The changing circumgalactic medium over the last 10 Gyr I: physical and dynamical properties
Ezra Huscher, Benjamin D. Oppenheimer, Alice Lonardi, Robert A. Crain, Alexander J. Richings, Joop Schaye
备注：
16 pages, 15 figures. Submitted to MNRAS. Comments welcome. (revision submitted on May 22, 2020 fixes Fig. 3. right panel that mistakenly displayed metal mass and now correctly displays total gas mass)
We present an analysis of the physical and dynamical states of two sets of EAGLE zoom simulations of galaxy haloes, one at high redshift ($z=2-3$) and the other at low redshift ($z=0$), with masses of $\approx 10^{12} M_{\odot}$. Our focus is how the circumgalactic medium (CGM) of these $L^*$ star-forming galaxies change over the last 10 Gyr. We find that the high-$z$ CGM is almost equally divided between the "cool" ($T<10^5$ K) and "hot" ($T\geq 10^5$ K) phases, while the low-$z$ hot CGM phase contains $5\times$ more mass. The high-$z$ hot CGM contains 60% more metals than the cool CGM, while the low-$z$ cool CGM contains 35% more metals than the hot CGM content. The metals are evenly distributed radially between the hot and cool phases throughout the high-$z$ CGM. At high $z$, the CGM volume is dominated by hot outflows, cool gas is mainly inflowing, but cool metals are flowing outward. At low $z$, the cool metals dominate the interior and the hot metals are more prevalent at larger radii. The low-$z$ cool CGM has tangential motions consistent with rotational support out to $0.2 R_{200}$, often exhibiting $r \approx 40$ kpc disc-like structures. The low-$z$ hot CGM has several times greater angular momentum than the cool CGM, and a more flattened radial density profile than the high-$z$ hot CGM. This study verifies that, just as galaxies demonstrate significant evolutionary stages over cosmic time, the gaseous haloes surrounding them also undergo considerable changes of their own both in physical characteristics of density, temperature and metallicity, and dynamic properties of velocity and angular momentum.
We discuss the production of $γ$-rays from cosmic rays (CR) in the circumgalactic medium (CGM) of Andromeda (M31) in light of the recent detection of $γ$-rays from an annular region of $\sim 5.5-120$ kpc away from the M31 disc. We consider the CRs accelerated as a result of the star-formation in the M31 disk, which are lifted to the CGM by advection due to outflow and CR diffusion. The advection time scale due to bulk flow of gas triggered by star formation activity in the M31 disc is comparable ($\sim$ Gyr) to the diffusion time scale with diffusion coefficient $\ge10^{29}$ cm$^2$ s$^{-1}$ fo…
Absorption-line measurements of the circumgalactic medium (CGM) display a highly non-uniform distribution of lower ionization state species accompanied by more widespread higher ionization state material. This suggests that the CGM is a dynamic, multiphase medium, such as arises in the presence of turbulence. To better understand this evolution, we perform hydrodynamic and magneto-hydrodynamic (MHD) simulations of the CGM surrounding Milky Way-like galaxies. In both cases, the CGM is initially in hydrostatic balance in a $10^{12}$ solar masses dark matter gravitational potential, and the simul…
Circumgalactic medium depletion drives satellite quenching in IllustrisTNG
European Southern Observatory（欧洲南方天文台）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Astronomisches Rechen Institut, Zentrum für Astronomie der Universität Heidelberg（海德堡大学天体物理计算研究所）；Fakultät für Physik, Ludwig-Maximilians-Universität München（慕尼黑大学物理学院）；College of Natural and Mathematical Sciences, University of Dodoma（多多马大学自然与数理科学学院）；School of Physics and Astronomy, University of Birmingham（伯明翰大学物理与天文学院）
Successful models of the low redshift circumgalactic medium (CGM) must account for (1) a large amount of gas, (2) relatively slow gas velocities, (3) a high degree of metal enrichment, (4) the similar absorption properties around both star-forming and passive galaxies, and (5) the observationally inferred temperature and densities of the CGM gas. We show that galactic wind-driven bubbles can account for these observed properties. We develop a model describing the motion of bubbles driven by a hot, fast galactic wind characteristic of supernova energy injection. The bubble size grows slowly to …
We present our investigation of the Extended Ultraviolet (XUV) disk galaxy, NGC 3344, conducted as part of Deciphering the Interplay between the Interstellar medium, Stars, and the Circumgalactic medium (DIISC) survey. We use surface and aperture photometry of individual young stellar complexes to study star formation and its effect on the physical properties of the interstellar medium. We measure the specific star-formation rate (sSFR) and find it to increase from $\rm10^{-10} yr^{-1}$ in the inner disk to $\rm>10^{-8} yr^{-1}$ in the extended disk. This provides evidence for inside-out disk …
Recent studies have revealed a dynamic interplay between the galaxy ecosystem and the circumgalactic medium (CGM). We investigate the CGM at high redshifts (z $\gtrsim$ 2) by using bright afterglows of gamma-ray bursts (GRB) as background sources. We compiled a sample of medium-resolution ($δ$v $<$ 50 km/s) and high signal-to-noise (typical SNR $\sim$ 10) spectra from 27 GRB afterglows covering z $\sim$ 2 - 6, with six of them at z $\gtrsim$ 4. We analyzed the high- and low-ionization absorption features within $\pm$400 km/s to extract the CGM and ISM kinematics. In the stacked spectra, high-i…
We analyze the low-redshift (z~0.2) circumgalactic medium by comparing absorption-line data from the COS-Halos Survey to absorption around a matched galaxy sample from two cosmological hydrodynamic simulations. The models include different prescriptions for galactic outflows, namely hybrid energy/momentum driven wind (ezw), and constant winds (cw). We extract for comparison direct observables including equivalent widths, covering factors, ion ratios, and kinematics. Both wind models are generally in good agreement with these observations for HI and certain low ionization metal lines, but show …
We explore the circumgalactic metal content traced by commonly observed low ion absorbers, including C II, Si II, Si III, Si IV, and Mg II. We use a set of cosmological hydrodynamical zoom simulations run with the EAGLE model and including a non-equilibrium ionization and cooling module that follows 136 ions. The simulations of z~0.2 L* (M_200=10^11.7-10^12.3 Msol) haloes hosting star-forming galaxies and group-sized (M_200=10^12.7-10^13.3 Msol) haloes hosting mainly passive galaxies reproduce key trends observed by the COS-Halos survey-- low ion column densities show 1) little dependence on g…
The relationship between a galaxy's properties and its circumgalactic medium (CGM) provides a unique view of how galaxies evolve. We present an interesting edge-on (i=86 degrees) disk galaxy (G1547) where the CGM is probed by a background quasar at a distance of 84 kpc and within 10 degrees of the galaxy major axis. G1547 does not have any detectable CGM absorption down to stringent limits, covering HI (EW$_r$<0.02A, log(N(HI)/cm$^{-2}$)<12.6) and a range of low and high ionisation absorption lines (OI, CII, NII, SiII, CIII, NIII, SiIII, CIV, SiIV, NV and OVI). This system is rare, given the c…
The majority of baryons reside beyond the optical extent of a galaxy in the circumgalactic and intergalactic media (CGM/IGM). Gaseous halos are inextricably linked to the appearance of their host galaxies through a complex story of accretion, feedback, and continual recycling. The energetic processes, which define the state of gas in the CGM, are the same ones that 1) regulate stellar growth so that it is not over-efficient, and 2) create the diversity of today's galaxy colors, SFRs, and morphologies spanning Hubble's Tuning Fork Diagram. They work in concert to set the speed of growth on the …
Davies et al. (2019) established that for L^* galaxies the fraction of baryons in the circumgalactic medium (CGM) is inversely correlated with the mass of their central supermassive black holes (BHs) in the EAGLE hydrodynamic simulation. The interpretation is that, over time, a more massive BH has provided more energy to transport baryons beyond the virial radius, which additionally reduces gas accretion and star formation. We continue this research by focusing on the relationship between the 1) BH masses, 2) physical and observational properties of the CGM, and 3) galaxy colours for Milky Way…
We introduce a series of 20 cosmological hydrodynamical simulations of Lstar (M_200 =10^11.7 - 10^12.3 Msol) and group-sized (M_200 = 10^12.7 - 10^13.3 Msol) haloes run with the model used for the EAGLE project, which additionally includes a non-equilibrium ionization and cooling module that follows 136 ions. The simulations reproduce the observed correlation, revealed by COS-Halos at z~0.2, between O VI column density at impact parameters b < 150 kpc and the specific star formation rate (sSFR=SFR/Mstar) of the central galaxy at z~0.2. We find that the column density of circumgalactic O VI is …
We report the discovery and analysis of only the third Lyman-limit system in which a high-quality resolution, echelle spectrum reveals no metal absorption lines, implying a metallicity $\lesssim$1/10000 solar. Our HIRES spectrum of the background quasar, PSS1723$+$2243, provides a neutral hydrogen column density range for LLS1723 of $N_\textrm{HI}=10^{\text{17.9--18.3}}$ cm$^{-2}$ at redshift $z_\textrm{abs}\approx4.391$. The lower bound on this range, and the lack of detectable absorption from the strongest low-ionisation metal lines, are combined in photoionisation models to infer a robust, …
Early onset of the hot circumgalactic medium around Milky Way galaxies
Lund University（隆德大学）；University of Bath（巴斯大学）；University of Sydney（悉尼大学）；University of Surrey（萨里大学）；Sorbonne Université（索邦大学）；University of Oxford（牛津大学）
We present basic data and modeling for a survey of the cool, photo-ionized Circum-Galactic Medium (CGM) of low-redshift galaxies using far-UV QSO absorption line probes. This survey consists of "targeted" and "serendipitous" CGM subsamples, originally described in Stocke et al. (2013, Paper 1). The targeted subsample probes low-luminosity, late-type galaxies at $z<0.02$ with small impact parameters ($\langleρ\rangle = 71$ kpc), and the serendipitous subsample probes higher luminosity galaxies at $z\lesssim0.2$ with larger impact parameters ($\langleρ\rangle = 222$ kpc). HST and FUSE UV spectro…
Using the IllustrisTNG simulation, we study the interaction of large-scale shocks with the circumgalactic medium (CGM) and interstellar medium (ISM) of star-forming (SF) satellite galaxies in galaxy clusters. These shocks are usually produced by mergers and massive accretion. Our visual inspection shows that approximately half of SF satellites have encountered shocks in their host clusters at $z\leq0.11$. After a satellite crosses a shock front and enters the postshock region, the ram pressure on it is boosted significantly. Both the CGM and ISM can be severely impacted, either by striping or …
We study the dark matter (DM) assembly in the central regions of massive early-type galaxies up to $z\sim 0.65$. We use a sample of $\sim 3800$ massive ($\log M_{\rm \star}/M_{\rm \odot} > 11.2$) galaxies with photometry and structural parameters from 156 sq. deg. of the Kilo Degree Survey, and spectroscopic redshifts and velocity dispersions from SDSS. We obtain central total-to-stellar mass ratios, $M_{\rm dyn}/M_{\rm \star}$, and DM fractions, by determining dynamical masses, $M_{\rm dyn}$, from Jeans modelling of SDSS aperture velocity dispersions and stellar masses, $M_{\rm \star}$, from …
We use zoom simulations to show how merger-driven disruption of the gas disc in a galaxy provides its central active galactic nucleus (AGN) with fuel to drive outflows that entrain and expel a significant fraction of the circumgalactic medium (CGM). This in turn suppresses replenishment of the interstellar medium, causing the galaxy to quench up to several Gyr after the merger. We start by performing a zoom simulation of a present-day star-forming disc galaxy with the EAGLE galaxy formation model. Then, we re-simulate the galaxy with controlled changes to its initial conditions, using the gene…
Many ultra-diffuse galaxies (UDGs) have been discovered in the Coma cluster, and there is evidence that some, notably Dragonfly 44, have Milky Way-like dynamical masses despite dwarf-like stellar masses. We used X-ray, UV, and optical data to investigate the star formation and nuclear activity in the Coma UDGs, and we obtained deep UV and X-ray data (Swift and XMM-Newton) for Dragonfly 44 to search for low-level star formation, hot circumgalactic gas, and the integrated emission from X-ray binaries. Among the Coma UDGs, we find UV luminosities consistent with quiescence but NUV$-r$ colors indi…
We conducted sub-millimeter observations with the Atacama Large Millimeter/sub-millimeter Array (ALMA) of star-forming galaxies at $z\sim3.3$, whose gas-phase metallicities have been previously measured. We investigate the dust and gas contents of the galaxies at $z\sim3.3$ and study how galaxies are interacting with their circumgalactic/intergalactic medium at this epoch by probing their gas mass fractions and gas-phase metallicities. Single-band dust continuum emission tracing dust mass and the relation between the gas-phase metallicity and gas-to-dust mass ratio are used to estimate the gas…
We present three-dimensional hydrodynamical simulations showing the effect of kinetic and radiative AGN feedback on a model galaxy representing a massive quiescent low-redshift early-type galaxy of $M_* = 8.41\times 10^{10} M_\odot$, harbouring a $M_\mathrm{BH} = 4\times 10^8 M_\odot $ black hole surrounded by a cooling gaseous halo. We show that, for a total baryon fraction of $\sim 20\%$ of the cosmological value, feedback from the AGN can keep the galaxy quiescent for about 4.35 Gyr and with properties consistent with black hole mass and X-ray luminosity scaling relations. However, this can…
Recent analysis of the SDSS-III/APOGEE Data Release 12 stellar catalogue has revealed that the Milky Way's metallicity distribution function (MDF) changes shape as a function of radius, transitioning from being negatively skewed at small Galactocentric radii to positively skewed at large Galactocentric radii. Using a high resolution, N-body+SPH simulation, we show that the changing skewness arises from radial migration - metal-rich stars form in the inner disk and subsequently migrate to the metal-poorer outer disk. These migrated stars represent a large fraction (> 50%) of the stars in the ou…
GA-NIFS: high prevalence of dusty and metal-enriched outflows in massive and luminous star-forming galaxies at $z\sim3-9$
Centro de Astrobiología (CAB), CSIC–INTA（天体生物学中心）；Università di Firenze（佛罗伦萨大学）；INAF - Osservatorio Astrofisico di Arcetri（国家天体物理研究所-阿尔切特里天文台）；Department of Physics, University of Oxford（牛津大学物理系）；Scuola Normale Superiore（比萨高等师范学院）；Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique de Paris（索邦大学）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory - Astrophysics Group, University of Cambridge（剑桥大学卡文迪许实验室）
