We study the relation between the UV-slope, $β$, and the ratio between the infrared- and UV-luminosities (IRX) of galaxies from TNG50, the latest installment of the IllustrisTNG galaxy formation simulations. We select 7280 star-forming main-sequence (SFMS) galaxies with stellar mass $10^9M_\odot$ at redshifts $0 \leq z \leq 4$ and perform radiative transfer with SKIRT to model effects of interstellar medium dust on the emitted stellar light. Assuming a Milky Way (MW) dust type and a dust-to-metal ratio of 0.3, we find that TNG50 SFMS galaxies generally agree with observationally-derived IRX-$β$ relations at $z \lesssim 1$. However, we find a redshift-dependent systematic offset with respect to empirically-derived local relations, with the TNG50 IRX-$β$ relation shifting towards lower $β$ and steppening at higher redshifts. This is partially driven by variations in the dust-uncorrected UV-slope of galaxies, due to different star-formation histories of galaxies selected at different cosmic epochs; we suggest the remainder of the effect is caused by differences in the effective dust attenuation curves (EDACs) of galaxies as a function of redshift. We find a typical galaxy-to-galaxy variation of 0.3 dex in IRX at fixed $β$, correlated with intrinsic galaxy properties: galaxies with higher star-formation rates, star-formation efficiencies, gas metallicities and stellar masses exhibit larger IRX values. We demonstrate a degeneracy between stellar age, dust geometry and dust composition: $z=4$ galaxies with a Small Magellanic Cloud dust type follow the same IRX-$β$ relation as low-redshift galaxies with MW dust. We provide a redshift-dependent fitting function for the IRX-$β$ relation for MW dust based on our models.
We study the drivers of the scatter in the IRX-beta relation using 23,000 low-redshift galaxies from the GALEX-SDSS-WISE Legacy Catalog 2 (GSWLC-2). For each galaxy we derive, using CIGALE and the SED+LIR fitting technique, the slope of the dust attenuation curve and the strength of the UV bump, plus many other galaxy parameters. We find that the IRX-beta scatter is driven entirely by a wide range of attenuation curves - primarily their slopes. Once the slope and the UV bump are fixed, the scatter in the IRX-beta vanishes. The question of the IRX-beta scatter is the direct manifestation of a m…
The use of ultraviolet (UV) emission as a tracer of galaxy star-formation rate (SFR) is hampered by dust obscuration. The empirical relationship between UV slope, $β$, and the ratio between far-infrared and UV luminosity, IRX, is commonly employed to account for obscured UV emission. We present a simple model that explores the physical origin of variations in the IRX - $β$ dust attenuation relation. A relative increase in FUV attenuation compared to NUV attenuation and an increasing stellar population age cause variations towards red UV slopes for a fixed IRX. Dust geometry effects (turbulence…
We compare the infrared excess (IRX) and Balmer decrement (${\rm Hα/Hβ}$) as dust attenuation indicators in relation to other galaxy parameters using a sample of $\sim$32 000 local star-forming galaxies (SFGs) carefully selected from SDSS, GALEX and WISE. While at fixed ${\rm Hα/Hβ}$, IRX turns out to be independent on galaxy stellar mass, the Balmer decrement does show a strong mass dependence at fixed IRX. We find the discrepancy, parameterized by the color excess ratio $R_{\rm EBV} \equiv E(B-V)_{\rm IRX}/E(B-V)_{\rm Hα/Hβ}$, is not dependent on the gas-phase metallicity and axial ratio but…
We use a sample of star-forming field and protocluster galaxies at z=2.0-2.5 with Keck/MOSFIRE K-band spectra, a wealth of rest-frame UV photometry, and Spitzer/MIPS and Herschel/PACS observations, to dissect the relation between the ratio of IR to UV luminosity (IRX) versus UV slope ($β$) as a function of gas-phase metallicity (12+log(O/H)~8.2-8.7). We find no significant dependence of the IRX-$β$ trend on environment. However, we find that at a given $β$, IRX is highly correlated with metallicity, and less correlated with mass, age, and sSFR. We conclude that, of the physical properties test…
We present the results of a new study of the relationship between infrared excess (IRX), UV spectral slope (beta) and stellar mass at redshifts 2<z<3, based on a deep Atacama Large Millimeter Array (ALMA) 1.3-mm continuum mosaic of the Hubble Ultra Deep Field (HUDF). Excluding the most heavily-obscured sources, we use a stacking analysis to show that z~2.5 star-forming galaxies in the mass range 9.25 <= log(M/Msun) <= 10.75 are fully consistent with the IRX-beta relation expected for a relatively grey attenuation curve, similar to the commonly adopted Calzetti law. Based on a large, mass compl…
We utilise a series of high-resolution cosmological zoom simulations of galaxy formation to investigate the relationship between the ultraviolet (UV) slope, beta, and the ratio of the infrared luminosity to UV luminosity (IRX) in the spectral energy distributions (SEDs) of galaxies. We employ dust radiative transfer calculations in which the SEDs of the stars in galaxies propagate through the dusty interstellar medium. Our main goals are to understand the origin of, and scatter in the IRX-beta relation; to assess the efficacy of simplified stellar population synthesis screen models in capturin…
Evolution of dust attenuation in star-forming galaxies with UV slope, stellar mass, and redshift out to $z \sim 5$
Nicolaus Copernicus University（尼古拉·哥白尼大学）；University of Edinburgh（爱丁堡大学）；National Centre for Nuclear Research（国家核研究中心）；Adam Mickiewicz University（亚当·密茨凯维奇大学）
We use a newly assembled large sample of 3,545 star-forming galaxies with secure spectroscopic, grism, and photometric redshifts at z=1.5-2.5 to constrain the relationship between UV slope (beta) and dust attenuation (L(IR)/L(UV)=IRX). Our sample benefits from the combination of deep Hubble WFC3/UVIS photometry from the Hubble Deep UV (HDUV) Legacy survey and existing photometric data compiled in the 3D-HST survey, and extends the range of UV luminosity and beta probed in previous UV-selected samples. IRX is measured using stacks of deep Herschel/PACS 100 and 160 micron data, and the results a…
Variations in the attenuation law have a significant impact on observed spectral energy distributions for galaxies. As one important observational property for galaxies at ultraviolet and infrared wavelength bands, the correlation between infrared-to-ultraviolet luminosity ratio and ultraviolet color index (or ultraviolet spectral slope), i.e., the IRX-UV relation (or IRX-beta relation), offered a widely used recipe for correcting dust attenuation in galaxies, but the usability appears to be in doubt now because of considerable dispersion in this relation found by many studies. In this paper, …
We present results on the dust attenuation of galaxies at redshift $\sim3-6$ by studying the relationship between the UV spectral slope ($β_{\rm UV}$) and the infrared excess (IRX; $L_{\rm IR}$/$L_{\rm UV}$) using ALMA far-infrared continuum observations. Our study is based on a sample of 67 massive, star-forming galaxies with a median mass of $M_{\ast}\sim 10^{10.7}\,M_{\rm \odot}$ spanning a redshift range $z=2.6-3.7$ (median $z=3.2$) that were observed with ALMA at $λ_{rest}=300\,{\rm μm}$. Both the individual ALMA detections (41 sources) and stacks including all galaxies show the IRX-$β_{\…
Recent high-resolution infrared space missions have revealed supernova remnants (SNRs) of diverse morphology in infrared (IR) dust emission that is often very different from their X-ray appearance. The observed range of infrared-to-X-ray (IRX) flux ratios of SNRs are also wide. For a sample of 20 Galactic SNRs, we obtain their IR and X-ray properties and investigate the physical causes for such large differences. We find that the observed IRX flux ratios ($R_{IRX.obs}$) are related to the IRX morphology, with SNRs with the largest $R_{IRX,obs}$ showing anticorrelated IRX morphology. By analyzi…
Dust emission from high-redshift galaxies gives us a clue to the origin and evolution of dust in the early Universe. Previous studies have shown that different sources of dust (stellar dust production and dust growth in dense clouds) predict different ultraviolet (UV) extinction curves for galaxies at $z\sim 7$ but that the observed attenuation curves depend strongly on the geometry of dust and star distributions. Thus, we perform radiative transfer calculations under the dust-stars geometries computed by a cosmological hydrodynamic simulation (IllustrisTNG). This serves to investigate the dus…
We present dust attenuation properties of spectroscopically confirmed star forming galaxies on the main sequence at a redshift of ~4.4-5.8. Our analyses are based on the far infrared continuum observations of 118 galaxies at rest-frame 158μm obtained with the Atacama Large Millimeter Array (ALMA) Large Program to INvestigate [CII] at Early times (ALPINE). We study the connection between the ultraviolet (UV) spectral slope ($β$), stellar mass (M_*), and infrared excess (IRX=L_IR/L_UV). Twenty-three galaxies are individually detected in the continuum at >3.5 sigma significance. We perform a stac…
Dust has been detected in high-redshift ($z>5$) galaxies but its origin is still being debated. Dust production in high-redshift galaxies could be dominated by stellar production or by accretion (dust growth) in the interstellar medium. Previous studies have shown that these two dust sources predict different grain size distributions, which lead to significantly different extinction curves. In this paper, we investigate how the difference in the extinction curves affects the dust attenuation properties of galaxies by performing radiative transfer calculations. To examine the major effects of t…
The correlation between infrared-to-ultraviolet luminosity ratio and ultraviolet color, i.e. the IRX-UV relation, was regarded as a prevalent recipe for correcting extragalactic dust attenuation. Considerable dispersion in this relation discovered for normal galaxies, however, complicates its usability. In order to investigate the cause of the dispersion, in this paper, we select five nearby spiral galaxies, and perform spatially resolved studies on each of the galaxies, with a combination of ultraviolet and infrared imaging data. We measure all positions within each galaxy and divide the extr…
We present an analysis of the dust attenuation of star forming galaxies at $z=2.5-4.0$ through the relationship between the UV spectral slope ($β$), stellar mass ($M_{\ast}$) and the infrared excess (IRX$=L_{\rm{IR}}/L_{\rm{UV}}$) based on far-infrared continuum observations from the Atacama Large Millimeter/sub-millimeter Array (ALMA). Our study exploits the full ALMA archive over the COSMOS field processed by the A$^3$COSMOS team, which includes an unprecedented sample of $\sim1500$ galaxies at $z\sim3$ as primary or secondary targets in ALMA band 6 or 7 observations with a median continuum …
We study the relationship between the UV continuum slope and infrared excess (IRX$\equiv L_{\rm IR}/L_{\rm FUV}$) predicted by performing dust radiative transfer on a suite of hydrodynamical simulations of galaxies. Our suite includes both isolated disk galaxies and mergers intended to be representative of galaxies at both $z \sim 0$ and $z \sim 2-3$. Our low-redshift isolated disks and mergers often populate a region around the the locally calibrated \citet[][M99]{M99} relation but move well above the relation during merger-induced starbursts. Our high-redshift simulated galaxies are blue and…
The relation between infrared excess (IRX) and UV spectral slope ($β_{\rm UV}$) is an empirical probe of dust properties of galaxies. The shape, scatter, and redshift evolution of this relation are not well understood, however, leading to uncertainties in estimating the dust content and star formation rates (SFRs) of galaxies at high redshift. In this study, we explore the nature and properties of the IRX-$β_{\rm UV}$ relation with a sample of $z=2-6$ galaxies ($M_*\approx 10^9-10^{12}\,M_\odot$) extracted from high-resolution cosmological simulations (MassiveFIRE) of the Feedback in Realistic…
We present a new analysis of high-redshift UV observations using a semi-analytic galaxy formation model, and provide self-consistent predictions of the infrared excess (IRX) -- $β$ relations and cosmic star formation rate density. We combine the Charlot & Fall dust attenuation model with the Meraxes semi-analytic model, and explore three different parametrisations for the dust optical depths, linked to star formation rate, dust-to-gas ratio and gas column density respectively. A Bayesian approach is employed to statistically calibrate model free parameters including star formation efficiency, …
We investigate dust obscuration as parameterised by the infrared excess IRX$\equiv$$L_{\rm IR}/L_{\rm UV}$ in relation to global galaxy properties, using a sample of $\sim$32$\,$000 local star-forming galaxies (SFGs) selected from SDSS, GALEX and WISE. We show that IRX generally correlates with stellar mass ($M_\ast$), star formation rate (SFR), gas-phase metallicity ($Z$), infrared luminosity ($L_{\rm IR}$) and the half-light radius ($R_{\rm e}$). A weak correlation of IRX with axial ratio (b/a) is driven by the inclination and thus seen as a projection effect. By examining the tightness and …
Dust is a crucial component of the interstellar medium of galaxies. The presence of dust strongly affects the light produced by stars within a galaxy. As these photons are our main information vector to explore the stellar mass assembly and therefore understand a galaxy's evolution, modeling the luminous properties of galaxies and taking into account the impact of the dust is a fundamental challenge for semi-analytical models.We present the complete prescription of dust attenuation implemented in the new semi-analytical model: G.A.S. This model is based on a two-phase medium originating from a…
The infrared-to-X-ray (IRX) flux ratio traces the relative importance of dust cooling to gas cooling in astrophysical plasma such as supernova remnants (SNRs). We derive IRX ratios of SNRs in the LMC using Spitzer and Chandra SNR survey data and compare them with those of Galactic SNRs. IRX ratios of all the SNRs in the sample are found to be moderately greater than unity, indicating that dust grains are a more efficient coolant than gas although gas cooling may not be negligible. The IRX ratios of the LMC SNRs are systematically lower than those of the Galactic SNRs. As both dust cooling and …
Recent studies have found a significant evolution and scatter in the IRX-$β$ relation at z > 4, suggesting different dust properties of these galaxies. The total far-infrared (FIR) luminosity is key for this analysis but poorly constrained in normal (main-sequence) star-forming z > 5 galaxies where often only one single FIR point is available. To better inform estimates of the FIR luminosity, we construct a sample of local galaxies and three low-redshift analogs of z > 5 systems. The trends in this sample suggest that normal high-redshift galaxies have a warmer infrared (IR) SED compared to av…
We build a set of composite galaxy SEDs by de-redshifting and scaling multi-wavelength photometry from galaxies in the ZFOURGE survey, covering the CDFS, COSMOS, and UDS fields. From a sample of ~4000 K_s-band selected galaxies, we define 38 composite galaxy SEDs that yield continuous low-resolution spectra (R~45) over the rest-frame range 0.1-4 um. Additionally, we include far infrared photometry from the Spitzer Space Telescope and the Herschel Space Observatory to characterize the infrared properties of our diverse set of composite SEDs. From these composite SEDs we analyze the rest-frame U…
We examine the rest-frame ultra-violet (UV) properties of 10 [CII]$\lambda158\,{\rm μm}$$-$detected galaxies at $z\sim5.5$ in COSMOS using new HST/WFC3 near-infrared imaging. Together with pre-existing $158\,{\rm μm}-$continuum and [CII] line measurements by ALMA, we study their dust attenuation properties on the IRX-$β$ diagram, which connects the total dust emission ($\propto$ IRX=log($L_{FIR}/L_{1600}$)) to the line-of-sight dust column ($\proptoβ$). We find systematically bluer UV continuum spectral slopes ($β$) compared to previous low-resolution ground-based measurements, which relieves …
We use a sample of 4178 Lyman break galaxies (LBGs) at z = 3, 4 and 5 in the UKIRT Infrared Deep Sky Survey (UKIDSS) Ultra Deep Survey (UDS) field to investigate the relationship between the observed slope of the stellar continuum emission in the ultraviolet, β, and the thermal dust emission, as quantified via the so-called 'infrared excess' (IRX = LIR/LUV). Through a stacking analysis we directly measure the 850-μm flux density of LBGs in our deep (0.9mJy) James Clerk Maxwell Telescope (JCMT) SCUBA-2 850-μm map, as well as deep public Herschel/SPIRE 250-, 350- and 500-μm imaging. We establish…
At intermediate and high redshifts, measurements of galaxy star-formation rates are usually based on rest-frame ultraviolet (UV) data. A correction for dust attenuation, A_UV, is needed for these measurements. This correction is typically inferred from UV spectral slopes (beta) using an equation known as "Meurer's Relation." In this paper, we study this relation at a redshift of 1.5 using images and photometric measurements in the rest-frame UV (HST) through mid-infrared (Spitzer). It is shown that massive star-forming galaxies (above 10^10 Msun) have dust corrections that are dependent on the…
We present an analysis of 98 galaxies of low-dust content, selected from the Spitzer Local Volume Legacy survey, aimed at examining the relation between the ultraviolet (UV) color, beta, and dust attenuation in normal star-forming galaxies. The IRX-beta diagram relates the total dust attenuation in a galaxy, traced by the far-IR (FIR) to UV ratio, to the observed UV color, indicated by beta. Previous research has indicated that while starburst galaxies exhibit a relatively tight IRX-beta relation, normal star-forming galaxies do not, and have a much larger spread in the total-IR to far-UV (FUV…
By stacking publicly available deep Spitzer/MIPS 24 $μ$m and Herschel/PACS images for 213 $z \simeq 2.18$ Ly$α$ Emitters (LAEs) in GOODS-South, we obtain a strong upper limit to the IR luminosity of typical LAEs and discuss their attenuation curve for the first time. The $3σ$ upper limit $L_{\rm TIR}^{3σ}= 1.1 \times 10^{10} L_\odot$, determined from the MIPS data providing the lowest limit, gives $IRX \equiv L_{\rm TIR}/L_{\rm UV} \leq 2.2$. Here we assume that the local calibration between the 8 $μ$m emission and the dust SED shape and metallicity applies at high redshifts and that our LAEs …
We compare common star-formation rate (SFR) indicators in the local Universe in the GAMA equatorial fields (around 160 sq. deg.), using ultraviolet (UV) photometry from GALEX, far-infrared (FIR) and sub-millimetre (sub-mm) photometry from H-ATLAS, and Halpha spectroscopy from the GAMA survey. With a high-quality sample of 745 galaxies (median redshift 0.08), we consider three SFR tracers: UV luminosity corrected for dust attenuation using the UV spectral slope beta (SFRUV,corr), Halpha line luminosity corrected for dust using the Balmer decrement (BD) (SFRHalpha,corr), and the combination of U…
We analyse 870um Atacama Large Millimetre Array (ALMA) dust continuum detections of 41 canonically-selected z~3 Lyman-break galaxies (LBGs), as well as 209 ALMA-undetected LBGs, in follow-up of SCUBA-2 mapping of the UKIDSS Ultra Deep Survey (UDS) field. We find that our ALMA-bright LBGs lie significantly off the locally calibrated IRX-beta relation and tend to have relatively bluer rest-frame UV slopes (as parametrised by beta), given their high values of the 'infrared excess' (IRX=L_IR/L_UV), relative to the average 'local' IRX-beta relation. We attribute this finding in part to the young ag…
The gas in galaxies is both the fuel for star formation and a medium that attenuates the light of the young stars. We study the relations between UV attenuation, spectral slope, star formation rates, and molecular gas surface densities in a sample of 28 z$\sim$1 and a reference sample of 32 z$\sim$0 galaxies that are detected in CO, far-infrared, and rest frame UV. The samples are dominated by disc-like galaxies close to the main SFR--mass relation. We find that the location of the z$\sim$1 galaxies on the IRX-$β$ plane is correlated with their gas-depletion time-scale $τ_{dep}$ and can predic…
UV and optical surveys are essential to gain insight into the processes driving galaxy formation and evolution. The rest-frame UV emission is key to measure the cosmic SFR. However, UV light is strongly reddened by dust. In starburst galaxies, the UV colour and the attenuation are linked, allowing to correct for dust extinction. Unfortunately, evidence has been accumulating that the relation between UV colour and attenuation is different for normal star-forming galaxies when compared to starburst galaxies. It is still not understood why star-forming galaxies deviate from the UV colour-attenuat…
Using the First Light And Reionisation Epoch Simulations (\textsc{Flares}) we explore the dust driven properties of massive high-redshift galaxies at $z\in[5,10]$. By post-processing the galaxy sample using the radiative transfer code \textsc{skirt} we obtain the full spectral energy distribution. We explore the resultant luminosity functions, IRX-$β$ relations as well as the luminosity-weighted dust temperatures in the Epoch of Reionisation (EoR). We find that most of our results are in agreement with the current set of observations, but under-predict the number densities of bright IR galaxie…
We present a theoretical model aimed at explaining the IRX-$β$ relation for high redshift (z >5) galaxies. Recent observations (Capak+2015; Bouwens+2016) have shown that early Lyman Break Galaxies, although characterized by a large UV attenuation (e.g. flat UV beta slopes), show a striking FIR deficit, i.e. they are "infrared-dark". This marked deviation from the local IRX-beta relation can be explained by the larger molecular gas content of these systems. While dust in the diffuse ISM attains relatively high temperatures (Td = 45 K for typical size a=0.1 um; smaller grains can reach Td = 60 K…
Dust attenuation in star-forming spiral galaxies affects stars and gas in different ways due to local variations in dust geometry. We present spatially resolved measurements of dust attenuation for a sample of 232 such star-forming spiral galaxies, derived from spectra acquired by the SDSS-IV MaNGA survey. The dust attenuation affecting the stellar populations of these galaxies (obtained using full spectrum stellar population fitting methods) is compared with the dust attenuation in the gas (derived from the Balmer decrement). Both of these attenuation measures increase for local regions of ga…
We explore from a statistical point of view the far-infrared (far-IR) and sub-millimeter (sub-mm) properties of a large sample of LBGs (22,000) at z~3 in the COSMOS field. The large number of galaxies allows us to split it in several bins as a function of UV luminosity, UV slope, and stellar mass to better sample their variety. We perform stacking analysis in PACS (100 and 160 um), SPIRE (250, 350 and 500 um) and AzTEC (1.1 mm) images. Our stacking procedure corrects the biases induced by galaxy clustering and incompleteness of our input catalogue in dense regions. We obtain the full IR spectr…
Studying the UV dust attenuation, as well as its relation to other galaxy parameters such as the stellar mass, plays an important role in multi-wavelength research. This work relates the dust attenuation to the stellar mass of star forming galaxies, and its evolution with redshift. A sample of galaxies with an estimate of the dust attenuation computed from the infrared excess was used. The dust attenuation vs. stellar mass data, separated in redshift bins, was modelled by a single parameter linear function, assuming a nonzero constant apparent dust attenuation for low mass galaxies. But the or…
Analysing a large representative sample of local galaxies (8707), we find that the variation in the shape of their dust attenuation curves is driven primarily by their structure, i.e., distribution of stars (and dust) within them. The attenuation curve for spheroid dominated galaxies, as compared to the disc dominated ones, is nearly twice as steep. Both structural types cover distinct ranges of attenuation slope values. Similar findings are reflected in the case of star-forming and passive galaxies. Spheroids and passive galaxies witness minimal attenuation in the optical compared to UV wavel…
Mapping Dust Attenuation at Kiloparsec Scales. IV. A Dust-model Interpretation of Attenuation Curves in Nearby Galaxies
Tsinghua University（清华大学）；INAF–Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；The Chinese University of Hong Kong（香港中文大学）
Dust attenuation is a crucial but highly uncertain parameter that hampers the determination of intrinsic galaxy properties, such as stellar masses, star formation rates and star formation histories. The shape of the dust attenuation law is not expected to be uniform between galaxies, nor within a galaxy. Our DustKING project was introduced at the first BINA workshop in 2016 and aims to study the variations of dust attenuation curves in nearby galaxies. At the second BINA workshop in 2018, I presented the results of our pilot study for the spiral galaxy NGC628. We find that the average attenuat…
One of the most common methods for inferring galaxy attenuation curves is via spectral energy distribution (SED) modeling, where the dust attenuation properties are modeled simultaneously with other galaxy physical properties. In this paper, we assess the ability of SED modeling to infer these dust attenuation curves from broadband photometry, and suggest a new flexible model that greatly improves the accuracy of attenuation curve derivations. To do this, we fit mock SEDs generated from the Simba cosmological simulation with the Prospector SED fitting code. We consider the impact of the common…
We present the Empirical Dust Attenuation (EDA) framework -- a flexible prescription for assigning realistic dust attenuation to simulated galaxies based on their physical properties. We use the EDA to forward model synthetic observations for three state-of-the-art large-scale cosmological hydrodynamical simulations: SIMBA, IllustrisTNG, and EAGLE. We then compare the optical and UV color-magnitude relations, $(g-r) - M_r$ and $(FUV-NUV)-M_r$, of the simulations to a $M_r < -20$ and UV complete SDSS galaxy sample using likelihood-free inference. Without dust, none of the simulations match obse…
We examine the evolution of dust attenuation curve using a sample of 9504 disk star-forming galaxies (SFGs) selected from the CANDELS and 3D-HST surveys and a new technique relying on the fact that disk SFGs of similar stellar masses at the same cosmic epoch are statistically identical in stellar populations. We attribute the discrepancy in median magnitude between face-on (b/a>0.7) and edge-on (b/a<=0.4) subsamples solely to dust attenuation, and obtain the average attenuation in the rest-frame UV and optical as functions of stellar mass and redshift out to z=2.5. Our results show that the at…
We develop a method to estimate the dust attenuation curve of galaxies from full spectral fitting of their optical spectra. Motivated from previous studies, we separate the small-scale features from the large-scale spectral shape, by performing a moving average method to both the observed spectrum and the simple stellar population model spectra. The intrinsic dust-free model spectrum is then derived by fitting the observed ratio of the small-scale to large-scale (S/L) components with the S/L ratios of the SSP models. The selective dust attenuation curve is then determined by comparing the obse…
We investigate the stellar and dust properties of massive (log$(M_*/M_\odot) \ge 10.5$) and dusty ($A_V \ge 1$) galaxies at $1 \le z \le 4$ by modeling their spectral energy distributions (SEDs) obtained from the combination of UltraVISTA DR3 photometry and \textit{Herschel} PACS-SPIRE data using MAGPHYS. Although the rest-frame U-V vs V-J (UVJ) diagram traces well the star-formation rates (SFR) and dust obscuration (A$_V$) out to $z \sim 3$, $\sim$15-20\% of the sample surprisingly resides in the quiescent region of the UVJ diagram, while $\sim50$\% at $3<z<4$ fall in the unobscured star-form…
The spatial distribution of dust in galaxies affects the global attenuation, and hence inferred properties, of galaxies. We trace the spatial distribution of dust in five fields (at 0.6-0.9 kpc scale) of M31 by comparing optical attenuation with the total dust mass distribution. We measure the attenuation from the Balmer decrement using Integral Field Spectroscopy and the dust mass from Herschel far-IR observations. Our results show that M31's dust attenuation closely follows a foreground screen model, contrary to what was previously found in other nearby galaxies. By smoothing the M31 data we…
In this work we investigate the far-UV to NIR shape of the dust attenuation curve of a sample of IR selected dust obscured (U)LIRGs at z$\sim$2. The spectral energy distributions (SEDs) are fitted with CIGALE, a physically-motivated spectral synthesis model based on energy balance. Its flexibility allows us to test a wide range of different analytical prescriptions for the dust attenuation curve, including the well-known Calzetti and Charlot & Fall curves, and modified versions of them. The attenuation curves computed under the assumption of our reference double power-law model are in very goo…
