We present a method to self-consistently propagate M$_{*}$ and SFR ($Ψ$) uncertainties onto intercept, slope and intrinsic scatter estimates for a simple model of the main sequence of star forming galaxies where $Ψ= α+ β$M$_{*} + \mathcal{N}(0,σ)$. From simple idealised models set up with broad-band photometry from NIRCam filters at $z\sim5$, we test the method and compare to methods in the literature. Simplifying the $Ψ$ estimate by basing it on dust-corrected MUV can help to reduce the impact of template set degeneracies on slope and intercept estimates, but act to bias the intrinsic scatter estimate. We find that broad-band fluxes alone cannot constrain the contribution from emission lines, implying that strong priors on the emission-line contribution are required if no medium-band constraints are available. Therefore at high redshifts, where emission lines contribute a higher fraction of the broad-band flux, photometric fitting is sensitive to $Ψ$ variations on short ($\sim$ 10 Myr) timescales. Priors on age imposed with a constant (or rising) star formation history (SFH) do not allow one to investigate a possible dependence of $σ$ on M$_{*}$ at high redshifts. Delayed exponential SFHs have less constrained priors, but do not account for $Ψ$ variations on short timescales, a problem if $σ$ increases due to stochasticity of star formation. A simple SFH with current star formation decoupled from the previous history is appropriate. We show that, for simple exposure-time calculations assuming point sources, with low levels of dust, we should be able to obtain unbiased estimates of the main sequence down to log(M/M$_{\odot}$) $\sim$ 8 at $z\sim5$ with the James Webb Space Telescope while allowing for stochasticity of star formation.
We measure abundances of 12 elements (Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) in a sample of 86 metal-poor ($-2 \lesssim \text{[Fe/H]} \lesssim -1$) subgiant stars in the solar neighborhood. Abundances are derived from high-resolution spectra taken with the Potsdam Echelle Polarimetric and Spectroscopic Instrument on the Large Binocular Telescope, modeled using iSpec and MOOG. By carefully quantifying the impact of photon-noise ($< 0.05$ dex for all elements) we robustly measure the intrinsic scatter of abundance ratios. At fixed [Fe/H] the RMS intrinsic scatter in [X/Fe] ranges from 0.…
We explore a class of simple non-equilibrium star formation models within the framework of a feedback-regulated model of the ISM, applicable to kiloparsec-scale resolved star formation relations (e.g. Kennicutt-Schmidt). Combining a Toomre-Q-dependent local star formation efficiency per free-fall time with a model for delayed feedback, we are able to match the normalization and scatter of resolved star formation scaling relations. In particular, this simple model suggests that large ($\sim$dex) variations in star formation rates (SFRs) on kiloparsec scales may be due to the fact that supernova…
Untangling dust emission and cosmic infrared background anisotropies with the scattering transform statistics
National Institute of Science Education and Research（印度科学教育研究所）；Homi Bhabha National Institute（霍米·巴巴国立研究所）；Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité（巴黎高等师范学院物理实验室）；Laboratoire d’Océanographie Physique et Spatiale (LOPS), Univ. Brest, CNRS, Ifremer, IRD（布列斯特大学海洋物理与空间实验室）
Using VIPERS, we estimated a set of SFR based on photometric and spectroscopic data. We used, as estimators, photometric bands from ultraviolet to mid-infrared, and spectral lines. Assuming a reference SFR obtained from the spectral energy distribution reconstructed with Code Investigating GALaxy Emission, we estimated the reliability of each band as an SFR tracer. We used GSWLC to trace the dependence of these SFR calibrators with redshift. The far and near UV, u-band and 24-$μ$m bands, as well as $L_{TIR}$, are found to be good SFR tracers up to $z\sim0.9$ with a strong dependence on the att…
Observatoire Astronomique de Strasbourg, Université de Strasbourg（斯特拉斯堡天文台，斯特拉斯堡大学）；Institut d’Astrophysique de Paris, Sorbonne Université（巴黎天体物理研究所，索邦大学）；Sterrenkundig Observatorium, Universiteit Gent（根特大学天文台）；Department of Astronomy and Yonsei University Observatory, Yonsei University（延世大学天文系及延世大学天文台）
Using a sample of 11,478 spaxels in 34 galaxies with molecular gas, star formation and stellar maps taken from the ALMA-MaNGA QUEnching and STar formation (ALMaQUEST) survey, we investigate the parameters that correlate with variations in star formation rates on kpc scales. We use a combination of correlation statistics and an artificial neural network to quantify the parameters that drive both the absolute star formation rate surface density (Sigma_SFR), as well as its scatter around the resolved star forming main sequence (Delta Sigma_SFR). We find that Sigma_SFR is primarily regulated by mo…
We investigate the use of the [O II] $\lambda3727$ emission line as a star formation rate (SFR) estimator using Sloan Digital Sky Spectra for nearly 100,000 star-forming galaxies and 5,500 galaxies with narrow-line active galactic nuclei. Consistent with previous work, we find that the [O II]/H$α$ ratio in star-forming galaxies depends strongly on gas-phase metallicity. Using metallicities derived from the [N II] $λ6584$/[O II] $λ3727$ method, we refine a metallicity-dependent SFR estimator based on [O II] that is calibrated within a scatter of 0.056 dex against the more commonly used SFR indi…
We use 789 disk-like, star-forming galaxies (with 596 HI detections) from HI follow-up observations for the SDSS-IV MaNGA survey to study the possible role of inner HI gas in causing secondary dependences in the mass-gas-phase metallicity relation. We use the gas-phase metallicity derived at the effective radii of the galaxies. We derive the inner HI mass witHIn the optical radius, but also use the total HI mass and star formation rate (SFR) for a comparison. We confirm the anticorrelation between the total HI mass and gas-phase metallicity at fixed stellar mass, but the anticorrelation is sig…
We investigate how the NIHAO galaxies match the observed star formation main sequence (SFMS) and what the origin of its scatter is. The NIHAO galaxies reproduce the SFMS and generally agree with observations, but the slope is about unity and thus significantly larger than observed values. This is because observed galaxies at large stellar masses, although still being part of the SFMS, are already influenced by quenching. This partial suppression of star formation by AGN feedback leads to lower star formation rates and therefore to lower observed slopes. We confirm that including the effects of…
Aims. We aim to study the far-infrared radio correlation (FIRC) at 150 MHz in the local Universe (at a median redshift z~0:05) and improve the use of the rest-frame 150-MHz luminosity, L150, as a star-formation rate (SFR) tracer, which is unaffected by dust extinction. Methods. We cross-match the 60-um selected Revised IRAS Faint Source Survey Redshift (RIFSCz) catalogue and the 150-MHz selected LOFAR value-added source catalogue in the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) Spring Field. We estimate L150 for the cross-matched sources and compare it with the total infrared (IR)…
We measure the gas disc thicknesses of the edge-on galaxy NGC 4013 and the less edge-on galaxies (NGC 4157 and 5907) using CO (CARMA/OVRO) and/or HI (EVLA) observations. We also estimate the scale heights of stars and/or the star formation rate (SFR) for our sample of five galaxies using Spitzer IR data (3.6 $μ$m and 24 $μ$m). We derive the average volume densities of the gas and the SFR using the measured scale heights along with radial surface density profiles. Using the volume density that is more physically relevant to the SFR than the surface density, we investigate the existence of a vol…
X-ray luminosity ($L_X$) originating from high-mass X-ray binaries (HMXBs) is tightly correlated with the host galaxy's star-formation rate (SFR). We explore this connection at sub-galactic scales spanning ${\sim}$7 dex in SFR and ${\sim}$8 dex in specific SFR (sSFR). There is good agreement with established relations down to ${\rm SFR {\simeq} 10^{-3}\,M_\odot \, yr^{-1}}$, below which an excess of X-ray luminosity emerges. This excess likely arises from low mass X-ray binaries. The intrinsic scatter of the $L_X$-SFR relation is constant, not correlated with SFR. Different star formation indi…
The Panchromatic Hubble Andromeda Treasury. VI. The reliability of far-ultraviolet flux as a star formation tracer on sub-kpc scales
我们利用全色哈勃仙女座宝库（PHAT）的光学观测，测量了M31中33个FUV明亮区域的最近（<5亿年）恒星形成历史（SFHS）。区域面积范围从~ $10^4$到$10^6$ pc $^2$，这使我们能够测试FUV通量作为亚千秒差距尺度上最近恒星形成示踪剂的可靠性。恒星形成率（SFR）来自于修正后的观测FUV通量，平均而言，与1亿年的平均SFR的SFH内的1 $σ$分散一致。总体而言，分散性大于SFR的不确定性，在最小区域中尤其明显。分散是一致的，甚至组合的离散采样的初始质量函数和高变异性的SFHS。这一结果表明，为获得精确的SFR估计从FUV通量满足全IMF和恒定的SFR假设的重要性。假设一个强大的FUV消光校正，我们估计，一个因素的2.5不确定性，可以预期在FUV为基础的SFR的区域小于$10^5$ pc $^2$，或几百个pc。我们还研究了年龄和质量来自紫外线通量的共同假设下，该地区是简单的恒星星族（SSP）。SFHS表明，大多数地区不是SSP，年龄和质量估计相应地从SFHS不一致。对于这些地区的SSP样SFH，我们发现平均差异10万年的年龄和3至4的质量的一个因素。基于积分FUV通量，不可能将SSP样区域与其他区域区分开。
Current galaxy observations suggest that a roughly linear correlation exists between the [CII] emission and the star formation rate, either as spatially-resolved or integrated quantities. Observationally, this correlation seems to be independent of metallicity, but the very large scatter does not allow to properly assess whether this is true. On the other hand, theoretical models tend to suggest a metallicity dependence of the correlation. In this study, we investigate the metallicity evolution of the correlation via a high-resolution zoom-in cosmological simulation of a dwarf galaxy employing…
Star formation and quenching are two of the most important processes in galaxy formation and evolution. We explore in the local Universe the interrelationships among key integrated galaxy properties, including stellar mass $M_*$, star formation rate (SFR), specific SFR (sSFR), molecular gas mass $M_{\rm H_2}$, star formation efficiency (SFE) of the molecular gas and molecular gas to stellar mass ratio $μ$. We aim to identify the most fundamental scaling relations among these key galaxy properties and their interrelationships. We show the integrated $M_{\rm H_2}$-SFR, SFR-$M_*$ and $M_{\rm H_2}…
We present multi-wavelength global star formation rate (SFR) estimates for 326 galaxies from the Star Formation Reference Survey (SFRS) in order to determine the mutual scatter and range of validity of different indicators. The widely used empirical SFR recipes based on 1.4 GHz continuum, 8.0 $μ$m polycyclic aromatic hydrocarbons (PAH), and a combination of far-infrared (FIR) plus ultraviolet (UV) emission are mutually consistent with scatter of $\raise{-0.8ex}\stackrel{\textstyle <}{\sim }$0.3 dex. The scatter is even smaller, $\raise{-0.8ex}\stackrel{\textstyle <}{\sim }$0.24 dex, in the int…
We present the first predictions for the $L_{\rm [CII]}$ - SFR relation and [CII] luminosity function (LF) in the Epoch of Reionization (EoR) based on cosmological hydrodynamics simulations using the SIMBA suite plus radiative transfer calculations via SÍGAME. The sample consists of 11,137 galaxies covering halo mass $\log M_{\rm halo}\in$[9, 12.4] $M_\odot$, star formation rate SFR$\in$[0.01, 330] $M_\odot$ yr$^{-1}$, and metallicity $<Z_{\rm gas}>_{\rm SFR}\in$[0.1, 0.9] $Z_\odot$. The simulated $L_{\rm [CII]}$-SFR relation is consistent with the range observed, but with a spread of $\simeq$…
Unveiling the Hot Interstellar Medium in Nearby Galaxies with eROSITA
Friedrich-Alexander-Universität Erlangen-Nürnberg（埃尔朗根-纽伦堡弗里德里希·亚历山大大学）；Dr. Karl Remeis Observatory, Erlangen Centre for Astroparticle Physics（卡尔·雷梅斯天文台，埃尔朗根高能天体物理中心）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理研究所）；University of Crete（克里特大学）；Foundation for Research and Technology-Hellas（希腊研究与技术基金会）
Previous studies have shown that the normalization and scatter of the galaxy 'main sequence' (MS), the relation between star formation rate (SFR) and stellar mass ($M_*$), evolves over cosmic time. However, such studies often rely on photometric redshifts and/or only rest-frame UV to near-IR data, which may underestimate the SFR and $M_*$ uncertainties. We use MAGPHYS+photo-z to fit the UV to radio spectral energy distributions of 12,380 galaxies in the COSMOS field at $0.5<z<3.0$ and self-consistently include photometric redshift uncertainties on the derived SFR and $M_*$. We quantify the eff…
Radio continuum (RC) emission in galaxies allows us to measure star formation rates (SFRs) unaffected by extinction due to dust, of which the low-frequency part is uncontaminated from thermal (free-free) emission. We calibrate the conversion from the spatially resolved 140 MHz RC emission to the SFR surface density ($Σ_{\rm SFR}$) at 1 kpc scale. We used recent observations of three galaxies (NGC 3184, 4736, and 5055) from the LOFAR Two-metre Sky Survey (LoTSS), and archival LOw-Frequency ARray (LOFAR) data of NGC 5194. Maps were created with the facet calibration technique and converted to ra…
We examine and quantify how hybrid (e.g., UV+IR) star formation rate (SFR) estimators and the $A_{\rm FUV}$-$β$ relation depend on inclination for disk-dominated galaxies using spectral energy distribution modeling that utilizes the inclination-dependent attenuation curves described in Doore et al. We perform this analysis on a sample of 133 disk-dominated galaxies from the CANDELS fields and 18 disk galaxies from the Spitzer Infrared Nearby Galaxies Survey and Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel samples. We find that both the hybrid SFR estimators and the $A_{…
Does the Fundamental Metallicity Relation Evolve with Redshift? I: The Correlation Between Offsets from the Mass-Metallicity Relation and Star Formation Rate
The scatter of the spatially resolved star formation main sequence (SFMS) is investigated in order to reveal signatures about the processes of galaxy formation and evolution. We have assembled a sample of 355 nearby galaxies with spatially resolved Hα and mid-infrared fluxes from the Survey for Ionized Neutral Gas in Galaxies and the Wide-field Infrared Survey Explorer, respectively. We examine the impact of various star formation rate (SFR) and stellar mass transformations on the SFMS. Ranging from 10^6 to 10^11.5 M_sun and derived from color to mass-to-light ratio methods for mid-infrared ba…
Exploiting a sample of 680 star-forming galaxies from the Padova-Millennium GalaxyGroup Catalog (PM2GC) (Calvi et al. 2011) in the range 0.038<z<0.104, we present a detailed analysis of the Star Formation Rate (SFR)-stellar mass (M_star) and specific SFR(SSFR)-M_star relations as a function of environment. We adopt three different parameterizations of environment, to probe different scales. We consider separately 1) galaxies in groups, binary and single systems, defined in terms of a Friends-of-Friends algorithm, 2) galaxies located at different projected local densities, 3) galaxies in haloes…
We use new and updated gas and dust-corrected SFR surface densities to revisit the integrated star formation law for local "quiescent" spiral, dwarf, and low-surface-brightness galaxies. Using UV-based SFRs with individual IR-based dust corrections, we find that "normal" spiral galaxies alone define a tight $Σ_{(\textrm{HI}+\textrm{H}_{2})}$-$Σ_{\textrm{SFR}}$ relation described by a $n=1.41^{+0.07}_{-0.07}$ power law with a dispersion of $0.28^{+0.02}_{-0.02}$ (errors reflect fitting and statistical uncertainties). The SFR surface densities are only weakly correlated with HI surface densities…
Calibrating Photometric Mid-Infrared Star Formation Rates for JWST
Space Telescope Science Institute（太空望远镜科学研究所）；Steward Observatory, University of Arizona（亚利桑那大学斯特沃德天文台）；Centro de Astrobiología (CAB), CSIC-INTA（天体生物学中心（CAB），西班牙国家科学技术研究委员会-国家航空航天技术研究所）；Department of Astronomy, University of Geneva（日内瓦大学天文学系）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯玻尔研究所）；Cosmic Dawn Center (DAWN)（宇宙黎明中心（DAWN））；Department of Astronomy & Astrophysics, The Pennsylvania State University（宾夕法尼亚州立大学天文学与天体物理学系）；Department for Astrophysical and Planetary Science, University of Colorado（科罗拉多大学天体物理与行星科学系）
Recently a number of studies have proposed that the dispersion along the star formation rate - stellar mass relation ($σ_{\mathrm{sSFR}}$-M$_{*}$) is indicative of variations in star-formation history (SFH) driven by feedback processes. They found a 'U'-shaped dispersion and attribute the increased scatter at low and high stellar masses to stellar and active galactic nuclei feed-back respectively. However, measuring $σ_{\mathrm{sSFR}}$ and the shape of the $σ_{\mathrm{sSFR}}$-M$_{*}$ relation is problematic and can vary dramatically depending on the sample selected, chosen separation of passiv…
We present the star formation rate (SFR) measurements based on the spectral energy distribution (SED) analysis with new sub-mm fluxes combined with archival multi-wavelength data for a sample of 52 AGN host galaxies at z $<0.2$. We carried out sub-mm observations using the SCUBA-2 camera at the James Clerk Maxwell Telescope, and obtained flux or an upper limit at 450 and 850 $μ$m for each target. By experimenting the effect of the AGN dust component in the SED fit, we find that dust luminosity can be overestimated if AGN contribution is ignored. While the SFR based on 4000Å break shows a signi…
We present observations of CO(3-2) in 13 main-sequence $z=2.0-2.5$ star-forming galaxies at $\log(M_*/M_{\odot})=10.2-10.6$ that span a wide range in metallicity (O/H) based on rest-optical spectroscopy. We find that CO(3-2)/SFR decreases with decreasing metallicity, implying that the CO luminosity per unit gas mass is lower in low-metallicity galaxies at $z\sim2$. We constrain the CO-to-H$_2$ conversion factor ($α_{\text{CO}}$) and find that $α_{\text{CO}}$ inversely correlates with metallicity at $z\sim2$. We derive molecular gas masses ($M_{\text{mol}}$) and characterize the relations among…
Measurements of short-timescale star formation variations (i.e., "burstiness") are integral to our understanding of star formation feedback mechanisms and the assembly of stellar populations in galaxies. We expand upon the work of Broussard et al. (2019) by introducing a new analysis of galaxy star formation burstiness that accounts for variations in the $Q_{sg}=\mathrm{E(B-V)_{stars}}/\mathrm{E(B-V)_{gas}}$ distribution, a major confounding factor. We use Balmer decrements from the MOSFIRE Deep Evolution Field (MOSDEF) survey to measure $Q_{sg}$, which we use to construct mock catalogs from t…
Star-formation activity is a key property to probe the structure formation and hence characterise the large-scale structures of the universe. This information can be deduced from the star formation rate (SFR) and the stellar mass (Mstar), both of which, but especially the SFR, are very complex to estimate. Determining these quantities from UV, optical, or IR luminosities relies on complex modeling and on priors on galaxy types. We propose a method based on the machine-learning algorithm Random Forest to estimate the SFR and the Mstar of galaxies at redshifts in the range 0.01<z<0.3, independen…
