Detection of the self-regulation of star formation in galaxy discs
Javier Zaragoza-Cardiel, Jacopo Fritz, Itziar Aretxaga, Divakara Mayya, Daniel Rosa-González, John E. Beckman, Gustavo Bruzual, Stephane Charlot, Luis Lomelí-Núñez
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Accepted for publication in MNRAS Letters. 6 pages, 3 figures
Stellar feedback has a notable influence on the formation and evolution of galaxies. However, direct observational evidence is scarce. We have performed stellar population analysis using MUSE optical spectra of the spiral galaxy NGC 628 and find that current maximum star formation in spatially resolved regions is regulated according to the level of star formation in the recent past. We propose a model based on the self-regulator or "bathtub" models, but for spatially resolved regions of the galaxy. We name it the "resolved self-regulator model" and show that the predictions of this model are in agreement with the presented observations. We observe star formation self-regulation and estimate the mass-loading factor, $η=2.5 \pm 0.5$, consistent with values predicted by galaxy formation models. The method described here will help provide better constraints on those models.
The VariableTNG project: mass-dependent regulation of galaxy morphology by baryonic feedback
Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；University of Chinese Academy of Sciences（中国科学院大学）；Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）；Institute of Astrophysics, School of Physics, Zhengzhou University（郑州大学物理学院天体物理研究所）；Key Laboratory for Computational Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台计算天体物理重点实验室）
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…
We present half-light sizes measured from H$α$ emission tracing star-formation in 281 star-forming galaxies from the KMOS3D survey at 0.7 < z < 2.7. Sizes are derived by fitting 2D exponential disk models, with bootstrap errors averaging 20%. H$α$ sizes are a median (mean) of 1.19 (1.26) times larger than those of the stellar continuum, which due to radial dust gradients places an upper limit on the growth in stellar size via star formation, with just 43% intrinsic scatter. At fixed continuum size the H$α$ size shows no residual trend with stellar mass, star formation rate, redshift or morphol…
SUNRISE-3D: Sharp UNveiling of AGN feedback Regulation and its Impact on Star-formation at the cosmic noon Epoch
INAF – Istituto di Astrofisica Spaziale e Fisica Cosmica Milano（意大利国家天体物理研究所空间天体物理与宇宙学米兰研究所）；INAF - Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Department of Mathematics and Physics, Roma Tre University（罗马第三大学数学与物理系）
The evolution of galaxies is governed by equations with chaotic solutions: gravity and compressible hydrodynamics. While this micro-scale chaos and stochasticity has been well studied, it is poorly understood how it couples to macro-scale properties examined in simulations of galaxy formation. In this paper, we show how perturbations introduced by floating-point roundoff, random number generators, and seemingly trivial differences in algorithmic behaviour can produce non-trivial differences in star formation histories, circumgalactic medium (CGM) properties, and the distribution of stellar mas…
We introduce the "Engineering Dwarfs at Galaxy formation's Edge" (EDGE) project to study the cosmological formation and evolution of the smallest galaxies in the Universe. In this first paper, we explore the effects of resolution and sub-grid physics on a single low mass halo ($M_{\rm halo}=10^{9}~M_\odot$), simulated to redshift $z=0$ at a mass and spatial resolution of $\sim 20~M_\odot$ and $\sim 3$ pc. We consider different star formation prescriptions, supernova feedback strengths and on-the-fly radiative transfer (RT). We show that RT changes the mode of galactic self-regulation at this h…
We present results from the semi-analytic model of galaxy formation SAG applied on the MultiDark simulation MDPL2. SAG features an updated supernova (SN) feedback scheme and a robust modelling of the environmental effects on satellite galaxies. This incorporates a gradual starvation of the hot gas halo driven by the action of ram pressure stripping (RPS), that can affect the cold gas disc, and tidal stripping (TS), which can act on all baryonic components. Galaxy orbits of orphan satellites are integrated providing adequate positions and velocities for the estimation of RPS and TS. The star fo…
In the pre-main-sequence stage, star-disc interactions have been shown to remove stellar angular momentum and regulate the rotation periods of stars with M2 and earlier spectral types. Whether disc regulation also extends to stars with later spectral types still remains a matter of debate. Here we present a star-disc interaction study in a sample of over 180 stars with spectral types M3 and later (corresponding to stellar masses $\leq 0.3 M_\odot$) in young stellar cluster NGC 2264. Combining rotation periods from the literature, new and literature spectral types, and newly presented deep Spit…
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）
Using archival data from the Chandra X-ray telescope, we have measured the spatial extent of the hot interstellar gas in a sample of 49 nearby interacting galaxy pairs, mergers, and merger remnants. For systems with SFR > 1 M(sun)/yr, the volume and mass of hot gas are strongly and linearly correlated with the star formation rate (SFR). This supports the idea that stellar/supernovae feedback dominates the production of hot gas in these galaxies. We compared the mass of X-ray-emitting hot gas Mx(gas) with the molecular and atomic hydrogen interstellar gas masses in these galaxies (M(H2) and M(H…
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…
We investigate the formation and early evolution of a protostellar disc from a magnetized pre-stellar core using non-ideal magnetohydrodynamic (MHD) simulations including ambipolar diffusion and Ohmic dissipation. The dynamical contraction of the pre-stellar core ultimately leads to the formation of a first hydrostatic core, after ambipolar diffusion decouples the magnetic field from the predominantly neutral gas. The hydrostatic core accumulates angular momentum from the infalling material, evolving into a rotationally supported torus; this `first hydrostatic torus' then forms an accreting pr…
