We present a systematic analysis of the spatially resolved star formation histories (SFHs) using Hubble Space Telescope imaging data of $\sim 997$, intermediate redshifts $0.5 \leq z \leq 2.0$ galaxies from the GOODS-S field, with stellar mass range $9.8 \leq \log \mathrm{M}_{\star}/\mathrm{M}_{\odot} \leq 11.5$. We estimate the SFHs in three spatial regions (central region within the half-mass radii $\mathrm{R}_{50s}$, outskirts between $1-3~\mathrm{R}_{50s}$, and the whole galaxy) using pixel-by-pixel spectral-energy distribution (SED) fitting, assuming exponentially declining tau model in individual pixels. The reconstructed SFHs are then used to derive and compare the physical properties such as specific star-formation rates (sSFRs), mass-weighted ages (t$_{\mathrm{50}}$), and the half-mass radii to get insights on the interplay between the structure and star-formation in galaxies. The correlation of sSFR ratio of the center and outskirts with the distance from the main sequence (MS) indicates that galaxies on the upper envelope of the MS tend to grow outside-in, building up their central regions, while those below the MS grow inside-out, with more active star formation in the outskirts. The findings suggest a self-regulating process in galaxy size growth when they evolve along the MS. Our observations are consistent with galaxies growing their inner bulge and outer disc regions, where they appear to oscillate about the average MS in cycles of central gas compaction, which leads to bulge growth, and subsequent central depletion possibly due to feedback from the starburst, resulting in more star formation towards the outskirts from newly accreted gas.
The Prevalence of Turbulence-Regulated Multiphase Galactic Winds in Star-Forming Galaxies
Johns Hopkins University（约翰斯·霍普金斯大学）；Max-Planck Institute for Astrophysics（马克斯·普朗克天体物理学研究所）；Universität Heidelberg（海德堡大学）；Northwestern University（西北大学）；Space Telescope Science Institute（太空望远镜科学研究所）；University of Pittsburgh（匹兹堡大学）
Self-regulated galaxy evolution within a self-consistently varying galaxy-wide IMF
Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn（波恩大学赫尔姆霍兹射线与核物理研究所）；Argelander-Institut für Astronomie, Universität Bonn（波恩大学阿尔格兰德天文学研究所）；Astronomical Institute, Faculty of Mathematics and Physics, Charles University（查理大学数学与物理学院天文研究所）；Department of Astrophysics, University of Vienna（维也纳大学天体物理学系）
Several recent simulations of galaxy formation predict two main phases of supermassive black hole (BH) accretion: an early, highly intermittent phase (during which BHs are under-massive relative to local scaling relations), followed by a phase of accelerated growth. We investigate physical factors that drive the transition in BH accretion in cosmological zoom-in simulations from the FIRE project, ranging from dwarf galaxies to galaxies sufficiently massive to host luminous quasars. The simulations model multi-channel stellar feedback, but neglect AGN feedback. We show that multiple physical pr…
Jet Feedback and the Self-Regulated Growth of Black Holes Embedded in AGN Disks
Columbia University（哥伦比亚大学）；Northwestern University（西北大学）；Harvard University（哈佛大学）；Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究所）；Stony Brook University（石溪大学）
We explore the scaling between the size of star-forming clumps and rotational support in massively star-forming galactic disks. The analysis relies on simulations of a clumpy galaxy at $z=2$ and the observed DYNAMO sample of rare clumpy analogs at $z\approx0.1$ to test a predictive clump size scaling proposed by \citet{Fisher2017ApJ...839L...5F} in the context of the Violent Disk Instability (VDI) theory. We here determine the clump sizes using a recently presented 2-point estimator, which is robust against resolution/noise effects, hierarchical clump substructure, clump-clump overlap and othe…
We apply a turbulence-regulated model of star formation to calculate the star formation rate (SFR) of dense star-forming clouds in simulations of jet-ISM interactions. The method isolates individual clumps and accounts for the impact of virial parameter and Mach number of the clumps on the star formation activity. This improves upon other estimates of the SFR in simulations of jet--ISM interactions, which are often solely based on local gas density, neglecting the impact of turbulence. We apply this framework to the results of a suite of jet-ISM interaction simulations to study how the jet reg…
Star formation in galaxies is inefficient, and understanding how star formation is regulated in galaxies is one of the most fundamental challenges of contemporary astrophysics. Radiative cooling, feedback from supernovae and active galactic nuclei, large-scale dynamics and dissipation of turbulent energy act over various time and spatial scales, and all regulate star formation in a complex gas cycle. This paper presents the physics implemented in a new semi-analytical model of galaxy formation and evolution: G.A.S.. The fundamental underpinning of our new model is the development of a multi-ph…
We present the $Iκεα$ model of galaxy formation, in which a galaxy's star formation rate is set by the balance between energy injected by feedback from massive stars and energy lost by the deepening of the potential of its host dark matter halo due to cosmological accretion. Such a balance is secularly stable provided that the star formation rate increases with the pressure in the star forming gas. The $Iκεα$ model has four parameters that together control the feedback from star formation and the cosmological accretion rate onto a halo. $Iκεα$ reproduces accurately the star formation rate as a…
In this paper we compare the molecular gas depletion times and mid-plane hydrostatic pressure in turbulent, star forming disk galaxies to internal properties of these galaxies. For this analysis we use 17 galaxies from the DYNAMO sample of nearby ($z\sim0.1$) turbulent disks. We find a strong correlation, such that galaxies with lower molecular gas depletion time (t_{dep}) have higher gas velocity dispersion ($σ$). Within the scatter of our data, our observations are consistent with the prediction that depletion time is inversely proportionate to velocity dispersion made in theories of feedbac…
RIGEL: Feedback-regulated cloud-scale star formation efficiency in a simulated dwarf galaxy merger
Tsinghua University（清华大学）；University of Bologna（博洛尼亚大学）；INAF, Astrophysics and Space Science Observatory Bologna（意大利国家天体物理研究所博洛尼亚天文与空间科学观测站）；Institute for Advanced Study, Tsinghua University（清华大学高等研究院）；Universität Heidelberg（海德堡大学）；The University of Texas at Dallas（德克萨斯大学达拉斯分校）；York University（约克大学）；Columbia University（哥伦比亚大学）
Supermassive black holes (SMBHs) are tightly correlated with their hosts but the origin of such connection remains elusive. To explore the cosmic build-up of this scaling relation, we present an empirically-motivated model that tracks galaxy and SMBH growth down to z=0. Starting from a random mass seed distribution at z=10, we assume that each galaxy evolves on the star-forming "main sequence" (MS) and each BH follows the recently-derived stellar mass (M$_{\star}$) dependent ratio between BH accretion rate and star formation rate, going as BHAR/SFR$\propto$M$_{\star}^{0.73[+0.22,-0.29]}$. Our …
We argue that the interplay between cosmic rays, the initial mass function, and star formation plays a crucial role in regulating the star-forming "main sequence". To explore these phenomena we develop a toy model for galaxy evolution in which star formation is regulated by a combination of a temperature-dependent initial mass function and heating due to starlight, cosmic rays and, at very high redshift, the cosmic microwave background. This produces an attractor, near-equilibrium solution which is consistent with observations of the star-forming main sequence over a broad redshift range. Addi…
The star formation rate (SFR) in galactic disks depends on both the quantity of available interstellar medium (ISM) gas and its physical state. Conversely, the ISM's physical state depends on the SFR, because the "feedback" energy and momentum injected by recently-formed massive stars is crucial to offsetting losses from turbulent dissipation and radiative cooling. The ISM's physical state also responds to the gravitational field that confines it, with increased weight driving higher pressure. In a quasi-steady state, it is expected that the mean total pressure of different thermal phases will…
We present the evolution of the star-formation dispersion - stellar mass relation ($σ_{SFR}$-M$_{\star}$) in the DEVILS D10 region using new measurements derived using the ProSpect spectral energy distribution fitting code. We find that $σ_{SFR}$-M$_{\star}$ shows the characteristic 'U-shape' at intermediate stellar masses from 0.1<z<0.7 for a number of metrics, including using the deconvolved intrinsic dispersion. A physical interpretation of this relation is the combination of stochastic star-formation and stellar feedback causing large scatter at low stellar masses and AGN feedback causing …
The first galaxies forming a few hundred million years after the Big Bang are the key drivers of cosmic evolution and ideal laboratories to study theories of galaxy formation. We here study the role of UV radiation in suppressing star formation in primordial galaxies by destroying molecular hydrogen, the main coolant in primordial gas and provide estimates of cold dense gas at the onset of star formation. To accomplish this goal, we perform three dimensional cosmological simulations of minihalos in different environments forming at $ z\sim 25$ by varying strength of background UV flux below th…
Formation of supermassive black holes (BHs) remains a theoretical challenge. In many models, especially beginning from stellar relic "seeds," this requires sustained super-Eddington accretion. While studies have shown BHs can violate the Eddington limit on accretion disk scales given sufficient "fueling" from larger scales, what remains unclear is whether or not BHs can actually capture sufficient gas from their surrounding ISM. We explore this in a suite of multi-physics high-resolution simulations of BH growth in magnetized, star-forming dense gas complexes including dynamical stellar feedba…
We present ALMA Band~7 observations at $850μ$m of 20 luminous ($\log\, L_{\rm bol}>46.9$ [erg s$^{-1}$]) unobscured quasars at $z\sim2$. We detect continuum emission for 19/20 quasars. After subtracting an AGN contribution, we measure the total far-IR luminosity for 18 quasars, assuming a modified blackbody model, and attribute the emission as indicative of the star formation rate (SFR). Our sample can be characterized with a log-normal SFR distribution having a mean of 140 $M_\odot$ yr$^{-1}$ and a dispersion of 0.5 dex. Based on an inference of their stellar masses, the SFRs are similar, in …
Recent studies show that a universal relation between black-hole (BH) growth and stellar mass ($M_\bigstar$) or star formation rate (SFR) is an oversimplification of BH-galaxy co-evolution, and that morphological and structural properties of host galaxies must also be considered. Particularly, a possible connection between BH growth and host-galaxy compactness was identified among star-forming (SF) galaxies. Utilizing $\approx 6300$ massive galaxies with $I_{\rm 814W}~<~24$ at $z$ $<$ 1.2 in the COSMOS field, we perform systematic partial-correlation analyses to investigate how sample-averaged…
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…
Variation of the stellar initial mass function in semi-analytical models III: testing the cosmic ray regulated integrated galaxy-wide initial mass function
Far-Ultraviolet (FUV) radiation greatly exceeds ultraviolet, supernovae and winds in the energy budget of young star clusters but is poorly modeled in galaxy simulations. We present results of the first isolated galaxy disk simulations to include photo-electric heating of gas via dust grains from FUV radiation self-consistently, using a ray-tracing approach that calculates optical depths along the source-receiver sight-line. This is the first science application of the TREVR radiative transfer algorithm. We find that FUV radiation alone cannot regulate star formation. However, FUV radiation pr…
In this paper, we use the Herschel Reference Survey to make a direct test of the hypothesis that the growth of a stellar bulge leads to a reduction in the star-formation efficiency of a galaxy (or conversely a growth in the gas-depletion timescale) as a result of the stabilisation of the gaseous disk by the gravitational field of the bulge. We find a strong correlation between star-formation efficiency and specific star-formation rate in galaxies without prominent bulges and in galaxies of the same morphological type, showing that there must be some other process besides the growth of a bulge …
On the Last 10 Billion Years of Stellar Mass Growth in Star-Forming Galaxies
恒星形成率-恒星质量关系（SFR-M*）及其演化（即，SFR主序）描述了给定恒星质量和给定红移的星系的增长率。假设现在的恒星形成星系在过去总是恒星形成的，这些增长率观测可以被整合来计算平均恒星形成历史（SFH）。使用这种主序列积分（MSI）方法，我们可以追溯到现在的大质量恒星形成星系，当它们是当前恒星质量的10-20%时。在这些时期的整合是强大的：支持我们的计算的SFR数据是一致的恒星质量密度在这个政权的演变。这些SFH的分析近似。基于积分的结果重申了以前的建议，即目前的恒星形成星系形成几乎所有的恒星质量在z <2. It follows that massive galaxies observed at z>2不是典型的祖先恒星形成星系今天。我们还检查基于MSI的SFH对那些从化石记录的分析推断-从光谱能量分布（SED）的恒星形成星系在斯隆数字巡天，和色星等图（CMD）的矮不规则星系解决恒星。一旦考虑到恒星星族年龄的不确定性，主序列与基于SED的SFH（来自VESPA）非常一致。外推SFR主序星观测到矮星系，我们发现的ACS附近的星系巡天金库和本星系群星系的CMD分析的MSI结果和SFH之间的差异。解析出的矮星系似乎比主序列趋势所暗示的要慢得多，也比质量稍高的SED分析星系慢。这种差异可能标志着SFH测定的问题，但它也可能标志着在最低恒星质量下恒星形成趋势的转变。
Simulations of idealised star-forming filaments of finite length typically show core growth which is dominated by two cores forming at its respective end. The end cores form due to a strong increasing acceleration at the filament ends which leads to a sweep-up of material during the filament collapse along its axis. As this growth mode is typically faster than any other core formation mode in a filament, the end cores usually dominate in mass and density compared to other cores forming inside a filament. However, observations of star-forming filaments do not show this prevalence of cores at th…
Tracing grain growth in the forming prestellar core L1506C with 3D modeling of Herschel, IRAM, and CFHT observations
Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse, CNRS, CNES（天体物理学与行星学研究所以及图卢兹大学）；University of Helsinki（赫尔辛基大学）；Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale（萨克雷大学）；Observatoire de Paris, PSL, CNRS, UPMC, Univ. Paris-Diderot（巴黎天文台）
In addition to occupying the extreme, diffuse tail of the dwarf galaxy population, Ultra-Diffuse Galaxies (UDGs) are themselves a key laboratory in which to study star formation in extreme low-density environments. In the second paper of this series, we compare the spatially resolved star formation activity of 22 HI-selected UDGs and 21 "normal" dwarf galaxies within 120 Mpc to predictions within the pressure-regulated, feedback-modulated (PRFM) theory of star formation. To do so, we employ a joint SED fitting method that allows us to estimate star formation rate and stellar mass surface densi…
