准确的空间解析尘埃校正对于解释恒星形成星系的结构和演化至关重要。我们提出一个经验模型，利用Apache Point Observatory Mapping Nearby Galaxies (MaNGA)调查的积分场光谱数据，预测恒星形成星系的解析尘埃消光（A_V）。使用5155个星系样本（7.20 < M* < 11.14 和 0.0002 < z < 0.1444），我们从巴尔末消光率中推导出超过1,898,954个恒星形成spaxels的A_V地图。使用局部恒星形成率面密度（Σ_SFR）作为预测因子，模型达到R²=0.69和RMSE=0.22 mag，残差近似高斯分布且中心接近零。模型在kpc尺度上预测A_V的因子约为1.3。我们还证明该关系可以迭代应用以从未校正的值中恢复尘埃校正的Σ_SFR，第四次迭代时残差偏置最小（-0.01 mag）且RMSE低（0.42 mag）。该模型在多样化的形态和取向中准确再现A_V地图，包括边缘视星系。它还恢复了观测到的径向A_V分布，捕捉其对恒星质量及相对恒星形成活动的依赖性，更高质量和更强烈恒星形成星系显示出更陡的梯度。
英文摘要：
Accurate spatially resolved dust corrections are critical for interpreting the structure and evolution of star-forming galaxies (SFGs). We present an empirical model for predicting spatially resolved dust attenuation ($A_V$) in SFGs using integral field spectroscopy from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. Using a sample of 5,155 galaxies over $7.20<M_\ast<11.14$ and $0.0002 < z < 0.1444$, we derive $A_V$ maps from the Balmer decrement across more than 1,898,954 star-forming spaxels. Using local star formation rate surface density ($Σ_{\text{SFR}}$) as a predictor, the model achieves $R^2 = 0.69$ and RMSE $=0.22$ mag, with residuals that are approximately Gaussian and centred near zero. It predicts $A_V$ within a factor of $\sim$1.3 on kpc scales. We also demonstrate that the relation can be applied iteratively to recover dust-corrected $Σ_{\mathrm{SFR}}$ from uncorrected values, converging by the fourth iteration with minimal residual bias ($-0.01$ mag) and low RMSE ($0.42$ mag). The model accurately reproduces $A_V$ maps across diverse morphologies and orientations, including edge-on systems. It also recovers the observed radial $A_V$ profiles, capturing their dependence on stellar mass and relative star formation activity, with more massive and more strongly star-forming galaxies showing steeper gradients.
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 investigate the dust attenuation in both stellar populations and ionized gas in kpc-scale regions in nearby galaxies, using integral field spectroscopy data from MaNGA MPL-9. We identify star-forming (HII) and diffuse ionized gas (DIG) regions from MaNGA datacubes. From the stacked spectrum of each region, we measure the stellar attenuation, $E(B-V)_{\rm star}$, using the technique developed by Li et al.(2020), as well as the gas attenuation, $E(B-V)_{\rm gas}$, from the Balmer decrement. We then examine the correlation of $E(B-V)_{\rm star}$, $E(B-V)_{\rm gas}$, $E(B-V)_{\rm gas}-E(B-V)_{\…
A fundamental assumption adopted in nearly every extragalactic emission-line study is that the attenuation of different emission lines can be described by a single attenuation curve. Here we show this assumption fails in many cases with important implications for derived results. We developed a new method to measure the differential nebular attenuation among three kinds of transitions: the Balmer lines of hydrogen, high-ionization transitions, and low-ionization transitions. This method bins the observed data in a multidimensional space spanned by attenuation-insensitive line ratios. Within ea…
The H$α$ and H$β$ emission line luminosities measured in a single integrated spectrum are affected in non-trivial ways by point-to-point variations in dust attenuation in a galaxy. This work investigates the impact of this variation when estimating global H$α$ luminosities corrected for the presence of dust by a global Balmer decrement. Analytical arguments show that the dust-corrected H$α$ luminosity is always underestimated when using the global H$α$/H$β$ flux ratio to correct for dust attenuation. We measure this effect on 156 face-on star-forming galaxies from the Mapping Nearby Galaxies a…
The MAGPI Survey: Evidence for Non-Universal Resolved Dust Attenuation Relations Beyond the Local Universe
Macquarie University（麦考瑞大学）；University of Groningen（格罗宁根大学）；Indiana University（印第安纳大学）；National Astronomical Observatory of Japan（日本国立天文台）；Durham University（杜伦大学）；The University of Western Australia（西澳大学）；Australian National University（澳大利亚国立大学）；The University of Sydney（悉尼大学）
研究 MAGPI 巡天星系中尘埃消光与恒星形成率面密度的关系，通过与 MaNGA 本地关系比较，发现中等红移处两者关系非通用，本地校准关系无法完全描述，强调解释星系属性时需考虑星系群体和红移的消光校准。
The attenuation of light in star forming galaxies is correlated with a multitude of physical parameters including star formation rate, metallicity and total dust content. This variation in attenuation is even more prevalent on the kiloparsec scale, which is relevant to many current spectroscopic integral field unit surveys. To understand the cause of this variation, we present and analyse \textit{Swift}/UVOT near-UV (NUV) images and SDSS/MaNGA emission-line maps of 29 nearby ($z<0.084$) star forming galaxies. We resolve kiloparsec-sized star forming regions within the galaxies and compare thei…
We present the MaNGA FIREFLY Value-Added-Catalogue (VAC) - a catalogue of ~3.7 million spatially resolved stellar population properties across 10,010 nearby galaxies from the final data release of the MaNGA survey. The full spectral fitting code firefly is employed to derive parameters such as stellar ages, metallicities, stellar and remnant masses, star formation histories, star formation rates and dust attenuation. In addition to Voronoi-binned measurements, our VAC also provides global properties, such as central values and radial gradients. Two variants of the VAC are available: presenting…
We present a method of fitting optical spectra of galaxies using a basis set of six vectors obtained from principal component analysis (PCA) of a library of synthetic spectra of 40000 star formation histories (SFHs). Using this library, we provide estimates of resolved effective stellar mass-to-light ratio ($\log Υ^*$) for thousands of galaxies from the SDSS-IV/MaNGA integral-field spectroscopic survey. Using a testing framework built on additional synthetic SFHs, we show that the estimates of stellar mass-to-light ratio are reliable (as are their uncertainties) at a variety of signal-to-noise…
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…
Dust attenuation of an inclined galaxy can cause additional asymmetries in observations, even if the galaxy has a perfectly symmetric structure. {Taking advantage of the integral field spectroscopic data observed by the SDSS-IV MaNGA survey, we investigate the asymmetries of the emission-line and continuum maps of star-forming disk galaxies.} We define new parameters, $A_a$ and $A_b$, to estimate the asymmetries of a galaxy about its major and minor axes, respectively. Comparing $A_a$ and $A_b$ in different inclination bins, we attempt to detect the asymmetries caused by dust. For the continuu…
The role of active galactic nuclei (AGNs) during galaxy interactions and how they influence the star formation in the system are still under debate. We use a sample of 1156 galaxies in galaxy pairs or mergers (hereafter `pairs') from the MaNGA survey. This pair sample is selected by the velocity offset, projected separation, and morphology, and is further classified into four cases along the merger sequence based on morphological signatures. We then identify a total of 61 (5.5%) AGNs in pairs based on the emission-line diagnostics. No evolution of the AGN fraction is found, either along the me…
Bars are common in low-redshift disk galaxies, and hence quantifying their influence on their host is of importance to the field of galaxy evolution. We determine the stellar populations and star formation histories of 245 barred galaxies from the MaNGA galaxy survey, and compare them to a mass- and morphology-matched comparison sample of unbarred galaxies. At fixed stellar mass and morphology, barred galaxies are optically redder than their unbarred counterparts. From stellar population analysis using the full spectral fitting code Starlight, we attribute this difference to both older and mor…
In this work, we investigate the strength and impact of ionised gas outflows within $z \sim 0.04$ MaNGA galaxies. We find evidence for outflows in 322 galaxies ($12\%$ of the analysed line-emitting sample), 185 of which show evidence for AGN activity. Most outflows are centrally concentrated with a spatial extent that scales sublinearly with $R_{\rm e}$. The incidence of outflows is enhanced at higher masses, central surface densities and deeper gravitational potentials, as well as at higher SFR and AGN luminosity. We quantify strong correlations between mass outflow rates and the mechanical d…
Mapping Dust Attenuation at Kiloparsec Scales. III. The 2175Å Bump
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）
We investigate the star formation history and the dust attenuation in the galaxy merger Mrk848. Thanks to the multiwavelength photometry from the ultraviolet (UV) to the infrared (IR), and MaNGA's integral field spectroscopy, we are able to study this merger in a detailed way. We divide the whole merger into the core and tail regions, and fit both the optical spectrum and the multi-band spectral energy distribution (SED) to models to obtain the star formation properties for each region respectively. We find that the color excess of stars in the galaxy $E(B-V)_s^{SED}$ measured with the multi-b…
We combine Hubble Space Telescope (HST) Paschen $β$ (Pa$β$) imaging with ground-based, previously published H$α$ maps to estimate the attenuation affecting H$α$, A(H$α$), across the nearby, face-on galaxies NGC 5194 and NGC 6946. We estimate A(H$α$) in ~ 2,000 independent 2" ~75 pc diameter apertures in each galaxy, spanning out to a galactocentric radius of almost 10 kpc. In both galaxies, A(H$α$) drops with radius, with a bright, high attenuation inner region, though in detail the profiles differ between the two galaxies. Regions with the highest attenuation-corrected H$α$ luminosity show th…
The state-of-the-art geometry models of stars/dust suggest that dust attenuation toward nebular regions ($A_{V,gas}$) is always larger than that of stellar regions ($A_{V,star}$). Utilizing the newly released integral field spectroscopic data from the MaNGA survey, we investigate whether and how the $A_{V,star}/A_{V,gas}$ ratio varies from subgalactic to galactic scales. On a subgalactic scale, we report a stronger correlation between $A_{V,star}$ and $A_{V,gas}$ for more active HII regions. The local $A_{V,star}/A_{V,gas}$ is found to have moderate nonlinear correlations with three tracers of…
P-MaNGA: Full spectral fitting and stellar population maps from prototype observations
MANGA（Mapping Nearby Galerkin at Apache Point Observatory）是一项为期6年的SDSS-IV巡天计划，将获得3600 $Å$至10300 $Å$的光谱，代表超过10，000个邻近星系的样本。在本文中，我们推导出空间分辨的恒星星族属性和径向梯度进行全光谱拟合观测星系光谱的P-MaNGA，原型的MaNGA仪器。这些数据包括18个星系的光谱，涵盖了大范围的形态类型。我们推导出年龄，金属丰度，尘埃和恒星质量图，以及它们的径向梯度，使用高光谱分辨率的恒星星族模型，并评估不同的恒星库输入模型的影响。我们介绍了一种方法来确定尘埃消光，即使在高和空间不均匀的尘埃衰减的情况下，也能够得到平滑的恒星质量图。与光谱拟合，我们产生详细的地图，恒星星族的属性，使我们能够识别银河系的功能，如螺旋结构，光滑的径向配置文件，在球状星系的方位角结构少，空间上不同的星系子组件之间的这种不同的样本。与文献一致，我们发现早期型星系的年龄梯度平均为平，金属丰度为负（-0.15 dex / R $_e$），而晚期型星系的年龄梯度平均为负（-0.39 dex / R $_e$），金属丰度为平。我们演示了不同水平的数据质量如何改变径向梯度的测量精度。我们展示了这种分析，扩展到大量的MANGA星系，将有可能揭示星系的结构和演化。
Mapping star-formation rates (SFR) within galaxies is key to unveiling their assembly and evolution. Calibrations exist for computing SFR from a combination of ultraviolet and infrared bands for galaxies as integrated systems, but their applicability to sub-galactic (kpc) scales remains largely untested. Here we use integral field spectroscopy of 19 nearby ($D <$ 20 Mpc) galaxies obtained by PHANGS-MUSE to derive accurate Balmer decrements (H$α$/H$β$) and attenuation-corrected H$α$ maps. We combine this information with mid-infrared maps from WISE at 22 $\rm μm$, and ultraviolet maps from GALE…
The fraction of ionizing photons that escape high-redshift galaxies sensitively determines whether galaxies reionized the early universe. However, this escape fraction cannot be measured from high-redshift galaxies because the opacity of the intergalactic medium is large at high redshifts. Without methods to indirectly measure the escape fraction of high-redshift galaxies, it is unlikely that we will know what reionized the universe. Here, we analyze the far-ultraviolet (UV) H I (Lyman series) and low-ionization metal absorption lines of nine low-redshift, confirmed Lyman continuum emitting ga…
We investigate the star formation histories (SFHs) of massive red spiral galaxies with stellar mass $M_\ast>10^{10.5}M_\odot$, and make comparisons with blue spirals and red ellipticals of similar masses. We make use of the integral field spectroscopy from the SDSS-IV/DR15 MaNGA sample, and estimate spatially resolved SFHs and stellar population properties of each galaxy by applying a Bayesian spectral fitting code to the MaNGA spectra. We find that both red spirals and red ellipticals have experienced only one major star formation episode at early times, and the result is independent of the a…
Knowledge of the number density of H$α$ emitting galaxies is vital for assessing the scientific impact of the Euclid and WFIRST missions. In this work we present predictions from a galaxy formation model, Galacticus, for the cumulative number counts of H$α$-emitting galaxies. We couple Galacticus to three different dust attenuation methods and examine the counts using each method. A $χ^2$ minimisation approach is used to compare the model predictions to observed galaxy counts and calibrate the dust parameters. We find that weak dust attenuation is required for the Galacticus counts to be broad…
Predicting ionised gas emission in 3D with SKIRT. I. Framework and validation
Department of Physics and Astronomy, Proeftuinstraat 86 N3, B-9000 Ghent, Belgium（根特大学物理与天文学系）；Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, USA（德克萨斯大学达拉斯分校物理系）；Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK（剑桥大学卡文迪许实验室）
The ultraviolet (UV) to sub-millimetre (submm) spectral energy distribution of galaxies can be roughly divided into two sections: the stellar emission (attenuated by dust) at UV to near-infrared wavelengths and dust emission at longer wavelengths. In Dobbels et al. (2020), we show that these two sections are strongly related, and we can predict the global dust properties from the integrated UV to mid-infrared emission with the help of machine learning techniques. We investigate if these machine learning techniques can also be extended to resolved scales. Our aim is to predict resolved maps of …
Spatially resolved star-formation histories of local post-starburst galaxies: Starburst and quenching spatial patterns consistent with recent mergers
University of St Andrews（圣安德鲁斯大学）；University of Edinburgh（爱丁堡大学）；Imperial College London（帝国理工学院）；University of Hertfordshire（赫特福德大学）；Anqing Normal University（安庆师范大学）
We present an analysis of star formation and quenching in the SDSS-IV MaNGA-DR15, utilising over 5 million spaxels from $\sim$3500 local galaxies. We estimate star formation rate surface densities ($Σ_{\rm SFR}$) via dust corrected $Hα$ flux where possible, and via an empirical relationship between specific star formation rate (sSFR) and the strength of the 4000 Angstrom break (D4000) in all other cases. We train a multi-layered artificial neural network (ANN) and a random forest (RF) to classify spaxels into `star forming' and `quenched' categories given various individual (and groups of) par…
Exploring the interplay between star formation efficiency and dust in regulating the UV luminosity of early systems in the JWST and ALMA era
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）；David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto（多伦多大学大卫A邓普勒天文与天体物理系）
Euclid preparation. Predicting star-forming galaxy scaling relations with the spectral stacking code SpectraPyle
Alma Mater Studiorum Università di Bologna（博洛尼亚大学）；INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（博洛尼亚天文物理与空间科学研究所）；INAF-IASF Milano（米兰天文物理与空间科学研究所）；Università di Padova（帕多瓦大学）；INAF-Osservatorio Astronomico di Padova（帕多瓦天文台）；Oxford University（牛津大学）；Aix-Marseille Université（艾克斯-马赛大学）；ESAC/ESA（欧洲空间应用中心/欧洲空间局）
Unveiling the (in)consistencies among the galaxy stellar mass function, star formation histories, satellite abundances and intracluster light from a semi-empirical perspective
