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 (\(\sigma\approx\) 400km s\(^{-1}\)) which is observed in the inner 1-2arcsec and a narrower component (\(\sigma\approx\) 200km s\(^{-1}\)) which is present over the entire field-of-view. We identify the broader component as due to an unresolved nuclear outflow. The narrower component velocity field shows strong isovelocity twists relative to a rotation pattern, implying the presence of strong non-circular motions. The subtraction of a rotational model reveals that these twists are caused by outflowing gas in the inner \(\approx\) 1arcsec, and by inflows associated with two spiral arms at larger radii. We calculate an ionized gas mass outflow rate of \(\dot{M}_{out}\approx\) 0.16M\(_{\odot}\)yr\(^{-1}\). We calculate the net gas mass flow rate across a series of concentric rings, obtaining a maximum mass inflow rate in ionized gas of \(\approx\) 2.8M\(_{\odot}\)year\(^{-1}\) at 800pc from the nucleus, which is two orders of magnitude larger than the accretion rate necessary to power this AGN. However, as the mass inflow rate decreases at smaller radii, most of the gas probably will not reach the AGN, but accumulate in the inner few hundred parsecs. This will create a reservoir of gas that can trigger the formation of new stars.
NGC 3393, a nearby Seyfert 2 galaxy with nuclear radio jets, large-scale and nuclear bars, and a posited secondary super massive black hole, provides an interesting laboratory to test the physics of ...inflows and outflows. Here we present and analyse the molecular gas (ALMA observations of CO J:2-1 emission over a field of view (FOV) of 45\arcsec \times 45\arcsec, at 0\farcs56 (143 pc) spatial and 5 km/s spectral resolution), ionised gas and stars (GEMINI-GMOS/IFU; over a FOV of 4\arcsec \times 5\arcsec, at 0\farcs62 (159 pc) spatial and 23 km/s spectral resolution) in NGC 3393. The ionised gas emission, detected over the complete GEMINI-GMOS FOV, has three identifiable kinematic components. A narrow (\sigma < 115 km/s) component present in the complete FOV, which is consistent with rotation in the galaxy disk. A broad (\sigma > 115 km/s) redshifted component, detected near the NE and SW radio lobes; which we interpret as a radio jet driven outflow. And a broad (\sigma > 115 km/s) blueshifted component that shows high velocities in a region perpendicular to the radio jet axis; we interpret this as an equatorial outflow. The CO J:2-1 emission is detected in spiral arms on 5\arcsec - 20\arcsec scales, and in two disturbed circumnuclear regions. The molecular kinematics in the spiral arms can be explained by rotation. The highly disturbed kinematics of the inner region can be explained by perturbations induced by the nuclear bar and interactions with the large scale bar. We find no evidence for, but cannot strongly rule out, the presence of the posited secondary black hole.
Apresentamos mapas bidimensionais (2D) para a cinemática do gás na região central (algumas centenas de parsecs) das galáxias ativas NGC 1566, M81, NGC 3982 e NGC 4450, e para a cinemática estelar ...para a galáxia' M81. As observações foram feitas com a Unidade de Campo Integral (IFU) do GMOS (Gemini Multi-Object Spectrograph) nos telescópios Gemini. Obtivemos campos de velocidades e mapas de dispersão de velocidades pelo ajuste das linhas de emissão do gás Hα, NIIλ6584 e SIl λλ6717,31. Nosso objetivo foi procurar a assinatura de movimentos de queda do gás em direção ao núcleo da galáxia para alimentar o buraco negro central. Para a galáxia NGC 1566, foi possível ajustar um modelo de rotação para o gás no plano da galáxia. o que possibilitou a construção de um mapa de resíduos através da subtração do campo de velocidades modelado do campo de velocidades do gás. Nós comparamos estes mapas de resíduos e dispersão de velocidades com mapas de estrutura, construídos a partir de observações com o telescópio espacial Hubble, em busca de uma relação entre os filamentos de poeira vistos nos mapas de estrutura e fluxos de gás, no intuito de testar a hipótese de que espirais nucleares são canais pelos quais a matéria é levada de escalas galácticas até a região nuclear para alimentar o buraco negro central. Para a galáxia M81, foi possível obter o campo de velocidades estelar, que foi subtraído do campo de velocidades do gás para isolar movimentos não circulares. Para as demais galáxias, o campo de velocidades e o mapa de dispersão de velocidades foram comparados diretamente ao mapa de estrutura, uma vez que não foi possível ajustar um modelo de rotação no plano. Todas as galáxias mostram associação entre movimentos não circulares e aumentos de dispersão de velocidades com filamentos escuros observados nos mapas de estrutura. Além disso, estimamos a taxa de acreção necessária para reproduzir a luminosidade do núcleo e, também, a massa do buraco negro central para todas as galáxias da amostra e, no caso de NGC 1566 e M81, estimamos também a taxa de infiow de gás em regiões onde encontramos fluxos de gás em direção ao núcleo e comparamos esta taxa com a taxa de acreção.
Apresentamos mapas bidimensionais (2D) para a cinemática do gás e das estrelas e fluxo das linhas de emissão na região central (algumas centenas de parsecs) das galáxias ativas M 81, NGC 1667, NGC ...2110 e NGC 7213. As observações foram feitas com a Unidade de Campo Integral (IFU) do GMOS (Gemini Multi-Object Spectrograph) nos telescópios Gemini. Obtivemos campos de velocidades, mapas de dispersão de velocidades e mapas de fluxos pelo ajuste das linhas de emissão do gás Hα, NII λ6584˚A e SII λλ6717,31˚A. Obtivemos medidas da cinemática estelar a partir da aplicação da técnica pPXF. Utilizamos modelagens da cinemática estelar e do gás, além de técnicas de PCA, com o objetivo de detectar movimentos não circulares do gás e investigar a natureza desses movimentos. Detectamos influxos de gás em todas as quatro galáxias e ejeções de gás nas galáxias NGC 2110 e M 81. Verificamos que movimentos não circulares interpretados como influxos de gás se relacionam a espirais e filamentos associados a poeira vista em mapas de estrutura. Obtivemos taxas de influxo de massa para todas as galáxias e taxas de ejeções de massa para a galáxia NGC 2110 e comparamos estes resultados à taxa de acreção de matéria de cada galáxia. Encontramos que as taxas de influxo de gás ionizado variam de 0,01 a 1 M⊙/ano e são, em todos os casos, maiores que a taxa de acreção, o que sugere que a maior parte desse gás se acumulará na região central.
Feeding and Feedback in NGC3081 Schnorr-Müller, Allan; Storchi-Bergmann, Thaisa; Robinson, Andrew ...
arXiv.org,
01/2016
Paper, Journal Article
Odprti dostop
We present two-dimensional gaseous kinematics of the inner 1.2 \(\times\) 1.8 kpc\(^2\) of the Seyfert 2 galaxy NGC3081, from optical spectra (5600--7000Å) obtained with the GMOS integral field ...spectrograph on the Gemini North telescope at a spatial resolution of \(\approx\) 100pc. We have identified two-components in the line emitting gas. A narrower component (FWHM \(\approx\) 60-100km s\(^{-1}\)), which appears to be gas in the galaxy disk, and which shows a distorted rotation pattern, is observed over the whole field of view. A broader component (FWHM \(\approx\)150-250 km s\(^{-1}\)) is present in the inner \(\approx\) 2arcsec (200pc) and shows blueshifts and redshifts in the near and far sides of the galaxy, respectively, consistent with a bipolar outflow. Assuming this to be the case, we estimate that the mass outflow rate in ionized gas (\(\dot{M}_{out}\)) is between 1.9 \(\times 10^{-3}\)M\(_{\odot}\) yr\(^{-1}\) and 6.9 \(\times 10^{-3}\)M\(_{\odot}\) yr\(^{-1}\). The subtraction of a rotation model from the narrower component velocity field reveals a pattern of excess blueshifts of \(\approx\) 50km s\(^{-1}\) in the far side of the galaxy and similar excess redshifts in the near side, which are cospatial with a previously known nuclear bar. We interpret these residuals as due to gas following non-circular orbits in the barred potential. Under the assumption that these motions may lead to gas inflows, we estimate an upper limit for the mass inflow rate in ionized gas of \(\phi\) \(\approx\) 1.3 \(\times 10^{-2}\)M\(_{\odot}\) yr\(^{-1}\).
Gaussianization is a simple generative model that can be trained without backpropagation. It has shown compelling performance on low dimensional data. As the dimension increases, however, it has been ...observed that the convergence speed slows down. We show analytically that the number of required layers scales linearly with the dimension for Gaussian input. We argue that this is because the model is unable to capture dependencies between dimensions. Empirically, we find the same linear increase in cost for arbitrary input \(p(x)\), but observe favorable scaling for some distributions. We explore potential speed-ups and formulate challenges for further research.
We present optical integral field spectroscopy of the inner \(2.5 \times 3.4\) kpc\(^2\) of the broad-line radio galaxy Pictor A, at a spatial resolution of \(\approx 400\) pc. Line emission is ...observed over the whole field-of-view, being strongest at the nucleus and in an elongated linear feature (ELF) crossing the nucleus from the south-west to the north-east along PA \(\sim 70^\circ\). Although the broad double-peaked H\(\alpha\) line and the OI6300/H\(\alpha\) and SII6717+31/H\(\alpha\) ratios are typical of AGNs, the NII6584/H\(\alpha\) ratio (0.15 - 0.25) is unusually low. We suggest that this is due to the unusually low metallicity of the gas. Centroid velocity maps show mostly blueshifts to the south and redshifts to the north of the nucleus, but the velocity field is not well fitted by a rotation model. Velocity dispersions are low (< 100 km s\(^{-1}\)) along the ELF, ruling out a jet-cloud interaction as the origin of this structure. The ELF shows both blueshifts and redshifts in channel maps, suggesting that it is close to the plane of the sky. The ELF is evidently photoionized by the AGN, but its kinematics and inferred low metallicity suggest that this structure may have originated in a past merger event with another galaxy. We suggest that the gas acquired in this interaction may be feeding the ELF.
We present two-dimensional stellar and gaseous kinematics of the inner 0.7 \(\times\) 1.2 kpc\(^{2}\) of the Seyfert galaxy ESO 362-G18, derived from optical spectra obtained with the GMOS/IFU on the ...Gemini South telescope at a spatial resolution of \(\approx\)170 pc and spectral resolution of 36 km s\(^{-1}\). ESO 362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a minor merger approaching along the NE direction. Previous studies have shown that the OIII emission shows a fan-shaped extension of \(\approx\) 10\arcsec\ to the SE. We detect the OIII doublet, NII and H\({\alpha}\) emission lines throughout our field of view. The stellar kinematics is dominated by circular motions in the galaxy plane, with a kinematic position angle of \(\approx\)137\(^{\circ}\). The gas kinematics is also dominated by rotation, with kinematic position angles ranging from 122\(^{\circ}\) to 139\(^{\circ}\). A double-Gaussian fit to the OIII\(\lambda\)5007 and H\({\alpha}\) lines, which have the highest signal to noise ratios of the emission lines, reveal two kinematic components: (1) a component at lower radial velocities which we interpret as gas rotating in the galactic disk; and (2) a component with line of sight velocities 100-250 km s\(^{-1}\) higher than the systemic velocity, interpreted as originating in the outflowing gas within the AGN ionization cone. We estimate a mass outflow rate of 7.4 \(\times\) 10\(^{-2}\) M\(_{\odot}\) yr\(^{-1}\) in the SE ionization cone (this rate doubles if we assume a biconical configuration), and a mass accretion rate on the supermassive black hole (SMBH) of 2.2 \(\times\) 10\(^{-2}\) M\(_{\odot}\) yr\(^{-1}\). The total ionized gas mass within \(\sim\)84 pc of the nucleus is 3.3 \(\times\) 10\(^{5}\) M\(_{\odot}\); infall velocities of \(\sim\)34 km s\(^{-1}\) in this gas would be required to feed both the outflow and SMBH accretion.
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 dominated by non-circular motions, mainly along two spiral arms extending from the nucleus out to 4arcsec (280pc) to the NW and SE, that are cospatial with a nuclear dusty spiral seen in a structure map of the nuclear region of the galaxy. The projected gas velocities along the spiral arms show blueshifts in the far side and redshifts in the near side, with values of up to 200km/s. This kinematics can be interpreted as gas inflows towards the nucleus along the spiral arms if the gas is in the plane of the galaxy. We estimate the mass inflow rate using two different methods. The first is based of the observed velocities and geometry of the flow, and gives a mass inflow rate in the ionised gas of 7x10^-2 M_sun/yr. In the second method, we calculate the net ionised gas mass flow rate through concentric circles of decreasing radii around the nucleus resulting in mass inflow rates ranging from 0.4 M_sun/yr at 300pc down to 0.2 M_sun/yr at 100pc from the nucleus. These rates are larger than necessary to power the active nucleus.
We present stellar and gaseous kinematics of the inner 120x250pc^2 of the Liner/Seyfert 1 galaxy M81, from optical spectra obtained with the GMOS integral field spectrograph on the Gemini North ...telescope at a spatial resolution of 10pc. The stellar velocity field shows circular rotation but deviations are observed close to the minor axis which can be attributed to stellar motions possibly associated to a nuclear bar. The stellar velocity dispersion of the bulge is 162km/s leading to a black hole mass of M_BH=5.5x10^7M_sun based on the M_BH-sigma relationship. The gas kinematics is dominated by non-circular motions and the subtraction of the stellar velocity field reveals blueshifts of ~-100km/s on the far side of the galaxy and a few redshifts on the near side. These characteristics can be interpreted in terms of streaming towards the center if the gas is in the plane. On the basis of the observed velocities and geometry of the flow, we estimate a mass inflow rate in ionized gas of ~4.0x10^-3M_sun/year, which is of the order of the accretion rate necessary to power the LINER nucleus of M81. We have also applied the technique of Principal Component Analysis (PCA) to our data, which reveals the presence of a rotating nuclear gas disk within ~50pc from the nucleus and a compact outflow, approximately perpendicular to the disk. The PCA combined with the observed gas velocity field shows that the nuclear disk is being fed by gas circulating in the galaxy plane. The presence of the outflow is supported by a compact jet seen in radio observations at a similar orientation, as well as by an enhancement of the OI\Halpha line ratio, probably resulting from shock excitation of the circumnuclear gas by the radio jet. With these observations we are thus resolving both the feeding -- via the nuclear disk and observed gas inflow, and the feedback -- via the outflow, around the nucleus of M81.
