves by applying a two-component dust model composed of graphite and silicate. As for the size distribution of grains, we consider two function forms of the power-law and lognormal distributions. We find that the steep extinction cu…
Dust extinction is one of the most reliable tracers of the gas distribution in the Milky Way. The near-infrared (NIR) Vista Variables in the Via Lactea (VVV) survey enables extinction mapping based on stellar photometry over a large area in the Galactic plane. We devise a novel extinction mapping approach, XPNICER, by bringing together VVV photometric catalogs, stellar parameter data from StarHorse catalogs, and previously published Xpercentile and PNICER extinction mapping techniques. We apply the approach to the VVV survey area, resulting in an extinction map that covers the Galactic disk be…
Interstellar dust plays a central role in shaping the detailed structure of the interstellar medium, thus strongly influencing star formation and galaxy evolution. Dust extinction provides one of the main pillars of our understanding of interstellar dust while also often being one of the limiting factors when interpreting observations of distant objects, including resolved and unresolved galaxies. The ultraviolet (UV) and mid-infrared (MIR) wavelength regimes exhibit features of the main components of dust, carbonaceous and silicate materials, and therefore provide the most fruitful avenue for…
We study the near-infrared (NIR) scattering in LDN 1642, its correlation with the cloud structure, and the ability of dust models to simultaneously explain sub-millimetre emission, NIR extinction, and NIR scattering. We use observations from the HAWK-I instrument to measure the NIR surface brightness and extinction. These are compared with Herschel data on dust emission and, with radiative transfer modelling, with predictions calculated for different dust models. We find an optical depth ratio $τ(250\,μ{\rm m})/τ(J)\approx 10^{-3}$, confirming earlier findings of high sub-millimetre emissivity…
While it is well recognized that both the Galactic interstellar extinction curves and the gas-phase abundances of dust-forming elements exhibit considerable variations from one sight line to another, as yet most of the dust extinction modeling efforts have been directed to the Galactic average extinction curve, which is obtained by averaging over many clouds of different gas and dust properties. Therefore, any details concerning the relationship between the dust properties and the interstellar environments are lost. Here we utilize the wealth of extinction and elemental abundance data obtained…
Observed extinction curves of active galactic nuclei (AGNs) are significantly different from those observed in the Milky Way. The observations require preferential removal of small grains at the AGN environment; however, the physics for this remains unclear. In this paper, we propose that dust destruction by charging, or Coulomb explosion, may be responsible for AGN extinction curves. Harsh AGN radiation makes a dust grain highly charged through photoelectric emission, and grain fission via the Coulomb explosion occurs when the electrostatic tensile stress of a charge grain exceeds its tensile…
The dust extinction curves toward individual sight lines in M33 are derived for the first time with a sample of reddened O-type and B-type supergiants obtained from the LGGS. The observed photometric data are obtained from the LGGS, PS1 Survey, UKIRT, PHATTER Survey, GALEX, Swift/UVOT and XMM-SUSS. We combine the intrinsic spectral energy distributions (SEDs) obtained from the ATLAS9 and Tlusty stellar model atmosphere extinguished by the model extinction curves from the silicate-graphite dust model to construct model SEDs. The extinction traces are distributed along the arms in M33, and the d…
We map the dust distribution in the central 180" (~680 pc) region of the M31 bulge, based on HST/WFC3 and ACS observations in ten bands from near-ultraviolet (2700 A) to near-infrared (1.5 micron). This large wavelength coverage gives us great leverage to detect not only dense dusty clumps, but also diffuse dusty molecular gas. We fit a pixel-by-pixel spectral energy distributions to construct a high-dynamic-range extinction map with unparalleled angular resolution (~0.5" , i.e., ~2 pc) and sensitivity (the extinction uncertainty, δA_V~0.05). In particular, the data allow to directly fit the f…
An Anomalous Extinction Law in the Cep OB3b Young Cluster: Evidence for dust processing during gas dispersal
我们确定通过Cep OB 3b，一个年轻的星团的3000颗恒星进行气体扩散的消光定律。对76个用MMT/Hectospec光谱鉴定的背景K巨星进行了消光测量。使用文献中的$V$和$R$光度测定法，SDSS中的$g$、$r$、$i$和$z$光度测定法，以及2 MASS中的$J$、$H$和$K_{s}$光度测定法，测定每个巨星系的颜色过量比率。这些颜色过量比率被用来构建通过与Cep OB 3b相关的尘埃物质的消光定律。通过Cep OB 3b的消光定律介于$R_{V} = 3.1$定律和$R_{V} = 5$定律之间，这两种定律分别常用于弥漫原子ISM和致密分子云。消光定律对视线$A_{V}$的依赖性进行了研究，我们发现消光定律在具有$A_{V} > 2.5$星等的区域变得更浅。我们推测，中间尘埃法律的结果从尘埃处理过程中的分子云的集群。
Large Variations Seen in First Ultraviolet Spectroscopic M33 Dust Extinction Curves
Space Telescope Science Institute（太空望远镜科学研究所）；Sterrenkundig Observatorium, Universiteit Gent（根特大学天文台）；Institute of Astronomy and NAO, Bulgarian Academy of Sciences（保加利亚科学院天体物理研究所）；University of Sofia, Faculty of Physics（索非亚大学物理学院）；Space Science Institute（空间科学研究所）；Department of Physics & Astronomy, Louisiana State University（路易斯安那州立大学物理与天文学系）；Maria Mitchell Association（玛丽亚·米切尔协会）；European Space Agency (ESA)（欧洲航天局）；Department of Physics & Astronomy, Johns Hopkins University（约翰斯·霍普金斯大学物理与天文学系）
We use Hubble Space Telescope (HST) observations of red clump stars taken as part of the Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE) program to measure the average dust extinction curve in a ~ 200 pc x 100 pc region in the southwest bar of the Small Magellanic Cloud (SMC). The rich information provided by our 8-band ultra-violet through near-infrared photometry allows us to model the color-magnitude diagram of the red clump accounting for the extinction curve shape, a log-normal distribution of $A_{V}$, and the depth of the stellar distribution along the line of sig…
We examine the three-dimensional structure and dust extinction properties in a ~ 200 pc $\times$ 100 pc region in the southwest bar of the Small Magellanic Cloud (SMC). We model a deep Hubble Space Telescope optical color-magnitude diagram (CMD) of red clump and red giant branch stars to infer the dust extinction and galactic structure. We model the distance distribution of the stellar component with a Gaussian and find a centroid distance of 65.2 kpc (distance modulus $μ$ = 19.07 mag) with a FWHM $\approx$ 11.3 kpc. This large extent along the line of sight reproduces results from previous st…
Polarized extinction and emission from dust in the interstellar medium (ISM) are hard to interpret, as they have a complex dependence on dust optical properties, grain alignment and magnetic field orientation. This is particularly true in molecular clouds. The data available today are not yet used to their full potential. The combination of emission and extinction, in particular, provides information not available from either of them alone. We combine data from the scientific literature on polarized dust extinction with Planck data on polarized emission and we use them to constrain the possibl…
Spinning small silicate grains were recently invoked to account for the Galactic foreground anomalous microwave emission. These grains, if present, will absorb starlight in the far ultraviolet (UV). There is also renewed interest in attributing the enigmatic 2175 Angstrom interstellar extinction bump to small silicates. To probe the role of silicon in the UV extinction, we explore the relations between the amount of silicon required to be locked up in silicates [Si/H]_{dust} and the 2175 Angstrom bump or the far-UV extinction rise, based on an analysis of the extinction curves along 46 Galacti…
We interpret the interstellar extinction observed towards the Galactic Center (GC) in the wavelength range $λ= 1 - 20\,\mkm$. Its main feature is the flat extinction at $3 - 8\,\mkm$ whose explanation is still a problem for the cosmic dust models. We search for structure and chemical composition of dust grains that could explain the observed extinction. In contrast to earlier works we use laboratory measured optical constants and consider particles of different structure. We show that a mixture of compact grains of aromatic carbon and of some silicate is better suited for reproducing the flat …
Connecting the dusty dots: dust depletion and extinction of local interstellar clouds
University of Geneva（日内瓦大学）；Wits Centre for Astrophysics, School of Physics, University of the Witwatersrand（威特沃特斯兰德大学物理学院天体物理中心）；European Southern Observatory（欧洲南方天文台）；Université Claude Bernard Lyon 1, Centre de Recherche Astrophysique de Lyon UMR5574（里昂第一大学克洛德·贝尔纳大学，里昂天体物理研究中心UMR5574）；French-Chilean Laboratory for Astronomy (FCLA), CNRS-IRL3386, U. de Chile（法智利天体物理实验室(FCLA)，CNRS-IRL3386，智利大学）；AURA for ESA, Space Telescope Science Institute（ESA支持的AURA，太空望远镜科学研究所）
We formulate and calculate the evolution of dust in a galaxy focusing on the distinction among various dust components -- silicate, aromatic carbon, and non-aromatic carbon. We treat the galaxy as a one-zone object and adopt the evolution model of grain size distribution developed in our previous work. We further include aromatization and aliphatization (inverse reaction of aromatization). We regard small aromatic grains in a radius range of 3--50 Å as polycyclic aromatic hydrocarbons (PAHs). We also calculate extinction curves in a consistent manner with the abundances of silicate and aromati…
Dust plays a central role in the unification theory of active galactic nuclei (AGNs). Whether the dust that forms the torus around an AGN is tenth-$μ$m-sized like interstellar grains or much larger has a profound impact on correcting for the obscuration of the dust torus to recover the intrinsic spectrum and luminosity of the AGN. Here we show that the ratio of the optical extinction in the visual band ($A_V$) to the optical depth of the 9.7 $μ$m silicate absorption feature ($Δτ_{9.7}$) could potentially be an effective probe of the dust size. The anomalously lower ratio of $A_V/Δτ_{9.7} \appr…
JWST Spectroscopic View of a Rapidly Growing Dust-obscured Quasar at $z \sim 4$: Effect of Dust Extinction Correction on Black Hole Mass and Eddington Ratio Estimation
Elements in the interstellar medium (ISM) exist in the form of gas or dust. The interstellar extinction and elemental abundances provide crucial constraints on the composition, size and quantity of interstellar dust. Most of the extinction modeling efforts have assumed the total abundances (both in gas and in dust) of the dust-forming elements---known as the "interstellar abundances", the "interstellar reference abundances", or the "cosmic abundances"---to be solar and the gas-phase abundances to be independent of the interstellar environments. However, it remains unclear if the solar abundanc…
Dust enrichment from core-collapse supernovae and extinction curves in the high-redshift universe
The University of Tokyo（东京大学）；Dipartimento di Fisica, “Sapienza” Università di Roma（罗马大学物理系）；INAF/Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；INFN, Sezione Roma I（意大利国家核物理研究所罗马第一分所）；Sapienza School for Advanced Studies（萨皮恩扎高等研究学院）；INAF/Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切尔天文台）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯玻尔研究所）；Kavli Institute for the Physics and Mathematics of the Universe (WPI)（宇宙物理与数学科学卡弗里研究所）
We aim to compare variations in the full-UV dust extinction curve (912-3000 Angstrom), with the HI/H$_2$/total H content along diffuse Milky Way sightlines, to investigate possible connections between ISM conditions and dust properties. We combine an existing sample of 75 UV extinction curves based on IUE and FUSE data, with atomic and molecular column densities measured through UV absorption. The H$_2$ column density data are based on existing Lyman-Werner absorption band models from earlier work on the extinction curves. Literature values for the HI column density were compiled, and improved…
Expanded Sample of Small Magellanic Cloud Ultraviolet Dust Extinction Curves: Correlations between the 2175 A bump, q_pah, UV extinction shape, and N(HI)/A(V)
Red quasars are very red in the optical through near-infrared (NIR) wavelengths, which is possibly due to dust extinction in their host galaxies as expected in a scenario in which red quasars are an intermediate population between merger-driven star-forming galaxies and unobscured type 1 quasars. However, alternative mechanisms also exist to explain their red colors: (i) an intrinsically red continuum; (ii) an unusual high covering factor of the hot dust component, that is, $\rm CF_{HD} = {\it L}_{HD} / {\it L}_{bol}$, where the ${L}_{\rm HD}$ is the luminosity from the hot dust component and …
The large field and wavelength range of MUSE is well suited to mapping Galactic planetary nebulae (PN). The bright PN NGC 7009 was observed with MUSE on the VLT during the Science Verification of the instrument in seeing of 0.6". Emission line maps in hydrogen Balmer and Paschen lines were formed from analysis of the MUSE cubes. The measured electron temperature and density from the MUSE cube were employed to predict the theoretical hydrogen line ratios and map the extinction distribution across the nebula. After correction for the interstellar extinction to NGC 7009, the internal dust-to-gas …
Dust polarization observations at optical wavelengths help to understand the dust grain properties and trace the plane-of-the-sky component of the magnetic field. In this study, we make use of the $I$-band polarization data acquired from AIMPOL along with the distances ($d$) and extinction ($A_{V}$) data to study the variation of polarization fraction ($P$) as a function of $A_{V}$ and $d$ towards the star-forming region, NGC 1893. We employ a broken power-law fit and Bayesian analysis on extinction ($A_{V}$) versus polarization efficiency ($P$/$A_{V}$) and distance ($d$) versus rate of polari…
Interstellar dust affects astronomical observations through absorption and reddening, yet this extinction is also a powerful tool for studying interstellar matter in galaxies. 3D reconstructions of dust extinction and density in the Milky Way have suffered from artefacts such as the fingers-of-god effect and negative densities, and have been limited by large computational costs. Here we aim to overcome these issues with a novel algorithm that derives the 3D extinction density of dust in the Milky Way using a latent variable Gaussian Process and variational inference. Our model maintains non-ne…
Estimation of Dust Mass from Infrared Emission and Extinction of Supernova Remnants: G93.7-0.2, G109.1-1.0, G156.2+5.7, and G166.0+4.3
School of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学前沿天文与天体物理研究所）；Center for Astrophysics, Guangzhou University（广州大学天体物理中心）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Institute of Astronomy and Physics, Inner Mongolia University（内蒙古大学天文物理研究所）；Departamento de Fisica y Astronomia, Facultad de Ciencias Exactas, Universidad Andres Bello（安第斯贝尔托大学精确科学学院物理与天文学系）
Inferences about the spatial density or phase-space structure of stellar populations in the Milky Way require a precise determination of the effective survey volume. The volume observed by surveys such as Gaia or near-infrared spectroscopic surveys, which have good coverage of the Galactic mid-plane region, is highly complex because of the abundant small-scale structure in the three-dimensional interstellar dust extinction. We introduce a novel framework for analyzing the importance of small-scale structure in the extinction. This formalism demonstrates that the spatially-complex effect of ext…
We present the first results from the Swift Ultraviolet Survey of the Magellanic Clouds (SUMaC), the highest resolution ultraviolet (UV) survey of the Magellanic Clouds yet completed. In this paper, we focus on the Small Magellanic Cloud (SMC). When combined with multi-wavelength optical and infrared observations, the three near-UV filters on the Swift Ultraviolet/Optical Telescope are conducive to measuring the shape of the dust extinction curve and the strength of the 2175Å dust bump. We divide the SMC into UV-detected star-forming regions and large 200" (58~pc) pixels and then model the spe…
DustRover: A Python Package for Modelling Dust Extinction Curves (Phase I)
Astrophysics and Space Technologies Research Centre, Macquarie University（天体物理学与空间技术中心，麦考瑞大学）；School of Mathematical and Physical Sciences, Macquarie University（数学与物理科学学院，麦考瑞大学）
Dust emission and extinction in the Orion OMC-3 cloud
University of Helsinki（赫尔辛基大学）；Université de Toulouse, UPS-OMP, IRAP（图卢兹大学，UPS-OMP，IRAP）；Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale（巴黎萨克雷大学，法国国家科学研究中心，空间天体物理研究所）
A first taste of MEAD (Measuring Extinction and Abundances of Dust) -- I. Diffuse Milky Way interstellar dust extinction features in JWST infrared spectra
We analyze low resolution Spitzer infrared (IR) 5-14 micron spectra of the diffuse emission toward a carefully selected sample of stars. The sample is composed of sight lines toward stars that have well determined ultraviolet (UV) extinction curves and which are shown to lie beyond effectively all of the extinguishing and emitting dust along their lines of sight. Our sample includes sight lines whose UV curve extinction curves exhibit a wide range of curve morphology and which sample a variety of interstellar environments. As a result, this unique sample enabled us to study the connection betw…
