Simba: The average properties of the circumgalactic medium of $2 \leq z \leq 3$ quasars are determined primarily by stellar feedback
Daniele Sorini, Romeel Davé, Daniel Anglés-Alcázar
备注：
Published in MNRAS. This is a pre-copyedited, author-produced PDF of an article accepted for publication in MNRAS following peer review. The version of record (Volume 499, Issue 2, December 2020, Pages 2760-2784) is available online at: https://academic.oup.com/mnras/article/499/2/2760/5918000
发表信息：
Monthly Notices of the Royal Astronomical Society, Volume 499, Issue 2, December 2020, Pages 2760-2784
We use the Simba cosmological hydrodynamic simulation suite to explore the impact of feedback on the circumgalactic medium (CGM) and intergalactic medium (IGM) around $2 \leq z \leq 3$ quasars. We identify quasars in Simba as the most rapidly-accreting black holes, and show that they are well-matched in bolometric luminosity and correlation strength to real quasars. We extract Lyman-alpha (Ly-a) absorption in spectra passing at different transverse distances (10 kpc $\lesssim b \lesssim$ 10 Mpc) around those quasars, and compare to observations of the mean Ly-a absorption profile. The observations are well reproduced, except within 100 kpc from the foreground quasar, where Simba overproduces absorption; this could potentially be mitigated by including ionisation from the quasar itself. By comparing runs with different feedback modules activated, we find that (mechanical) AGN feedback has little impact on the surrounding CGM even around these most highly luminous black holes, while stellar feedback has a significant impact. By further investigating thermodynamic and kinematic properties of CGM gas, we find that stellar feedback, and not AGN feedback, is the primary physical driver in determining the average properties of the CGM around $z\sim 2-3$ quasars. We also compare our results with previous works, and find that Simba predicts much more absorption within 100 kpc than the Nyx and Illustris simulations, showing that the Ly-a absorption profile can be a powerful constraint on simulations. Instruments such as VLT-MUSE and upcoming surveys (e.g., WEAVE and DESI) promise to further improve such constraints.
We examine the properties of the low-redshift circumgalactic medium (CGM) around star-forming and quenched galaxies in the Simba cosmological hydrodynamic simulations, focusing on comparing HI and metal line absorption to observations from the COS-Halos and COS-Dwarfs surveys. Halo baryon fractions are generally $\lesssim 50\%$ of the cosmic fraction due to stellar feedback at low masses, and jet-mode AGN feedback at high masses. Baryons and metals in the CGM of quenched galaxies are $\gtrsim 90\%$ hot gas, while the CGM of star-forming galaxies is more multi-phase. Hot CGM gas has low metalli…
We study the nature of the low-redshift CGM in the Simba cosmological simulations as traced by ultraviolet absorption lines around galaxies in bins of stellar mass ($M_\star>10^{10}M_\odot$) for star-forming, green valley and quenched galaxies at impact parameters $r_\perp\leq 1.25r_{200}$. We generate synthetic spectra for HI, MgII, CII, SiIII, CIV, and OVI, fit Voigt profiles to obtain line properties, and estimate the density, temperature, and metallicity of the absorbing gas. We find that CGM absorbers are most abundant around star forming galaxies with $M_\star < 10^{11}M_\odot$, while th…
We present the first systematic study of 50 low redshift ($0.66 < z < 1.63$) iron low-ionization broad absorption-line quasars (FeLoBALQs) using $SimBAL$ which represents a more than five-fold increase in the number of FeLoBALQs with detailed absorption line spectral analyses. We found the outflows have a wide range of ionization parameters, $-4\lesssim\log U\lesssim 1.2$ and densities, $2.8\lesssim\log n\lesssim8\ \rm[cm^{-3}]$. The objects in our sample showed FeLoBAL gas located at a wide range of distances $0\lesssim\log R\lesssim 4.4$ [pc], although we do not find any evidence for disk wi…
Cosmological hydrodynamical simulations of galaxy evolution are increasingly able to produce realistic galaxies, but the largest hurdle remaining is in constructing subgrid models that accurately describe the behavior of stellar feedback. As an alternate way to test and calibrate such models, we propose to focus on the circumgalactic medium. To do so, we generate a suite of adaptive-mesh refinement (AMR) simulations for a Milky-Way-massed galaxy run to z=0, systematically varying the feedback implementation. We then post-process the simulation data to compute the absorbing column density for a…
We examine the kinematics of the gas in the environments of galaxies hosting quasars at $z\sim2$. We employ 148 projected quasar pairs to study the circumgalactic gas of the foreground quasars in absorption. The sample selects foreground quasars with precise redshift measurements, using emission-lines with precision $\lesssim300\,{\rm km\,s^{-1}}$ and average offsets from the systemic redshift $\lesssim|100\,{\rm km\,s^{-1}}|$. We stack the background quasar spectra at the foreground quasar's systemic redshift to study the mean absorption in \ion{C}{2}, \ion{C}{4}, and \ion{Mg}{2}. We find tha…
We characterize the physical properties of the cool T ~10^4 K circumgalactic medium surrounding z ~2-3 quasar host galaxies, which are predicted to evolve into present day massive ellipticals. Using a statistical sample of 14 quasar pairs with projected separation < 300 kpc and high dispersion, high S/N spectra, we find extreme kinematics with low metal ion lines typically spanning ~ 500 km/s, exceeding any previously studied galactic population. The CGM is significantly enriched, even beyond the virial radius, with a median metallicity [M/H] ~ -0.6. The alpha/Fe abundance ratio is enhanced, s…
Resolving circumgalactic gas flows around a z$\approx$3.6 quasar using MUSE and ALMA
Università degli Studi di Milano-Bicocca（米兰比可卡大学）；DTU Space, Technical University of Denmark（丹麦技术大学空间中心）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；INAF–Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）；Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡普坦天文研究所）；INAF–Osservatorio di Astrofisica e Scienza dello Spazio（意大利国家天体物理研究所天文与空间科学观测站）；IUCAA（印度天体物理学与宇宙学大学研究中心）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）
Red quasars may represent a young stage of galaxy evolution that provide important feedback to their host galaxies. We are studying a population of extremely red quasars (ERQs) with exceptionally fast and powerful outflows, at median redshift $z$ = 2.6. We present Keck/KCWI integral field spectra of 11 ERQs, which have a median color $i-W3$ = 5.9~mag, median $\left\langle L_{\text{bol}} \right\rangle$ $\approx$ 5 $\times$ $10^{47}$ erg s$^{-1}$, Ly$α$ halo luminosity $\left\langle L_{\text{halo}} \right\rangle$ $=$ 5 $\times$ $10^{43}$ erg s$^{-1}$, and maximum linear size $>128$ kpc. The ERQ …
We survey the incidence and absorption strength of the metal-line transitions CII 1334 and CIV from the circumgalactic medium (CGM) surrounding z~2 quasars, which act as signposts for massive dark matter halos M_halo~10^12.5 Msun. On scales of the virial radius (Mvir~160kpc), we measure a high covering fraction fC=0.73+/-0.10 to strong CII absorption (rest equivalent width W1334>0.2A), implying a massive reservoir of cool (T~10^4K) metal enriched gas. We conservatively estimate a metal mass exceeding 10^8 Msun. We propose these metals trace enrichment of the incipient intragroup/intracluster m…
Deep observations have detected extended Ly$α$ emission nebulae surrounding tens of quasars at redshift 2 to 6. However, the metallicity of such extended haloes is still poorly understood. We perform a detailed analysis on a large sample of 80 quasars at $z\sim3$ based on MUSE-VLT data. We find clear evidence of extended emission of the UV nebular lines such as CIV or HeII for about 20$\%$ of the sample, while CIII] is only marginally detected in a few objects. By stacking the cubes we detect emission of CIV, HeII and CIII] out to a radius of about 45 kpc. CIV and HeII show a radial decline mu…
We performed a detailed study of the extended cool gas, traced by MgII absorption [$W_r(2796)\geq0.3$~Å], surrounding 14 narrow-line active galactic nuclei (AGNs) at 0.12<z<0.22 using background quasar sight-lines. The background quasars probe the AGNs at projected distances of $60\leq D\leq265$~kpc. We find that, between $100\leq D\leq200$~kpc, AGNs appear to have lower MgII gas covering fractions (0.09$^{+0.18}_{-0.08}$) than quasars (0.47$^{+0.16}_{-0.15}$) and possibly lower than in active field galaxies (0.25$^{+0.11}_{-0.09}$). We do not find a statistically significant azimuthal angle d…
The recent discovery by Cantalupo et al. (2014) of the largest (~500 kpc) and luminous Ly-alpha nebula associated with the quasar UM287 (z=2.279) poses a great challenge to our current understanding of the astrophysics of the halos hosting massive z~2 galaxies. Either an enormous reservoir of cool gas is required $M\simeq10^{12}$ $M_{\odot}$, exceeding the expected baryonic mass available, or one must invoke extreme gas clumping factors not present in high-resolution cosmological simulations. However, observations of Ly-alpha emission alone cannot distinguish between these two scenarios. We ha…
Circumgalactic medium of quasar host galaxies at 0.4<z<0.8 probed by strong Mg II absorption
Central University of Himachal Pradesh（喜马偕尔邦中央大学）；Inter-University Centre for Astronomy and Astrophysics（大学间天文学与天体物理学中心）；Indian Institute of Astrophysics（印度天体物理研究所）
Revealing the Gas Recycling in the Circumgalactic Medium (CGM) Utilizing a Luminous Ly$α$ Nebula Around a Type-II Quasar at z=2.6 with the Keck Cosmic Web Imager (KCWI)
Dusty quasars might be in a young stage of galaxy evolution with prominent quasar feedback. A recently discovered population of luminous, extremely red quasars at $z\sim$~2--4 has extreme spectral properties related to exceptionally powerful quasar-driven outflows. We present Keck/KCWI observations of the reddest known ERQ, at $z=$\,2.3184, with extremely fast [\ion{O}{III}]~$λ$5007 outflow at $\sim$6000~km~s$^{-1}$. The Ly$α$ halo spans $\sim$100~kpc. The halo is kinematically quiet, with velocity dispersion $\sim$300~km~s$^{-1}$ and no broadening above the dark matter circular velocity down …
The discovery of giant quasar Ly$α$ nebulae at $z>2$ has opened up the possibility to directly study in emission the Circumgalactic and Intergalactic Medium (CGM/IGM). However, the resonant nature of the Ly$α$ line and its different emission mechanisms hamper the ability to constrain both the kinematics and physical properties of the CGM/IGM. Here, we present results of a pilot project aiming at the detection of CGM H$α$ emission, a line which does not suffer from these limitations. To this end, we first used KCWI to detect Ly$α$ emission around three bright quasars with $2.25<z<2.27$, a range…
We analyze relative abundances and ionization conditions in a strong absorption system at z=6.84, seen in the spectrum of the z=7.54 background quasar ULAS J134208.10+092838.61. Singly ionized C, Si, Fe, Mg, and Al measurements are consistent with a warm neutral medium that is metal-poor but not chemically pristine. Firm non-detections of C IV and Si IV imply that any warm ionized phase of the IGM or CGM has not yet been enriched past the ultra-metal-poor regime (<0.001Z_{solar}), unlike lower redshift DLAs where these lines are nearly ubiquitous. Relative abundances of the heavy elements 794 …
This chapter presents a review of the current state of knowledge on the cool (T ~ 1e4 K) halo gas content around massive galaxies at z ~ 0.2-2. Over the last decade, significant progress has been made in characterizing the cool circumgalactic gas in massive halos of Mh ~ 1e12-1e14 Msun at intermediate redshifts using absorption spectroscopy. Systematic studies of halo gas around massive galaxies beyond the nearby universe are made possible by large spectroscopic samples of galaxies and quasars in public archives. In addition to accurate and precise constraints for the incidence of cool gas in …
The circumgalactic medium (CGM) plays a vital role in the formation and evolution of galaxies, acting as a lifeline between galaxies and the surrounding intergalactic medium (IGM). In this study we leverage a unique sample of quasar pairs to investigate the properties of the CGM with absorption line tomography. We present a new sample of medium resolution Keck/ESI, Magellan/MagE, and VLT/XSHOOTER spectra of 29 quasar pairs at redshift $2 < z < 3$. We supplement the sample with additional spectra of 32 pairs from the literature, creating a catalog of 61 quasar pairs with angular separations bet…
We introduce IGM-Vis, a novel astrophysics visualization and data analysis application for investigating galaxies and the gas that surrounds them in context with their larger scale environment, the Cosmic Web. Environment is an important factor in the evolution of galaxies from actively forming stars to quiescent states with little, if any, discernible star formation activity. The gaseous halos of galaxies (the circumgalactic medium, or CGM) play a critical role in their evolution, because the gas necessary to fuel star formation and any gas expelled from widely observed galactic winds must en…
Constraining the nature of active galactic nuclei through circumgalactic Lya emission at z=2-3
Tsinghua University（清华大学）；University of Milan Bicocca（米兰比可卡大学）；Universität Heidelberg（海德堡大学）；National Astronomical Observatory of Japan（日本国立天文台）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Xi’an Jiaotong-Liverpool University（西交利物浦大学）
A deep 400-ksec ACIS-S observation of the nearest quasar known, Mrk 231, is combined with archival 120-ksec data obtained with the same instrument and setup to carry out the first ever spatially resolved spectral analysis of a hot X-ray emitting circumgalactic nebula around a quasar. The 65 x 50 kpc X-ray nebula shares no resemblance with the tidal debris seen at optical wavelengths. One notable exception is the small tidal arc 3.5 kpc south of the nucleus where excess soft X-ray continuum emission and Si XIII 1.8 keV line emission are detected, consistent with star formation and its associate…
During the last years, Ly$α$ nebulae have been routinely detected around high-z, radio-quiet quasars (RQQs) thanks to the advent of sensitive integral field spectrographs. Constraining the physical properties of the Ly$α$ nebulae is crucial for a full understanding of the circum-galactic medium (CGM), which is a venue of feeding and feedback processes. The most luminous quasars are privileged test-beds to study these processes, given their large ionizing fluxes and dense CGM environments in which they are expected to be embedded. We aim at characterizing the rest-frame UV emission lines in the…
ALMA visits the QSO MUSEUM: Connecting molecular gas and the cool circumgalactic medium around 37 z~3 quasars
Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Academia Sinica Institute of Astronomy and Astrophysics (ASIAA)（中央研究院天文及天文物理研究所）；Universität Heidelberg, Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR)（海德堡大学跨学科科学计算中心）；Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik（海德堡大学天文学中心理论天体物理研究所）；Institut de Radioastronomie Millimétrique (IRAM)（毫米波射电天文研究所）
The hydrodynamical response of cold circumgalactic clouds to quasar radiation
Università degli Studi di Milano-Bicocca（米兰比可卡大学）；Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学开普天文学研究所）；Osaka University（大阪大学）；The University of Tokyo（东京大学）；University of Nevada, Las Vegas（内华达大学拉斯维加斯分校）；Musashino Art University（武藏野美术大学）；INAF – Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）
The Two Component Circumgalactic Medium Emission around z~2 Radio-loud Quasars
University of Arizona（亚利桑那大学）；University of California San Diego（加州大学圣地亚哥分校）；Florida Gulf Coast University（佛罗里达海湾海岸大学）；California Institute of Technology（加州理工学院）；Canadian Institute for Theoretical Astrophysics, University of Toronto（多伦多大学加拿大理论天体物理研究所）；Carnegie Science（卡内基科学）；University of Maryland Baltimore County（马里兰大学巴尔的摩郡分校）
We constrain gas inflow speeds in star-forming galaxies with color gradients consistent with inside-out disk growth. Our method combines new measurements of disk orientation with previously described circumgalactic absorption in background quasar spectra. Two quantities, a position angle and an axis ratio, describe the projected shape of each galactic disk on the sky, leaving an ambiguity about which side of the minor axis is tipped toward the observer. This degeneracy regarding the 3D orientation of disks has compromised previous efforts to measure gas inflow speeds. We present HST and Keck/L…
Broad absorption line (BAL) features in quasar spectra reveal an unambiguous signature of energetic outflows from central supermassive black holes, and thus BAL quasars are prime targets for investigating the potential process of luminous quasar feedback on galaxies. We analyzed the rest-UV spectrum of an "overlapping trough" iron low-ionization broad absorption line quasar (FeLoBAL) SDSS J135246.37+423923.5 using the novel spectral synthesis code SimBAL (Leighly et al. 2018) and discovered an extraordinarily fast and energetic BAL outflow. Our analysis revealed outflow velocities reaching $\s…
QSO MUSEUM III: the circumgalactic medium in Ly$α$ emission around 120 $z\sim3$ quasars covering the SDSS parameter space. Witnessing the instantaneous AGN feedback on halo scales
Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理学研究所）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Universität Heidelberg（海德堡大学跨学科科学计算中心）；Zentrum für Astronomie, Institut für Theoretische Astrophysik, Universität Heidelberg（海德堡大学天文学中心理论天体物理研究所）；International Gemini Observatory/NSF NOIRLab（国际吉米尼天文台/美国国家光学红外天文实验室）；Newcastle University（纽卡斯尔大学）
We present a framework for characterizing the large scale movement of baryons relative to dark matter in cosmological simulations, requiring only the initial conditions and final state of the simulation. This is performed using the spread metric which quantifies the distance in the final conditions between initially neighbouring particles, and by analysing the baryonic content of final haloes relative to that of the initial Lagrangian regions defined by their dark matter component. Applying this framework to the SIMBA cosmological simulations, we show that 40% (10%) of cosmological baryons hav…
We investigate the properties of the circumgalactic gas in the halo of quasar host galaxies from CIV absorption line systems. Optical spectroscopy of closely aligned pairs of quasars (projected distance \leq 200 kpc) obtained at the Gran Telescopio Canarias is used to investigate the distribution of the absorbing gas for a sample of 18 quasars at z \sim 2. We found that the detected absorption systems of EW \geq 0.3Ang associated with the foreground QSO are revealed up to 200 kpc from the center of the host galaxy. The structure of the absorbing gas is rather patchy with a covering fraction of…
Every quasar (QSO) spectrum contains absorption-line signatures from the interstellar medium, disk-halo interface, and circumgalactic medium (CGM) of the Milky Way (MW). We analyze Hubble Space Telescope/Cosmic Origins Spectrograph (COS) spectra of 132 QSOs to study the significance and origin of SiIV absorption at $|v_{\rm LSR}|\leq100$ km/s in the Galactic halo. The gas in the north predominantly falls in at $-50\lesssim v_{\rm LSR}\lesssim 0$ km/s, whereas in the south, no such pattern is observed. The SiIV column density has an average and a standard deviation of $\langle N_{\rm SiIV}\rang…
From our position embedded within the Milky Way's interstellar medium (ISM), we have limited ability to detect gas at low relative velocities in the extended Galactic halo because those spectral lines are blended with much stronger signals from dense foreground gas. As a result, the content of the Milky Way's circumgalactic medium (CGM) is poorly constrained at $|v_{\rm LSR}|$ $\lesssim$ 150 km s$^{-1}$. To overcome this complication, the QuaStar Survey applies a spectral differencing technique using paired quasar-star sightlines to measure the obscured content of the Milky Way's CGM for the f…
Multi-phase investigation of outflows in the circumgalactic and interstellar media of luminous quasars at z~5
University of Trieste（的里雅斯特大学）；INAF - Osservatorio Astronomico di Trieste（意大利国家天体物理研究所-的里雅斯特天文台）；IFPU - Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；Scuola Normale Superiore（比萨高等师范学院）
该研究结合 VLT/X-Shooter 与 ALMA 的发射、吸收及连续谱示踪剂，刻画 39 个 z~5 亮类星体的多相外流，发现高速电离外流及黑洞增长领先宿主星系的反馈证据。
We study the distribution and kinematics of the cool circumgalactic medium (CGM) of emission line galaxies (ELGs) traced by metal absorption lines. Using about 200,000 ELGs from SDSS-IV eBOSS and half a million background quasars from SDSS, we measure the median absorption strength of MgII and FeII lines in quasar spectra for impact parameters ranging from 10 kpc to 1 Mpc. For comparison we measure the same quantity around luminous red galaxies (LRGs). On scales greater than 100 kpc both ELGs and LRGs exhibit similar absorption profiles. However, metal absorption is 5-10 times stronger around …
Constraining the density distribution of the cold Circumgalactic Medium of quasars at z>2 through Lya, HeII and Ha emission
INAF – Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）；Dipartimento di Fisica "G. Occhialini", Università degli Studi di Milano-Bicocca（米兰比可卡大学G. Occhialini物理系）；Department of Physics and Astronomy, University of California, Riverside（加州大学河滨分校物理与天文学系）；Cahill Center for Astrophysics, California Institute of Technology（加州理工学院卡希尔天体物理学中心）；Institute for Cosmic Ray Research, The University of Tokyo（东京大学宇宙射线研究所）；Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡普坦天文研究所）；Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia（摩德纳和雷焦艾米利亚大学物理、信息学与数学系）
We describe the kinematics of circumgalactic gas near the galactic plane, combining new measurements of galaxy rotation curves and spectroscopy of background quasars. The sightlines pass within 19--93 kpc of the target galaxy and generally detect Mg II absorption. The Mg II Doppler shifts have the same sign as the galactic rotation, so the cold gas co-rotates with the galaxy. Because the absorption spans a broader velocity range than disk rotation can explain, we explore simple models for the circumgalactic kinematics. Gas spiraling inwards (near the disk plane) offers a successful description…
We present the first characterization of the circumgalactic medium of Ly$α$ emitters (LAEs), using a sample of 96 $z\approx3.3$ LAEs detected with the VLT/MUSE in fields centered on 8 bright background quasars. The LAEs have low Ly$α$ luminosities ($\sim 10^{42}\,\text{erg}\,\text{s}^{-1}$) and star formation rates (SFRs) $\sim 1~\text{M}_\odot\,\text{yr}^{-1}$, which for main sequence galaxies corresponds to stellar masses of only $\sim 10^{8.6}\,\text{M}_\odot$. The median transverse distance between the LAEs and the quasar sightlines is 165 proper kpc (pkpc). We stacked the high-resolution …
OVI absorption in quasar spectra caused by intervening circumgalactic atmospheres suggests a downturn in the atmospheric column density in sightlines passing beyond about 100 kpc from central star-forming galaxies. This turnover supports the hypothesis that the oxygen originates in the central galaxies. When converted into oxygen space density using an Abel integral inversion, the OVI columns require greater than $\approx 10^9 M_\odot$ of oxygen concentrated near 100 kpc. Circumgalactic gas within this radius cools in less than 1 Gyr and radiates $\sim 10^{42.2}$ erg s$^{-1}$ overall. The feed…
