Observational evidence revealing the main mechanisms that accelerate quasar outflows has proven difficult to obtain, due to the complexity of the absorption features that this gas produces in the spectra of the emission sources. We build 36 composite outflow spectra, covering a large range of outflow and quasar parameters, by stacking broad ($>450\,{\rm km\,s^{-1}}$) absorption line systems in the spectra of SDSS-III/BOSS DR12 quasars. The two lines of the atomic doublet of CIV, with a separation of $\approx 497\,{\rm km\,s^{-1}}$, as well as those of other species appear well resolved in most of our composites. This agrees with broad outflow troughs consisting in the superposition of narrow absorbers. We also report on the ubiquitous detection of the radiative-acceleration signature known as line locking in all our composite outflow spectra, including one spectrum strictly built from broad absorption line (BAL) systems. This is the first line-locking detection in BAL composite spectra. Line locking is driven by the CIV atomic doublet, and is visible on the blue side of most strong absorption transitions. Similar effects from the doublets of OVI, SiIV, or NV, however, seem to not be present. Our results confirm that radiation pressure is a prevalent mechanism for accelerating outflows in quasars.
Recent magneto-hydrodynamic simulations of the star-forming interstellar medium (ISM) with parsec scale resolution indicate that relativistic cosmic rays support the launching of galactic outflows on scales of a few kpc. If these fundamental constituents of the ISM are injected at the sites of supernova (SN) explosions, the outflows are smoother, colder, and denser than the highly structured, hot-phase driven outflows forming, e.g., by thermal SN energy injection alone. In this Letter we present computations of resonant Lyman-$α$ (Ly$α$) radiation transfer through snapshots of a suite of strat…
We observe 1.3~mm spectral lines at 2000~AU resolution toward four massive molecular clouds in the Central Molecular Zone of the Galaxy to investigate their star formation activities. We focus on several potential shock tracers that are usually abundant in protostellar outflows, including SiO, SO, CH$_3$OH, H$_2$CO, HC$_3$N, and HNCO. We identify 43 protostellar outflows, including 37 highly likely ones and 6 candidates. The outflows are found toward both known high-mass star forming cores and less massive, seemingly quiescent cores, while 791 out of the 834 cores identified based on the conti…
Massive galaxy-scale outflows of gas are one of the most commonly-invoked mechanisms to regulate the growth and evolution of galaxies throughout the universe. While the gas in outflows spans a large range of temperatures and densities, the cold molecular phase is of particular interest because molecular outflows may be capable of suppressing star formation in galaxies by removing the star-forming gas. We have conducted the first survey of molecular outflows at z > 4, targeting 11 strongly-lensed dusty, star-forming galaxies (DSFGs) with high-resolution Atacama Large Millimeter Array (ALMA) obs…
Galactic outflows of molecular gas are a common occurrence in galaxies and may represent a mechanism by which galaxies self-regulate their growth, redistributing gas that could otherwise have formed stars. We previously presented the first survey of molecular outflows at z > 4 towards a sample of massive, dusty galaxies. Here we characterize the physical properties of the molecular outflows discovered in our survey. Using low-redshift outflows as a training set, we find agreement at the factor-of-two level between several outflow rate estimates. We find molecular outflow rates 150-800Msun/yr a…
SQuIGG$\vec{L}$E: Ubiquitous Cool Gas Outflows with Large Mass-Loading Factors in $z\sim0.7$ Post-starburst Galaxies
Texas A&M University（德克萨斯农工大学）；Princeton University（普林斯顿大学）；Johns Hopkins University（约翰斯·霍普金斯大学）；Arizona State University（亚利桑那州立大学）；University of Pittsburgh（匹兹堡大学）
The imprint of AGN-driven outflows on the CGM: the case of Lyα nebulae around high-z quasars
European Southern Observatory（欧洲南方天文台）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理研究所）；Centre for Astrophysics Research, University of Hertfordshire（赫特福德大学天体物理学研究中心）；Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理研究所）；Newcastle University（纽卡斯尔大学）；International Gemini Observatory/NSF NOIRLab（国际双子座天文台/美国国家光学红外天文实验室）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di 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）
The prevalence and properties of kiloparsec-scale outflows in nearby Type 1 quasars have been the subject of little previous attention. This work presents Gemini integral field spectroscopy of ten Type 1 radio-quiet quasars at $z<0.3$. The excellent image quality, coupled with a new technique to remove the point spread function using spectral information, allow the fitting of the underlying host on a spaxel-by-spaxel basis. Fits to stars, line-emitting gas, and interstellar absorption show that 100% of the sample host warm ionized and/or cool neutral outflows with spatially-averaged velocities…
We present the rest-frame near-ultraviolet (NUV) spectroscopy of star-forming galaxies (SFGs) at 0.6<z<1.2 from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) in SDSS-IV. One of the eBOSS programs is to obtain 2 arcsec (about 15 kpc) fiber spectra of about 200,000 emission-line galaxies (ELGs) at redshift z>0.6. We use the data from the pilot observations of this program, including 8620 spectra of SFGs at 0.6<z<1.2. The median composite spectra of these SFGs at 2200 Ang < λ< 4000 Ang feature asymmetric, preferentially blueshifted non-resonant emission, Fe II*, and blueshifted res…
The circumgalactic medium (CGM) encodes signatures of the galaxy-formation process, including the interaction of galactic outflows driven by stellar and supermassive black hole (SMBH) feedback with the gaseous halo. Moving beyond spherically symmetric radial profiles, we study the \textit{angular} dependence of CGM properties around $z=0$ massive galaxies in the IllustrisTNG simulations. We characterize the angular signal of density, temperature, and metallicity of the CGM as a function of galaxy stellar mass, halo mass, distance, and SMBH mass, via stacking. TNG predicts that the CGM is aniso…
We present observations of 17 luminous (log(L[O III]/L_Sun) > 8.7) local (z < 0.11) type II AGN. Our aim is to investigate the prevalence and nature of AGN driven outflows in these galaxies by combining kinematic and ionization diagnostic information. We use non-parametric methods (e.g. W80, the width containing 80% of the line flux) to assess the line widths in the central regions of our targets. The maximum values of W80 in each galaxy are in the range 400 - 1600 km/s, with a mean of 790 +- 90 km/s. Such high velocities are strongly suggestive that these AGN are driving ionized outflows. Mul…
The velocity structure imprinted in the Hα emission line profiles contains valuable information about galactic outflows. Using a set of high-resolution zoom-in cosmological simulations of galaxies at z=2, we generate Hα emission line profiles, taking into account the temperature-dependent Hα emissivity, as well as dust extinction. The Hα line can be described as a sum of two gaussians, as typically done with observations. In general, its properties are in good agreement with those observed in local isolated galaxies with similar masses and star formation rates, assuming a spatially constant cl…
Higher resolution optical spectra of $M_*<10^{10}~M_{\odot}$ galaxies reveal outflow signatures unresolved by the SDSS
Institute of Theoretical Astrophysics, University of Oslo（奥斯陆大学理论天体物理研究所）；Dipartimento di Fisica e Astronomia Augusto Righi, Università degli Studi di Bologna（博洛尼亚大学阿戈斯蒂诺·里吉物理与天文系）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di 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）；INAF – Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；INAF – Fundación Galileo Galilei（意大利国家天体物理研究所伽利略基金会）；Armagh Observatory and Planetarium（阿马赫天文馆与天文台）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）；Department of Physics and Astronomy, University College London（伦敦大学学院物理与天文系）；INAF – Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）
The hosts of long duration gamma-ray bursts are predominantly starburst galaxies at subsolar metallicity. At redshifts z<1, this implies that most of them are low-mass galaxies similar to the populations of blue compact dwarfs and dwarf irregulars. What triggers the massive star-formation (SF) needed for producing a GRB progenitor is still largely unknown, as are the resolved gas properties and kinematics of these galaxies and their formation history. Here we present a sample of six spatially resolved GRB hosts at z<0.3 observed with 3D spectroscopy at high spectral resolution (R=8,000-13,000)…
While quasar outflows may be quasi-ubiquitous, there are significant differences on a source-by- source basis. These differences can be organized along the 4D Eigenvector 1 sequence: at least at low z, with only Population A sources radiating at relatively high Eddington ratio and showing prominent high-velocity outflows in Civ λ1549 line profiles. We discuss in this paper VLT-FORS observations of Civ λ1549 emission line profiles for a high-luminosity sample of Hamburg- ESO quasars and how they are affected by outflow motion as a function of quasar luminosity. Our high- luminosity sample has t…
We have identified ionized outflows in the narrow line region of all but one SDSS type 2 quasars (QSO2) at z<~0.1 (20/21, detection rate 95%), implying that this is a ubiquitous phenomenon in this object class also at the lowest z. The outflowing gas has high densities (n_e>1000 cm-3) and covers a region the size of a few kpc. This implies ionized outflow masses M~(0.3-2.4)x1e6 Msun and mass outflow rates M(dot)<few Msun yr-1. The triggering mechanism of the outflows is related to the nuclear activity. The QSO2 can be classified in two groups according to the behavior and properties of the out…
Many studies have considered the roles of clouds, outflows, and turbulence in producing the broad emission and absorption lines in the spectra of active galactic nuclei (AGNs). However, these are often treated as separate or even competing models. Here, we consider the possibility that AGN clouds are condensations formed within the thermally unstable zones of outflows and then compare the typical sizes of such condensations with the injection scale $k_0^{-1} \sim L_0$ of turbulence, where $L_0$ is assumed to be the scale height of a representative global outflow model. We find that for broad l…
We investigate the conditions that facilitate galactic-scale outflows using a sample of 155 typical star-forming galaxies at $z$~2 drawn from the MOSFIRE Deep Evolution Field (MOSDEF) survey. The sample includes deep rest-frame UV spectroscopy from the Keck Low-Resolution Imaging Spectrometer (LRIS), which provides spectral coverage of several low-ionisation interstellar (LIS) metal absorption lines and Ly$α$ emission. Outflow velocities are calculated from the centroids of the LIS absorption and/or Ly$α$ emission, as well as the highest-velocity component of the outflow from the blue wings of…
As a part of the CALYPSO large programme, we constrain the properties of protostellar jets and outflows in a sample of 21 Class 0 protostars with internal luminosities, Lint, from 0.035 to 47 Lsun. We analyse high angular resolution (~0.5"-1") IRAM PdBI observations in CO (2-1), SO ($5_6-4_5$), and SiO (5-4). CO (2-1), which probes outflowing gas, is detected in all the sources (for the first time in SerpS-MM22 and SerpS-MM18b). Collimated high-velocity jets in SiO (5-4) are detected in 67% of the sources (for the first time in IRAS4B2, IRAS4B1, L1448-NB, SerpS-MM18a), and 77% of these also sh…
Warm absorber (WA) is an ionised gas present in the line of sight to the AGN central engine. The effect of the absorber is imprinted in the absorption lines observed in X-ray spectra of AGN. In this work, we model the WA in Seyfert 1 galaxy Mrk 509 using its recently published shape of broad band spectral energy distribution (SED) as a continuum illuminating the absorber. Using the photoionization code {\sc Titan}, recently we have shown that the absorption measure distribution (AMD) found for this object can be successfully modelled as a single slab of gas in total pressure (radiation+gas) eq…
Outflows and rotation are two ubiquitous kinematic features in the gas kinematics of galaxies. Here we introduce a semi-analytic model to quantify how rotating outflows impact the morphology of the Lyman-$α$ emission line. The model is contrasted against Monte Carlo radiative transfer simulations of outflowing gas with additional solid body rotation. We explore a range of neutral Hydrogen optical depth of $10^5 \leq τ_{\mathrm{H}} \leq10^7$, rotational velocity $0 \leq v_{\mathrm{rot}}/\mathrm{km\ s}^{-1} \leq 100$ and outflow velocity $0\leq v_{\mathrm{out}}/\mathrm{km\ s}^{-1} \leq 50$. We f…
The origin of the Broad Line Region (BLR) in active galaxies remains unknown. It seems to be related to the underlying accretion disk but an efficient mechanism is required to rise the material from the disk surface without giving too strong signatures of the outflow in the case of the low ionization lines. We discuss in detail two proposed mechanisms: (i) radiation pressure acting on dust in the disk atmosphere creating a failed wind (ii) the gravitational instability of the underlying disk. We compare the predicted location of the inner radius of the BLR in those two scenarios with the obser…
Ton 34 recently transitioned from non-absorbing quasar into a BALQSO.Here, we report new HST-STIS observations of this quasar. Along with CIV absorption, we also detect absorption by NV+Ly alpha and possibly OVI+Ly beta. We follow the evolution of the CIV BAL, and find that, for the slower outflowing material, the absorption trough varies little (if at all) on a rest-frame timescale of 2 yr. However, we detect a strong deepening of the absorption in the gas moving at larger velocities (-20,000 - -23,000 km s-1). The data is consistent with a multistreaming flow crossing our line of sight to th…
Aims: We characterise the properties of stars, dust, and gas and their spatial distribution in the central region of the Seyfert 2 galaxy NGC1068. Method: Our study is based on near-infrared (YJH, 0.95-1.650 um, R=350) long-slit spectroscopy observations of the central region of NGC 1068 with a 0.4" spatial resolution. We decomposed the observed continuum emission into three components: hot dust, stars, and scattered light from the central engine. We measured their contributions at various distances from the nucleus. We also measured fluxes and Doppler shifts for the emission lines in our spec…
We measure the location and energetics of a SIV BALQSO outflow. This ouflow has a velocity of 10,800 km s$^{-1}$ and a kinetic luminosity of $10^{45.7}$ erg s$^{-1}$, which is 5.2% of the Eddington luminosity of the quasar. From collisional excitation models of the observed SIV$/$SIV* absorption troughs, we measure a hydrogen number density of $n_\mathrm{\scriptscriptstyle H}=10^{4.3}$ cm$^{-3}$, which allows us to determine that the outflow is located 110 pc from the quasar. Since SIV is formed in the same ionization phase as CIV, our results can be generalized to the ubiquitous CIV BALs. Our…
We perform two dimensional hydrodynamic numerical simulations to study the positive active galactic nucleus feedback which triggers, rather than suppresses, star formation. Recently, it was shown by Nayakshin et al. and Ishibashi et al. that star formation occurs when the cold interstellar medium is squeezed by the impact of mass outflow or radiation pressure, respectively. Mass outflow is ubiquitous in this astrophysical context, and radiation pressure is also important if the AGN is luminous. For the first time in this subject, we incorporate both mass outflow feedback and radiative feedback…
Recent detailed studies of Narrow Absorption Line (NAL) systems in QSO-spectra have revealed that at least 50% of QSOs have NALs associated with the central engine, and in most cases they are found to be outflowing. Will studies of NALs provide the much sort after evidence for ubiquitous QSO feedback that can halt the formation of stars in galaxies? I present new results on the distribution of line-of-sight velocity offsets between MgII absorbers and their background QSOs, based on a large catalogue of absorbers from SDSS DR6 and greatly improved QSO-redshift estimates. My analysis reveals a h…
Existing ubiquitously in the Universe with the highest luminosity, the Lyman-$α$ emission line encodes abundant physical information about the gaseous medium it interacts with. Nevertheless, the resonant nature of Ly$α$ complicates the radiative transfer (RT) modeling of the line profile, making the extraction of physical properties of the surrounding gaseous medium notoriously difficult. In this paper, we revisit the problem of deciphering the Ly$α$ emission line with RT modeling. We reveal intrinsic parameter degeneracies in the widely-used shell model in the optically thick regime for both …
JWST Spectra Conclusively Show an Excess of Neutral Gas Outflows in Quiescent Galaxies at z=2-5
University of Washington（华盛顿大学）；KAIST（韩国科学技术院）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；University of California, Santa Barbara（加州大学圣塔芭芭拉分校）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；University of Pittsburgh（匹兹堡大学）
Different physical processes in galaxy evolution, such as galaxy mergers that lead to coalescence of dual Active Galactic Nuclei (AGN) and outflows emanating from the narrow line region, can leave their imprint on the optical spectra of AGN in the form of double-peaked narrow emission lines. To investigate the neutral gas in the centres of such AGN, we have conducted a pilot survey of HI 21-cm absorption, using the upgraded Giant Metrewave Radio Telescope (uGMRT), in radio-loud AGN whose optical spectra show double-peaked [OIII] emission lines at z<=0.4 (median z~0.14). Among the eight sources…
