Allan Schnorr-Müller, Thaisa Storchi-Bergmann, Neil M. Nagar, Andrew Robinson, Davide Lena
备注:
12 pages, 11 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society. arXiv admin note: text overlap with arXiv:1701.00865
We use optical spectra from the inner 1.8 $\times$ 2.5kpc$^2$ of the Seyfert 2 galaxy NGC1358, obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of $\approx$ 165pc, to assess the feeding and feedback processes in this nearby active galaxy. Five gaseous kinematical components are observed in the emission line profiles. One of the components is present in the entire field-of-view and we interpret it as due to gas rotating in the disk of the galaxy. Three of the remaining components we interpret as associated to active galactic nucleus (AGN) feedback: a compact unresolved outflow in the inner 1 arcsec and two gas clouds observed at opposite sides of the nucleus, which we propose have been ejected in a previous AGN burst. The disk component velocity field is strongly disturbed by a large scale bar. The subtraction of a velocity model combining both rotation and bar flows reveals three kinematic nuclear spiral arms: two in inflow and one in outflow. We estimate the mass inflow rate in the inner 180pc obtaining $\dot{M}_{in}$ $\approx$ 1.5 $\times 10^{-2}$M$_{\odot}$yr$^{-1}$, about 160 times larger than the accretion rate necessary to power this AGN.
The transport of gas towards the centre of galaxies is critical for black hole feeding and, indirectly, it can control active galactic nucleus (AGN) feedback. We have quantified the molecular gas inflow in the central R<1kpc of M51 to be 1 Msun/yr, using a new gravitational torque map and the molecular gas traced by the PdBI Arcsecond Whirlpool Survey (PAWS). The nuclear stellar bar is responsible for this gas inflow. We have also used torque profiles to estimate the location of dynamical resonances, suggesting a corotation for the bar at R~20", and a corotation for the spiral at R~100". We de…
We present two-dimensional stellar and gaseous kinematics of the inner 0.8x1.1kpc^2 of the LINER/Seyfert 1 galaxy NGC7213, from optical spectra obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of 60pc. The stellar kinematics shows an average velocity dispersion of 177km/s, circular rotation with a projected velocity amplitude of 50km/s and a kinematic major axis at a position angle of -4degrees (west of north). From the average velocity dispersion we estimate a black hole mass of M_BH=8_{-6}^{+16}x10^7 M_sun. The gas kinematics is dominat…
We have obtained observations of the OH Megamaser galaxy IRAS03056+0234 using Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Very Large Array (VLA) and Hubble Space Telescope (HST). The HST data reveals spiral arms containing knots of emission associated to star forming regions. The GMOS-IFU data cover the spectral range of 4500 to 7500 Å at a velocity resolution of 90 km s$^{-1}$ and spatial resolution of 506 pc. The emission-line flux distributions reveal a ring of star forming regions with radius of 786 pc centred at the nucleus of the galaxy, with an ionized gas mass of…
We use optical spectra from the inner 2$\times$3kpc$^2$ of the Seyfert 2 galaxy NGC1667, obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of $\approx$ 240pc, to assess the feeding and feedback processes in this nearby AGN. We have identified two gaseous kinematical components in the emission line profiles: a broader component ($σ\approx$ 400km s$^{-1}$) which is observed in the inner 1-2arcsec and a narrower component ($σ\approx$ 200km s$^{-1}$) which is present over the entire field-of-view. We identify the broader component as due to an…
Aims. We probe the physical conditions in the core of Arp 299A and try to put constraints to the nature of its nuclear power source. Methods. We used Herschel Space Observatory far-infrared and submillimeter observations of H2O and OH rotational lines in Arp 299A to create a multi-component model of the galaxy. In doing this, we employed a spherically symmetric radiative transfer code. Results. Nine H2O lines in absorption and eight in emission as well as four OH doublets in absorption and one in emission, are detected in Arp 299A. No lines of the 18O isotopologues, which have been seen in com…
An analytical chemical evolution model is constructed to investigate the radial distribution of gas-phase and stellar metallicity for star-forming galaxies. By means of the model, the gas-phase and stellar metallicity can be obtained from the stellar-to-gas mass ratio. Both the gas inflow and outflow processes play an important role in building the final gas-phase metallicity, and there exists degeneracy effect between the gas inflow and outflow rates for star-forming galaxies. On the other hand, stellar metallicity is more sensitive to the gas outflow rate than to the gas inflow rate, and thi…
Gaseous inflows are necessary suppliers of galaxies' star-forming fuel, but are difficult to characterize at the survey scale. We use integral-field spectroscopic measurements of gas-phase metallicity and single-dish radio measurements of total atomic gas mass to estimate the magnitude and frequency of gaseous inflows incident on star-forming galaxies. We reveal a mutual correlation between steep oxygen abundance profiles between $0.25-1.5 R_e$, increased variability of metallicity between $1.25-1.75 R_e$, and elevated HI content at fixed total galaxy stellar mass. Employing a simple but intui…
Gas inflow feeds galaxies with low metallicity gas from the cosmic web, sustaining star formation across the Hubble time. We make a connection between these inflows and metallicity inhomogeneities in star-forming galaxies, by using synthetic narrow-band images of the Halpha emission line from zoom-in AMR cosmological simulations of galaxies with stellar masses of $M \simeq 10^9 $Msun at redshifts z=2-7. In $\sim$50\% of the cases at redshifts lower than 4, the gas inflow gives rise to star-forming, Halpha-bright, off-centre clumps. Most of these clumps have gas metallicities, weighted by Halph…
We constrain the rate of gas inflow into and outflow from a main-sequence star-forming galaxy at z~1.4 by fitting a simple analytic model for the chemical evolution in a galaxy to the observational data of the stellar mass, metallicity, and molecular gas mass fraction. The molecular gas mass is derived from CO observations with a metallicity-dependent CO-to-H2 conversion factor, and the gas metallicity is derived from the Hα and [NII]λ 6584 emission line ratio. Using a stacking analysis of CO integrated intensity maps and the emission lines of Hα and [NII], the relation between stellar mass, m…
In this letter we investigate the effect of boxy/peanut (b/p) bulges on bar-induced gas inflow to the central kiloparsec, which plays a crucial role on the evolution of disc galaxies. We carry out hydrodynamic gas response simulations in realistic barred galaxy potentials, including or not the geometry of a b/p bulge, to investigate the amount of gas inflow induced in the different models. We find that b/p bulges can reduce the gas inflow rate to the central kiloparsec by more than an order of magnitude, which leads to a reduction in the amount of gas available in the central regions. We also …
We have observed the nucleus of the nearby luminous infrared galaxy NGC 4418 with subarcsec resolution at 860 and 450 micron for the first time to characterize its hidden power source. A ~20 pc (0.1") hot dusty core was found inside a 100 pc scale concentration of molecular gas at the galactic center. The 860 micron continuum core has a deconvolved (peak) brightness temperature of 120-210 K. The CO(3-2) peak brightness temperature there is as high as 90 K at 50 pc resolution. The core has a bolometric luminosity of about 10^{11} Lsun, which accounts for most of the galaxy luminosity. It is Com…
We study the gas inflow rate ($ζ_{\rm inflow}$) and outflow rate ($ζ_{\rm outflow}$) evolution of local Milky Way-mass star-forming galaxies (SFGs) since $z=1.3$. The stellar mass growth history of Milky Way-mass progenitor SFGs is inferred from the evolution of the star formation rate (SFR)$-$stellar mass ($M_{\ast}$) relation, and the gas mass ($M_{\rm gas}$) is derived using the recently established gas scaling relations. With the $M_{\ast}+M_{\rm gas}$ growth curve, the net inflow rate $κ$ is quantified at each cosmic epoch. At $z\sim 1.3$, $κ$ is comparable with the SFR, whereas it rapidl…
We try to constrain the gas inflow and outflow rate of star-forming galaxies at $z\sim1.4$ by employing a simple analytic model for the chemical evolution of galaxies. The sample is constructed based on a large near-infrared (NIR) spectroscopic sample observed with Subaru/FMOS. The gas-phase metallicity is measured from the [\ion{N}{2}]$λ$6584/H$α$ emission line ratio and the gas mass is derived from the extinction corrected H$α$ luminosity by assuming the Kennicutt-Schmidt law. We constrain the inflow and outflow rate from the least-$χ^{2}$ fittings of the observed gas mass fraction, stellar …
Stellar bars are a common feature in massive disc galaxies. On a theoretical ground, the response of gas to a bar is generally thought to cause nuclear starbursts and, possibly, AGN activity once the perturbed gas reaches the central super-massive black hole. By means of high resolution numerical simulations we detail the purely dynamical effects that a forming bar exerts on the gas of an isolated disc galaxy. The galaxy is initially unstable to the formation of non-axisymmetric structures, and within 1 Gyr it develops spiral arms that eventually evolve into a central stellar bar on kpc scale.…
We investigate gas inflow and outflow histories in Milky Way-like disk galaxies, to get new insights into the baryonic processes in galaxy formation and evolution. For this purpose, we solve the equations for the evolutions of the surface mass densities of gas and metals at each radius in a galactic disk, based on the observed structural properties of distant star-forming galaxies, including the redshift evolution of their stellar mass distribution, their scaling relation between the mass of baryonic components, star formation rate (SFR) and chemical abundance, as well as the supposed evolutio…
NGC 1042 is a late type bulgeless disk galaxy which hosts a low luminosity Active Galactic Nuclei (AGN) coincident with a massive nuclear star cluster. In this paper, we present the integral-field-spectroscopy (IFS) studies of this galaxy, based on the data obtained with the Mitchell spectrograph on the 2.7 meter Harlan J. Smith telescope. In the central $100\textrm{-}300\ \mathrm{pc}$ region of NGC 1042, we find a circumnuclear ring structure of gas with enhanced ionization, which we suggest is mainly induced by shocks. Combining with the harmonic decomposition analysis of the velocity field …
Inflows at the dusty torus and smaller scales is crucial to investigate the process of supermassive black hole accretion. However, only few cases of inflowing gas at small scales have been reported through redshifted broad absorption lines so far. Here we report 9 redshifted narrow absorption lines (NALs) of $\rm Mg^+$ ions with inflowing speeds of 1071 -- 1979 km/s, which are likely along the directions close to the axes of accretion disks. The quasars showing inflowing Mg II NALs have on average slightly smaller Eddington ratios when compared to the sources with outflow Mg II NALs. The upper…
Dusty, neutral outflows and inflows are a common feature of nearby star-forming galaxies. We characterize these flows in eight galaxies -- mostly AGN -- selected for their widespread NaI D signatures from the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). This survey employs deep, wide field-of-view integral field spectroscopy at moderate spectral resolution (R=7000 at NaI D). We significantly expand the sample of sightlines in external galaxies in which the spatially-resolved relationship has been studied between cool, neutral gas properties -- N(NaI), Weq(NaI D) -- and du…
Numerical models of gas inflow towards a supermassive black hole (SMBH) show that star formation may occur in such an environment through the growth of a gravitationally unstable gas disc. We consider the effect of nuclear activity on such a scenario. We present the first three-dimensional grid-based radiative hydrodynamic simulations of direct collisions between infalling gas streams and a $4 \times 10^6~\text{M}_\odot$ SMBH, using ray-tracing to incorporate radiation consistent with an active galactic nucleus (AGN). We assume inflow masses of $ \approx 10^5~\text{M}_\odot$ and explore radiat…
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…
We present optical integral field spectroscopy of the circum-nuclear gas of the Seyfert 2 galaxy NGC 1386. The data cover the central 7$^{\prime\prime} \times 9^{\prime\prime}$ (530 $\times$ 680 pc) at a spatial resolution of 0.9" (68 pc), and the spectral range 5700-7000 Å at a resolution of 66 km s$^{-1}$. The line emission is dominated by a bright central component, with two lobes extending $\approx$ 3$^{\prime\prime}$ north and south of the nucleus. We identify three main kinematic components. The first has low velocity dispersion ($\bar σ\approx $ 90 km s$^{-1}$), extends over the whole f…
Dynamical interactions between colliding spiral galaxies strongly affect the state and distribution of their interstellar gas. Observations indicate that interactions funnel gas toward the nuclei, fueling bursts of star formation and nuclear activity. To date, most numerical simulations of galaxy mergers have assumed that the gaseous and stellar disks initially have the same distribution and size. However, observations of isolated disk galaxies show that this is seldom the case; in fact, most spirals have as much or more gas beyond their optical radii as they do within. Can gas in such extende…
Feeding the Dead: Neutral Gas Inflow in a Long-Quenched Ancient Massive Galaxy at $z\sim 2.7$ Observed with JWST/NIRSpec
Tufts University(塔夫茨大学);INAF - Osservatorio Astronomico di Brera(意大利国家天体物理研究所布雷拉天文台);INAF - Osservatorio Astronomico di Capodimonte(意大利国家天体物理研究所卡波迪蒙特天文台);Dipartimento di Fisica e Astronomia, Universitá di Bologna(博洛尼塔大学物理与天文学系);Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯玻尔研究所);European Space Research and Technology Centre(欧洲空间研究与技术中心);Universitá degli studi di Milano-Bicocca(米兰比可卡大学)
Nuclear spirals are ubiquitous in galaxy centers. They exist not only in strong barred galaxies but also in galaxies without noticeable bars. We use high-resolution hydrodynamic simulations to study the properties of nuclear gas spirals driven by weak bar-like and oval potentials. The amplitude of the spirals increases toward the center by a geometric effect, readily developing into shocks at small radii even for very weak potentials. The shape of the spirals and shocks depends rather sensitively on the background shear. When shear is low, the nuclear spirals are loosely wound and the shocks a…
The interaction between inflowing gas clouds and galactic outflows at the interface where the galactic disk transitions into the circumgalactic medium is an important process in galaxy fueling, yet remains poorly understood. Using a series of tall-box hydrodynamic ENZO simulations, we have studied the interaction between smooth gas inflow and supernovae-driven outflow at the disk-halo interface with pc-scale resolution. A realistic wind of outflowing material is generated by supernovae explosions in the disk, while inflowing gas is injected at the top boundary of the simulation box with an inj…
A key uncertainty in galaxy evolution is the physics regulating star formation, ranging from small-scale processes related to the life-cycle of molecular clouds within galaxies to large-scale processes such as gas accretion onto galaxies. We study the imprint of such processes on the time-variability of star formation with an analytical approach tracking the gas mass of galaxies ("regulator model"). Specifically, we quantify the strength of the fluctuation in the star-formation rate (SFR) on different timescales, i.e. the power spectral density (PSD) of the star-formation history, and connect …
Gaia has revealed clear evidence of bending waves in the vertical kinematics of stars in the Solar Neighbourhood. We study bending waves in two simulations, one warped, with the warp due to misaligned gas inflow, and the other unwarped. We find slow, retrograde bending waves in both models, with the ones in the warped model having larger amplitudes. We also find fast, prograde bending waves. Prograde bending waves in the unwarped model are very weak, in agreement with the expectation that these waves should decay on short, ~ crossing, timescales, due to strong winding. However, prograde bendin…
Disc galaxies show a large morphological diversity with varying contribution of three major structural components; thin discs, thick discs, and central bulges. Dominance of bulges increases with the galaxy mass (Hubble sequence) whereas thick discs are more prominent in lower mass galaxies. Because galaxies grow with the accretion of matter, this observed variety should reflect diversity in accretion history. On the basis of the prediction by the cold-flow theory for galactic gas accretion and inspired by the results of previous studies, we put a hypothesis that associates different accretion …
Figuring Out Gas & Galaxies In Enzo (FOGGIE) XI: Circumgalactic O VI Emission Traces Clumpy Inflowing Recycled Gas
Harvard & Smithsonian(哈佛大学和史密森尼学会);Space Telescope Science Institute(太空望远镜科学研究所);Johns Hopkins University(约翰斯·霍普金斯大学);Michigan State University(密歇根州立大学);University of California Observatories/Lick Observatory(加州大学观测台/利克天文台)
Comparing to the inactive and gas-poor normal lenticular galaxies (S0s) in the local universe, we study a barred star-forming S0 galaxy, PGC 34107, which has been observed by the Centro Astronómico Hispano Alemán (CAHA) 3.5-m telescope and the Northern Extended Millimeter Array (NOEMA). The spatially resolved ionized gas and molecular gas traced by $^{12}$CO(1-0), hereafter CO(1-0), show the similar distribution and kinematics to the stellar component with an off-center star-forming region, $\sim$380 pc away from the center. The resolved kinematics of molecular CO(1-0) emission reveals that th…
We present calculations of ultraviolet spectra resulting from the scattering of photons by gas in-falling onto an isotropically emitting source of radiation. The model is based on an adaptation of the semi-analytical line transfer (SALT) code of Scarlata & Panagia (2015), and designed to interpret the inverse P-Cygni profiles observed in the spectra of partially ionized galactic inflows. In addition to presenting the model, we explore the parameter space of the inflowing SALT model and recreate various physically motivated scenarios including spherical inflows, inflows with covering fractions …
We use a set of observational data for galaxy cold gas mass fraction and gas phase metallicity to constrain the content, inflow and outflow of gas in central galaxies hosted by halos with masses between $10^{11} M_{\odot}$ to $10^{12} M_{\odot}$. The gas contents in high redshift galaxies are obtained by combining the empirical star formation histories of Lu et al. (2014) and star formation models that relate star formation rate with the cold gas mass in galaxies. We find that the total baryon mass in low-mass galaxies is always much less than the universal baryon mass fraction since $z = 2$, …
Theory suggests that there are two primary modes of accretion through which dark matter halos acquire the gas to form and fuel galaxies, hot and cold mode accretion. In cold mode accretion, gas streams along cosmic web filaments to the center of the halo, allowing for the efficient delivery of star-forming fuel. Recently, two QSO-illuminated HI Lyman alpha (Lyα) emitting objects were reported to have properties of cold, rotating structures (Martin et al. 2015, Martin et al. 2016). However, the spatial and spectral resolution available was insufficient to constrain radial flows associated with …
Beyond the Fundamental Metallicity Relation: galaxy sizes encode the link between inflow and metallicity
School of Physics and Astronomy, University of St Andrews(圣安德鲁斯大学物理与天文学院);Institute for Astronomy, University of Edinburgh(爱丁堡大学天体物理研究所);Institute for Computational Cosmology, Department of Physics, Durham University(达勒姆大学物理系计算宇宙学研究所);Centre for Extragalactic Astronomy, Department of Physics, Durham University(达勒姆大学物理系河外天文中心);Departamento de Física–CFM, Universidade Federal de Santa Catarina(圣卡塔琳娜联邦大学物理系-中央科学系);Department of Physics & Astronomy, University College London(伦敦大学学院物理与天文系);Max Planck Institute for Radio Astronomy(马克斯·普朗克射电天文研究所)
Early studies of nearby Seyfert galaxies have led to the picture that the Narrow Line Region (NLR) is a cone-shaped region of gas ionized by radiation from a nuclear source collimated by a dusty torus, where the gas is in outflow. In this contribution, I discuss a 3D view of the NLR obtained via Integral Field Spectroscopy, showing that: (1) although the region of highest emission is elongated (and in some cases cone-shaped), there is also lower level emission beyond the "ionization cone", indicating that the AGN radiation leaks through the torus; (2) besides outflows, the gas kinematics inclu…
We present a low-redshift (z=0.029) Damped Lyman-alpha (DLA) system in the spectrum of a background Quasi-Stellar Object (QSO). The DLA is associated with an interacting galaxy pair within a galaxy group. We detected weak Lyman-alpha emission centered at the absorption trough of the DLA. The emission was likely tracing the neutral HI reservoir around the galaxies in the interacting pair, which scattered the Lyman-alpha generated by star formation within those galaxies. We also found that the interacting pair is enveloped by a large HI cloud with $M(HI)=2\times 10^{10}M_{\odot}$. We discovered …
Galactic Rain: Cool Gas Inflows in Red Geyser Galaxies and Their Connection to AGN Activity and Interactions
University of California, Santa Cruz(加州大学圣克鲁兹分校);Arizona State University(亚利桑那州立大学);Johns Hopkins University(约翰斯·霍普金斯大学);University of California Observatories(加州大学天文台);San Diego State University(圣地亚哥州立大学);University of California, San Diego(加州大学圣地亚哥分校)
NGC 6860, Mrk 915, and MCG -01-24-012. II. Inflowing and outflowing cold molecular gas and the connection with ionized gas in Seyfert galaxies
Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut(海德堡大学天文中心,天文计算研究所);Departamento de Astronomia, Universidade Federal do Rio Grande do Sul(南里奥格兰德联邦大学天文学系);Astronomy Department, Universidad de Concepción(康塞普西翁大学天文学系);Observatorio Astronómico Nacional (OAN-IGN)-Observatorio de Madrid(国家天文台(OAN-IGN)马德里天文台);Departamento de Física, CCNE, Universidade Federal de Santa Maria(圣玛丽亚联邦大学物理系,CCNE);Centro de Astrobiología (CAB), CSIC-INTA(西班牙国家技术研究委员会-国家航空航天技术研究所天体生物学中心);Finnish Centre for Astronomy with ESO, University of Turku(图尔库大学芬兰ESO天文学中心)
We study the gas distribution and kinematics of the inner kpc of six moderately luminous (43.43$\leq$log$L_{\rm bol}\leq$44.83) nearby ($0.004 \leq z \leq 0.014$) Seyfert galaxies observed with the Near-infrared Integral Field Spectrograph (NIFS) in the J(1.25$μ$m) and K(2.2$μ$m) bands. We analyse the most intense emission lines detected on these spectral wavebands: [Fe II] 1.2570 $μ$m and Pa$β$, which trace the ionised gas in the partially and fully ionised regions, and H$_2$2.1218$μ$m, that traces the hot ($\sim 2000$ K) molecular gas. The dominant kinematic component is rotation in the disc…
We present new calculations of the mass inflow and outflow rates around the Milky Way, derived from a catalog of ultraviolet metal-line high velocity clouds (HVCs). These calculations are conducted by transforming the HVC velocities into the Galactic Standard of Rest (GSR) reference frame, identifying inflowing (v_GSR < 0 km/s) and outflowing (v_GSR > 0 km/s) populations, and using observational constraints on the distance, metallicity, dust content, covering fractions, and total hydrogen column density of each population. After removing HVCs associated with the Magellanic Stream and the Fermi…
Identifying signatures of inflow onto face-on galaxies using the Balmer decrement
Columbia University(哥伦比亚大学);Tsinghua University(清华大学);Rensselaer Polytechnic Institute(伦斯勒理工学院);The University of Texas at Dallas(德克萨斯大学达拉斯分校);York University(约克大学)
The Galactic bar plays a critical role in the evolution of the Milky Way's Central Molecular Zone (CMZ), driving mass inward toward the Galactic Center via gas flows known as dust lanes. To explore the interaction between the CMZ and the dust lanes, we run hydrodynamic simulations in AREPO, modeling the potential of the Milky Way's bar in the absence of gas self-gravity and star formation physics, and we study the flows of mass using Monte Carlo tracer particles. We estimate the efficiency of the inflow via the dust lanes, finding that only about a third (30$\pm$12%) of the dust lanes' mass in…
The scaling relationship is a fundamental probe of the evolution of galaxies. Using the integral field spectroscopic data from the Mapping Nearby Galaxies at Apache Point Observatory survey, we select 1698 spaxels with significant detection of the auroral emission line \oiii$λ$4363 from 52 galaxies to investigate the scaling relationships at the low-metallicity end. We find that our sample's star formation rate is higher and its metallicity is lower in the scaling relationship than the star-forming sequence after removing the contribution of the Fundamental Metallicity Relation.We also find th…
Linking neutral gas inflows and outflows to offsets in the star-forming main sequence and mass-metallicity relation
Aix Marseille Univ, CNRS, CNES, LAM(艾克斯马赛大学);Department of Physics & Astronomy, University College London(伦敦大学学院物理与天文系);Max-Planck-Institut für Radioastronomie(马克斯·普朗克射电天文研究所);Institute for Astronomy, University of Edinburgh(爱丁堡大学天体物理研究所);Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室);Department of Physics, Boston University(波士顿大学物理系);Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano(米兰大学阿尔多·蓬特莫利物理系);INAF-Osservatorio Astronomico di Brera(意大利国家天体物理研究所布雷拉天文台);Departamento de Astrofísica, Universidad de La Laguna (ULL)(拉帕拉大学天体物理学系);Instituto de Astrofísica de Canarias(加那利天体物理学研究所)
We perform a stacking analysis of the neutral \nad\,$λλ$5889,5895\,Å ISM doublet using the SDSS DR7 spectroscopic data set to probe the prevalence and characteristics of cold (T\,$\lesssim$\,10$^{4}$\,K) galactic-scale gas flows in local (0.025$\leqslant z\leqslant$0.1) inactive and AGN-host galaxies across the SFR-M$_{*}$ plane. We find low-velocity outflows to be prevalent in regions of high SFRs and stellar masses (10 $\lesssim$log M$_{*}$/M$_{\odot}$ $\lesssim$ 11.5), however we do not find any detections in the low mass (log M$_{*}$/M$_{\odot}$ $\lesssim$ 10) regime. We also find tentativ…
We analyse the 2-dimensional distribution and kinematics of the stars as well as molecular and ionised gas in the central few hundred parsecs of 5 active and 5 matched inactive galaxies. The equivalent widths of the Br-gamma line indicate there is no on-going star formation in their nuclei, although recent (terminated) starbursts are possible in the active galaxies. The stellar velocity fields show no signs of non-circular motions, while the 1-0S(1) H_2 kinematics exhibit significant deviations from simple circular rotation. In the active galaxies the H_2 kinematics reveal inflow and outflow s…